Validating the operation of a transducer and an audio signal path

Systems and methods for validating the operation of a transducer and an audio signal path to the transducer. An example method includes switching, with an audio switch, the audio signal path between an audio power amplifier and an analog-to-digital converter. The method includes routing an audio signal received from the transducer to the analog-to-digital converter when the audio power amplifier is not enabled. The method includes, upon receiving a button signal, processing, with an electronic processor, a digital version of the audio signal received from the analog-to-digital converter to generate a sample. The method includes comparing the sample to a reference audio sample. The method includes generating an alert when the sample does not match the reference audio sample.

BACKGROUND OF THE INVENTION

Public safety personnel (for example, police, fire fighters, first responders, investigators, and the like) use portable communication devices to communicate with one another during the performance of their duties. Effective communications enhances the ability of such personnel to safely respond to emergencies, and to complete other assigned duties. The use of communication devices in hazardous environments or under stressful conditions may damage or impair the performance of some electronic components of the devices, resulting in degraded or interrupted communications between public safety personnel.

DETAILED DESCRIPTION OF THE INVENTION

As noted, public safety personnel use portable communication devices to communicate. A portable communication device is subject to wear (for example, extreme heat during firefighting, and physical shock and contact during an outdoor foot chase), which may result in damage to some of the device's components. For example, a speaker coil of a firefighter's two-way radio may fail due to excessive temperature, reducing its ability to produce intelligible audio. A portable communication device is also subject to contaminants from the environment (for example, water, dirt, chemicals, and smoke), which may result in damage to or interference with the operation of some of the device's components. For example, over time, a microphone port may become jammed with detritus, reducing the microphone's ability to pick up speech and other acoustic signals for transmission.

To reduce or prevent impaired communications caused by damaged or otherwise compromised components, some devices employ electronic self-tests to check components and communication paths. However, such tests may not be able to detect physical damage in some components. For example, a shorted speaker coil, a damaged speaker cone, an internal microphone failure, and an acoustic port blocked with detritus are all physical problems that impair communications. However, none of the foregoing would trigger a failure when an electrical continuity test is performed. Some devices test audio components by generating test signals (for example, by generating sound on a speaker and detecting it on the microphone). However, such tests are not able to determine which of the speaker and microphone has failed. Furthermore, such tests cannot be performed during active communications to avoid interrupting the communications. Periodic audio test signals may also be annoying to the user and surrounding persons. Accordingly, embodiments presented herein provide, among other things, systems and methods validating the operation of a transducer and an audio signal path to the transducer.

Some embodiments presented herein receive and analyze audio signals created when buttons on a portable communication device are pressed and released. Vibrations produced by the pressing and releasing of the buttons are converted to audio signals by a transducer of the device, for example, a speaker or a microphone. The audio signals received during operation of the device can be compared to audio signals that the transducer is known to produce when it is operating properly. By making such comparisons, the device can validate the integrity of the transducer and the audio signal path to the transducer. Such embodiments enable portable communication devices to detect component failures that may otherwise go undetected using current electrical-self tests. Using such embodiments, a portable communication device can determine when an audio signal path is degraded, and re-route the audio to another audio signal path in order to preserve communications. For example, a two-way radio may determine that an accessory speaker is not operating properly, and re-route received audio to the speaker in the two-way radio. Furthermore, because such testing is not intrusive, it may be performed more frequently than tests relying on the generation of audio test signals. For example, a portable communication device may test the operation of its speaker upon each press and release of the push-to-talk switch and track the results over time. Using such embodiments, slowly degrading or intermittently failing components may be more quickly identified.

One example embodiment provides a system for validating the operation of a transducer and an audio signal path to the transducer. The system includes an audio power amplifier, an analog-to-digital converter, and an audio switch coupled in the audio signal path. The audio switch is configured to switch the audio signal path between the audio power amplifier and the analog-to-digital converter, and to route an audio signal received from the transducer to the analog-to-digital converter when the audio power amplifier is not enabled. The system also includes an electronic processor coupled to the analog-to-digital converter. The electronic processor is configured to, upon receiving a button signal, process a digital version of the audio signal received from the analog-to-digital converter to generate a sample. The electronic processor is configured to compare the sample to a reference audio sample. The electronic processor is configured to, when the sample does not match the reference audio sample, generate an alert.

Another example embodiment provides a method for validating the operation of a transducer and an audio signal path to the transducer. The method includes switching, with an audio switch, the audio signal path between an audio power amplifier and an analog-to-digital converter. The method includes routing an audio signal received from the transducer to the analog-to-digital converter when the audio power amplifier is not enabled. The method includes, upon receiving a button signal, processing, with an electronic processor, a digital version of the audio signal received from the analog-to-digital converter to generate a sample. The method includes comparing the sample to a reference audio sample. The method includes generating an alert when the sample does not match the reference audio sample.

Another example embodiment provides a remote speaker microphone. The remote speaker microphone includes an audio power amplifier, an analog-to-digital converter, and an audio switch coupled in the audio signal path. The audio switch is configured to switch the audio signal path between the audio power amplifier and the analog-to-digital converter, and to route an audio signal received from the transducer to the analog-to-digital converter when the audio power amplifier is not enabled. The system also includes an electronic processor coupled to the analog-to-digital converter. The electronic processor is configured to, upon receiving a button signal, process a digital version of the audio signal received from the analog-to-digital converter to generate a sample. The electronic processor is configured to compare the sample to a reference audio sample. The electronic processor is configured to, when the sample does not match the reference audio sample, generate an alert.

For ease of description, some or all of the example systems presented herein are illustrated with a single exemplar of each of its component parts. Some examples may not describe or illustrate all components of the systems. Other example embodiments may include more or fewer of each of the illustrated components, may combine some components, or may include additional or alternative components.

FIG. 1is a diagram of an example communication system100. The communication system100includes a portable communication device102and an accessory device104. The portable communication device102transmits and receives audio, data, or combinations of both to other communication devices (not shown) using radio frequency signals. In some embodiments, the portable communication device102is a portable two-way radio (for example, one of the Motorola® APX™ series of radios). In some embodiments, the portable communication device102is a converged device including electronics, software, and other components sufficient to support both cellular and land mobile radio communications. In alternative embodiments, the portable communication device102may be any type of communication device including components and functionality as described herein.

The accessory device104is an electronic accessory to the portable communication device102. In some embodiments, the accessory device104is a remote speaker microphone (an “RSM”) (for example, a Motorola® APX™ XE Remote Speaker Microphone).

In the embodiment illustrated, the portable communication device102includes an electronic processor106, a memory108, an input/output interface110, a transceiver114, an antenna116, an internal speaker118, an internal microphone120, a push-to-talk switch122, a first audio power amplifier124, a first audio switch126, a first analog-to-digital converter128, a second audio power amplifier130, a second audio switch132, a second analog-to-digital converter134, and an accessory interface136. The illustrated components, along with other various modules and components are coupled to each other by or through one or more electrical connections (for example, control or data buses) that enable communication therebetween. The use of such connections, including control and data buses, for the interconnection between and exchange of information among the various modules and components would be apparent to a person skilled in the art. The illustrated components, along with other various components are contained in or integrated with a housing138. The housing138is a generally rigid structure. In some embodiments, the housing138is manufactured from plastic using injection molding. In other embodiments, the housing138is manufactured using other suitable materials or methods. In some embodiments, the portable communication device102includes fewer or additional components in configurations different from that illustrated inFIG. 1.

The electronic processor106obtains and provides information (for example, from the memory108and/or the input/output interface110), and processes the information by executing one or more software instructions or modules, capable of being stored, for example, in a random access memory (“RAM”) area of the memory108or a read only memory (“ROM”) of the memory108or another non-transitory computer readable medium (not shown). The software can include firmware, one or more applications, program data, filters, rules, one or more program modules, and other executable instructions. The electronic processor106is configured to retrieve from the memory108and execute, among other things, software related to the control processes and methods described herein. The memory108can include one or more non-transitory computer-readable media, and includes a program storage area and a data storage area. The program storage area and the data storage area can include combinations of different types of memory, as described herein. In the embodiment illustrated, the memory108stores, among other things, an audio path validation manager140, described more particularly below.

The input/output interface110receives input from, for example, a user input device of the portable communication device102, provides system output, or a combination of both. Output may be provided via the internal speaker118. The internal speaker118is a transducer for reproducing sound from electrical signals (for example, generated from a received audio stream) received from the electronic processor106. In some embodiments, the input/output interface110includes a display (not shown), for example, a liquid crystal display (LCD) touch screen, or an organic light-emitting diode (OLED) touch screen. Alternative embodiments may include other output mechanisms such as, for example, haptic feedback motors and light sources (not shown). Input may be provided via, for example, a keypad, a microphone, soft keys, icons, or soft buttons on a display, a scroll ball, buttons, and the like. The input/output interface110may include a graphical user interface (GUI) (for example, generated by the electronic processor106, from instructions and data stored in the memory108, and presented on a display) that enables a user to interact with the portable communication device102.

The electronic processor106is configured to control the transceiver114to transmit and receive audio (for example, voice) and other data to and from the portable communication device102. The electronic processor106encodes and decodes digital data sent and received by the transceiver114. The transceiver114transmits and receives radiofrequency signals from and to the portable communication device102using the antenna116. The electronic processor106and the transceiver114may include various digital and analog components, which for brevity are not described herein and which may be implemented in hardware, software, or a combination of both. In some embodiments, the electronic processor106is coupled to or performs the functions of a digital signal processor, a baseband processor, or both (not shown). Some embodiments include separate transmitting and receiving components, for example, a transmitter and a receiver, instead of a combined transceiver114.

The internal microphone120is a transducer capable of sensing sound, converting the sound to electrical signals, and transmitting the electrical signals to the electronic processor106. The electronic processor106processes the electrical signals received from the internal microphone120to produce an audio signal, which may be transmitted to other devices via the transceiver114.

The portable communication device102is capable of push-to-talk audio communication. Push-to-talk is a method of transmitting audio communications over a half-duplex communication channel. Push-to-talk communication may be between one individual and another individual or between one individual and a group of individuals (for example, via a talk group). A user of the portable communication device102controls push-to-talk communication using the push-to-talk switch122.

The push-to-talk switch122is an electromechanical switch (for example, a normally-open momentary switch). The push-to-talk switch122includes a spring or other mechanical means of keeping the switch in an open position until pressed (for example, a metal snap dome), and returning it to an open position when it is released. Because users may operate the portable communication device102without looking at it, in noisy environments, in low-light conditions, or while wearing protective gloves, the push-to-talk switch122produces a tactile click when actuated. The push-to-talk switch122is mechanically coupled to the housing138(for example, mounted onto a PCB board that is attached to a section of the housing). Because the housing138is rigid, the tactile clicks produced by the pressing and releasing of the button produces vibrations in the housing138, similar to a clapper ringing a bell. The push-to-talk switch122, when pressed, causes transmission of an audio communication (for example, an audio signal produced by the internal microphone120) from the portable communication device102via the electronic processor106and the transceiver114. When the push-to-talk switch122is released, the transceiver114is placed into a reception mode, for example, to receive a response to the audio communication.

When the portable communication device102is receiving communications, the electronic processor106receives radiofrequency signals via the transceiver114, and processes the signals to extract a digital received audio signal. The digital received audio signal is provided to the first audio power amplifier124and the second audio power amplifier130. The first audio power amplifier124and the second audio power amplifier130decode the digital audio signals with integral codecs (digital-to-analog converters) and amplify the analog audio signal to a speaker level signal (for example, 6 volts). The amplified signal is received by the first audio switch126and the second audio switch132. Each of the first audio switch126and the second audio switch132are electronic switches, controllable by the electronic processor106to switch between multiple audio inputs and outputs. When the portable communication device102is receiving communications, the first audio switch126is controlled to send the amplified audio signal to the accessory device104over an accessory interface cable142, and the second audio switch132is controlled to send the amplified audio signal to the internal speaker118. In some embodiments, the electronic processor106will only send the digital received audio signal to the second audio power amplifier130when the accessory device104is not connected to the portable communication device102.

The first audio switch126operates to switch the accessory interface136between the first audio power amplifier124and the first analog-to-digital converter128. The accessory interface136is an electrical connector for communicatively coupling the accessory device104to the portable communication device102. The portable communication device102is coupled to the accessory device104via the accessory interface136and an accessory interface cable142. The accessory interface cable142includes a plurality of wires for conveying audio and control signals to and from the accessory device104. When the transceiver114is not receiving an audio transmission, the first audio power amplifier124is not enabled, and the first audio switch126couples the audio signal received via the accessory interface136to the first analog-to-digital converter128. As described more particularly below, in some embodiments, the audio signal received is produced by an accessory speaker152of the accessory device104. The first audio switch126includes an amplifier and other electronic circuitry for boosting the audio signal from the accessory speaker152to a level that can be processed by the first analog-to-digital converter128. The first analog-to-digital converter128digitizes analog audio signals received from the first audio switch126, and sends them to the electronic processor106. The first analog-to-digital converter128includes multiple analog audio signal inputs, which are selectable by the electronic processor106. For example, as illustrated inFIG. 1, the first analog-to-digital converter128receives analog audio input signals from the first audio switch126and the accessory interface136.

When the transceiver114is receiving a transmission, the second audio switch132couples the amplified received audio signal from the second audio power amplifier130to the internal speaker118. When the transceiver114is not receiving a transmission, the second audio power amplifier130is not enabled, and the second audio switch132couples an audio signal received from the internal speaker118to the second analog-to-digital converter134. The second audio switch132includes an amplifier and other electronic circuitry for boosting the audio signal from the internal speaker118to a level that can be processed by the second analog-to-digital converter134. The second analog-to-digital converter134digitizes analog audio signals received from the second audio switch132, and sends them to the electronic processor106. The second analog-to-digital converter134includes multiple analog audio signal inputs, which are selectable by the electronic processor106. For example, as illustrated inFIG. 1, the second analog-to-digital converter134receives analog audio input signals from the second audio switch132and the internal microphone120.

In the example illustrated, the accessory device104includes the accessory speaker152, an accessory microphone154, and an accessory push-to-talk switch156. The accessory speaker152, the accessory microphone154, and the accessory push-to-talk switch156are housed or integrated into in an accessory housing158. The accessory housing158is a rigid housing of similar construction to the portable communication device housing138. The accessory speaker152, the accessory microphone154, and the accessory push-to-talk switch156are similar and operate similarly to their respective components in the portable communication device102, namely the internal speaker118, the internal microphone120, and the push-to-talk switch122. The accessory speaker152and the accessory microphone154exchange audio signals with the portable communication device102via the accessory interface cable142. The accessory push-to-talk switch156sends a push-to-talk signal to the electronic processor106via the accessory interface cable142.

In some embodiments, the accessory device104includes similar components as the portable communication device102, for example, electronic processors, audio power amplifiers, audio switches, and analog-to-digital converters. In such embodiments, the accessory device104may connect to the portable communication device102wirelessly (for example, via Bluetooth™).

As noted above, actuating or de-actuating the push-to-talk switch122“rings” the housing138, setting up vibrations in the housing138and the components contained therein. Similarly, actuating or de-actuating the accessory push-to-talk switch156“rings” the accessory housing158, setting up vibrations in the accessory housing158and the components contained therein. A speaker (for example, the internal speaker118and the accessory speaker152) is a transducer that produces sound in response to receiving an electrical signal. Conversely, when sound (or other vibration) encounters a speaker, the speaker produces an electrical signal in response. As a consequence, vibrations caused by the actuation or de-actuation of the push-to-talk switch122produce electrical currents (audio signals) in the internal speaker118and vibrations caused by the actuation or de-actuation of the accessory push-to-talk switch156produce electrical currents (audio signals) in the accessory speaker152. As described herein, these electrical currents may be used to test the speakers and other components of the system100.

FIG. 2illustrates an example method200for validating the operation of a transducer of the communication system100and an audio signal path to the transducer. The method200is described as being performed by the portable communication device102and, in particular, the first audio switch126and the electronic processor106. However, it should be understood that in some embodiments, portions of the method200may be performed external to the portable communication device102by other devices, including for example, the accessory device104. As an example, the method200is described in terms of validating the operation of the accessory speaker152and the audio signal path (including, for example, the accessory interface cable142) to the accessory speaker152using vibrations generated by the accessory push-to-talk switch156. However, the methods described herein are applicable to validating the operation of the internal speaker118using the second audio switch132, the second audio power amplifier130, and the electronic processor106. The method200may also be performed by an embodiment of the accessory device104that includes the appropriate components (for example, an electronic processor, and audio switch, and an analog-to-digital converter).

At block202, the method200begins with the portable communication device102in ordinary operation. For example, the transceiver114is tuned to a particular channel for communication with other devices and listening for radio communications. When a radio signal is received and a received audio signal is produced (at block204), the first audio switch126connects the first audio power amplifier124to the accessory interface136, and the audio is presented as sound via the accessory speaker152(at block206).

When no radio signal is received, and thus the audio power amplifier is not enabled (at block204), the first audio switch126routes an audio signal received from the accessory speaker152to the first analog-to-digital converter128(at block208). In this example, the audio signal is produced by the accessory speaker152acting as a microphone (that is, producing electrical signals in response to received vibrations).

As buttons, knobs, or other controls of the portable communication device102and the accessory device104are actuated, the electronic processor receives button signals from the controls. A button signal is an electrical signal that a button has been actuated or de-actuated. Button signals may be received on buses internal to the portable communication device102, or via the accessory interface cable142and the accessory interface136. In this example, the button signal is a push-to-talk release signal.

While no button signal (push-to-talk release signal) is received (at block210), the system100continues monitoring for receive audio, and routing audio signals using the audio switch (at blocks204through208).

When a push-to-talk release signal is received (at block210), the electronic processor106processes a digital version of the audio signal received from the first analog-to-digital converter128to generate a sample (at block212). In this example, the audio signal is generated by vibrations caused by the physical release of the accessory push-to-talk switch156.

At block214, the electronic processor106compares the sample to a reference audio sample. In this example, the reference audio sample represents the sound generated by a correctly-working accessory speaker152when the accessory push-to-talk switch156is released. In some embodiments, the electronic processor106compares the sample and the reference audio sample using a matched filter.

When the samples match (at block216), the electronic processor106determines that the accessory speaker152and the audio signal path are operating within specifications, and the communication system100continues ordinary operation (at block202). For example,FIG. 3Aincludes a chart300illustrating a matched filter to a reference audio sample302for a push-to-talk switch being pressed (304) and released (306) when the speaker is operating as expected.

Returning toFIG. 2, when the samples do not match (at block216), the electronic processor106generates an alert (at block218). For example,FIG. 3Aincludes a chart310illustrating a matched filter to a reference audio sample312for a push-to-talk switch being pressed (314) and released (316) when the speaker is not operating as expected (but yet is electrically continuous).

The electronic processor106generates the alert to notify the user of the communication system100that there is a problem with either the accessory speaker152or the audio signal path (for example, the accessory interface cable142). In some embodiments, the alert is an audio alert, a visual alert, a haptic alert, a network message (for example, sent to a communication system controller), or combinations of the foregoing. In some embodiments, in place of or in addition to generating the alert, the electronic processor106re-routes audio signals to an alternate audio signal path. For example, the electronic processor106may divert received audio signals from the accessory interface to the internal speaker118, so that the user of the system100is still able to receive audio communications from others.

The method200is described above in terms of vibrations caused by the actuation or de-actuation of a push-to-talk switch. It should be noted that the methods described herein are also applicable to vibrations produced by buttons or knobs other than push-to-talk switches. Other physical controls (for example, knobs, buttons, switches, and the like) that produce sufficient vibrations in the housing and an accompanying reference signal may be used.

The method200is described above in terms of validating the operation of a speaker and the audio signal path to the speaker. It should be noted that similar methods are applicable to validating the operation of the internal microphone120, the accessory microphone154, and audio signal paths to those components. In such embodiments, the electronic processor106does not operate the audio switches to route audio from the speakers. Instead, the electronic processor106processes and compares audio produced by the microphones in response to vibrations, for example, as caused by the actuation or de-actuation of a push-to-talk switch.