Patent Publication Number: US-8972251-B2

Title: Generating a masking signal on an electronic device

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to electronic devices. More specifically, the present disclosure relates to generating a masking signal on an electronic device. 
     BACKGROUND 
     In the last several decades, the use of electronic devices has become common. In particular, advances in electronic technology have reduced the cost of increasingly complex and useful electronic devices. Cost reduction and consumer demand have proliferated the use of electronic devices such that they are practically ubiquitous in modern society. As the use of electronic devices has expanded, so has the demand for new and improved features of electronic devices. More specifically, electronic devices that perform functions faster, more efficiently or with higher quality are often sought after. 
     Some electronic devices (e.g., audio recorders, cellular phones, smartphones, computers, etc.) use audio or speech signals. For example, a cellular phone captures a user&#39;s voice or speech using a microphone. For instance, the cellular phone converts an acoustic signal into an electronic signal using the microphone. This electronic signal may then be stored and/or transmitted to another device (e.g., cellular phone, smart phone, computer, etc.). 
     In some cases, the user of an electronic device may want to keep their speech or vocal information confidential. This may be difficult if the user is in a public place. For example, a user may desire to have a confidential conversation on a cellular phone while in public at an airport, on a bus or at a park. However, this may be difficult since other people may be listening nearby. As can be observed from this discussion, systems and methods that help maintain the confidentiality of vocal or speech information may be beneficial. 
     SUMMARY 
     An electronic device for generating a masking signal is disclosed. The electronic device includes a plurality of microphones and a speaker. The electronic device also includes a processor and instructions stored in memory that is in electronic communication with the processor. The electronic device obtains a plurality of audio signals from the plurality of microphones. The electronic device also obtains an ambience signal from the plurality of audio signals. Additionally, the electronic device determines an ambience feature based on the ambience signal. The electronic device further obtains a voice signal from the plurality of audio signals. The electronic device also determines a voice feature based on the voice signal. A masking signal is generated by the electronic device based on the voice feature and the ambience feature. The electronic device further outputs the masking signal using the speaker. The electronic device may also transmit the voice signal. The electronic device may be a wireless communication device. The electronic device may include a plurality of speakers. 
     The electronic device may also obtain a sound signal. Generating the masking signal may be further based on the sound signal. The sound signal may include music. Generating the masking signal may include adjusting the amplitude of the sound signal in a direct relationship with an envelope signal based on the voice signal. Generating the masking signal may include adjusting the amplitude of the sound signal in an inverse relationship with an amplitude based on the ambience signal. The sound signal may be selected based on an input. Generating the masking signal may include amplitude modulating the voice signal based on the voice feature. 
     The voice feature may include amplitude characteristics, spectral characteristics, spatial characteristics or temporal characteristics. The voice feature may include a loudness envelope. The ambience feature may include amplitude characteristics, spectral characteristics, spatial characteristics or temporal characteristics. The ambience feature may include a loudness characteristic. 
     Obtaining the voice signal may include removing the ambience signal from the plurality of audio signals. Obtaining the voice signal may include removing one or more echo signals from the plurality of audio signals using an echo canceller. 
     A method for generating a masking signal on an electronic device is also disclosed. The method includes obtaining a plurality of audio signals from a plurality of microphones. The method also includes obtaining an ambience signal from the plurality of audio signals. The method further includes determining an ambience feature based on the ambience signal. Additionally, the method includes obtaining a voice signal from the plurality of audio signals. The method also includes determining a voice feature based on the voice signal. Generating a masking signal based on the voice feature and the ambience feature is also included in the method. The method additionally includes outputting the masking signal using a speaker. 
     A computer-program product for generating a masking signal is also disclosed. The computer-program product includes a non-transitory tangible computer-readable medium with instructions. The instructions include code for causing an electronic device to obtain a plurality of audio signals from a plurality of microphones. The instructions also include code for causing the electronic device to obtain an ambience signal from the plurality of audio signals. The instructions further include code for causing the electronic device to determine an ambience feature based on the ambience signal. Additionally, the instructions include code for causing the electronic device to obtain a voice signal from the plurality of audio signals. Code for causing the electronic device to determine a voice feature based on the voice signal is also included in the instructions. The instructions also include code for causing the electronic device to generate a masking signal based on the voice feature and the ambience feature. The instructions additionally include code for causing the electronic device to output the masking signal using a speaker. 
     An apparatus for generating a masking signal is also disclosed. The apparatus includes means for obtaining a plurality of audio signals from a plurality of microphones. The apparatus also includes means for obtaining an ambience signal from the plurality of audio signals. The apparatus further includes means for determining an ambience feature based on the ambience signal. Additionally, the apparatus includes means for obtaining a voice signal from the plurality of audio signals. Means for determining a voice feature based on the voice signal are also included in the apparatus. The apparatus also includes means for generating a masking signal based on the voice feature and the ambience feature. The apparatus further includes means for outputting the masking signal using a speaker. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating one configuration of an electronic device in which systems and methods for generating a masking signal may be implemented; 
         FIG. 2  is a flow diagram illustrating one configuration of a method for generating a masking signal on an electronic device; 
         FIG. 3  is a block diagram illustrating one configuration of a transmitting wireless communication device in which systems and methods for generating a masking signal may be implemented; 
         FIG. 4  is a flow diagram illustrating a configuration of a method for generating a masking signal on a transmitting wireless communication device; 
         FIG. 5  is a block diagram illustrating one configuration of a wireless communication device in which systems and methods for generating a masking signal may be implemented; 
         FIG. 6  is a block diagram illustrating one example of generating a masking signal on an electronic device; 
         FIG. 7  is a flow diagram illustrating one configuration of a method for generating a masking signal on a wireless communication device; 
         FIG. 8  is a block diagram illustrating one configuration of several components in a wireless communication device in which systems and methods for generating a masking signal may be implemented; 
         FIG. 9  illustrates various components that may be utilized in an electronic device; and 
         FIG. 10  illustrates certain components that may be included within a wireless communication device. 
     
    
    
     DETAILED DESCRIPTION 
     The systems and methods disclosed herein may be applied to a variety of electronic devices. Examples of electronic devices include voice recorders, video cameras, audio players (e.g., Moving Picture Experts Group-1 (MPEG-1) or MPEG-2 Audio Layer 3 (MP3) players), video players, audio recorders, desktop computers/laptop computers, personal digital assistants (PDAs), gaming systems, etc. One kind of electronic device is a communication device, which may communicate with another device. Examples of communication devices include telephones, laptop computers, desktop computers, cellular phones, smartphones, wireless or wired modems, e-readers, tablet devices, gaming systems, cellular telephone base stations or nodes, access points, wireless gateways and wireless routers. 
     An electronic device or communication device (e.g., wireless communication device) may operate in accordance with certain industry standards, such as International Telecommunication Union (ITU) standards and/or Institute of Electrical and Electronics Engineers (IEEE) standards (e.g., Wireless Fidelity or “Wi-Fi” standards such as 802.11a, 802.11b, 802.11g, 802.11n and/or 802.11ac). Other examples of standards that a communication device may comply with include IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access or “WiMAX”), Third Generation Partnership Project (3GPP), 3GPP Long Term Evolution (LTE), Global System for Mobile Telecommunications (GSM) and others (where a communication device may be referred to as a User Equipment (UE), NodeB, evolved NodeB (eNB), mobile device, mobile station, subscriber station, remote station, access terminal, mobile terminal, terminal, user terminal, subscriber unit, etc., for example). While some of the systems and methods disclosed herein may be described in terms of one or more standards, this should not limit the scope of the disclosure, as the systems and methods may be applicable to many systems and/or standards. 
     It should be noted that some communication devices may communicate wirelessly and/or may communicate using a wired connection or link. For example, some communication devices may communicate with other devices using an Ethernet protocol. The systems and methods disclosed herein may be applied to communication devices that communicate wirelessly and/or that communicate using a wired connection or link. In one configuration, the systems and methods disclosed herein may be applied to a communication device that communicates with another device using a satellite. 
     There are many instances where an acoustic signal (e.g., a voice, speech or other signal) includes sensitive information. For example, a user may desire to discuss sensitive topics while on a cellular phone call. However, the user may be limited in his ability to discuss such sensitive topics while in a situation where the discussion may be overheard (e.g., in public) and risk disclosure of the sensitive topics. 
     The systems and methods disclosed herein provide a way to obscure or mask acoustic signals (e.g., voice, speech or other signal) using an electronic device. In one configuration, the electronic device captures a voice or speech signal and extracts one or more features from it. Examples of features include magnitude or amplitude (e.g., amplitude features), frequency (e.g., spectral features), timing (e.g., temporal features) and/or other features (e.g., spatial features). For instance, the electronic device may determine an envelope (e.g., amplitude or loudness envelope) of the voice signal and/or detect whether the voice signal satisfies one or more thresholds. The electronic device may also capture an ambience signal (e.g., background noise or other sounds that are not the voice or speech signal) and extract one or more features from it. The electronic device may control a sound signal based on the one or more extracted voice and/or ambience features. For example, the electronic device may modify an audio or sound signal such as music, pink noise, or some other sound source based on the extracted features to produce a masking signal. In one implementation, the electronic device may directly modulate (e.g., amplitude modulate) the voice signal to produce the masking signal. The electronic device then outputs the masking signal using a speaker (e.g., one or more speakers on a speaker phone, laptop computer, etc.). The voice or speech signal may thus be obscured, making it difficult for eavesdroppers to overhear or understand the content of the voice or speech signal. 
     The systems and methods disclosed herein may also allow the reduction or cancellation (e.g., approximate removal) of the masking signal. For example, if the voice signal is user speech on a cellular phone, the cellular phone may reduce or cancel out the masking sound from the voice signal before it is transmitted (to another device, for example). The systems and methods disclosed herein may also allow the voice signal to be obscured without being overpowering. For example, the masking signal may be just loud enough to effectively obscure the voice signal without becoming too distracting to the electronic device user or others in the vicinity. For instance, sound masking with ambient noise may be used in an office to enhance privacy. In one example, 40-48 A-weighted decibel (dB(A)) sound maskers may be used in a typical open office to obscure the voice signal without being overpowering. However, the systems and methods disclosed herein may be used in a smaller listening area, and the masker level may be tuned with the voice energy over time. 
     For clarity, examples of situations in which the systems and methods disclosed herein may be applied are given hereafter. Suppose that a user receives an important business call on a mobile phone while standing in a long airport security-check line. The user&#39;s boss expects him to take the call, yet he hesitates because the topic of discussion may be highly sensitive and he does not want others standing nearby to hear the details. If the user leaves the line to take the call in private, he could miss his flight. In some cases, the user might take the call and hope that others do not eavesdrop—a mistake that could be quite costly. 
     In one configuration, the systems and methods disclosed herein may allow voice calls to be private in any environment, such as in a line at the airport, in a cubical at work or while riding in a cramped elevator. The systems and methods disclosed herein may intelligently and dynamically mask a voice call so that others in the vicinity cannot hear the details. Rather than resorting to hiding in a closet or whispering on the phone, a user may talk in a normal tone of voice and clearly communicate while maintaining privacy in a public setting when the systems and methods disclosed herein are used. 
     The systems and methods disclosed herein describe a system that may use a user&#39;s voice to generate a masking signal. This masking signal may be used to protect the privacy of a user&#39;s voice or speech (e.g., phone conversation privacy). The near-end user&#39;s voice may be captured by one or more microphones on an electronic device. Furthermore, an ambient signal (e.g., background sounds or noise) may also be captured by one or more microphones. The voice signal may be analyzed with processes like envelope extraction and threshold detection, whose results may be used to control the characteristics of a masking signal. One or more features of the ambient signal may also be extracted and used to control the characteristics of the masking signal. The masking signal may then be reproduced through a loudspeaker on the same electronic device. In the local area around the near-end user, others may hear the user&#39;s voice together with the masking sound. The masking signal obscures the details of the user&#39;s speech and thus others around the user may find it difficult to understand the content of the user&#39;s voice or speech. 
     In one configuration of the systems and methods disclosed herein, an electronic device may automatically adjust a masking signal volume according to a user&#39;s voice or speech and/or according to ambient noise in real-time so that the masking sound is only as loud as needed to effectively obscure the user&#39;s voice. In another configuration, the system may additionally or alternatively adjust the pitch of the sound source(s) using a spectral centroid determined based on the voice signal. Furthermore, the system may automatically cancel out the masking signal or sound for a receiver of the voice signal so that another user may hear the user&#39;s speech clearly. For example, the masking signal may be used by an echo canceller on the electronic device to remove the masking sound from the user&#39;s speech signal. Additionally or alternatively, multiple types of masking sounds may be selected (e.g., “babbling brook”, “gentle waves”, “whale songs”, pop songs, pink noise, etc.) for best performance and personal interest. 
     The loudspeaker (e.g., a speakerphone speaker) may be included on the same device as the one or more microphones. When the masking signal is reproduced or output, the best accommodating acoustics of the device may be such that the maximum energy is emitted outwards and the near-end user&#39;s ear receives reduced or minimum energy from the masker. The system and methods disclosed herein may use, for example, multiple loudspeakers, directional loudspeakers, beam forming techniques and/or device insulation to improve system performance and/or user experience. 
     The masking signal or sound in open space may not be of interest to a far-end listener and therefore may be removed to maintain proper intelligibility. The masking signal may be reduced or removed from the transmitted signal through the use of an adaptive acoustic echo canceller. 
     The systems and methods disclosed herein may provide a choice of maskers or masking sounds. For example, a masker may be chosen so that, even if it is not totally masking a voice call by volume, the contents of the voice call should be hardly intelligible to others. On the other hand, the maskers may also be comfortable so that the intelligibility of the far-end user is not compromised, and also so that the near-end user can tolerate the sound during the course of a conversation. 
     For proof of concept, a personal computer (PC)-based real-time prototype with mock-up microphones and speakers was built. In this configuration, the microphones and speakers were on the same device. The microphones were positioned on the opposite side from and away from the speaker. The microphones and speakers were properly biased and amplified, respectively. Their line level signals were connected to the input and output of the sound card of a laptop computer. 
     On the laptop, a real-time audio programming software Max/MSP was configured to use the microphone signal and design maskers. In the prototype design, three maskers were experimented with: amplitude modulation of the speech itself, pink noise, and music. The levels of all maskers were smoothly controlled by the envelope of the captured voice from microphone with proper threshold settings (using ramp-up and/or ramp-down times, for example). Though not modeled in this prototype, an echo canceller may be implemented in accordance with the systems and methods disclosed herein. Many parameters in sound level analysis and masker design may be tunable. 
     With all three maskers in the prototype, once a masker level was proper, a person standing nearby could not understand the content of the conversation easily. Among the maskers, music may provide an appealing experience. For example, the music may not interfere with the near-end talker&#39;s conversation, and also functions as a soothing background event. At the same time, music may be very effective at privacy protection, especially when there is a vocal part in the sound track to mask near-end speech. 
     Maintaining privacy while mobile in high traffic public areas is very important, especially for business professionals, lawyers, etc. who handle highly sensitive information. One way others have approached this issue for on-screen data (e.g., visual data) is to provide a privacy screen filter. One example is the 3M Notebook Privacy Filter. This filter obscures data on a monitor when viewed outside of a 60 degree “Safe Area” directly in front of the monitor. This means that the user can see the data on the screen clearly, but people next to the user cannot. The 3M Notebook Privacy Filter is a successful product and may be useful. 
     In one configuration, generating a masking signal to prevent a bystander from eavesdropping on a conversation may be implemented as follows. A user may identify a bystander&#39;s direction. Each time near-end voice activity is detected, a noise pulse may be emitted in the bystander&#39;s direction, thereby masking the near end user&#39;s voice. Since the near-end user&#39;s earpiece may capture the generated noise pulses as well, some form of active noise control or cancellation (ANC) may be used for in-ear canal noise cancellation as well as receive voice enhancement (RVE) for maintaining far-end received voice intelligibility despite emitted noise shield. For example, RVE may boost different frequency regions of voice to maintain it above a certain noise floor. The noise reference generated to provide near-end noise reduction may be constructed using near-end microphones and/or the noise signals used in the masking signal generation may directly be fed to the noise reduction and RVE blocks/modules. The RVE block/module may be based on a constant signal-to-noise ratio (SNR) or a perceptual model so knowledge of the noise signal may quickly result in an enhanced far-end signal played back at the earpiece for best intelligibility. An echo cancellation (EC) block/module may also take advantage of knowledge of a played-back loudspeaker signal to contribute to the near-end speech enhancement task. The near-end microphone array may also be used to create a robust near-end user voice activity detector. More detail is given below. 
     In one configuration of the systems and methods disclosed herein, a voice microphone captures speech. The character of the speech may then be analyzed, from which an electronic device derives a control signal to manipulate a masker (e.g., masking signal generator). The masker source signal may be the speech itself, a synthesized signal and/or audio (e.g., a sound signal) from other sources such as media files inside a handset, for example. The sound may then be played through a speaker to interfere with eavesdroppers. 
     In another configuration, the systems and methods disclosed herein may use multi-microphone capabilities, not only to capture the speech, but also to collect more information about the surroundings. For example, multiple microphones instead of a single microphone may be used at a front end. After multi-microphone processing such as blind source separation, an electronic device may not only obtain a cleaner speech signal, but may also obtain ambience signals (from the residue, for example). 
     Further analysis may be performed on the ambience signals, such that knowledge may be gained about the loudness, direction and/or other characteristics, etc., about ambient noise. Then, a second control signal may be supplied to the masker (e.g., a masking signal level/characteristic controller) to further adjust the masking signal. In situations where the ambient noise level is high and/or the type of ambience is already a good masker, the masker (e.g., active masking signal generator) may not need to work as hard as when there is only silence in the ambient environment. 
     For example, compare a user of a handset that is implemented based on the systems and methods disclosed herein using the handset in three different situations. In a first scenario, the user is talking in a library. The environment is very quiet, and all the words the user says may be easily overheard and/or identified. The systems and methods disclosed herein may generate a sufficient masker level so that the privacy in the conversation is safe. In a second scenario, assume that the user is talking on a phone at the New York Stock Exchange. There may be many people around generating a lot of babble noise. Here, the babble noise may be nearly sufficient to obscure the phone conversation, so the masker may work at a much lower level so that any unmasked (by ambient babble noise) conversation may be protected. In a third scenario, assume that the user is talking in a bus or train. In this setting, the environment may produce a lot of low frequency noise, such that the low frequency part of the user speech is already masked. Here, the active masker may only need to cover and protect a higher frequency portion of the user&#39;s conversation. Thus, some spectral adjustments may be performed without the masker operating at full blast as in the first scenario. 
     Various configurations are now described with reference to the Figures, where like element names may indicate functionally similar elements. The systems and methods as generally described and illustrated in the Figures herein could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of several configurations, as represented in the Figures, is not intended to limit scope, as claimed, but is merely representative of the systems and methods. 
       FIG. 1  is a block diagram illustrating one configuration of an electronic device  102  in which systems and methods for generating a masking signal may be implemented. Examples of the electronic device  102  include audio recorders, telephones, digital cameras, digital camcorders, cellular phones, smartphones, laptop computers, desktop computers, gaming systems, personal digital assistants, music players (e.g., MP3 players), etc. The electronic device  102  may include one or more microphones  104   a - n , a multi-microphone processing block/module  106 , an ambience analysis block/module  112 , a speech feature extraction block/module  122 , a masker  136 , one or more sound sources  128  and/or one or more speakers  144 . As used herein, the term “block/module” may indicate that a particular element (e.g., ambience analysis block/module  112 ) may be implemented in hardware, software or a combination of both. 
     The one or more microphones  104   a - n  may be transducers (e.g., acoustoelectric transducers) used to convert acoustic signals into electrical or electronic signals. For example, the one or more microphones  140   a - n  may capture an acoustic voice signal  146  and/or one or more acoustic ambient signals  148   a - n  and convert them into electrical or electronic signals that are provided to the multi-microphone processing block/module  106 . For instance, each of the microphones  104   a - n  may generate an audio signal (e.g., electrical or electronic signal) that represents the acoustic voice signal  146 , acoustic ambient signals  148   a - n  or a mixture of both. In one configuration, multiple audio signals may thus be obtained using multiple microphones  104   a - n . Examples of the microphones  104   a - n  include dynamic microphones, condenser microphones, piezoelectric microphones, fiber optic microphones, laser microphones, etc. In some configurations, all of the one or more microphones  104   a - n  may be located on the same side of the electronic device  102 . In other configurations, one or more of the microphones  104   a - n  may be located on different sides (e.g., opposite sides) of the electronic device  102  from each other. For example, one or more of the microphones  104   a - n  may be designated or dedicated to capturing the acoustic voice signal  146 , while one or more of the microphones  104   a - n  may be designated or dedicated to capturing the acoustic ambient signals  148   a - n . It should also be noted that one or more of the microphones  104   a - n  may or may not be located on the same side of the electronic device  102  as one or more of the speaker(s)  144 . 
     The multi-microphone processing block/module  106  may be used to process the audio signals (e.g., electrical or electronic signals) provided by the one or more microphones  104   a - n . The multi-microphone processing block/module  106  may include a source separation block/module  108 . The source separation block/module  108  may generate (e.g., estimate) a voice signal  120 . For example, the source separation block/module  108  may remove an estimated ambience signal (e.g., ambient noise)  110  from the captured audio signal(s) in order to estimate the voice signal  120 . The voice signal  120  may be provided to the speech feature extraction block/module  122 . The voice signal  120  may optionally be provided to the masker  136 . In some configurations, the voice signal  120  may be stored in memory. For example, the electronic device  102  may be a digital voice recorder that may store the voice signal  120  in memory for later retrieval and/or output. 
     The speech feature extraction block/module  122  may be used to extract one or more features from the voice signal  120 . Examples of voice signal  120  features include magnitude or amplitude (e.g., loudness, volume, etc.), spectral (e.g., pitch or frequency), spatial (e.g., directional) and/or temporal (e.g., timing, transitional, phase) features, etc. The speech feature extraction block/module  122  may produce a first control signal  130  based on the one or more features extracted. In one configuration, the speech feature extraction block/module  122  may include an envelope detection block/module  124  and/or threshold detection block/module  126 . The envelope detection block/module  124  may determine an envelope signal (e.g., amplitude or loudness envelope) based on the voice signal  120 . For example, this envelope signal may indicate the amplitude or loudness (and variations thereof) of the voice signal  120 . This amplitude or loudness may be measured or characterized as sound pressure, sound pressure level (e.g., decibels), sound intensity, sound power, sones, phons, volts and/or amperes, etc. 
     The threshold detection block/module  126  may detect when the envelope signal meets or crosses one or more thresholds. For example, the threshold detection block/module  126  may detect when the envelope signal amplitude increases a given amount or decreases a given amount. In one example, several thresholds may be established in a range of amplitudes. In another example, one threshold may be established that is a certain amount or percentage higher than a reference sample or average of the envelope signal, while another threshold may be established that is a certain amount or percentage below the reference sample or average. The threshold detection block/module  126  may indicate when a threshold is met or crossed and/or which threshold is met or crossed by the envelope signal. This information may be provided to the masker as part of the first control signal  130 , for example. 
     Additionally or alternatively, the speech feature extraction block/module  122  may include an “other feature” detection block/module  150 . The other feature detection block/module  150  may detect other features of the voice signal  120 . Examples of other features include spectral (e.g., frequency), spatial (e.g., directional) and temporal (e.g., timing, phase, transitional, etc.) characteristics. 
     The first control signal  130  provided by the speech feature extraction block/module  122  may provide the actual features extracted (e.g., envelope signal, spectral characteristics, spatial characteristics, other characteristics etc.) and/or control information based on the extracted features (e.g., triggers for amplitude or loudness ramping, etc.). The first control signal  130  may be provided to the masker  136 . 
     The ambience analysis block/module  112  may analyze the ambience signal  110  to produce a second control signal  132  that is provided to the masker  136 . The ambience analysis block/module  112  may include an amplitude (e.g., loudness) detection block/module  114 , a direction detection block/module  116  and/or an other feature detection block/module  118 . The amplitude detection block/module  114  may detect or extract an amplitude or loudness of the ambience signal  110 . For example, the amplitude or loudness may be measured by detecting an envelope of the ambience signal  110 . This amplitude or loudness may be measured or characterized as sound pressure, sound pressure level (e.g., decibels), sound intensity, sound power, sones, phons, volts and/or amperes, etc. In some configurations, the amplitude or loudness of the ambience signal  110  may be measured across a spectrum or range of frequencies. In this way, the ambience signal  110  may be characterized based on the spectral magnitude of the acoustic ambient signals (e.g., sounds or noise)  148   a - n  received by the electronic device  102 , for example. 
     The direction detection block/module  116  may determine or estimate the direction (and/or other spatial characteristics) of the acoustic ambient signals (e.g., sounds or noise)  148   a - n . For example, the direction detection block/module  116  may use phase shifts between audio signals received by multiple microphones  104   a - n  to determine the direction of a particular acoustic ambient signal  148   a - n . The other feature detection block/module  118  may be used to detect other features of the ambience signal  110 , such as spectral (e.g., frequency) and/or temporal (e.g., timing, phase, transitional) characteristics. 
     The second control signal  132  provided by the ambience analysis block/module  112  may provide the actual features analyzed (e.g., amplitude, direction, spectral characteristics, etc.) and/or control information based on the analyzed features (e.g., triggers for amplitude or loudness ramping, etc.). The second control signal  132  may be provided to the masker  136 . 
     The one or more sound sources  128  may provide one or more sound signals  134  to the masker  136 . Examples of sound sources  128  include music or sound files (e.g., moving picture experts group (MPEG)-1 or MPEG-2 audio layer 3 (MP3) files, waveform audio file format (WAV) files, musical instrument digital interface (MIDI) files, etc.), synthesized sounds or noise and/or audio inputs or interfaces (for receiving a sound signal  134  from another device, for example), etc. For instance, one sound source  128  may be memory on the electronic device  102  that provides music or sound files, while another sound source  128  may be a port used to receive a sound signal  134  from another device. The one or more sound sources  128  may be optional. For example, the masker  136  may only use the voice signal  120  to generate the masking signal  142 . Additionally or alternatively, the masker  136  may use a sound signal  134  provided from one or more sound sources  128  to generate a masking signal  142 . In some configurations, the sound source  128  and/or sound signal  134  used may be selected based on an input. For example, the electronic device  102  may receive a user input via a user interface (not illustrated in  FIG. 1 ) that indicates a particular sound source  128  and/or sound signal  134  for use. For instance, the electronic device  102  may receive an input using a keyboard, mouse, touchscreen, microphone  104 , button, etc. that indicates a selected sound source  128  and/or sound signal  134 . 
     The masker  136  may be a block/module used to generate a masking signal  142 . The masking signal  142  may be output as an acoustic masking signal  152  using one or more speakers  144  (e.g., loudspeakers) in order to obscure or mask the acoustic voice signal  146 . The masker  136  may generate the masking signal  142  based on the first control signal  130  and the second control signal  132 . As described above, the masking signal  142  may also be based on a sound signal  134  in addition to or alternatively from the voice signal  120 . For example, the masking signal  142  may comprise music provided as a sound signal  134  from memory that has been adjusted and/or modified based on the first control signal  130  and the second control signal  132 . In another example, the masking signal  142  may comprise the voice signal  120  that has been adjusted and/or modified based on the first control signal  130  and the second control signal  132 . 
     The masker  136  may include, for example, a level control block/module  138  and/or a feature control block/module  140 . The level control block/module  138  may adjust the level (e.g., amplitude, magnitude, volume, loudness, etc.) of an input signal (e.g., voice signal  120  and/or sound signal  134 ) based on the first control signal  130  and/or the second control signal  132 . In one example, the masker  136  may amplitude modulate the voice signal  120  based on a speech envelope provided in the first control signal  130 . 
     In another example, the level control  138  may adjust the input signal amplitude or loudness in a direct relationship with a speech envelope (or threshold triggers based on the speech envelope) provided in the first control signal  130 . For instance, if the speech envelope increases in amplitude or loudness, the level control  138  may increase (e.g., ramp up) the amplitude or loudness of the input signal. However, if the speech envelope decreases in amplitude or loudness, the level control  138  may decrease (e.g., ramp down) the amplitude or loudness of the input signal. For example, as a user speaks louder or softer, the electronic device  102  may respectively produce a louder or softer acoustic masking signal  152  to effectively obscure the acoustic voice signal  146 . This may provide an acoustic masking signal  152  that is loud enough to obscure the acoustic voice signal  146  without being overpowering or annoying. 
     Additionally or alternatively, the level control block/module  138  may adjust the level (e.g., amplitude, loudness, etc.) of an input signal (e.g., voice signal  120  and/or sound signal  134 ) based on the second control signal  132 . For example, the level control  138  may adjust the input signal amplitude or loudness in an inverse relationship with an ambience amplitude or loudness (or threshold triggers based on the amplitude or loudness) provided in the second control signal  132 . For instance, if the ambience signal  110  increases in amplitude or loudness, the level control  138  may decrease (e.g., ramp down) the amplitude or loudness of the input signal. However, if the ambience signal  110  decreases in amplitude or loudness, the level control  138  may increase (e.g., ramp up) the amplitude or loudness of the input signal. For example, as acoustic ambient signals (e.g., sounds or noise)  148   a - n  become louder or softer, the electronic device  102  may respectively produce a softer or louder acoustic masking signal  152 . For instance, if the ambient signals (e.g., sounds or noise)  148   a - n  are loud enough and/or of the correct characteristics to effectively mask the acoustic voice signal  146 , then the electronic device  102  may not need to produce a loud acoustic masking signal  152 . Thus, the masker  136  may operate more efficiently, possibly saving power. 
     The masker  136  may additionally or alternatively include a feature control  140 . The feature control  140  may control one or more features of the input signal (e.g., voice signal  120  and/or sound signal  134 ) based on the first control signal  130  and/or the second control signal  132 . For example, the feature control  140  may adjust spectral characteristics of the input signal (e.g., voice signal  120  and/or sound signal  134 ) based on spectral characteristics of the voice signal  120  and/or the ambience signal  110 . For instance, if the second control signal  132  indicates that there is enough low-frequency noise in the acoustic ambient signals (e.g., sounds)  148   a - n  to effectively obscure a low-frequency portion of the acoustic voice signal  146  but not enough high-frequency noise in the acoustic ambient signals  148   a - n  to effectively obscure a high-frequency portion, then the feature control  140  may (independently or use the level control  138  to) increase the amplitude or loudness in a high frequency portion of a sound signal  134  in order to produce an acoustic masking signal  152  that effectively masks the high-frequency portion of the acoustic voice signal  146 . 
     In another example, the feature control  140  may adjust the spatial characteristics (e.g., directionality) of the acoustic masking signal  152  based on the first control signal  130  and/or second control signal  132 . For instance, the first control signal  130  may indicate the direction of the received acoustic voice signal  146 , while the second control signal  132  may indicate one or more directions of acoustic ambient signals (e.g., sounds)  148   a - n . The feature control  140  may use this information to adjust the directionality of the acoustic masking signal  152 , steering it  152  away from the user (e.g., the source of the acoustic voice signal  146 ). Additionally or alternatively, the feature control  140  may steer the acoustic masking signal  152  away from strong ambient signals (e.g., sounds)  148   a - n  that are sufficient to mask the acoustic voice signal  146  and/or potentially towards quiet ambient signals  148   a - n  and/or in directions without acoustic ambient signals  148   a - n . This may help to obscure the acoustic voice signal  146  in directions where it  146  might be more easily overheard, for example. 
     It should be noted that the one or more speakers  144  may be transducers (e.g., electroacoustic transducers) that convert an electrical or electronic signal (e.g., the masking signal  142 ) into an acoustic signal (e.g., the acoustic masking signal  152 ). In one configuration, the one or more speakers  144  may be omnidirectional. In other configurations, the one or more speakers  144  may be directional. For example, an array of speakers  144  may be used in some configurations to direct the acoustic masking signal  152  in a particular direction. In some configurations, one or more speakers  144  may be located on a different side (e.g., opposite side) of the electronic device  102  in relation to one or more microphones  104   a - n . In other configurations, one or more of the speakers  144  may be located on the same side of the electronic device  102  as one or more microphones  104   a - n.    
       FIG. 2  is a flow diagram illustrating one configuration of a method  200  for generating a masking signal  142  on an electronic device  102 . The electronic device  102  may obtain  202  a plurality of audio signals from a plurality of microphones  104   a - n . For example, the plurality of microphones  104   a - n  may convert an acoustic voice signal  146  and/or one or more acoustic ambient signals  148   a - n  into electrical or electronic audio signals. 
     The electronic device  102  may obtain  204  an ambience signal  110  from the plurality of audio signals. For example, the electronic device  102  may estimate ambient sounds and/or noise in the audio signals. In one configuration, the electronic device  102  may use a voice activity detector to estimate the ambient sounds and/or noise in the audio signals. In this configuration, for example, more dynamic and sporadic audio activities may be classified as voice, while more stationary sounds may be classified as the ambient sounds. In another configuration, a blind source separation (BSS) signal processing mechanism may remove a voice signal from multiple microphone-captured signals, thereby providing a better estimation of ambient sounds. 
     The electronic device  102  may determine  206  an ambience feature based on the ambience signal  110 . Examples of features include amplitude (e.g., magnitude, loudness, etc.) characteristics, spatial characteristics (e.g., direction), spectral characteristics (e.g., pitch, frequency) and/or temporal characteristics, etc. For instance, the electronic device  102  may determine  206  the amplitude (e.g., a loudness envelope) of the ambience signal  110 . Additionally or alternatively, the electronic device  102  may determine  206  acoustic ambient signal  148   a - n  spatial characteristics (e.g., directionality) using observed phase shifts in the audio signals. Additionally or alternatively, the electronic device  102  may determine  206  spectral characteristics (e.g., amplitude or magnitude of the ambience signal  110  over a range of frequencies). In some configurations, the electronic device  102  may generate a second control signal  132  based on the ambience feature. 
     The electronic device  102  may obtain  208  a voice signal  120  from the plurality of audio signals. For example, the electronic device  102  may separate the voice signal  120  from the audio signals. In one configuration, the electronic device  102  may subtract or remove a noise estimate (e.g., the ambience signal  110 ) from the audio signals in order to estimate the voice signal  120 . One typical robust unmixing example is blind source separation (BSS). For instance, when signal sources are equal to or less than the number of microphones  104   a - n , one of the sources (e.g., voice) may be extracted through BSS signal processing. 
     The electronic device  102  may determine  210  a voice feature based on the voice signal  120 . Examples of features include amplitude (e.g., magnitude, loudness, etc.) characteristics, temporal characteristics, spatial characteristics (e.g., direction) and/or spectral characteristics, etc. For instance, the electronic device  102  may determine  210  the amplitude (e.g., a loudness envelope) of the voice signal  120 . Additionally or alternatively, the electronic device  102  may determine  210  acoustic voice signal  142  directionality using observed phase shifts in the audio signals. Additionally or alternatively, the electronic device  102  may determine  210  spectral characteristics (e.g., amplitude or magnitude of the voice signal  120  over a range of frequencies). In some configurations, the electronic device  102  may generate a first control signal  130  based on the voice feature. 
     The electronic device  102  may generate  212  a masking signal  142  based on the voice feature and the ambience feature (e.g., based on the first control signal  130  and the second control signal  132 ). For example, the electronic device  102  may adjust a signal (e.g., sound signal  134 ) amplitude, magnitude, loudness or volume based on the voice feature and the ambience feature to generate  212  the masking signal  142 . In one configuration, the electronic device  102  adjusts the signal (e.g., sound signal  134 ) amplitude or loudness in a direct relationship with a voice envelope (e.g., amplitude or loudness envelope) and adjusts the signal amplitude or loudness in an inverse relationship with an ambience amplitude or loudness (e.g., amplitude or loudness envelope). In another configuration, the electronic device  102  may amplitude modulate a signal (e.g., voice signal  120  and/or sound signal  134 ) based on the voice feature and/or the ambience feature. 
     In another example, the electronic device  102  may adjust spectral characteristics of a signal (e.g., modulated voice signal  120  and/or sound signal  134 ) based on voice feature and/or ambience feature. For instance, if the ambience feature indicates that there is enough low-frequency noise in the acoustic ambient signals (e.g., sounds)  148   a - n  to effectively obscure a low-frequency portion of the acoustic voice signal  146  but not enough high-frequency noise in the acoustic ambient signals  148   a - n  to effectively obscure a high-frequency portion, then the electronic device  102  may increase the amplitude or loudness in a high-frequency portion of a sound signal  134  in order to produce an acoustic masking signal  152  that effectively masks the high-frequency portion of the acoustic voice signal  146 . 
     In yet another example, the electronic device  102  may adjust the spatial characteristics (e.g., directionality) of a signal (e.g., modulated voice signal  120  and/or sound signal  134 ) to generate  212  the masking signal  142 . For instance, the voice feature may indicate the direction of the received acoustic voice signal  146 , while the ambience feature may indicate one or more directions of acoustic ambient signals (e.g., sounds)  148   a - n . This information may be used to adjust the directionality of the acoustic masking signal  152 , steering it  152  away from the user (e.g., the source of the acoustic voice signal  146 ). Additionally or alternatively, the acoustic masking signal  152  may be steered away from strong ambient signals (e.g., sounds)  148   a - n  that are sufficient to mask the acoustic voice signal  146  and/or potentially towards quiet ambient signals  148   a - n  and/or in directions without acoustic ambient signals  148   a - n . This may help to obscure the acoustic voice signal  146  in directions where it  146  might be more easily overheard, for example. 
     The electronic device  102  may output  214  the masking signal  142 . For example, the electronic device  102  may provide the masking signal  142  to one or more speakers  144 , which may convert the masking signal  142  into an acoustic masking signal  152 . 
     It should be noted that the method  200  illustrated in  FIG. 2  may be performed in real time by the electronic device  102 . For example, the audio signals may be obtained  202 , the ambience signal  110  may be obtained  204 , the ambience feature may be determined  206 , the voice signal  120  may be obtained  208 , the voice feature may be determined  210  and/or the masking signal  142  may be generated  212  and output  214  in real time. The method  200  may be performed in real time in order to effectively mask the acoustic voice signal  146  with a corresponding acoustic masking signal  152 . 
       FIG. 3  is a block diagram illustrating one configuration of a transmitting wireless communication device  302  in which systems and methods for generating a masking signal may be implemented. Examples of the transmitting wireless communication device  302  include cellular phones, smartphones, laptop computers, tablet devices, gaming systems, personal digital assistants, music players (e.g., MP3 players), etc. The transmitting wireless communication device  302  may include one or more microphones  304   a - n , a multi-microphone processing block/module  306 , an ambience analysis block/module  312 , a speech feature extraction block/module  322 , a masker  336 , one or more sound sources  328 , one or more speakers  344 , an encoder  354 , a modulator  356 , a transmitter  358  and/or one or more antennas  360   a - n.    
     The one or more microphones  304   a - n  may be transducers (e.g., acoustoelectric transducers) used to convert acoustic signals into electrical or electronic signals. For example, the one or more microphones  304   a - n  may capture an acoustic voice signal and/or one or more acoustic ambient signals and convert them into electrical or electronic signals that are provided to the multi-microphone processing block/module  306 . For instance, each of the microphones  304   a - n  may generate an audio signal (e.g., electrical or electronic signal) that represents the acoustic voice signal, acoustic ambient signals or a mixture of both. In one configuration, multiple audio signals may thus be obtained using multiple microphones  304   a - n . Examples of the microphones  304   a - n  include dynamic microphones, condenser microphones, piezoelectric microphones, fiber optic microphones, laser microphones, etc. 
     The multi-microphone processing block/module  306  may be used to process the audio signals (e.g., electrical or electronic signals) provided by the one or more microphones  304   a - n . The multi-microphone processing block/module  306  may include a source separation block/module  308 . The source separation block/module  308  may generate (e.g., estimate) a voice signal  320 . For example, the source separation block/module  308  may remove an estimated ambience signal (e.g., ambient noise)  310  from the captured audio signal(s) in order to estimate the voice signal  320 . The voice signal  320  may be provided to the speech feature extraction block/module  322 . The voice signal  320  may optionally be provided to the masker  336  and/or to the encoder  354 . 
     The speech feature extraction block/module  322  may be used to extract one or more features from the voice signal  320 . Examples of voice signal  320  features include magnitude or amplitude (e.g., loudness, volume, etc.), spectral (e.g., pitch or frequency), spatial (e.g., directional) and/or temporal (e.g., phase, timing, etc.) features, etc. The speech feature extraction block/module  322  may produce a first control signal  330  based on the one or more features extracted. In one configuration, the speech feature extraction block/module  322  may include an envelope detection block/module  324  and/or threshold detection block/module  326 . The envelope detection block/module  324  may determine an envelope signal (e.g., amplitude or loudness envelope) based on the voice signal  320 . For example, this envelope signal may indicate the amplitude or loudness (and variations thereof) of the voice signal  320 . This amplitude or loudness may be measured or characterized as sound pressure, sound pressure level (e.g., decibels), sound intensity, sound power, sones, phons, volts and/or amperes, etc. 
     The threshold detection block/module  326  may detect when the envelope signal meets or crosses one or more thresholds. For example, the threshold detection block/module  326  may detect when the envelope signal increases a given amount or decreases a given amount. In one example, several thresholds may be established in a range of amplitudes. In another example, one threshold may be established that is a certain amount or percentage higher than a reference sample or average of the envelope signal, while another threshold may be established that is a certain amount or percentage below the reference sample or average. The threshold detection block/module  326  may indicate when a threshold is met or crossed and/or which threshold is met or crossed by the envelope signal. 
     Additionally or alternatively, the speech feature extraction block/module  322  may include an “other feature” detection block/module  350 . The other feature detection block/module  350  may detect other features of the voice signal  320 . Examples of other features include spectral (e.g., frequency), spatial (e.g., directional) and temporal (e.g., timing, phase, transitional, etc.) characteristics. 
     The first control signal  330  provided by the speech feature extraction block/module  322  may provide the actual features extracted (e.g., envelope signal, spectral characteristics, etc.) and/or control information based on the extracted features (e.g., triggers for amplitude or loudness ramping, etc.). The first control signal  330  may be provided to the masker  336 . 
     The ambience analysis block/module  312  may analyze the ambience signal  310  to produce a second control signal  332  that is provided to the masker  336 . The ambience analysis block/module  312  may include an amplitude (e.g., loudness) detection block/module  314 , a direction detection block/module  316  and/or an other feature detection block/module  318 . The amplitude detection block/module  314  may detect or extract an amplitude or loudness of the ambience signal  310 . For example, the amplitude or loudness may be measured by detecting an envelope of the ambience signal  310 . This amplitude or loudness may be measured or characterized as sound pressure, sound pressure level (e.g., decibels), sound intensity, sound power, sones, phons, volts and/or amperes, etc. In some configurations, the amplitude or loudness of the ambience signal  310  may be measured across a spectrum or range of frequencies. In this way, the ambience signal  310  may be characterized based on the spectral magnitude of the acoustic ambient signals (e.g., sounds or noise) received by the transmitting wireless communication device  302 , for example. 
     The direction detection block/module  316  may determine or estimate the direction of the acoustic ambient signals (e.g., sounds or noise). For example, the direction detection block/module  316  may use phase shifts between audio signals received by multiple microphones  304   a - n  to determine the direction of a particular acoustic ambient signal. The other feature detection block/module  318  may be used to detect other features of the ambience signal  310 , such as spectral (e.g., frequency) and/or temporal (e.g., timing, phase, transitional) characteristics. 
     The second control signal  332  provided by the ambience analysis block/module  312  may provide the actual features analyzed (e.g., amplitude, direction, spectral characteristics, etc.) and/or control information based on the analyzed features (e.g., triggers for amplitude or loudness ramping, etc.). The second control signal  332  may be provided to the masker  336 . 
     The one or more sound sources  328  may provide one or more sound signals  334  to the masker  336 . Examples of sound sources  328  include music or sound files (e.g., moving picture experts group (MPEG)-1 or MPEG-2 audio layer 3 (MP3) files, waveform audio file format (WAV) files, musical instrument digital interface (MIDI) files, etc.), synthesized sounds or noise and/or audio inputs or interfaces (for receiving a sound signal  334  from another device, for example), etc. For instance, one sound source  328  may be memory on the transmitting wireless communication device  302  that provides music or sound files, while another sound source  328  may be a port used to receive a sound signal  334  from another device. The one or more sound sources  328  may be optional. For example, the masker  336  may only use the voice signal  320  to generate the masking signal  342 . Additionally or alternatively, the masker  336  may use a sound signal  334  provided from one or more sound sources  328  to generate a masking signal  342 . In some configurations, the sound source  328  and/or sound signal  334  used may be selected based on an input. For example, the transmitting wireless communication device  302  may receive a user input via a user interface (not illustrated in  FIG. 3 ) that indicates a particular sound source  328  and/or sound signal  334  for use. For instance, the transmitting wireless communication device  302  may receive an input using a keyboard, mouse, touchscreen, microphone  304 , button, etc. that indicates a selected sound source  328  and/or sound signal  334 . 
     The masker  336  may be a block/module used to generate a masking signal  342 . The masking signal  342  may be output as an acoustic masking signal using one or more speakers  344  (e.g., loudspeakers) in order to obscure or mask the acoustic voice signal. The masker  336  may generate the masking signal  342  based on the first control signal  330  and the second control signal  332 . As described above, the masking signal  342  may also be based on a sound signal  334  in addition to or alternatively from the voice signal  320 . For example, the masking signal  342  may comprise music provided as a sound signal  334  from memory that has been adjusted and/or modified based on the first control signal  330  and the second control signal  332 . In another example, the masking signal  342  may comprise the voice signal  320  that has been adjusted (e.g., amplitude modulated) based on the first control signal  330  and the second control signal  332 . 
     The masker  336  may include, for example, a level control block/module  338  and/or a feature control block/module  340 . The level control block/module  338  may adjust the level (e.g., amplitude, magnitude, volume, loudness, etc.) of an input signal (e.g., voice signal  320  and/or sound signal  334 ) based on the first control signal  330  and/or the second control signal  332 . 
     For example, the level control  338  may adjust the input signal amplitude or loudness in a direct relationship with a speech envelope (or threshold triggers based on the speech envelope) provided in the first control signal  330 . For instance, if the speech envelope increases in amplitude or loudness, the level control  338  may increase (e.g., ramp up) the amplitude or loudness of the input signal. However, if the speech envelope decreases in amplitude or loudness, the level control  338  may decrease (e.g., ramp down) the amplitude or loudness of the input signal. For example, as a user speaks louder or softer, the transmitting wireless communication device  302  may respectively produce a louder or softer acoustic masking signal to effectively obscure the acoustic voice signal. This may provide an acoustic masking signal that is loud enough to obscure the acoustic voice signal without being overpowering or annoying. 
     Additionally or alternatively, the level control block/module  338  may adjust the level (e.g., amplitude, loudness, etc.) of an input signal (e.g., voice signal  320  and/or sound signal  334 ) based on the second control signal  332 . For example, the level control  338  may adjust the input signal amplitude or loudness in an inverse relationship with an ambience amplitude or loudness (or threshold triggers based on the amplitude or loudness) provided in the second control signal  332 . For instance, if the ambience signal  310  increases in amplitude or loudness, the level control  338  may decrease (e.g., ramp down) the amplitude or loudness of the input signal. However, if the ambience signal  310  decreases in amplitude or loudness, the level control  338  may increase (e.g., ramp up) the amplitude or loudness of the input signal. For example, as acoustic ambient signals (e.g., sounds or noise) become louder or softer, the transmitting wireless communication device  302  may respectively produce a softer or louder acoustic masking signal. For instance, if the ambient signals (e.g., sounds or noise) are loud enough and/or of the correct characteristics to effectively mask the acoustic voice signal, then the transmitting wireless communication device  302  may not need to produce a loud acoustic masking signal. Thus, the masker  336  may operate more efficiently, possibly saving battery power. 
     The masker  336  may additionally or alternatively include a feature control  340 . The feature control  340  may control one or more features of the input signal (e.g., voice signal  320  and/or sound signal  334 ) based on the first control signal  330  and/or the second control signal  332 . For example, the feature control  340  may adjust spectral characteristics of the input signal (e.g., voice signal  320  and/or sound signal  334 ) based on spectral characteristics of the voice signal  320  and/or the ambience signal  310 . For instance, if the second control signal  332  indicates that there is enough low-frequency noise in the acoustic ambient signals (e.g., sounds) to effectively obscure a low-frequency portion of the acoustic voice signal but not enough high-frequency noise in the acoustic ambient signals to effectively obscure a high-frequency portion, then the feature control  340  may (independently or use the level control  338  to) increase the amplitude or loudness in a high frequency portion of a sound signal  334  in order to produce an acoustic masking signal that effectively masks the high-frequency portion of the acoustic voice signal. 
     In another example, the feature control  340  may adjust the directionality of the acoustic masking signal based on the first control signal  330  and/or second control signal  332 . For instance, the first control signal  330  may indicate the direction of the received acoustic voice signal, while the second control signal  332  may indicate one or more directions of acoustic ambient signals (e.g., sounds). The feature control  340  may use this information to adjust the directionality of the acoustic masking signal, steering it away from the user (e.g., the source of the acoustic voice signal). Additionally or alternatively, the feature control  340  may steer the acoustic masking signal away from strong ambient signals (e.g., sounds) that are sufficient to mask the acoustic voice signal and/or potentially towards quiet ambient signals and/or in directions without acoustic ambient signals. This may help to obscure the acoustic voice signal in directions where it might be more easily overheard, for example. 
     It should be noted that the one or more speakers  344  may be transducers (e.g., electroacoustic transducers) that convert an electrical or electronic signal (e.g., the masking signal  342 ) into an acoustic signal (e.g., the acoustic masking signal). In one configuration, the one or more speakers  344  may be omnidirectional. In other configurations, the one or more speakers  344  may be directional. For example, an array of speakers  344  may be used in some configurations to direct the acoustic masking signal in a particular direction. 
     The voice signal  320  may be provided to the encoder  354 . The encoder  354  may encode the voice signal  320  to produce an encoded voice signal. In some configurations, the encoder  354  may also add error detection and/or correction coding to the encoded voice signal. The encoded voice signal may be provided to a modulator  356 . The modulator  356  modulates the encoded voice signal into a particular constellation based on the type of modulation used. Some examples of modulation include quadrature amplitude modulation (QAM), phase shift keying (PSK) modulation, etc. The encoded and modulated voice signal may be provided to a transmitter  358 . The transmitter  358  may perform further operations on the encoded and modulated voice signal, such as providing amplification in preparation for transmission. The transmitter  358  may transmit the encoded and modulated voice signal as one or more electromagnetic signals using one or more antennas  360   a - n.    
     It should be noted that the transmitting wireless communication device  302  may perform additional or alternative operations on the voice signal  320 . For example, the transmitting wireless communication device  302  may map voice signal  320  data to one or more frequencies (e.g., orthogonal frequency division multiplexing (OFDM) subcarriers), time slots, spatial channels, etc. 
     The one or more electromagnetic signals transmitted from the one or more transmitting wireless communication device  302  antennas  360   a - n  may be received by a receiving wireless communication device  364 . Examples of the receiving wireless communication device  364  include cellular phones, smartphones, laptop computers, tablet devices, gaming systems, personal digital assistants, music players (e.g., MP3 players), etc. In one configuration, the receiving wireless communication device  364  may include one or more speakers  374 , a decoder  370 , a demodulator  368 , a receiver  366  and/or one or more antennas  362   a - n . The receiver  366  may receive the one or more transmitted electromagnetic signals using the one or more antennas  362   a - n . The received signal may be provided to a demodulator  368 . The demodulator  368  demodulates the received signal to produce an encoded signal, which is provided to the decoder  370 . The decoder  370  decodes the encoded signal to produce a decoded voice signal  372 . The decoded voice signal  372  may be provided to the one or more speakers  374 , which may output the decoded voice signal  372  as an acoustic signal. 
     In some configurations, the electromagnetic signals transmitted from the transmitting wireless communication device  302  to the receiving wireless communication device  364  may be relayed by one or more devices. For example, the transmitting communication device  302  may transmit the electromagnetic signals to a base station, which may receive the signals and provide them to one or more network devices. The signals may be routed to another base station, where they may be relayed or retransmitted to the receiving wireless communication device  364 . 
       FIG. 4  is a flow diagram illustrating a configuration of a method  400  for generating a masking signal  342  on a transmitting wireless communication device  302 . The transmitting wireless communication device  302  may obtain  402  a plurality of audio signals from a plurality of microphones  304   a - n . For example, the plurality of microphones  304   a - n  may convert an acoustic voice signal and/or one or more acoustic ambient signals into electrical or electronic audio signals. 
     The transmitting wireless communication device  302  may obtain  404  an ambience signal  310  from the plurality of audio signals. For example, the transmitting wireless communication device  302  may estimate ambient sounds and/or noise in the audio signals. In one configuration, the transmitting wireless communication device  302  may use a voice activity detector to estimate the ambient sounds and/or noise in the audio signals. In this configuration, for example, more dynamic and sporadic audio activities may be classified as voice, while more stationary sounds may be classified as the ambient sounds. In another configuration, a blind source separation (BSS) signal processing mechanism may remove a voice signal from multiple microphone-captured signals, thereby providing a better estimation of ambient sounds. 
     The transmitting wireless communication device  302  may determine  406  an ambience feature based on the ambience signal  310 . Examples of features include amplitude (e.g., magnitude, loudness, etc.), spatial characteristics (e.g., direction), spectral characteristics, etc. For instance, the transmitting wireless communication device  302  may determine  406  the amplitude (e.g., a loudness envelope) of the ambience signal  310 . Additionally or alternatively, the transmitting wireless communication device  302  may determine  406  acoustic ambient signal spatial characteristics (e.g., directionality) using observed phase shifts in the audio signals. Additionally or alternatively, the transmitting wireless communication device  302  may determine  406  spectral characteristics (e.g., amplitude or magnitude of the ambience signal  310  over a range of frequencies). In some configurations, the transmitting wireless communication device  302  may generate a second control signal  332  based on the ambience feature. 
     The transmitting wireless communication device  302  may obtain  408  a voice signal  320  from the plurality of audio signals. For example, the transmitting wireless communication device  302  may separate the voice signal  320  from the audio signals. In one configuration, the transmitting wireless communication device  302  may subtract or remove a noise estimate (e.g., the ambience signal  310 ) from the audio signals in order to estimate the voice signal  320 . One typical robust unmixing example may be blind source separation (BSS). For instance, when signal sources are equal to or less than the number of microphones  304   a - n , one of the sources (e.g., voice) may be extracted through BSS signal processing. 
     The transmitting wireless communication device  302  may determine  410  a voice feature based on the voice signal  320 . Examples of features include amplitude (e.g., magnitude, loudness, etc.), temporal characteristics, spatial characteristics (e.g., direction), spectral characteristics, etc. For instance, the transmitting wireless communication device  302  may determine  410  the amplitude (e.g., a loudness envelope) of the voice signal  320 . Additionally or alternatively, the transmitting wireless communication device  302  may determine  410  acoustic voice signal  342  directionality using observed phase shifts in the audio signals. Additionally or alternatively, the transmitting wireless communication device  302  may determine  410  spectral characteristics (e.g., amplitude or magnitude of the voice signal  320  over a range of frequencies). In some configurations, the transmitting wireless communication device  302  may generate a first control signal  330  based on the voice feature. 
     The transmitting wireless communication device  302  may obtain  412  a sound signal  334 . For example, the transmitting wireless communication device  302  may obtain  412  music or sound files (e.g., MP3 files, WAV files, MIDI files, etc.), synthesized sounds or noise and/or an audio input (from another device, for example), etc. In one configuration, the transmitting wireless communication device  302  retrieves a sound signal  334  from memory. Additionally or alternatively, the transmitting wireless communication device  302  may synthesize sounds or noise using an algorithm and/or stored data. Additionally or alternatively, the transmitting wireless communication device  302  retrieves a sound signal  334  from a removable memory device, such as a secure digital (SD) card, universal serial bus (USB) thumb drive, etc., or receives a sound signal  334  (e.g., stream) from another device. 
     The transmitting wireless communication device  302  may generate  414  a masking signal  342  based on the voice feature (e.g., the first control signal  330 ), the ambience feature (e.g., the second control signal  332 ) and the sound signal  334 . For example, the transmitting wireless communication device  302  may adjust the sound signal  334  amplitude, magnitude, loudness or volume based on the voice feature and the ambience feature to generate  414  the masking signal  342 . In one configuration, the transmitting wireless communication device  302  adjusts the sound signal  334  amplitude or loudness in a direct relationship with a voice envelope (e.g., amplitude or loudness envelope) and adjusts the signal amplitude or loudness in an inverse relationship with an ambience amplitude or loudness (e.g., amplitude or loudness envelope). 
     In another example, the transmitting wireless communication device  302  may adjust spectral characteristics of the sound signal  334  based on voice feature and/or ambience feature. For instance, if the ambience feature indicates that there is enough low-frequency noise in the acoustic ambient signals (e.g., sounds) to effectively obscure a low-frequency portion of the acoustic voice signal but not enough high-frequency noise in the acoustic ambient signals to effectively obscure a high-frequency portion, then the transmitting wireless communication device  302  may increase the amplitude or loudness in a high-frequency portion of the sound signal  334  in order to produce an acoustic masking signal that effectively masks the high-frequency portion of the acoustic voice signal. 
     In yet another example, the transmitting wireless communication device  302  may adjust the spatial characteristics (e.g., directionality) of the sound signal  334  to generate  414  the masking signal  342 . For instance, the voice feature may indicate the direction of the received acoustic voice signal, while the ambience feature may indicate one or more directions of acoustic ambient signals (e.g., sounds). This information may be used to adjust the directionality of the acoustic masking signal, steering it away from the user (e.g., the source of the acoustic voice signal). Additionally or alternatively, the acoustic masking signal may be steered away from strong ambient signals (e.g., sounds) that are sufficient to mask the acoustic voice signal and/or potentially towards quiet ambient signals and/or in directions without acoustic ambient signals. This may help to obscure the acoustic voice signal in directions where it might be more easily overheard, for example. 
     The transmitting wireless communication device  302  may output  416  the masking signal  342 . For example, the transmitting wireless communication device  302  may provide the masking signal  342  to one or more speakers  344 , which may convert the masking signal  342  into an acoustic masking signal. 
     The transmitting wireless communication device  302  may transmit  418  the voice signal  320 . For example, the transmitting wireless communication device  302  may encode, modulate, amplify and/or transmit  418  the voice signal  320 . The voice signal  320  may be transmitted as one or more electromagnetic signals using one or more antennas  360   a - n . Before transmission, the transmitting wireless communication device  302  may additionally or alternatively map the voice signal  320  data to one or more spatial streams, antennas, frequencies (e.g., subcarriers), time slots, etc. 
     It should be noted that the method  400  illustrated in  FIG. 4  may be performed in real time by the transmitting wireless communication device  302 . For example, the audio signals may be obtained  402 , the ambience signal  310  may be obtained  404 , the ambience feature may be determined  406 , the voice signal  320  may be obtained  408 , the voice feature may be determined  410 , the sound signal  334  may be obtained  412  and/or the masking signal  342  may be generated  414  and output  416  in real time. The method  400  may be performed in real time in order to effectively mask the acoustic voice signal  346  with a corresponding acoustic masking signal  352 . 
       FIG. 5  is a block diagram illustrating one configuration of a wireless communication device  502  in which systems and methods for generating a masking signal may be implemented. Examples of the wireless communication device  502  include cellular phones, smartphones, laptop computers, tablet devices, gaming systems, personal digital assistants, music players (e.g., MP3 players), etc. The wireless communication device  502  may include one or more microphones  504   a - n , a multi-microphone processing block/module  506 , an ambience analysis block/module  512 , a speech feature extraction block/module  522 , a masker  536 , one or more sound sources  528 , one or more speakers  544 , one or more earpiece speakers  576 , an RVE block/module  578 , a decoder  580 , a demodulator  582 , a receiver  584 , an encoder  554 , a modulator  556 , a transmitter  558  and/or one or more antennas  560   a - n.    
     The one or more microphones  504   a - n  may be transducers (e.g., acoustoelectric transducers) used to convert acoustic signals into electrical or electronic signals. For example, the one or more microphones  504   a - n  may capture an acoustic voice signal and/or one or more acoustic ambient signals and convert them into electrical or electronic signals that are provided to the multi-microphone processing block/module  506 . For instance, each of the microphones  504   a - n  may generate an audio signal (e.g., electrical or electronic signal) that represents the acoustic voice signal, acoustic ambient signals or a mixture of both. In one configuration, multiple audio signals may thus be obtained using multiple microphones  504   a - n . Examples of the microphones  504   a - n  include dynamic microphones, condenser microphones, piezoelectric microphones, fiber optic microphones, laser microphones, etc. 
     The multi-microphone processing block/module  506  may be used to process the audio signals (e.g., electrical or electronic signals) provided by the one or more microphones  504   a - n . The multi-microphone processing block/module  506  may include an echo cancellation block/module  586 , one or more analog-to-digital converters (ADCs)  596 , a source separation and/or noise reduction block/module  508 , a noise estimation block/module  590  and/or a voice activity detector  594 . The one or more analog-to-digital converters  596  may convert the one or more analog audio signals (captured by the one or more microphones  504   a - n ) to one or more digital audio signals  598   a - n . The one or more digital audio signals  598   a - n  may be provided to the voice activity detector  594 , the noise estimation block/module  590  and/or the source separation/noise reduction block/module  508 . 
     The voice activity detector  594  may detect when voice activity is present in the digital audio signal(s)  598   a - n . For example, the voice activity detector  594  may determine when voice or speech is present in the digital audio signal(s)  598   a - n  as opposed to silence and/or noise, etc. The voice activity detector  594  may provide a voice activity indicator  592  to the noise estimation block/module  590  that indicates when voice activity is present in the digital audio signal(s)  598   a - n.    
     The noise estimation block/module  590  may estimate an ambience signal (e.g., ambient noise)  510  based on the digital audio signal(s)  598   a - n  and the voice activity indicator  592 . For example, the noise estimation block/module  590  may estimate stationary and non-stationary ambient or background noise that is present in the digital audio signal(s)  598   a - n . In one configuration, for instance, the noise estimation block/module  590  may estimate a noise floor based on periods in the digital audio signal(s)  598   a - n  where the voice activity indicator  592  does not indicate voice activity. Thus, the noise estimation block/module  590  may estimate an ambience signal  510 . The ambience signal  510  may be provided to the source separation/noise reduction block/module  508  and the ambience analysis block/module  512 . 
     The echo cancellation block/module  586  may be used to reduce or cancel echo in the digital audio signal(s)  598   a - n  from one or more signals that may be output by the wireless communication device  502 . For example, the wireless communication device  502  may output one or more acoustic signals from the one or more earpiece speakers  576  and/or from the one or more speakers (e.g., loudspeakers)  544 . As described above, for instance, the wireless communication device  502  may output an acoustic masking signal from the one or more speakers  544  based on a masking signal  542 . Additionally or alternatively, the wireless communication device  502  may output other acoustic signals (e.g., voice signals, music, etc.) from the earpiece speaker(s)  576 . For example, a user may be using the wireless communication device  502  to make a phone call. During the phone call, the wireless communication device  502  may output voice or speech from the one or more earpiece speakers  576  in addition to or alternatively from an acoustic masking signal output from the one or more speakers  544 . The echo cancellation block/module  586  may use one or more received signals (that are also provided to the earpiece speaker(s)  576 ) and the masking signal  542  to produce an echo signal  588  that may be provided to the source separation/noise reduction block/module  508 . 
     The source separation block/module  508  may generate (e.g., estimate) a voice signal  520 . For example, the source separation block/module  508  may remove an estimated ambience signal (e.g., ambient noise)  510  and/or an echo signal  588  from the digital audio signal(s)  598   a  in order to estimate the voice signal  520 . The voice signal  520  may be provided to the speech feature extraction block/module  522 . The voice signal  520  may additionally or alternatively be provided to the masker  536  and/or the encoder  554 . 
     The speech feature extraction block/module  522  may be used to extract one or more features from the voice signal  520 . Examples of voice signal  520  features include magnitude or amplitude (e.g., loudness, volume, etc.), spectral (e.g., pitch or frequency), spatial (e.g., directional) and/or temporal (e.g., phase) features, etc. The speech feature extraction block/module  522  may produce a first control signal  530  based on the one or more features extracted. In one configuration, the speech feature extraction block/module  522  may include an envelope detection block/module  524  (abbreviated as “Envelope  524 ” for convenience in  FIG. 5 ) and/or threshold detection block/module  526  (abbreviated as “Threshold  526 ” for convenience in  FIG. 5 ). The envelope detection block/module  524  may determine an envelope signal (e.g., amplitude or loudness envelope) based on the voice signal  520 . For example, this envelope signal may indicate the amplitude or loudness (and variations thereof) of the voice signal  520 . This amplitude or loudness may be measured or characterized as sound pressure, sound pressure level (e.g., decibels), sound intensity, sound power, sones, phons, volts and/or amperes, etc. 
     The threshold detection block/module  526  may detect when the envelope signal meets or crosses one or more thresholds. For example, the threshold detection block/module  526  may detect when the envelope signal increases a given amount or decreases a given amount. In one example, several thresholds may be established in a range of amplitudes. In another example, one threshold may be established that is a certain amount or percentage higher than a reference sample or average of the envelope signal, while another threshold may be established that is a certain amount or percentage below the reference sample or average. The threshold detection block/module  526  may indicate when a threshold is met or crossed and/or which threshold is met or crossed by the envelope signal. 
     Additionally or alternatively, the speech feature extraction block/module  522  may include one or more other feature detection blocks/modules  550 . The other feature detection block(s)/module(s)  550  may detect other features of the voice signal  520 . For example, the speech feature extraction block/module may include a spectral detection block/module  550   a  (abbreviated as “Spectral  550   a ” for convenience in  FIG. 5 ), a spatial detection block/module  550   b  (abbreviated as “Spatial  550   b ” for convenience in  FIG. 5 ) and/or a temporal detection block/module  550   c  (abbreviated as “Temporal  550   c ” for convenience in  FIG. 5 ). For instance, these blocks/modules  550   a - c  may be used to detect and/or extract spectral (e.g., frequency), spatial (e.g., directional) and/or temporal (e.g., timing, phase, transitional, etc.) features or characteristics of the voice signal  520 . More specifically, the spectral detection block/module  550   a  may detect and/or extract spectral (e.g., pitch, frequency, etc.) features of the voice signal  520 . For instance, the spectral detection block/module  550   a  may determine a spectral amplitude or magnitude of the voice signal  520 . Additionally or alternatively, the spatial detection block/module  550   b  may detect and/or extract spatial (e.g., directional) features of the voice signal  520 . For example, the spatial detection block/module  550   b  may determine a direction of received acoustic voice relative to the wireless communication device  502  (e.g., relative to the one or more microphones  504   a - n ). Additionally or alternatively, the temporal detection block/module  550   c  may detect and/or extract temporal (e.g., timing, phase) features of the voice signal  520 . For example, the temporal detection block/module  550   c  may determine when speech occurs in the voice signal  520 , how long phrases and/or pauses in speech tend to occur, etc. 
     The first control signal  530  provided by the speech feature extraction block/module  522  may provide the actual features extracted (e.g., envelope signal, spectral, spatial, temporal characteristics, etc.) and/or control information based on the extracted features (e.g., triggers for amplitude or loudness ramping, etc.). The first control signal  530  may be provided to the masker  536 . 
     The ambience analysis block/module  512  may analyze the ambience signal  510  to produce a second control signal  532  that is provided to the masker  536 . The ambience analysis block/module  512  may include an amplitude (e.g., loudness) detection block/module  514  (abbreviated as “Amplitude  514 ” in  FIG. 5  for convenience), a spatial (e.g., directional) detection block/module  516  (abbreviated as “Spatial  516 ” in  FIG. 5  for convenience), a spectral detection block/module  518   a  (abbreviated as “Spectral  518   a ” in  FIG. 5  for convenience) and/or a temporal detection block/module  518   b  (abbreviated as “Temporal  518   b ” in  FIG. 5  for convenience). The amplitude detection block/module  514  may detect or extract an amplitude or loudness of the ambience signal  510 . For example, the amplitude or loudness may be measured by detecting an envelope of the ambience signal  510 . This amplitude or loudness may be measured or characterized as sound pressure, sound pressure level (e.g., decibels), sound intensity, sound power, sones, phons, volts and/or amperes, etc. In some configurations, the amplitude or loudness of the ambience signal  510  may be measured across a spectrum or range of frequencies. In this way, the ambience signal  510  may be characterized based on the spectral magnitude of the acoustic ambient signals (e.g., sounds or noise) received by the wireless communication device  502 , for example. 
     The spatial (e.g., direction) detection block/module  516  may determine or estimate spatial features or characteristics of acoustic ambient signals (e.g., sounds or noise). For example, the spatial detection block/module  516  may use phase shifts between audio signals received by multiple microphones  504   a - n  to determine the direction of a particular acoustic ambient signal. More specifically, the spatial detection block/module  516  may determine a direction of received acoustic ambient signals relative to the wireless communication device  502  (e.g., relative to the one or more microphones  504   a - n ). 
     The spectral detection block/module  518   a  may detect and/or extract spectral (e.g., pitch, frequency, etc.) features of the ambience signal  510 . For instance, the spectral detection block/module  518   a  may determine a spectral amplitude or magnitude of the ambience signal  510 . Additionally or alternatively, the temporal detection block/module  518   b  may detect and/or extract temporal (e.g., timing, phase) features of the ambience signal  510 . For example, the temporal detection block/module  518   b  may determine when ambient noise occurs in the ambience signal  510 , how often and/or how long particular noises tend to occur, etc. 
     The second control signal  532  provided by the ambience analysis block/module  512  may provide the actual features analyzed (e.g., amplitude, spatial, spectral and/or temporal characteristics, etc.) and/or control information based on the analyzed features (e.g., triggers for amplitude or loudness ramping, etc.). The second control signal  532  may be provided to the masker  536 . 
     The one or more sound sources  528  may provide one or more sound signals  534  to the masker  536 . Examples of sound sources  528  include music or sound files (e.g., moving picture experts group (MPEG)-1 or MPEG-2 audio layer 3 (MP3) files, waveform audio file format (WAV) files, musical instrument digital interface (MIDI) files, etc.), synthesized sounds or noise and/or audio inputs or interfaces (for receiving a sound signal  534  from another device, for example), etc. For instance, one sound source  528  may be memory on the wireless communication device  502  that provides music or sound files, while another sound source  528  may be a port used to receive a sound signal  534  from another device. The one or more sound sources  528  may be optional. For example, the masker  536  may only use the voice signal  520  to generate the masking signal  542 . Additionally or alternatively, the masker  536  may use a sound signal  534  provided from one or more sound sources  528  to generate a masking signal  542 . In some configurations, the sound source  528  and/or sound signal  534  used may be selected based on an input. For example, the transmitting wireless communication device  502  may receive a user input via a user interface (not illustrated in  FIG. 5 ) that indicates a particular sound source  528  and/or sound signal  534  for use. For instance, the transmitting wireless communication device  502  may receive an input using a keyboard, mouse, touchscreen, microphone  504 , button, etc. that indicates a selected sound source  528  and/or sound signal  534 . 
     The masker  536  may be a block/module used to generate a masking signal  542 . The masking signal  542  may be output as an acoustic masking signal using one or more speakers  544  (e.g., loudspeakers) in order to obscure or mask the acoustic voice signal. The masker  536  may generate the masking signal  542  based on the first control signal  530  and the second control signal  532 . As described above, the masking signal  542  may also be based on a sound signal  534  in addition to or alternatively from the voice signal  520 . For example, the masking signal  542  may comprise music provided as a sound signal  534  from memory that has been adjusted and/or modified based on the first control signal  530  and the second control signal  532 . In another example, the masking signal  542  may comprise the voice signal  520  that has been adjusted (e.g., amplitude modulated) based on the first control signal  530  and the second control signal  532 . 
     The masker  536  may include, for example, a level control block/module  538  and/or a feature control block/module  540 . The level control block/module  538  may adjust the level (e.g., amplitude, magnitude, volume, loudness, etc.) of an input signal (e.g., voice signal  520  and/or sound signal  534 ) based on the first control signal  530  and/or the second control signal  532 . 
     For example, the level control  538  may adjust the input signal amplitude or loudness in a direct relationship with a speech envelope (or threshold triggers based on the speech envelope) provided in the first control signal  530 . For instance, if the speech envelope increases in amplitude or loudness, the level control  538  may increase (e.g., ramp up) the amplitude or loudness of the input signal. However, if the speech envelope decreases in amplitude or loudness, the level control  538  may decrease (e.g., ramp down) the amplitude or loudness of the input signal. For example, as a user speaks louder or softer, the wireless communication device  502  may respectively produce a louder or softer acoustic masking signal to effectively obscure the acoustic voice signal. This may provide an acoustic masking signal that is loud enough to obscure the acoustic voice signal without being overpowering or annoying. 
     Additionally or alternatively, the level control block/module  538  may adjust the level (e.g., amplitude, loudness, etc.) of an input signal (e.g., voice signal  520  and/or sound signal  534 ) based on the second control signal  532 . For example, the level control  538  may adjust the input signal amplitude or loudness in an inverse relationship with an ambience amplitude or loudness (or threshold triggers based on the amplitude or loudness) provided in the second control signal  532 . For instance, if the ambience signal  510  increases in amplitude or loudness, the level control  538  may decrease (e.g., ramp down) the amplitude or loudness of the input signal. However, if the ambience signal  510  decreases in amplitude or loudness, the level control  538  may increase (e.g., ramp up) the amplitude or loudness of the input signal. For example, as acoustic ambient signals (e.g., sounds or noise) become louder or softer, the wireless communication device  502  may respectively produce a softer or louder acoustic masking signal. For instance, if the ambient signals (e.g., sounds or noise) are loud enough and/or of the correct characteristics to effectively mask the acoustic voice signal, then the wireless communication device  502  may not need to produce a loud acoustic masking signal. Thus, the masker  536  may operate more efficiently, possibly saving battery power. 
     The masker  536  may additionally or alternatively include a feature control  540 . The feature control  540  may control one or more features of the input signal (e.g., voice signal  520  and/or sound signal  534 ) based on the first control signal  530  and/or the second control signal  532 . For example, the feature control  540  may adjust spectral characteristics of the input signal (e.g., voice signal  520  and/or sound signal  534 ) based on spectral characteristics of the voice signal  520  and/or the ambience signal  510 . For instance, if the second control signal  532  indicates that there is enough low-frequency noise in the acoustic ambient signals (e.g., sounds) to effectively obscure a low-frequency portion of the acoustic voice signal but not enough high-frequency noise in the acoustic ambient signals to effectively obscure a high-frequency portion, then the feature control  540  may (independently or use the level control  538  to) increase the amplitude or loudness in a high frequency portion of a sound signal  534  in order to produce an acoustic masking signal that effectively masks the high-frequency portion of the acoustic voice signal. 
     In another example, the feature control  540  may adjust the spatial characteristics (e.g., directionality) of the acoustic masking signal based on the first control signal  530  and/or second control signal  532 . For instance, the first control signal  530  may indicate the direction of the received acoustic voice signal, while the second control signal  532  may indicate one or more directions of acoustic ambient signals (e.g., sounds). The feature control  540  may use this information to adjust the directionality of the acoustic masking signal, steering it away from the user (e.g., the source of the acoustic voice signal). Additionally or alternatively, the feature control  540  may steer the acoustic masking signal away from strong ambient signals (e.g., sounds) that are sufficient to mask the acoustic voice signal and/or potentially towards quiet ambient signals and/or in directions without acoustic ambient signals. This may help to obscure the acoustic voice signal in directions where it might be more easily overheard, for example. Additionally or alternatively, the feature control  540  may steer the acoustic masking signal in the same direction as the acoustic voice signal is propagating (e.g., away from the user). 
     It should be noted that the one or more speakers  544  may be transducers (e.g., electroacoustic transducers) that convert an electrical or electronic signal (e.g., the masking signal  542 ) into an acoustic signal (e.g., the acoustic masking signal). In one configuration, the one or more speakers  544  may be omnidirectional. In other configurations, the one or more speakers  544  may be directional. For example, an array of speakers  544  may be used in some configurations to direct the acoustic masking signal in a particular direction. Additionally or alternatively, the one or more speaker  544  may be placed in different locations on the wireless communication device  502  in order to provide a directional output capability. 
     The voice signal  520  and/or the ambience signal  510  may be provided to the encoder  554 . The encoder  554  may encode the voice signal  520  to produce an encoded voice signal. In some configurations, the encoder  554  may also add error detection and/or correction coding to the encoded voice signal. The encoded voice signal may be provided to a modulator  556 . The modulator  556  modulates the encoded voice signal into a particular constellation based on the type of modulation used. Some examples of modulation include quadrature amplitude modulation (QAM), phase shift keying (PSK) modulation, etc. The encoded and modulated voice signal may be provided to a transmitter  558 . The transmitter  558  may perform further operations on the encoded and modulated voice signal, such as providing amplification in preparation for transmission. The transmitter  558  may transmit the encoded and modulated voice signal as one or more electromagnetic signals using one or more antennas  560   a - n . Similar operations may be performed on the ambience signal  510  by the encoder, modulator  556 , transmitter  558  and/or antenna(s)  560   a - n  in order to transmit the ambience signal  510  as a noise reference signal. For example, a receiving wireless communication device may use the noise reference signal to suppress noise in a received voice signal. 
     It should be noted that the wireless communication device  502  may perform additional or alternative operations on the voice signal  520 . For example, the wireless communication device  502  may map voice signal  520  and/or ambience signal  510  data to one or more frequencies (e.g., orthogonal frequency division multiplexing (OFDM) subcarriers), time slots, spatial channels, etc. 
     The wireless communication device  502  may receive one or more electromagnetic signals transmitted from another device (e.g., another wireless communication device) using the one or more antennas  560   a - n . The receiver  584  may receive the one or more transmitted electromagnetic signals using the one or more antennas  560   a - n . The received signal may be provided to the demodulator  582 . The demodulator  582  demodulates the received signal to produce an encoded signal, which is provided to the decoder  580 . The decoder  580  decodes the encoded signal to produce a decoded voice signal, which may be provided to an RVE block/module  578 . The RVE block/module  578  may boost different frequency regions of voice to maintain it above a certain noise floor, for example. The output of the RVE block/module  578  (a received voice signal) may be provided to one or more earpiece speakers  576 , which may output the received voice signal as an acoustic signal. 
     In some configurations, the electromagnetic signals received by the wireless communication device  502  may have been relayed by one or more devices. For example, the wireless communication device  502  may receive electromagnetic signals from a base station, which may have received the signals from one or more network devices. These signals may have been received by another base station, from another wireless communication device. 
       FIG. 6  is a block diagram illustrating one example of generating a masking signal  642  on an electronic device  602 . The speech feature extraction block/module  622  may be used to extract an amplitude or loudness envelope  601  from a voice signal  620 . The speech feature extraction block/module  622  may produce a first control signal  630  based on an envelope signal  601 . For example, the speech feature extraction block/module  622  includes an envelope detection block/module  624 . The envelope detection block/module  624  determines an envelope signal (e.g., amplitude or loudness envelope)  601  based on the voice signal  620 . For example, the voice signal  620  may be characterized as an undulating waveform. The envelope signal  601  may approximately track the positive peaks of the voice signal  620 . In other words, the envelope signal  601  may approximately connect the periodic maximum values (e.g., peaks) of the voice signal  620 . Thus, the envelope signal  601  may provide an approximation of the amplitude or loudness of the voice signal  620 . This amplitude or loudness may be measured or characterized as sound pressure, sound pressure level (e.g., decibels), sound intensity, sound power, sones, phons, volts and/or amperes, etc. 
     The envelope signal  601  may be provided to a threshold detection block/module  626  included in the speech feature extraction block/module  622 . The threshold detection block/module  626  may detect when the envelope signal meets or crosses one or more thresholds. For example, the threshold detection block/module  626  may detect when the envelope signal  601  increases a given amount or decreases a given amount. In one example, several thresholds may be established in a range of amplitudes. In another example, one threshold may be established that is a certain amount or percentage higher than a reference sample or average of the envelope signal  601 , while another threshold may be established that is a certain amount or percentage below the reference sample or average. The threshold detection block/module  626  may indicate when a threshold is met or crossed and/or which threshold is met or crossed by the envelope signal  601  as part of the first control signal  630 . The first control signal  630  may be provided to the masker  636 . 
     The ambience analysis block/module  612  may analyze the ambience signal  610  to produce a second control signal  632  that is provided to the masker  636 . The ambience analysis block/module  612  may include an amplitude (e.g., loudness) detection block/module  614 . The amplitude detection block/module  614  may detect or extract an amplitude or loudness of the ambience signal  610 . For example, the amplitude or loudness may be measured by detecting an envelope of the ambience signal  610 . The amplitude of the ambience signal  610  may be determined similarly to or differently from the envelope  601  of the voice signal  620 . For example, the amplitude may be determined as an average of peak values of the ambience signal  610 , root mean square (RMS) of the ambience signal  610 , etc. This amplitude or loudness may be measured or characterized as sound pressure, sound pressure level (e.g., decibels), sound intensity, sound power, sones, phons, volts and/or amperes, etc. The ambience analysis block/module  612  may determine the second control signal  632  based on the amplitude detected by the amplitude detection block/module  614 . For example, the second control signal  632  may indicate particular thresholds that have been met or crossed by the amplitude of the ambience signal  610 . In another example, the second control signal  632  may be the amplitude of the ambience signal  610  as determined by the ambience analysis block/module  612 . The second control signal  632  may be provided to the masker  636 . 
     The sound source  628  may provide one or more sound signals  634  to the masker  636 . Examples of sound sources  628  include music or sound files, synthesized sounds or noise and/or audio inputs or interfaces (for receiving a sound signal  634  from another device, for example), etc. For instance, one sound source  628  may be memory on the electronic device  602  that provides music or sound files, while another sound source  628  may be a port used to receive a sound signal  634  from another device. In the example illustrated in  FIG. 6 , the sound source  628  may provide a sound signal  634  (e.g., input signal) to the masker  636 . In some configurations, the sound signal  634  provided to the masker may be selected based on a selection input  603 . For example, a user may select a music file containing a song by his favorite band. The corresponding sound signal  634  may then be provided to the masker  636 . 
     The masker  636  may be a block/module used to generate a masking signal  642 . The masking signal  642  may be output as an acoustic masking signal using one or more speakers  644  (e.g., loudspeakers) in order to obscure or mask an acoustic voice signal. The masker  636  may generate the masking signal  642  based on the sound signal  634 , the first control signal  630  and the second control signal  632 . For example, the masking signal  642  may comprise music provided as a sound signal  634  from memory that has been adjusted and/or modified based on the first control signal  630  and the second control signal  632 . 
     In this example, the masker  636  includes a level control block/module  638 . The level control block/module  638  may adjust the level (e.g., amplitude, magnitude, volume, loudness, etc.) of the sound signal  634  based on the first control signal  630  and the second control signal  632 . For example, the level control  638  may adjust the sound signal  634  amplitude or loudness in a direct relationship with a speech envelope using threshold triggers provided in the first control signal  630 . For instance, if the speech envelope  601  increases in amplitude or loudness, the level control  638  may increase (e.g., ramp up) the amplitude or loudness of the input signal. However, if the speech envelope decreases in amplitude or loudness, the level control  638  may decrease (e.g., ramp down) the amplitude or loudness of the input signal. For example, as a user speaks louder or softer, the electronic device  602  may respectively produce a louder or softer acoustic masking signal to effectively obscure an acoustic voice signal. This may provide an acoustic masking signal that is loud enough to obscure the acoustic voice signal without being overpowering or annoying. 
     In some configurations, the level control  638  may (initially) ramp the sound signal  634  to a certain level in relation to the voice signal  620 . For example, the level control  638  may initially (before other adjustments are made) ramp the sound signal  634  such that it is a number of decibels louder than the voice signal  620 . 
     Additionally or alternatively, the level control block/module  638  may adjust the level (e.g., amplitude, loudness, etc.) of the sound signal  634  based on the second control signal  632 . For example, the level control  638  may adjust the sound signal  634  amplitude or loudness in an inverse relationship with an ambience amplitude or loudness (using threshold triggers based on the amplitude or loudness, for example) provided in the second control signal  632 . For instance, if the ambience signal  610  increases in amplitude or loudness, the level control  638  may decrease (e.g., ramp down) the amplitude or loudness of the sound signal  634 . However, if the ambience signal  610  decreases in amplitude or loudness, the level control  638  may increase (e.g., ramp up) the amplitude or loudness of the sound signal  634 . For example, as acoustic ambient signals (e.g., sounds or noise) become louder or softer, the wireless communication device  602  may respectively produce a softer or louder acoustic masking signal. For instance, if the ambient signals (e.g., sounds or noise) are loud enough and/or of the correct characteristics to effectively mask the acoustic voice signal, then the wireless communication device  602  may not need to produce a loud acoustic masking signal. Thus, the masker  636  may operate more efficiently, possibly saving battery power. 
     In some configurations, the level control  638  may ramp the sound signal  634  such that the sound signal  634  in combination with the ambience signal  610  is at a certain level in relation to the ambience signal  610 . For example, if the ambience signal  610  in combination with the sound signal  634  (after adjusting the sound signal  634  based on a speech feature, for example) is not a certain number of decibels louder than the voice signal  620  (at least), the level control  638  may increase (e.g., ramp up) the sound signal  634  amplitude such that the combination of the ambience signal  610  and the sound signal  634  is a number of decibels louder than the voice signal  620 . However, if the sound signal  634  in combination with the ambience signal  610  is greater than a number of decibels louder than the voice signal  620 , the level control  638  may decrease (e.g., ramp down) the sound signal  634  until the sound signal  634  in combination with the ambience signal  610  is a number of decibels louder than the voice signal  620  and/or until the sound signal  634  is decreased to a certain level (e.g., no amplitude and/or a set level). 
     The sound signal  634  that has been modified and/or adjusted based on the speech feature (e.g., the first control signal  630 ) and the ambience feature (e.g., the second control signal  632 ) may be the masking signal  642  provided to the speaker  644 . The speaker  644  may convert the masking signal  642  from an electrical or electronic signal into an acoustic masking signal. It should be noted that in the example described in  FIG. 6 , only amplitude (e.g., loudness, volume) characteristics of the sound signal  634  may be adjusted. In other examples and/or configurations, however, additional or alternative characteristics (e.g., spatial, spectral and/or temporal characteristics, etc.) may be used to adjust and/or modify the sound signal  634  (and/or a voice signal  620 ). 
       FIG. 7  is a flow diagram illustrating a configuration of a method  700  for generating a masking signal  542  on a wireless communication device  502 . The wireless communication device  502  may obtain  702  a plurality of audio signals from a plurality of microphones  504   a - n . For example, the plurality of microphones  504   a - n  may convert an acoustic voice signal and/or one or more acoustic ambient signals into electrical or electronic audio signals. 
     The wireless communication device  502  may obtain  704  an ambience signal  510  from the plurality of audio signals. For example, the wireless communication device  502  may estimate ambient sounds and/or noise in the audio signals. In one configuration, the wireless communication device  502  may use a voice activity detector  594  to estimate the ambient sounds and/or noise in the audio signals. 
     The wireless communication device  502  may determine  706  an ambience amplitude (e.g., ambience signal  510  amplitude) based on the ambience signal  510 . For instance, the wireless communication device  502  may determine  706  an amplitude (e.g., loudness) envelope of the ambience signal  510 . This may be done, for example, by using a low-pass filter, calculating an RMS value of the ambience signal  510  and/or calculating an average maximum peak value, interpolating maximum peak values, etc. In some configurations, the wireless communication device  502  may generate a second control signal  532  based on the ambience amplitude. 
     The wireless communication device  502  may obtain  708  a voice signal  520  from the plurality of audio signals. For example, the wireless communication device  502  may separate the voice signal  520  from the audio signals. In one configuration, the wireless communication device  502  may subtract or remove a noise estimate (e.g., the ambience signal  510 ) from the audio signals in order to estimate the voice signal  520 . 
     The wireless communication device  502  may determine  710  an envelope signal based on the voice signal  520 . This may be done, for example, by using a low-pass filter, calculating an RMS value of the voice signal  520  and/or calculating an average maximum peak value, interpolating maximum peak values, etc. The envelope signal may represent an amplitude, magnitude, loudness, etc. of the voice signal  520 , for instance. In some configurations, the wireless communication device  502  may generate a first control signal  530  based on the envelope signal. 
     The wireless communication device  502  may obtain  712  a sound signal  534 . For example, the wireless communication device  502  may obtain  712  music or sound files (e.g., MP3 files, WAV files, MIDI files, etc.), synthesized sounds or noise and/or an audio input (from another device, for example), etc. In one configuration, the wireless communication device  502  retrieves a sound signal  534  from memory. Additionally or alternatively, the wireless communication device  502  may synthesize sounds or noise using an algorithm and/or stored data. Additionally or alternatively, the wireless communication device  502  retrieves a sound signal  534  from a removable memory device, such as a secure digital (SD) card, universal serial bus (USB) thumb drive, etc. In one configuration, the wireless communication device  502  may obtain  712  a sound signal  534  based on a selection input. For example, a user may designate a particular sound source  528  or sound signal  534  to use as a masking signal  542  (with modification and/or adjustments in accordance with the systems and methods herein). For instance, a user may want to use a particular source, song and/or sound for the masking signal  542 , which may be indicated by the selection input. 
     The wireless communication device  502  may adjust  714  a sound signal  534  amplitude based on the envelope signal (e.g., the first control signal  530 ) and the ambience amplitude (e.g., the second control signal  532 ) to generate a masking signal  542 . For example, the wireless communication device  502  may adjust  714  the sound signal  534  amplitude, magnitude, loudness or volume based on the envelope signal and the ambience amplitude to generate the masking signal  542 . In one configuration, the wireless communication device  502  adjusts the sound signal  534  amplitude or loudness in a direct relationship with a voice envelope (e.g., amplitude or loudness envelope) and adjusts the signal amplitude or loudness in an inverse relationship with an ambience amplitude or loudness (e.g., amplitude or loudness envelope). This may be done as described in connection with  FIG. 6  above. 
     The wireless communication device  502  may output  716  the masking signal  542 . For example, the wireless communication device  502  may provide the masking signal  542  to one or more speakers  544 , which may convert the masking signal  542  into an acoustic masking signal. 
     The wireless communication device  502  may transmit  718  the voice signal  520 . For example, the wireless communication device  502  may encode, modulate, amplify and/or transmit  718  the voice signal  520 . The voice signal  520  may be transmitted as one or more electromagnetic signals using one or more antennas  560   a - n . Before transmission, the wireless communication device  502  may additionally or alternatively map the voice signal  520  data to one or more spatial streams, antennas, frequencies (e.g., subcarriers), time slots, etc. 
       FIG. 8  is a block diagram illustrating one configuration of several components in a wireless communication device  802  in which systems and methods for generating a masking signal may be implemented. The wireless communication device  802  may include an application processor  809 . The application processor  809  generally processes instructions (e.g., runs programs) to perform functions on the wireless communication device  802 . The application processor  809  may be coupled to an audio coder/decoder (codec)  807 . 
     The audio codec  807  may be an electronic device (e.g., integrated circuit) used for coding and/or decoding audio signals. The audio codec  807  may be coupled to one or more speakers  844 , one or more earpiece speakers  876 , an output jack  805  and/or one or more microphones  804 . The speakers  844  may include one or more electro-acoustic transducers that convert electrical or electronic signals into acoustic signals. For example, the speakers  844  may be used to play music or output a speakerphone conversation, etc. The one or more earpiece speakers  876  may include one or more speakers or electro-acoustic transducers that can be used to output acoustic signals (e.g., speech signals) to a user. For example, one or more earpiece speakers  876  may be used such that only a user may reliably hear the acoustic signal. The output jack  805  may be used for coupling other devices to the wireless communication device  802  for outputting audio, such as headphones. The speakers  844 , one or more earpiece speakers  876  and/or output jack  805  may generally be used for outputting an audio signal from the audio codec  807 . The one or more microphones  804  may be acousto-electric transducers that convert an acoustic signal (such as a user&#39;s voice) into electrical or electronic signals that are provided to the audio codec  807 . 
     The application processor  809  may include a masker block/module  836 . The masker block/module  836  may be used to generate a masking signal in accordance with the systems and methods disclosed herein. It should be noted that the wireless communication device  802  may be configured similarly to and/or may be an example of the electronic devices  102 ,  602 , transmitting wireless communication device  302  and/or wireless communication device  502  described above. For example, the wireless communication device  802  may perform one or more of the methods  200 ,  400 ,  700  described above. More specifically, the masker  836  may be configured similarly to the maskers  136 ,  336 ,  536 ,  636  described above. Although the masker block/module  836  is illustrated as being implemented in the application processor  809 , the masker block/module  836  may additionally or alternatively be implemented in a digital signal processor (DSP) or in other similar blocks/modules. 
     The application processor  809  may be coupled to a power management circuit  817 . One example of a power management circuit  817  is a power management integrated circuit (PMIC), which may be used to manage the electrical power consumption of the wireless communication device  802 . The power management circuit  817  may be coupled to a battery  819 . The battery  819  may generally provide electrical power to the wireless communication device  802 . 
     The application processor  809  may be coupled to one or more input devices  821  for receiving input. Examples of input devices  821  include infrared sensors, image sensors, accelerometers, touch sensors, keypads, etc. The input devices  821  may allow user interaction with the wireless communication device  802 . The application processor  809  may also be coupled to one or more output devices  823 . Examples of output devices  823  include printers, projectors, screens, haptic devices, etc. The output devices  823  may allow the wireless communication device  802  to produce output that may be experienced by a user. 
     The application processor  809  may be coupled to application memory  825 . The application memory  825  may be any electronic device that is capable of storing electronic information. Examples of application memory  825  include double data rate synchronous dynamic random access memory (DDRAM), synchronous dynamic random access memory (SDRAM), flash memory, etc. The application memory  825  may provide storage for the application processor  809 . For instance, the application memory  825  may store data and/or instructions for the functioning of programs that are run on the application processor  809 . In one configuration, the application memory  825  may store and/or provide data and/or instructions for performing one or more of the methods  200 ,  400 ,  700  described above. 
     The application processor  809  may be coupled to a display controller  827 , which in turn may be coupled to a display  829 . The display controller  827  may be a hardware block that is used to generate images on the display  829 . For example, the display controller  827  may translate instructions and/or data from the application processor  809  into images that can be presented on the display  829 . Examples of the display  829  include liquid crystal display (LCD) panels, light emitting diode (LED) panels, cathode ray tube (CRT) displays, plasma displays, etc. 
     The application processor  809  may be coupled to a baseband processor  811 . The baseband processor  811  generally processes communication signals. For example, the baseband processor  811  may demodulate and/or decode received signals. Additionally or alternatively, the baseband processor  811  may encode and/or modulate signals in preparation for transmission. 
     The baseband processor  811  may be coupled to baseband memory  831 . The baseband memory  831  may be any electronic device capable of storing electronic information, such as SDRAM, DDRAM, flash memory, etc. The baseband processor  811  may read information (e.g., instructions and/or data) from and/or write information to the baseband memory  831 . Additionally or alternatively, the baseband processor  811  may use instructions and/or data stored in the baseband memory  831  to perform communication operations. 
     The baseband processor  811  may be coupled to a radio frequency (RF) transceiver  813 . The RF transceiver  813  may be coupled to a power amplifier  815  and one or more antennas  860 . The RF transceiver  813  may transmit and/or receive radio frequency signals. For example, the RF transceiver  813  may transmit an RF signal using a power amplifier  815  and one or more antennas  860 . The RF transceiver  813  may also receive RF signals using the one or more antennas  860 . 
       FIG. 9  illustrates various components that may be utilized in an electronic device  902 . The illustrated components may be located within the same physical structure or in separate housings or structures. One or more of the electronic devices  102 ,  602  and/or wireless communication devices  302 ,  502 ,  802  described previously may be configured similarly to the electronic device  902 . The electronic device  902  includes a processor  939 . The processor  939  may be a general purpose single- or multi-chip microprocessor (e.g., an ARM), a special purpose microprocessor (e.g., a digital signal processor (DSP)), a microcontroller, a programmable gate array, etc. The processor  939  may be referred to as a central processing unit (CPU). Although just a single processor  939  is shown in the electronic device  902  of  FIG. 9 , in an alternative configuration, a combination of processors  939  (e.g., an ARM and DSP) could be used. 
     The electronic device  902  also includes memory  933  in electronic communication with the processor  939 . That is, the processor  939  can read information from and/or write information to the memory  933 . The memory  933  may be any electronic component capable of storing electronic information. The memory  933  may be random access memory (RAM), read-only memory (ROM), magnetic disk storage media, optical storage media, flash memory devices in RAM, on-board memory included with the processor  939 , programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable PROM (EEPROM), registers, and so forth, including combinations thereof. 
     Data  937   a  and instructions  935   a  may be stored in the memory  933 . The instructions  935   a  may include one or more programs, routines, sub-routines, functions, procedures, etc. The instructions  935   a  may include a single computer-readable statement or many computer-readable statements. The instructions  935   a  may be executable by the processor  939  to implement one or more of the methods  200 ,  400 ,  700  described above. Executing the instructions  935   a  may involve the use of the data  937   a  that is stored in the memory  933 .  FIG. 9  shows some instructions  935   b  and data  937   b  being loaded into the processor  939  (which may come from instructions  935   a  and data  937   a ). 
     The electronic device  902  may also include one or more communication interfaces  943  for communicating with other electronic devices  902 . The communication interface  943  may be based on wired communication technology, wireless communication technology, or both. Examples of different types of communication interfaces  943  include a serial port, a parallel port, a Universal Serial Bus (USB), an Ethernet adapter, an IEEE 1394 bus interface, a small computer system interface (SCSI) bus interface, an infrared (IR) communication port, a Bluetooth wireless communication adapter, and so forth. 
     The electronic device  902  may also include one or more input devices  945  and one or more output device  949 . Examples of different kinds of input devices  945  include a keyboard, mouse, microphone, remote control device, button, joystick, trackball, touchpad, lightpen, etc. For instance, the electronic device  902  may include one or more microphones  947  for capturing acoustic signals. In one configuration, a microphone  947  may be a transducer that converts acoustic signals (e.g., voice, speech) into electrical or electronic signals. Examples of different kinds of output devices  949  include a speaker, printer, etc. For instance, the electronic device  902  may include one or more speakers  951 . In one configuration, a speaker  951  may be a transducer that converts electrical or electronic signals into acoustic signals. One specific type of output device  949  which may be typically included in an electronic device  902  is a display device  953 . Display devices  953  used with configurations disclosed herein may utilize any suitable image projection technology, such as a cathode ray tube (CRT), liquid crystal display (LCD), light-emitting diode (LED), gas plasma, electroluminescence, or the like. A display controller  955  may also be provided, for converting data  937   a  stored in the memory  933  into text, graphics, and/or moving images (as appropriate) shown on the display device  953 . 
     The various components of the electronic device  902  may be coupled together by one or more buses, which may include a power bus, a control signal bus, a status signal bus, a data bus, etc. For simplicity, the various buses are illustrated in  FIG. 9  as a bus system  941 . It should be noted that  FIG. 9  illustrates only one possible configuration of an electronic device  902 . Various other architectures and components may be utilized. 
       FIG. 10  illustrates certain components that may be included within a wireless communication device  1002 . One or more of the electronic devices  102 ,  602  and/or the wireless communication devices  302 ,  502 ,  802  described above may be configured similarly to the wireless communication device  1002  that is shown in  FIG. 10 . 
     The wireless communication device  1002  includes a processor  1075 . The processor  1075  may be a general purpose single- or multi-chip microprocessor (e.g., an ARM), a special purpose microprocessor (e.g., a digital signal processor (DSP)), a microcontroller, a programmable gate array, etc. The processor  1075  may be referred to as a central processing unit (CPU). Although just a single processor  1075  is shown in the wireless communication device  1002  of  FIG. 10 , in an alternative configuration, a combination of processors  1075  (e.g., an ARM and DSP) could be used. 
     The wireless communication device  1002  also includes memory  1057  in electronic communication with the processor  1075  (i.e., the processor  1075  can read information from and/or write information to the memory  1057 ). The memory  1057  may be any electronic component capable of storing electronic information. The memory  1057  may be random access memory (RAM), read-only memory (ROM), magnetic disk storage media, optical storage media, flash memory devices in RAM, on-board memory included with the processor  1075 , programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable PROM (EEPROM), registers, and so forth, including combinations thereof. 
     Data  1059   a  and instructions  1061   a  may be stored in the memory  1057 . The instructions  1061   a  may include one or more programs, routines, sub-routines, functions, procedures, code, etc. The instructions  1061   a  may include a single computer-readable statement or many computer-readable statements. The instructions  1061   a  may be executable by the processor  1075  to implement one or more of the methods  200 ,  400 ,  700  described above. Executing the instructions  1061   a  may involve the use of the data  1059   a  that is stored in the memory  1057 .  FIG. 10  shows some instructions  1061   b  and data  1059   b  being loaded into the processor  1075  (which may come from instructions  1061   a  and data  1059   a  in memory  1057 ). 
     The wireless communication device  1002  may also include a transmitter  1071  and a receiver  1073  to allow transmission and reception of signals between the wireless communication device  1002  and a remote location (e.g., another electronic device, wireless communication device, etc.). The transmitter  1071  and receiver  1073  may be collectively referred to as a transceiver  1069 . An antenna  1077  may be electrically coupled to the transceiver  1069 . The wireless communication device  1002  may also include (not shown) multiple transmitters  1071 , multiple receivers  1073 , multiple transceivers  1069  and/or multiple antenna  1077 . 
     In some configurations, the wireless communication device  1002  may include one or more microphones  1063  for capturing acoustic signals. In one configuration, a microphone  1063  may be a transducer that converts acoustic signals (e.g., voice, speech) into electrical or electronic signals. Additionally or alternatively, the wireless communication device  1002  may include one or more speakers  1065 . In one configuration, a speaker  1065  may be a transducer that converts electrical or electronic signals into acoustic signals. 
     The various components of the wireless communication device  1002  may be coupled together by one or more buses, which may include a power bus, a control signal bus, a status signal bus, a data bus, etc. For simplicity, the various buses are illustrated in  FIG. 10  as a bus system  1067 . 
     The term “determining” encompasses a wide variety of actions and, therefore, “determining” can include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” can include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” can include resolving, selecting, choosing, establishing and the like. 
     The phrase “based on” does not mean “based only on,” unless expressly specified otherwise. In other words, the phrase “based on” describes both “based only on” and “based at least on.” 
     The functions described herein may be stored as one or more instructions on a processor-readable or computer-readable medium. The term “computer-readable medium” refers to any available medium that can be accessed by a computer or processor. By way of example, and not limitation, such a medium may comprise RAM, ROM, EEPROM, flash memory, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer or processor. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray® disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. It should be noted that a computer-readable medium may be tangible and non-transitory. The term “computer-program product” refers to a computing device or processor in combination with code or instructions (e.g., a “program”) that may be executed, processed or computed by the computing device or processor. As used herein, the term “code” may refer to software, instructions, code or data that is/are executable by a computing device or processor. 
     Software or instructions may also be transmitted over a transmission medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of transmission medium. 
     The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is required for proper operation of the method that is being described, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims. 
     It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the systems, methods, and apparatus described herein without departing from the scope of the claims.