Vehicle Audio System

Abstract

The present disclosure provides a "vehicle audio system". A two-wire communication system includes a first audio circuit and a second audio circuit, wherein the second audio circuit is electrically connected to the first audio circuit via a two-wire bidirectional multi-node communication bus. The communication bus connects the first audio circuit to the second audio circuit, wherein an audio signal, an enable signal, and a clipping detection signal are transmitted through the bus.

Description

Technical Field

[0001] The present invention relates to the field of vehicle audio systems, and more particularly to vehicle audio communication systems. Background Art

[0002] Vehicle audio circuits (such as radios, media players, amplifiers, etc.) are typically interconnected via wiring to carry audio signals and / or control signals. Vehicles typically include separate wires that interconnect audio circuits to each other. Summary of the invention

[0003] A two-wire communication system is disclosed herein, comprising a first audio circuit and a second audio circuit electrically connected to the first audio circuit via a two-wire bidirectional multi-node communication bus, wherein the two-wire bidirectional multi-node communication bus connects the first audio circuit to the second audio circuit, wherein an audio signal, an enable signal, and a limit detection signal are transmitted through the bus.

[0004] The two-wire communication system may also include: a first two-wire communication circuit having an audio enable input, a limit detection output, and a first two-wire communication chip electrically connected to a bus, wherein the audio enable input and the limit detection output are electrically coupled to the first audio circuit; and a second two-wire communication circuit having an audio enable output, a limit detection input, and a second two-wire communication chip electrically connected to the first two-wire communication chip via the bus, wherein the audio enable output and the limit detection input are electrically coupled to the second audio circuit.

[0005] The first audio circuit may include a first two-wire communication circuit that communicates with the first processor, and the second audio circuit may include a second two-wire communication circuit that communicates with the second processor.

[0006] The second audio circuit may also include a second processor and a second memory storing instructions executable by the second processor to detect clipping based on an amplitude of the received audio signal.

[0007] The audio enable output may be electrically connected to the second processor.

[0008] The first audio circuit may also include a first processor and a first memory. The first memory may store instructions executable by the first processor to generate an enable signal based on a received activation request from the human-machine interface.

[0009] The audio enable input and the clip detect output may be electrically connected to the first processor.

[0010] The first memory may store further instructions executable by the first processor to adjust the amplitude of an audio signal transmitted by the first audio circuit based on the clipping detection signal.

[0011] The two-wire communication system may also include a first signal converter circuit that electrically couples the first two-wire communication circuit and the first audio circuit, wherein the first signal converter circuit is configured to generate an enable signal on the audio enable input based on an analog voltage sensed at a three-state input output of the first signal converter circuit.

[0012] The first signal converter circuit may be configured to adjust an analog voltage of the tri-state input output based on the clipping detection signal.

[0013] The two-wire communication system may also include a second signal converter circuit that electrically couples the second two-wire communication circuit and the second audio circuit, wherein the second signal converter circuit is configured to generate a clipping detection signal based on an analog voltage sensed at a three-state input output of the second signal converter circuit.

[0014] The first two-wire communication circuit may be configured to transmit the audio signal and the enable signal, and to receive the clipping detection signal via the bus.

[0015] The amplitude of the audio signal may be adjusted based on the clipping detection signal.

[0016] The second audio circuit may be activated based on the enable signal.

[0017] The two-wire communication system may further include a third audio circuit, wherein the first, second, and third audio circuits are daisy-chain connected via the two-wire bidirectional multi-node communication bus.

[0018] The first audio circuit may include a radio and the second audio circuit includes an audio amplifier circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 An example vehicle including an example audio system is shown.

[0020] Figure 2A An example audio system having two electrically connected audio circuits is shown.

[0021] Figure 2B Another example audio system having multiple daisy-chained audio circuits is shown.

[0022] Figure 3 An example communication bus between two audio circuits is shown.

[0023] Figure 4 Another example communication bus including first and second signal converter circuits is shown.

[0024] Figure 5 An example first signal converter circuit is shown.

[0025] Figure 6 An example second signal converter circuit is shown.

[0026] Figure 7 is a flow chart of an example process for transmitting an audio signal.

[0027] Figure 8 is a flow chart of an example process for receiving an audio signal. DETAILED DESCRIPTION

[0028] A vehicle audio system (e.g., a radio, a media player, etc.) typically includes one or more audio circuits that generate audio signals and one or more amplifiers that output the audio signals, for example, via a speaker. An amplifier typically cannot output an audio signal with an amplitude greater than a maximum limit (e.g., a function of its power supply voltage). When the maximum limit of the amplifier is reached, increasing the gain may distort (or limit) the output audio signal. A speaker coupled to the amplifier output may have a maximum acceptable audio signal amplitude and / or power. An increase in the amplitude of an audio signal output to a speaker with an amplitude that exceeds the maximum acceptable audio signal amplitude of the speaker may damage the speaker. Therefore, the amplifier may output a limit detection signal to an audio signal generating circuit such as a radio to indicate that the amplitude of the audio signal has reached a maximum limit associated with the amplifier and / or speaker. Additionally or alternatively, the audio circuit (e.g., a radio) may output an enable signal to the amplifier to activate the amplifier. The limit detection signal and / or the enable signal may be transmitted between the audio circuits via electrical wiring connecting the audio circuits. Typically, the clip detection signal and / or the enable signal are transmitted via dedicated wiring, meaning that the wire only transmits a specific signal (e.g., the clip detection signal) from the amplifier to the radio. The vehicle's audio system can be designed to reduce the cost of wiring the vehicle's audio circuits. An example of a cost-effective audio system is designed to transmit the clip detection signal and the enable signal via the same wire that transmits audio signals between the vehicle's audio circuits, such as from a radio to an amplifier.

[0029] The illustrated elements may take many different forms and include multiple and / or alternative components and facilities. The illustrated example components are not intended to be limiting. In practice, additional or alternative components and / or implementations may be used. Furthermore, unless explicitly stated as such, the illustrated elements are not necessarily drawn to scale.

[0030] Figure 1 An example vehicle 100 is shown. The vehicle 100 may be powered by, for example, an electric motor and / or an internal combustion engine. The vehicle 100 may be a land vehicle such as a car, truck, etc. The vehicle 100 may include a computer 110, an audio system 120, sensors 130, and a human-machine interface (HMI) 140.

[0031] The computer 110 includes a processor and a memory. The memory includes one or more forms of computer-readable media and stores instructions executable by the computer 110 for performing various operations, including those disclosed herein.

[0032] The computer 110 is programmed to operate one or more of vehicle braking, propulsion (e.g., control of vehicle acceleration by controlling one or more of an internal combustion engine, an electric motor, a hybrid engine, etc.), steering, climate control, an audio system 120, etc.

[0033] The computer 110 may include or may be communicatively coupled to various devices included in the vehicle 100 for monitoring and / or controlling various vehicle controllers, such as a powertrain controller, a brake controller, a steering controller, etc. The computer 110 may be connected to a vehicle communication network, which may include a bus in the vehicle 100, such as a controller area network (CAN), etc., and / or other wired and / or wireless mechanisms.

[0034] The computer 110 transmits messages to and / or receives messages from various devices in the vehicle (e.g., HMI 140, etc.) via the vehicle 100 network. Alternatively or additionally, in instances where the computer 110 includes multiple devices, the vehicle 100 communication network may be used for communications between the devices represented as the computer 110. As discussed further below, various electronic controllers and / or sensors 130 may provide data to the computer 110 via the vehicle communication network.

[0035] The sensors 130 of the vehicle 100 may include various devices known to provide data via a vehicle communication bus. For example, the sensors 130 may include one or more microphones, cameras, radars, infrared sensors, and / or lidar sensors 130 disposed in and / or on the vehicle 100, providing data including at least some of the exterior of the vehicle 100.

[0036] The HMI 140 may be programmed to receive user input, for example, during operation of the vehicle 100. For example, a user may select a radio station for the audio system 120, for example, by providing input via the HMI 140. In addition, the HMI 140 may be programmed to present information to the user. As another example, a user may select a volume (loudness) of an audio signal output by the sound system 120 via the HMI 140. The HMI 140 may be implemented via electronic components, a touch screen, buttons, knobs, etc.

[0037] The audio system 120 may include various devices for providing audio signals via speakers included in the vehicle 100. The audio system 120 may include devices that capture and / or generate audio signals (such as a radio, a media player, etc.), and devices that receive the generated audio signals and output the audio signals in the form of sound waves (such as an amplifier and / or a speaker).

[0038] Figure 2A An example implementation of a sound system 120 is shown that includes a first audio circuit 210 and a second audio circuit 220 electrically connected to the first audio circuit 210 via a two-wire bidirectional multi-node communication bus 230. The communication bus 230 (or sometimes referred to as a communication link) connects, for example, the first audio circuit 210 to the second audio circuit 220. Audio signals, enable signals, and clip detection signals are transmitted over the bus 230.

[0039] The device (such as a radio, a media player, etc.) that captures and / or generates an audio signal (e.g., with a radio) is referred to as a first audio circuit 210, and the device (such as a speaker and / or an audio amplifier circuit) that receives the audio signal is referred to as a second audio circuit 220. The amplifier can receive the audio signal, amplify the amplitude of the received audio signal, and output the amplified audio signal to, for example, a speaker. Additionally or alternatively, the device can include a combination of the first audio circuit 210 and the second audio circuit 220.

[0040] In the context of the present disclosure, the communication bus 230 may be implemented by wires, connectors, chips, electronic circuits, etc. "Bidirectional" means that data such as audio signals, enable signals, and clip detection signals can be transmitted in both directions via the communication bus 230. For example, the audio signal and the enable signal can be transmitted from the first audio circuit 210 to the second audio circuit 220, while the clip detection signal can be transmitted from the second audio circuit 220 to the first audio circuit 210. The bus 230 may include a two-wire medium such as a twisted pair. The bus 230 may electrically connect the terminals 240 of the first audio circuit 210 and the second audio circuit 220.

[0041] In this context, “multi-node” means that a plurality of first audio circuits 210 and second audio circuits 220 are included in the sound system 120 and are communicatively connected. Figure 2B A multi-node communication bus 230 is shown that provides communication between the plurality of first audio circuits 210 and second audio circuits 220. The communication bus 230 may allow point-to-point (i.e., between the first audio circuits 210 and the second audio circuits 220) connections and may allow the plurality of first audio circuits 210 and second audio circuits 220 to communicate at different locations within the interior of the vehicle 100 (e.g., front, rear, etc.).

[0042] The sound system 120 may include a plurality of audio circuits, each of which has a first audio circuit 210 and a second audio circuit 220. Thus, the sound system 120 may include a plurality of audio circuits (e.g., one or more of the first audio circuits 210 and one or more of the second audio circuits 220), which are daisy-chained via a two-wire bidirectional multi-node communication bus 230. “Daisy-chained” means that the first audio circuit 210 and the second audio circuit 220 are connected together in sequence (via the bus 230). For example, Figure 2B As shown, the sound system 120 may include one or more first audio circuits 210 and one or more second audio circuits 220 (e.g., two of the first audio circuits 210a, 210b, such as a radio and a media player, and four of the second audio circuits 220a, 220b, 220c, 220d, such as four amplifiers), wherein speakers are located in four corners of the interior of the vehicle 100, as shown in FIG. Figure 2B As shown. The communication bus 230 in daisy-chain mode can provide communication to multiple audio circuits 210, 220, so that the first audio circuit 210a and the second audio circuit 220b are connected via the first bus 230, the second audio circuits 220a, 220b are connected via the second bus 230, etc., and the second audio circuit 220d and the first audio circuit 210a are connected to establish a daisy chain. In an example, each of the first audio circuit 210 and the second audio circuit 220 may include two terminals 240a, 240b, and the first audio circuit 210 and the second audio circuit 220 may be daisy-chained by connecting the terminals 240a, 240b to another two first audio circuits 210 and / or second audio circuits 220.

[0043] Figure 3 An example sound system 120 is shown in which two first audio circuits 210 and a second audio circuit 220 are connected via two two-wire communication circuits 310 and a bus 230. The first two-wire communication circuit 310 may include an audio enable input 320, a clipping detection output 330, and a first two-wire communication chip 340a electrically connected to the bus 230. The audio enable input 320 and the clipping detection output 330 may be electrically coupled to the first audio circuit 210. The second two-wire communication circuit 350 may include an audio enable output 360, a clipping detection input 370, and a second two-wire communication chip 340b electrically connected to the first two-wire communication chip 340a via the bus 230. The audio enable output 360 and the clipping detection input 370 may be electrically coupled to the second audio circuit 220. The first chip 340a and the second chip 340b may be electrically connected to the first audio circuit 210 and / or the second audio circuit 220.

[0044] The first chip 340a and the second chip 340b can transmit and receive data including audio signals, audio enable and clip detection signals via the two-wire bus 230. In one example, the first chip 340a and the second chip 340b can operate based on the automotive audio bus (A2B) protocol. Therefore, the first chip 340a and the second chip 340b can use time division multiplexing technology to transmit and receive data. In the time division multiplexing technology, each time slot can be associated with a predetermined content and / or a predetermined first audio circuit 210 and / or a second audio circuit 220. The two-wire bus 230 can be used to transmit various types of information, including audio signals, enable signals, clip detection signals, etc. The first chip 340a and / or the second chip 340b can be programmed to transmit and / or receive various types of data through the bus 230. In one example, the computer 110 can be programmed to command the first chip 340a and / or the second chip 340b to provide communication between the first audio circuit 210 and / or the second audio circuit 220. The computer 110 may be programmed to command the first chip 340 to transmit an audio signal and an enable signal. The computer 110 may be programmed to command the second chip 340 to receive an audio signal and transmit a clipping detection signal. Additionally or alternatively, the computer 110 may be programmed to command the chip 340, for example, based on an input received via the HMI 140. For example, the computer 110 may receive an input requesting activation of the first audio circuit 210 (e.g., a radio) to output sound via the second audio circuit 220 (e.g., a front speaker inside the vehicle 100). Based on the received input, the computer 110 may be programmed to command the first chip 340 to transmit an audio signal and an enable signal of the radio (i.e., the first audio circuit 210) and receive a clipping detection signal. The computer 110 may be programmed to command the second chip 340 to receive an audio signal and an enable signal and transmit a clipping detection signal.

[0045] In one example, the first two-wire communication circuit 310 and the second two-wire communication circuit 350 may be included in the first audio circuit 210 and / or the second audio circuit 220. For example, the electrical connector of the first audio circuit 210 and / or the second audio circuit 220 may include terminals 240a, 240b, which may be electrically connected via, for example, the bus 230 to form a daisy chain. In another example, the two-wire communication circuits 310, 350 may be disposed outside the first audio circuit 210 and / or the second audio circuit 220, for example, inside a wiring harness connector housing that provides a mechanical and electrical connection between the bus 230 and the first audio circuit 210 and / or the second audio circuit 220.

[0046] The first audio circuit 210 may include a first processor 380a in communication with the first two-wire communication circuit 310. For example, the first processor 380a of the first audio circuit 210 may be electrically connected to the audio enable input 320 and the clipping detection output 330 of the first two-wire communication circuit 310. The first processor 380a may be programmed to generate an enable signal based on a received activation request from the HMI 140, for example.

[0047] The first processor 380a may be programmed to adjust the amplitude of the audio signal output from the first audio circuit 210 based on the clipping detection signal. For example, the first processor 380a may be programmed to reduce the amplitude of the audio signal when the clipping detection signal is activated. In one example, the first processor 380a may be programmed to reduce the amplitude of the audio signal by a predetermined amount (e.g., approximately 5%) and determine whether the state of the clipping detection signal becomes inactive after a predetermined time (e.g., approximately 200 milliseconds (ms)); otherwise, gradually reduce the amplitude of the audio signal, etc.

[0048] The second audio circuit 350 may include an amplifier 390. The amplifier 390 may include electronic components and / or integrated circuits such as one or more operational amplifier (OpAmp) circuits. The amplifier 390 may receive an audio signal from the first audio circuit 210, amplify the amplitude of the received audio signal, and output the amplified audio signal to, for example, a speaker included in and / or electrically connected to the second audio circuit 220. The amplifier 390 may include an amplitude detection circuit that is programmed to generate an amplitude detection signal due to the amplitude of the received audio signal exceeding a predetermined threshold (e.g., 90% of the power supply voltage of the amplifier 390). Additionally or alternatively, the second audio circuit 220 may include a second processor 380b that is programmed to detect amplitude limiting based on the amplitude of the received audio signal. The amplitude detection signal may be transmitted to, for example, the first audio circuit 210 via the amplitude detection input 370 of the second audio circuit 350 and the bus 230. The second processor 380b of the second audio circuit 220 may be electrically connected to the audio enable output 360. The second processor 380b can be programmed to receive an enable signal via the audio enable output 360. The state of the received enable signal can be one of activation or inactivation. The second processor 380b can be programmed to activate the amplifier 390 to output the audio signal, for example, via a speaker, due to the activation of the enable signal. Additionally or alternatively, the audio enable output 360 can be connected to, for example, an enable input of the amplifier 390. The amplifier 390 can be configured to operate and / or shut down based on the state of the received enable signal at the amplifier 390 enable input.

[0049] As described above, the communication between the first audio circuit 210 and / or the second audio circuit 220 may be a multi-node communication. In one example, the vehicle 100 computer 110 may be programmed to command the chips 340a, 340b of the two-wire communication circuits 310, 350 to operate according to, for example, user input received via the HMI 140 of the vehicle 100. Thus, the computer 110 may be programmed to command the chips 340 of the two-wire communication circuits 310, 350 to be "transmitters" and / or "receivers". In this context, commanding the chip 340 to be a transmitter means that the corresponding chip 340 transmits an audio signal and an enable signal, and receives a clipping detection signal. In this context, commanding the chip 340 to be a receiver means that the corresponding chip 340 receives an audio signal and an enable signal, and transmits a clipping detection signal. The computer 110 may be programmed to determine which of the first audio circuit 210 and / or the second audio circuit 220 should operate as a transmitter and / or a receiver based on the input received via the HMI 140. Additionally, the computer 110 may be programmed to command the chip 340 of the two-wire communication circuit 310, 350 to be "off," ie, to operate neither as a transmitter nor as a receiver.

[0050] Figure 4 Another example sound system 120 is shown, in which two first audio circuits 210 and second audio circuits 220 are connected via two two-wire communication circuits 310, 350 and signal converters 410, 450. In this example, this may occur in the case where the first audio circuit 210 and / or the second audio circuit 220 lack the ability to transmit and / or receive the enable signal and / or the clipping detection signal as different digital signals, and the first audio circuit 210 can transmit and receive the enable signal and the clipping detection signal via a three-state analog signal. In the context of the present disclosure, a "three-state analog signal" (hereinafter sometimes referred to as a "three-state signal") means that the analog signal has three possible states: audio disabled (e.g., 0 volts); audio enabled (e.g., 5 volts); and clipping detected (e.g., 8 volts). Therefore, for example, an 8 volt signal value of the three-state signal means that clipping has been detected. In this example, as described below, the three-state signals of the audio circuits 210, 220 can be converted to audio enable and clipping detection signals using converters, as described below.

[0051] The sound system 120 may include a first signal converter circuit 410 that electrically connects the first two-wire communication circuit 310 and the first audio circuit 210. The first signal converter circuit 410 may be configured to generate an enable signal on the audio enable input 320 based on an analog voltage sensed at a tri-state input output 420 of the first signal converter circuit 410. The first signal converter 410 may be configured to activate the enable signal at a terminal 430 when, for example, a 5 volt signal is sensed at the tri-state input output 420. The first signal converter circuit 410 may be configured to adjust the analog voltage of the tri-state input output 420 based on a clipping detection signal received via a terminal 440. For example, the first signal converter circuit 410 may be configured to increase the analog voltage of the tri-state input output 420 due to the activation of the clipping detection signal at the terminal 440. Figure 5 An example implementation of a first signal converter 410 including electrical components such as transistors, resistors, diodes, etc. is shown.

[0052] The sound system 120 may include a second signal converter circuit 450 that electrically connects the second two-wire communication circuit 350 and the second audio circuit 220. The second signal converter circuit 450 may be configured to receive an enable signal on a terminal 470 and generate a clipping detection signal on a terminal 480. The second signal converter 450 may be electrically coupled to the second audio circuit 220 via a tri-state input output 460, and may be electrically coupled to the audio enable output 360 and the clipping detection input 370 of the second two-wire communication circuit 350 via terminals 470, 480. The second signal converter circuit 450 may be configured to generate a clipping detection signal based on an analog voltage sensed at the tri-state input output 460 of the second signal converter circuit 450. The terminal 480 may be electrically connected to the clipping detection input 370. The second signal converter 450 may be configured to activate the clipping detection signal when a voltage exceeding a threshold value (e.g., 8 volts) is sensed at the tri-state input output 460. The second signal converter 450 may be configured to output 0 (zero) or 5 volts via the tri-state input output 460 upon determining that the enable signal received via the terminal 470 connected to the audio enable output 360 is inactive or active, respectively. Figure 6 An example implementation of a second signal converter 450 including electrical components such as transistors, resistors, diodes, etc. is shown.

[0053] deal with

[0054] Figure 7 is a flow chart of an example process 700 for transmitting an audio signal. The processor 380a of the first audio circuit 210 may be programmed to perform the blocks of the process 700.

[0055] The process 700 begins in decision block 710, where the processor 380a determines whether a voice activation request is received. For example, the processor 380a may be programmed to receive user input via the HMI 140 of the vehicle 100. The user input may include a request to activate, for example, the second audio circuit 220 to output the radio sound generated by the first audio circuit 210 via the speaker of the second audio circuit 220. If the processor 380a determines that a voice activation request is received, the process 700 proceeds to block 720; otherwise, the process 700 returns to decision block 710.

[0056] In block 720 , the processor 380 a activates the enable signal. The processor 380 a may be programmed to activate an output pin of the processor 380 a electrically connected to the audio enable input 320 .

[0057] After block 720, decision block 750, or block 760, in block 730, the processor 380a activates the first chip 340a to transmit the audio signal and the enable signal. For example, the processor 380a may be programmed to activate the first chip 340a to transmit the audio signal and the enable signal to the second audio circuit 220 via the two-wire bidirectional bus 230 (see Figure 3 As another example, the processor 380a may be programmed to transmit the audio signal and the enable signal to the second audio circuit 220d via a daisy chain (see Figure 2B ).

[0058] Next, in decision block 740, processor 380a determines whether a sound deactivation request is received. Processor 380a may be programmed to determine whether user input including a request to, for example, turn off the sound is received via HMI 140. If processor 380a determines that a sound deactivation request is received, process 700 proceeds to block 770; otherwise, process 700 proceeds to decision block 750.

[0059] In decision block 750, processor 380a receives the clipping detection signal and determines that the received clipping detection signal has an active state. Processor 380a may be programmed to receive the clipping detection signal from clipping detection output 330 via an input pin of processor 380a. If processor 380a determines that the state of the clipping detection signal is active, process 700 proceeds to block 760; otherwise, process 700 returns to block 730.

[0060] In block 760 , processor 380 a adjusts the amplitude of the audio signal. For example, processor 380 a may be programmed to reduce the amplitude of the audio signal by a predetermined amount (eg, approximately 5%). After block 760 , process 700 returns to block 730 .

[0061] In block 770, processor 380a deactivates the audio enable signal, for example, by turning off an output of processor 380a electrically connected to audio enable input 320. After block 770, process 700 ends, or alternatively returns to decision block 710, although Figure 7 Not shown in FIG.

[0062] Figure 8 is a flow chart of an example process 800 for receiving an audio signal. The processor 380b of the second audio circuit 220 may be programmed to perform the blocks of the process 800.

[0063] Process 800 begins in block 805, where processor 380b determines whether an enable signal is activated. Processor 380b may be programmed to receive the enable signal from audio enable output 360 via an input pin of processor 380b. Processor 380b may be programmed to determine the state of the enable signal. If processor 380b determines that the enable signal is activated, process 800 proceeds to block 808; otherwise, process 800 proceeds to block 805.

[0064] In block 808, processor 380b activates amplifier 390. Processor 380b may be programmed to turn on power to amplifier 390.

[0065] Next, in decision block 810, processor 380b determines whether the enable signal is still activated. Processor 380b may be programmed to receive the enable signal from audio enable output 360 via an input pin of processor 380b. Processor 380b may be programmed to determine the state of the enable signal. If processor 380b determines that the enable signal is still activated, process 800 proceeds to block 820; otherwise, process 800 proceeds to block 850.

[0066] In block 820 , the processor 380 b activates the amplifier 390 to amplify the received audio signal and output the amplified audio signal, for example, via one or more speakers of the second audio circuit 220 .

[0067] Next, in decision block 830, processor 380b determines whether clipping of the amplified audio signal is detected. Processor 380b can be programmed to determine clipping when it is determined that the amplitude of the amplified audio signal exceeds the maximum limit of the amplifier and / or speaker. If processor 380b detects clipping, process 800 proceeds to block 840; otherwise, process 800 returns to decision block 810.

[0068] In block 840, processor 380b transmits the activated clipping detection signal to, for example, first audio circuit 210. Processor 380b may be programmed to command second chip 340b to transmit the clipping detection signal to one or more first audio circuits 210 via two-wire bidirectional bus 230. After block 840, process 800 returns to decision block 810.

[0069] In block 850, processor 380b disables amplifier 390. Processor 380b may be programmed to shut off power to amplifier 390.

[0070] After block 850, process 800 ends, or alternatively returns to decision block 710, although Figure 8 Not shown in FIG.

[0071] The articles "a" and "the" modifying nouns are to be understood to mean one or more, unless stated otherwise or the context requires otherwise. The phrase "based on" includes partly or wholly based on.

[0072] The computing devices discussed herein generally each include instructions that can be executed by one or more computing devices such as those identified above and used to perform the blocks or steps of the above-described processes. The computer-executable instructions can be compiled or interpreted by a computer program created using a variety of programming languages ​​and / or technologies, including, alone or in combination, Java, and / or other programming languages. TM , C, C++, Visual Basic, Java Script, Perl, HTML, etc. In general, a processor (e.g., a microprocessor) receives instructions, such as from a memory, a computer-readable medium, etc., and executes these instructions to perform one or more processes, including one or more of the processes described herein. A variety of computer-readable media can be used to store and transmit such instructions and other data. Files in a computing device are typically collections of data stored on a computer-readable medium (such as a storage medium, a random access memory, etc.).

[0073] Computer readable media include any media that participate in providing data (e.g., instructions) that can be read by a computer. Such media can take many forms, including but not limited to non-volatile media, volatile media, etc. Non-volatile media include, for example, optical or magnetic disks and other permanent storage. Non-volatile media include dynamic random access memory (DRAM) that usually constitutes main memory. Common forms of computer readable media include, for example, floppy disks, floppy disks, hard disks, magnetic tapes, any other magnetic media, CD-ROMs, DVDs, any other optical media, punch cards, paper tapes, any other physical media with hole patterns, RAM, PROMs, EPROMs, FLASH, EEPROMs, any other memory chips or cassettes, or any other media from which a computer can read.

[0074] With respect to the media, processes, systems, methods, etc. described herein, it should be understood that although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes may be implemented with the described steps performed in an order other than the order described herein. It should also be understood that certain steps may be performed simultaneously, other steps may be added, or certain steps described herein may be omitted. In other words, the descriptions of systems and / or processes herein are provided for the purpose of illustrating certain embodiments and should in no way be construed as limiting the disclosed subject matter.

[0075] Therefore, it should be understood that the present disclosure, including the above description and the accompanying drawings and the appended claims, is intended to be illustrative and not restrictive. After reading the above description, many embodiments and applications other than the examples provided will be apparent to those skilled in the art. The scope of the present invention should not be determined with reference to the above description, but instead should be determined with reference to the claims attached and / or included in the non-provisional patent application based thereon together with the full scope of equivalents to which the claims are entitled. It is conceivable and expected that further developments will occur in the fields discussed herein, and the disclosed systems and methods will be incorporated into such future embodiments. In summary, it should be understood that the disclosed subject matter is capable of modification and variation.

[0076] According to the present invention, a two-wire communication system is provided, which has: a first audio circuit; and a second audio circuit, which is electrically connected to the first audio circuit via a two-wire bidirectional multi-node communication bus, wherein the two-wire bidirectional multi-node communication bus connects the first audio circuit to the second audio circuit, wherein an audio signal, an enable signal and a limit detection signal are transmitted through the bus.

[0077] According to one embodiment, the above invention is also characterized by: a first two-wire communication circuit, which has an audio enable input, a limit detection output and a first two-wire communication chip electrically connected to a bus, wherein the audio enable input and the limit detection output are electrically coupled to the first audio circuit; and a second two-wire communication circuit, which has an audio enable output, a limit detection input and a second two-wire communication chip electrically connected to the first two-wire communication chip via the bus, wherein the audio enable output and the limit detection input are electrically coupled to the second audio circuit.

[0078] According to one embodiment, the first audio circuit includes a first two-wire communication circuit in communication with the first processor, and the second audio circuit includes a second two-wire communication circuit in communication with the second processor.

[0079] According to one embodiment, the second audio circuit further includes a second processor and a second memory storing instructions executable by the second processor to detect clipping based on the amplitude of the received audio signal.

[0080] According to one embodiment, the audio enable output is electrically connected to the second processor.

[0081] According to one embodiment, the first audio circuit further includes a first processor and a first memory storing instructions executable by the first processor to generate an enable signal based on a received activation request from the human-machine interface.

[0082] According to one embodiment, the audio enable input and the clip detect output are electrically connected to the first processor.

[0083] According to one embodiment, the first memory stores further instructions executable by the first processor to adjust the amplitude of an audio signal transmitted by the first audio circuit based on the clipping detection signal.

[0084] According to one embodiment, the above invention is also characterized by a first signal converter circuit that electrically couples the first two-wire communication circuit and the first audio circuit, wherein the first signal converter circuit is configured to generate an enable signal on the audio enable input based on an analog voltage sensed at a three-state input output of the first signal converter circuit.

[0085] According to one embodiment, the first signal converter circuit is configured to adjust an analog voltage of a tri-state input output based on a clipping detection signal.

[0086] According to one embodiment, the above invention is also characterized by a second signal converter circuit that electrically couples the second two-wire communication circuit and the second audio circuit, wherein the second signal converter circuit is configured to generate a clipping detection signal based on an analog voltage sensed at a three-state input output of the second signal converter circuit.

[0087] According to one embodiment, the first two-wire communication circuit is configured to transmit an audio signal and an enable signal, and to receive a clipping detection signal via a bus.

[0088] According to one embodiment, the amplitude of the audio signal may be adjusted based on the clipping detection signal.

[0089] According to one embodiment, the second audio circuit is activated based on the enable signal.

[0090] According to one embodiment, the above invention is further characterized by a third audio circuit, wherein the first, second, and third audio circuits are daisy-chained via a two-wire bidirectional multi-node communication bus.

[0091] According to one embodiment, the first audio circuit includes a radio and the second audio circuit includes an audio amplifier circuit.

Claims

1. A two-wire communication system, comprising: a first audio circuit; a second audio circuit electrically connected to the first audio circuit via a two-wire bidirectional multi-node communication bus, wherein the two-wire bidirectional multi-node communication bus connects the first audio circuit to the second audio circuit, wherein an audio signal, an enable signal, and a clipping detection signal are transmitted over the two-wire bidirectional multi-node communication bus; a first two-wire communication circuit having an audio enable input, a clip detect output, and a first two-wire communication chip electrically connected to the two-wire bidirectional multi-node communication bus, wherein the audio enable input and the clip detect output are electrically coupled to the first audio circuit; as well as a second two-wire communication circuit having an audio enable output, a clip detect input, and a second two-wire communication chip electrically connected to the first two-wire communication chip via the two-wire bidirectional multi-node communication bus, wherein the audio enable output and the clip detect input are electrically coupled to the second audio circuit.

2. The two-wire communication system of claim 1, wherein the first audio circuit comprises the first two-wire communication circuit in communication with a first processor, and the second audio circuit comprises the second two-wire communication circuit in communication with a second processor.

3. The two-wire communication system of claim 2, wherein the second audio circuit further comprises the second processor and a second memory, the second memory storing instructions executable by the second processor to detect the clipping based on the amplitude of the received audio signal.

4. The two-wire communication system of claim 3, wherein the audio enable output is electrically connected to the second processor.

5. The two-wire communication system of claim 2, wherein the first audio circuit further comprises the first processor and a first memory storing instructions executable by the first processor to generate the enable signal based on the received activation request from the human-machine interface.

6. The two-wire communication system of claim 5, wherein the audio enable input and the clip detect output are electrically connected to the first processor.

7. The two-wire communication system of claim 5, wherein the first memory stores further instructions executable by the first processor to adjust the amplitude of the audio signal transmitted by the first audio circuit based on the clip detection signal.

8. The two-wire communication system of claim 1 , further comprising a first signal converter circuit electrically coupling the first two-wire communication circuit and the first audio circuit, wherein the first signal converter circuit is configured to generate the enable signal on the audio enable input based on an analog voltage sensed at a three-state input output of the first signal converter circuit.

9. The two-wire communication system of claim 8, wherein the first signal converter circuit is configured to adjust the analog voltage of the tri-state input output based on the clipping detection signal.

10. The two-wire communication system of claim 1 , further comprising a second signal converter circuit electrically coupling the second two-wire communication circuit and the second audio circuit, wherein the second signal converter circuit is configured to generate the clipping detection signal based on an analog voltage sensed at a three-state input output of the second signal converter circuit.

11. The two-wire communication system of claim 1, wherein the first two-wire communication circuit is configured to transmit the audio signal and the enable signal and to receive the clipping detection signal via the two-wire bidirectional multi-node communication bus.

12. The two-wire communication system of claim 1, wherein the amplitude of the audio signal is adjustable based on the clip detection signal, and the first audio circuit comprises a radio, and the second audio circuit comprises an audio amplifier circuit.

13. The two-wire communication system of claim 1, wherein the second audio circuit is activated based on the enable signal.

14. The two-wire communication system of claim 1, further comprising a third audio circuit, wherein the first audio circuit, the second audio circuit, and the third audio circuit are daisy-chained via a two-wire bidirectional multi-node communication bus.

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