Abstract:
Commands for modifying audio playback, such as to mute and unmute or pause and play audio, may be input to a mobile device by a user through interacting with the speaker in the device. The user input may be facilitated by monitoring a characteristic of the speaker and identifying signatures in the changing characteristics of the speaker that correspond with predetermined user activities. For example, a resonance frequency of the speaker may be monitored for a change resulting from a user placing a hand to cover the speaker output. When the resonance frequency change is detected, the audio playback may be muted. The speaker may continue to be monitored for a change indicating removal of the user&#39;s hand, and then audio playback may be unmuted.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    The instant disclosure relates to electronic devices. More specifically, portions of this disclosure relate to receiving user input through a speaker of the electronic device. 
       BACKGROUND 
       [0002]    Mobile devices provide interactive experiences for users by receiving user input commands and responding to those commands. Receiving user input on a mobile device can be challenging, as the small size of the mobile device can restrict options for interacting with the user. A user&#39;s approval, and subsequent purchase decisions, rests largely on whether their interaction with the mobile device is pleasant, intuitive, and simple. Conventionally on a mobile device nearly all interaction with a user occurs through a touch screen display integrated with the mobile device. Although touch screens may be useful for presenting complex information and a large number of options in a programmable manner, the information display and user interface may be difficult to navigate to get to a particular command. For example, to mute audio during a call or music playback, a user often needs to remove the mobile device from his pocket, power on the display, enter a password to operate the device, swipe down from the top of the screen to access a settings display, and then tap a mute button. Such an operation is needlessly complex. Some solutions to this problem may include building dedicated hardware buttons into the mobile device, such as a mute switch. However, mobile devices are continuing to shrink in dimensions, including thickness, and physical switches can be difficult to fit into a small mobile device, integrate with a casing to provide water resistance for the device, and/or achieve desired aesthetics of the device. 
         [0003]    Shortcomings mentioned here are only representative and are included simply to highlight that a need exists for improved electrical components, particularly for receiving user input in consumer-level devices, such as mobile phones. Embodiments described herein address certain shortcomings but not necessarily each and every one described here or known in the art. 
       SUMMARY 
       [0004]    Some components of a mobile device may be used as alternative means for providing user input to the mobile device and/or control operation of the mobile device. Any component in the mobile device that has a feedback signal for monitoring the component or conditions around the component may be used in this manner. In one embodiment, a transducer, such as a speaker, of a mobile device may provide feedback signals to a logic device, such as a processor, that can be used to detect user input. For example, a speaker monitoring circuit may provide voltage and/or current signals to the processor for monitoring the conditions of the speaker. A user may provide input by performing an action that deliberately alters the monitored characteristic of the speaker. A speaker&#39;s impedance and/or resonance frequency may be modified by placing an object in the radiation field of the speaker. In one embodiment, a speaker&#39;s resonance frequency may be modified by covering the housing of the speaker. The changes in the speaker characteristic may be determined by monitoring voltage and/or current signals from the speaker. When the characteristic of the speaker changes exhibits a change known to correlate with particular user behavior, the device may determine the user has input a command to the device. Some commands that may be issued to the mobile device through the speaker may include play, pause, fast forward, rewind, mute, unmute, or increase or decrease a volume of the audio. 
         [0005]    After a first user input is provided to the device through the speaker, a second user input may be provided through the speaker. The device may wait for another change of a characteristic of the speaker or a return to a prior status of the previously-monitored characteristic. The second user input may be, for example, a follow-up action that reverses the first user input, such as a mute command followed by an unmute command. The second user input may be based on the same monitoring as monitoring for the first user input, or the second user input may be detected by monitoring for different conditions than those that indicate the first user input. In one embodiment, the processor may detect a first user input of covering of the speaker and respond by muting the speaker, then the processor may wait to detect taps on the speaker and respond by unmuting the speaker. In some embodiments, both the first user input and the second user input may modify the same characteristic of the speaker, but in other embodiments different characteristics may be modified. For example, the covering of the speaker as part of the first user input may modify the resonance frequency of the speaker, whereas the tapping of the speaker as part of the second user input may modify the voltage and/or current at the speaker. 
         [0006]    According to one embodiment, a method may include detecting a user input through a transducer (such as a partial or complete coverage of a transducer) while the transducer is outputting audio by monitoring a characteristic (such as a voltage, current, or resonance frequency) of the transducer, and then performing a first action that modifies the audio being output through the transducer based, at least in part, on detecting the user input received through the transducer. The action performed may include an action that modifies the audio such as by muting the audio, pausing playback, fast forwarding, rewinding, and/or changing a volume of the audio. In certain embodiments, the method may include detecting coverage by monitoring at least one of a voltage across the transducer and a current through the transducer, monitoring the resonance frequency of the transducer for an increase in resonance frequency by at least a threshold amount, and/or monitoring the resonance frequency of the transducer for an increase in resonance frequency to above 1 kilohertz. In some embodiments, any of these methods or variations thereof may be performed by an apparatus having a controller coupled to a transducer and configured with hard-wired circuitry, firmware, and/or software to perform the steps of the method. 
         [0007]    In some embodiments, the method may also include detecting a command and performing a second action. For example, the method may include detecting a second user input through the transducer to perform a second action after performing the first action, and then performing a second action that modifies the audio being output through the transducer based, at least in part, on detecting the second user input. The detection of the second user input may include monitoring a voltage and/or a current through the transducer, detecting a double-tap on the transducer, outputting inaudible signals through the transducer after performing the first action, and/or detecting an uncovering of the transducer. The apparatus having a controller described above may also be configured to perform any of these additional functions. 
         [0008]    According to another embodiment, an apparatus may include a transducer; at least one analog-to-digital converter (ADC) coupled to the transducer; and a processor coupled to the transducer and coupled to the at least one analog-to-digital converter (ADC). The processor may be configured, such as through firmware or software code, to perform certain steps in interacting with a user and controlling the transducer or other aspects of a device containing the processor, such controlling audio software on a mobile device. In some embodiments, the processor may be configured to perform steps including receiving data regarding the transducer from the at least one analog-to-digital converter (ADC); detecting user input (such as a partial or complete coverage) of a transducer of a device while the transducer is outputting audio by calculating a characteristic (such as voltage, current, impedance, or resonance frequency) of the transducer based, at least in part, on the received data from the at least one analog-to-digital converter (ADC); and performing a first action that modifies the audio being output through the transducer based, at least in part, on detecting the user input received through the transducer. The apparatus may also include an amplifier coupled to the processor and to the transducer, in which the amplifier may be controlled by the processor to mute and unmute audio output or perform other actions that modify the audio output to the transducer. The apparatus may also include a switch coupled to the processor and to the transducer, in which the switch may be toggled to mute and unmute audio output or perform other actions that modify the audio output to the transducer. 
         [0009]    In some embodiments, the processor may be further configured to detect another command and perform a second action. For example, the processor may be configured to perform steps including receiving second data regarding the transducer from the at least one analog-to-digital converter (ADC); detecting a second user input through the transducer to perform a second action based, at least in part, on the second data after the step of performing the action that modifies the audio; and/or performing the second action that modifies the audio being output through the transducer based, at least in part, on detecting the second user input. The user indication may include a double-tap on the transducer or in the vicinity of the transducer that can be detected by identifying a particular signature in the second data received from the at least one ADC, such as spikes in a voltage and/or current signal from the transducer. The second user input may alternatively or additionally include uncovering the transducer. To aid in detecting the uncovering, the processor may be configured to output inaudible signals through the transducer after performing the first action that modifies the audio. The inaudible signals may be used by the processor to monitor current and/or voltage at the transducer and identify changes of the impedance of the transducer that indicate an uncovering of the transducer. 
         [0010]    The foregoing has outlined rather broadly certain features and technical advantages of embodiments of the present invention in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter that form the subject of the claims of the invention. It should be appreciated by those having ordinary skill in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same or similar purposes. It should also be realized by those having ordinary skill in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. Additional features will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended to limit the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    For a more complete understanding of the disclosed system and methods, reference is now made to the following descriptions taken in conjunction with the accompanying drawings. 
           [0012]      FIG. 1  is a flow chart illustrating an example method for interacting with a user by detecting user input through a transducer and performing an appropriate action according to one embodiment of the disclosure. 
           [0013]      FIG. 2  is a block diagram illustrating an example apparatus for interacting with a user by detecting user input through a transducer and performing an appropriate action according to one embodiment of the disclosure. 
           [0014]      FIG. 3  is a block diagram illustrating an example apparatus using a processor that is configured to detect user input through a transducer and perform an appropriate action according to one embodiment of the disclosure. 
           [0015]      FIG. 4A  is an illustration showing a user covering a transducer of a mobile phone to mute the sound according to one embodiment of the disclosure. 
           [0016]      FIG. 4B  is a graph illustrating an example resonance frequency for an uncovered transducer according to one embodiment of the disclosure. 
           [0017]      FIG. 4C  is a graph illustrating an example resonance frequency for a covered transducer according to one embodiment of the disclosure. 
           [0018]      FIG. 5  is an illustration showing a user uncovering a transducer of a mobile phone to unmute the sound according to one embodiment of the disclosure. 
           [0019]      FIG. 6A  is an illustration showing a user tapping the transducer of the mobile phone to unmute the sound according to one embodiment. 
           [0020]      FIG. 6B  is a graph illustrating example voltage and current signals for a transducer being tapped on by a user according to one embodiment of the disclosure. 
           [0021]      FIG. 7  is a flow chart illustrating an example method of performing actions to modify audio output to a transducer by detecting covering and uncovering of the transducer according to one embodiment of the disclosure. 
           [0022]      FIG. 8  is a flow chart illustrating an example method of detecting user input through a transducer by monitoring voltage and/or current levels at the transducer according to one embodiment of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    The transducer may be used as an input device for receiving user input and performing actions on a device that includes or is coupled to the transducer. The user input may be received by monitoring for changes in a characteristic of the transducer, such as voltage, current, impedance, or resonance frequency, and correlating the changes in the characteristic with a particular user activity intended to provide input to the device.  FIG. 1  is a flow chart illustrating an example method for interacting with a user by detecting user input through a transducer and performing an appropriate action according to one embodiment of the disclosure. A method  100  may begin at block  102  with detecting a change in characteristics of a transducer corresponding to a command from a user to perform an action, such as to modify playback of audio, including music, sounds, or voices, through the transducer. In some embodiments, the change in characteristic may be detected through a monitoring circuit coupled to the transducer and configured to monitor the transducer, such as by monitoring a voltage across the transducer and/or a current through the transducer as audio is played through the transducer. Then, at block  104 , in response to the detected change in characteristics of the transducer, an action may be performed, such as to modify the audio being output through the transducer. 
         [0024]    One hardware configuration for a device that monitors the transducer is shown in  FIG. 2 .  FIG. 2  is a block diagram illustrating an example apparatus for interacting with a user by detecting user input through a transducer and performing an appropriate action according to one embodiment of the disclosure. A controller  200  may perform audio processing for reproducing sounds at a transducer  220 . For example, the controller  200  may receive audio signals in analog or digital format at audio input node  202 . The controller may include an audio processing module  212  for processing the received audio signals to generate an output signal, at audio output node  204 , to drive transducer  220 . The processing module  212  may perform processing including converting from digital to analog and/or amplifying signals to drive transducer  220  at a desired volume. The controller  200  may be integrated with a mobile device, such as a mobile phone, tablet, entertainment device, wireless headphones, and/or a wireless speaker. The controller  200  may alternatively be integrated as part of a processor or other integrated circuit in an electronic device. 
         [0025]    The controller  200  may receive and process feedback from the transducer  220  for determining when user input is received through the transducer  220 . For example, the controller  200  may include a feedback processing module  214  that processes input received at a first feedback input node  206  and a second feedback input node  208 . In some embodiments, the feedback from the transducer  220  at input nodes  206  and  208  may be received as a signal proportional to a voltage across the transducer  220  and a signal proportional to a current through the transducer  220 . The voltage and/or current signals may be used by feedback processing module  214  to monitor changes in one or more characteristics of the transducer  220  and to detect changes in the characteristics that are the result of specific user interaction with the transducer  220 . For example, the feedback processing module  214  may monitor a resonance frequency of the transducer  220 . The resonance frequency may change when the user places a hand or other object that partially or completely covers the transducer  220 . The user&#39;s hand introduces an impedance in the radiation field of the transducer  220  that alters its resonance frequency. Covering the transducer  220  may change other characteristics, such as impedance, voltage, or current, that may also or alternatively be detected by the feedback processing module  214 . Further, other user actions may be detectable by monitoring the transducer  220 , such as detecting when a user taps the transducer and the number of taps and force of each of the taps. 
         [0026]    One implementation of the controller  200  is shown in  FIG. 3  as part of a system or device  300 .  FIG. 3  is a block diagram illustrating an example apparatus using a processor that is configured to detect user input through a transducer and perform an appropriate action according to one embodiment of the disclosure. The controller  200  may include circuitry that performs the functions of the audio processing module  212  and the feedback processing module  214 . The processor  302 , the coder/decoder (CODEC)  304 , and the amplifier  306  may perform functions related to audio processing. The processor  302 , the analog-to-digital converter (ADC)  308 A, and the analog-to-digital converter (ADC)  308 B may perform functions related to feedback processing. The processor  302  may be, for example, a digital signal processor (DSP), a microcontroller, an application-specific integrated circuit (ASIC), or other logic circuitry. The processor  302  may receive an audio signal from an application processor  310  that may be co-located in the electronic device with the controller  200  or integrated with the controller  200 . The received audio signal may be processed by the processor  302  to prepare the signal for output to the transducer  220 , such as application of equalizers, application of adaptive noise cancellation (ANC) signals, application of speaker protection algorithms, or other processing. A processed audio signal is then passed to the CODEC  304  and the amplifier  306  for output to the transducer  220 . In some embodiments, a switch  306 A may be located in circuitry before the audio signal reaches the amplifier  306 . The switch  306 A may be toggled to an open state to mute output of audio to transducer  220 . In some embodiments, the amplifier  306  may be toggled on and off to mute output of audio to transducer  220  without the switch  306 A. 
         [0027]    The transducer  220  reproduces the sounds within the processed audio signals by generating pressure waves that are interpreted by users as audible sounds. The characteristics of the transducer  220  may change over time, and those changes monitored through one or more analog-to-digital converters (ADCs)  308 A and  308 B. The ADCs  308 A-B may be coupled to the transducer  220  to receive analog signals related to the transducer  220 , convert those analog signals to digital values, and provide those digital values to the processor  302 . In the embodiment of  FIG. 3 , the ADC  308 A is configured to measure a voltage across the transducer  220  and to provide the voltage as a digital value to the processor  302 , and the ADC  308 B is configured to measure a current through the transducer  220  using a resistor and to provide the current as a digital value to the processor  302 . In other embodiments, different characteristics of the transducer  220  may be monitored and digital values generated therefrom and supplied to the processor  302 . 
         [0028]    The voltage and current values produced by ADCs  308 A-B may be used by the processor  302  to determine characteristics of the transducer  220  and detect user input by identifying signatures within the changing characteristics. For example,  FIG. 4A  is an illustration showing a user covering a transducer of a mobile phone to mute the sound according to one embodiment of the disclosure. When the user&#39;s hand is placed over the transducer  220  to partially or completely cover the transducer, the resonance frequency of the transducer  220  may change. This change in resonance frequency may be correlated with the user&#39;s activity shown in  FIG. 4A  and be sufficiently unique from normal changes of the resonance frequency during operation such that the processor  302  may detect the signature of the changing resonance frequency using the digital values from ADC  308 A and/or  308 B. The signature may be detected by the processor  302 , for example, when the resonance frequency increases more than a threshold amount and/or when the resonance frequency increases to a value over 1 kilohertz. One such change in resonance frequency is shown in the graphs of  FIGS. 4B-C .  FIG. 4B  is a graph illustrating an example resonance frequency for an uncovered transducer according to one embodiment of the disclosure. A resonance frequency  402  of the transducer when uncovered may be below 1000 hertz, such as approximately 850 hertz. When the user partially covers the transducer, the resonance frequency may increase.  FIG. 4C  is a graph illustrating an example resonance frequency for a covered transducer according to one embodiment of the disclosure. A resonance frequency  404  of the transducer when covered may be above 1000 hertz, such as approximately 1650 hertz. 
         [0029]    Other actions may likewise be detected by the processor  302  by monitoring characteristics of the transducer  220  through ADCs  308 A-B. For example,  FIG. 5  is an illustration showing a user uncovering the transducer of the mobile phone to unmute the sound according to one embodiment of the disclosure. The uncovering may be detected by a change of the resonance frequency back from the frequency  404  of  FIG. 4C  to the frequency  402  of  FIG. 4B . In some embodiments, the action performed when the transducer is covered is to mute the audio output. To facilitate monitoring the characteristics of the transducer  220 , an inaudible signal may be applied to the transducer  220  during the time the audio is muted. For example, an ultrasonic signal may be applied to the transducer to facilitate measurement of voltage and current by the ADCs  308 A-B. 
         [0030]    Another action that may be detected by the processor  302  by monitoring characteristics of the transducer  220  through ADCs  308 A-B is tapping on the transducer  220 .  FIG. 6A  is an illustration showing a user tapping the transducer of the mobile phone to unmute the sound according to one embodiment. A tap on the transducer  220  may produce a spike in the voltage or current of the transducer  220 , which may be detected by the processor  302  from the ADCs  308 A-B. Examples of the signatures for taps on the transducer are shown in  FIG. 6B .  FIG. 6B  is a graph illustrating example voltage and current signals for a transducer being tapped by a user according to one embodiment of the disclosure. A line  602  illustrates a sample voltage measurement; a line  604  illustrates a sample current measurement. Peaks for each of the lines  602  and  604  are shown at times  612 ,  614 ,  616 , and  618  and correspond to a user tapping on the transducer as shown in  FIG. 6A . In some embodiments, a reduction in false positives for detection of tapping may be obtained by detecting a signature of two or more taps on the transducer. The signature identified by the processor  302  may be the pattern  622  of peaks  612  and  614  or the pattern  624  of peaks  616  and  618 . The signature may be detected and a corresponding command, such as unmute, is decoded by the processor  302 . The processor  302  may take action to perform the action, such as to turn amplifier  306  back on. In some embodiments, the processor  302  may perform the action by relaying the decoded command to the application processor  310 , where the application processor  310  executes the decoded command. In some embodiments, the number of taps and strength of the taps may be detected by the processor  302  and correspond to user input for different commands, similar to Morse code. For example, a hard tap followed by a soft tap may indicate fast forward command and a soft tap followed by a hard tap may indicate a rewind command. 
         [0031]    The methods and apparatuses described above for detecting user input through the transducer and taking action based on the detected user input may be adapted to detect many ways for a user to interact with the device. Some detailed examples of an electronic device interacting with a user through input to the transducer are described below. However, detailed examples are only some applications of the general methods and apparatuses described above. 
         [0032]    In one embodiment, a user may use a first input, such as covering the transducer, to issue a first command, such as muting audio playback, and the user may use a second input, such as uncovering the transducer, to issue a second command, such as unmuting audio playback.  FIG. 7  is a flow chart illustrating an example method of performing actions to modify audio output to a transducer by detecting covering and uncovering of the transducer according to one embodiment of the disclosure. A method  700  may begin at block  702  with playing back audio through a transducer of a device, such as by playing music or a telephone call to a micro speaker of a mobile device. Then, at block  704 , coverage of the transducer may be detected while the transducer is outputting the audio of block  702 . Detection at block  704  may include, for example, detecting a change in resonance frequency of the transducer. After coverage is detected at block  704 , an action may be performed that modifies the audio output to the transducer at block  706 , such as by muting the audio playback. 
         [0033]    After a first command is received and appropriate action performed at blocks  704  and  706 , the method  700  may proceed to wait to detect a second command and perform an appropriate action in response to the received second command. The second command may be paired with the first command. For example, when the first command is a mute command, the second command may be an unmute command. In another example, when the first command is a pause command, the second command may be a play command. That is, the same user input activity (e.g., changing of the resonance frequency) may designate different commands based on a past command. When the last command was mute, the device may be expecting that the next command will be unmute. At block  708 , the uncovering of the transducer may be detected. Subsequently, another action may be performed that modifies the audio output at block  710 , such as by unmuting the audio. The method  700  of  FIG. 7  may be performed by the processor  302  of  FIG. 3 , the application processor  310  of  FIG. 3 , or other logic circuitry coupled to the transducer  220  of  FIG. 3 . 
         [0034]    Another example embodiment for interacting with a user by receiving input through the transducer by monitoring voltage and current at the transducer.  FIG. 8  is a flow chart illustrating an example method of detecting user input through a transducer by monitoring voltage and/or current levels at the transducer according to one embodiment of the disclosure. A method  800  begins at block  802  with receiving an input voltage and/or an input current from a transducer. At block  804 , a resonance frequency is determined for the transducer. At block  806 , it is determined when the resonance frequency changes by more than a threshold amount. If no threshold change is detected, the method  800  returns to block  802  and continues to monitor the transducer. When the threshold change of resonance frequency occurs at block  806 , the method  800  continues to block  808  to perform an action. The action may be, for example, muting the audio playback through the transducer when the resonance frequency is changed by a user covering the transducer. Although a resonance frequency is described at blocks  804  and  806 , any characteristic of the transducer may be determined and examined to determine when user input is received, and that characteristic may be determined from the received voltage and/or current at block  802 . 
         [0035]    After a first command is received and appropriate action performed at blocks  806  and  808 , the method  800  may proceed to wait to detect a second command and perform an appropriate action in response to the received second command. At block  810 , the device is configured to receive additional user input through the transducer. For example, an ultrasonic signal may be output to the transducer to facilitate further voltage and/or current measurements from the transducer. Then, at block  812 , an input voltage and/or input current are received from the transducer. It may be determined at block  814  whether a user input is detected in the received voltage and/or current of block  816 . If no user input is detected, the method  800  may return to block  812  to monitor the transducer. When user input is detected, the method  800  continues to block  816  to perform a second action in response to the received second command detected at block  814 . The second command may be paired with the first command. For example, when the first command is a mute command, the second command may be an unmute command. In another example, when the first command is a pause command, the second command may be a play command. Thus, at block  814 , the uncovering of the transducer may be detected. Subsequently, another action may be performed that modifies the audio output at block  816 , such as by unmuting the audio. The method  800  of  FIG. 8  may be performed by the processor  302  of  FIG. 3 , the application processor  310  of  FIG. 3 , or other logic circuitry coupled to the transducer  220  of  FIG. 3 . 
         [0036]    Embodiments of the invention described above allow a user to interact with an electronic device through devices that have conventionally been limited to providing outputs. These embodiments and other embodiments of the invention may provide for thinner and lighter devices by reducing or eliminating a need for additional physical switches or other components. Further, these and other embodiments may reduce power consumption on the device by reducing the amount of time a user is interacting with a power-consuming touchscreen display. Monitoring a speaker for detecting changes in characteristics that indicate user input is described above, however other components could also be monitored. In some embodiments, the circuitry for monitoring the speaker may be shared with other functionality on the device to reduce any additional cost or size in the electronic device. For example, the circuitry for monitoring the speaker may be used for speaker protection in addition to detecting user input through the speaker. Thus, the manners of receiving user input through a speaker or other monitored component as described above may have many advantages for an electronic device, and particularly for a mobile device, such as a mobile phone, tablet, laptop computer, or portable entertainment device. 
         [0037]    The schematic flow chart diagrams of  FIG. 1 ,  FIG. 7 , and  FIG. 8  are generally set forth as a logical flow chart diagram. As such, the depicted order and labeled steps are indicative of aspects of the disclosed method. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more steps, or portions thereof, of the illustrated method. Additionally, the format and symbols employed are provided to explain the logical steps of the method and are understood not to limit the scope of the method. Although various arrow types and line types may be employed in the flow chart diagram, they are understood not to limit the scope of the corresponding method. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the method. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted method. Additionally, the order in which a particular method occurs may or may not strictly adhere to the order of the corresponding steps shown. 
         [0038]    If implemented in firmware and/or software, functions described above may be stored as one or more instructions or code on a computer-readable medium. Examples include non-transitory computer-readable media encoded with a data structure and computer-readable media encoded with a computer program. Computer-readable media includes physical computer storage media. A storage medium may be any available medium that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise random access memory (RAM), read-only memory (ROM), electrically-erasable programmable read-only memory (EEPROM), compact disc read-only 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. Disk and disc includes compact discs (CD), laser discs, optical discs, digital versatile discs (DVD), floppy disks and Blu-ray discs. Generally, disks reproduce data magnetically, and discs reproduce data optically. Combinations of the above should also be included within the scope of computer-readable media. 
         [0039]    In addition to storage on computer readable medium, instructions and/or data may be provided as signals on transmission media included in a communication apparatus. For example, a communication apparatus may include a transceiver having signals indicative of instructions and data. The instructions and data are configured to cause one or more processors to implement the functions outlined in the claims. 
         [0040]    Although the present disclosure and certain representative advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. For example, although analog-to-digital converters (ADCs) are described throughout the detailed description, aspects of the invention may be applied to the design of other converters, such as digital-to-analog converters (DACs) and digital-to-digital converters, or other circuitry and components based on delta-sigma modulation. As another example, although digital signal processors (DSPs) are described throughout the detailed description, aspects of the invention may be applied to the design of other processors, such as graphics processing units (GPUs) and central processing units (CPUs). Further, although ones (1s) and zeros (0s) or highs and lows are given as example bit values throughout the description, the function of ones and zeros may be reversed without change in operation of the processor described in embodiments above. As one of ordinary skill in the art will readily appreciate from the present disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.