Audio processing circuit, vehicle-mounted player, bluetooth playing system and vehicle

Abstract

The embodiment of the application discloses an audio processing circuit, a vehicle-mounted player, a Bluetooth playing system and a vehicle, wherein the method comprises: a signal acquisition module, the signal acquisition module is a wireless input module and / or a wired input module, the wireless input module receives an audio signal based on wireless technology, and the wired input module is used for receiving an audio signal based on wired technology; an audio processing module is used for processing the audio signal received by the signal acquisition module to improve the sound quality; an FM transmitting module is used for frequency modulation transmission of the audio signal output by the audio processing module; a power supply module is used for power supply to the signal acquisition module, the audio processing module and the FM transmitting module. Thus, the audio signal optimization is realized in the front end of the FM transmitting module through the audio processing module, the quality of the audio signal received by the car radio is higher, the sound quality of the audio played by the car radio is greatly improved, and the user experience is improved.

Description

Technical Field

[0001] This application relates to the field of audio technology, and in particular to an audio processing circuit, an in-vehicle player, a Bluetooth playback system, and a vehicle. Background Technology

[0002] Currently, car audio players connect to mobile devices via Bluetooth. The audio signal from the mobile device is transmitted to the car audio player's Bluetooth main control chip, which then decodes and performs digital-to-analog conversion before sending it to the FM transmitter chip. The FM transmitter chip then wirelessly tunes the audio signal before sending it to the car radio, enabling the car radio to wirelessly play music from the mobile device and make and receive phone calls. However, this technology suffers from multiple transmissions. The audio signal is first sent from the mobile device to the Bluetooth main control chip, then from the Bluetooth main control chip to the FM transmitter chip, and finally from the FM transmitter chip to the car radio. This multiple path transformation weakens the audio signal, resulting in significant distortion and high background noise in the audio signal received by the car radio. The resulting music quality is unacceptable, causing considerable inconvenience and a poor user experience when listening to music or making phone calls. Summary of the Invention

[0003] Based on this, it is necessary to address the technical problem that when existing car radios use in-vehicle players to wirelessly play music from mobile devices and make and receive calls, the audio signal is damaged and weakened after multiple path turns, resulting in high distortion and low background noise in the audio signal received by the car radio. This paper proposes an audio processing circuit, an in-vehicle player, a Bluetooth playback system, and a vehicle.

[0004] This application discloses an audio processing circuit, the audio processing circuit comprising: A signal acquisition module, wherein the signal acquisition module is a wireless input module and / or a wired input module, wherein the wireless input module receives audio signals based on wireless technology, and the wired input module is used to receive audio signals based on wired technology; An audio processing module is used to process the audio signal received by the signal acquisition module to improve the sound quality; An FM transmitter module is used to transmit the audio signal output by the audio processing module in frequency modulation. The power supply module is used to supply power to the signal acquisition module, the audio processing module and the FM transmission module.

[0005] This application also proposes a vehicle-mounted media player, the vehicle-mounted media player comprising: an audio processing circuit, the audio processing circuit comprising: A signal acquisition module, wherein the signal acquisition module is a wireless input module and / or a wired input module, wherein the wireless input module receives audio signals based on wireless technology, and the wired input module is used to receive audio signals based on wired technology; An audio processing module is used to process the audio signal received by the signal acquisition module to improve the sound quality; An FM transmitter module is used to transmit the audio signal output by the audio processing module in frequency modulation. The power supply module is used to supply power to the signal acquisition module, the audio processing module, and the FM transmission module. powered by.

[0006] This application also proposes a Bluetooth playback system, the Bluetooth playback system comprising: an audio processing circuit, the audio processing circuit comprising: A signal acquisition module, wherein the signal acquisition module is a wireless input module and / or a wired input module, wherein the wireless input module receives audio signals based on wireless technology, and the wired input module is used to receive audio signals based on wired technology; An audio processing module is used to process the audio signal received by the signal acquisition module to improve the sound quality; An FM transmitter module is used to transmit the audio signal output by the audio processing module in frequency modulation. The power supply module is used to supply power to the signal acquisition module, the audio processing module and the FM transmission module.

[0007] This application also proposes a means of transportation, the means of transportation comprising: an audio processing circuit, the audio processing circuit comprising: A signal acquisition module, wherein the signal acquisition module is a wireless input module and / or a wired input module, wherein the wireless input module receives audio signals based on wireless technology, and the wired input module is used to receive audio signals based on wired technology; An audio processing module is used to process the audio signal received by the signal acquisition module to improve the sound quality; An FM transmitter module is used to transmit the audio signal output by the audio processing module in frequency modulation. The power supply module is used to supply power to the signal acquisition module, the audio processing module and the FM transmission module.

[0008] The audio processing circuit of this application includes: a Bluetooth module that receives audio signals based on Bluetooth technology; an audio processing module that processes the audio signals received by the Bluetooth module to improve sound quality; and an FM transmission module that performs frequency modulation transmission of the audio signals output by the audio processing module. Thus, the audio processing module optimizes the audio signals at the front end of the FM transmission module, resulting in higher quality audio signals received by the car radio and significantly improved sound quality of the audio played by the car radio, thereby enhancing the user experience. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] in: Figure 1 This is a block diagram of an audio processing circuit in one embodiment; Figure 2 This is a circuit schematic diagram of the second processing submodule of the audio processing circuit in one embodiment; Figure 3 This is a circuit schematic diagram of a portion of the circuitry of the first processing submodule of the audio processing circuit in one embodiment; Figure 4 This is a circuit schematic diagram of a portion of the circuitry of the first processing submodule of the audio processing circuit in one embodiment; Figure 5 This is a circuit schematic diagram of the power supply module of the audio processing circuit in one embodiment; Figure 6 This is a circuit schematic of the Bluetooth module of the audio processing circuit in one embodiment; Figure 7 This is a schematic diagram of the FM transmitter module circuit of the audio processing circuit in one embodiment; Figure 8 This is a block diagram of an in-vehicle player with audio processing circuitry in one embodiment. Detailed Implementation

[0011] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0012] like Figure 1 As shown, in one embodiment, this application proposes an audio processing circuit, the audio processing circuit comprising: The signal acquisition module 1 is a wireless input module and / or a wired input module. The wireless input module receives audio signals based on wireless technology, and the wired input module is used to receive audio signals based on wired technology. Audio processing module 2 is used to process the audio signal received by signal acquisition module 1 to improve sound quality; FM transmitter module 3 is used to transmit the audio signal output by the audio processing module 2 in frequency modulation. The power supply module 4 is used to supply power to the signal acquisition module 1, the audio processing module 2 and the FM transmission module 3.

[0013] This embodiment optimizes the audio signal at the front end of the FM transmitter module 3 through the audio processing module 2, resulting in higher quality audio signals received by the car radio and significantly improved sound quality of the audio played by the car radio, thus enhancing the user experience.

[0014] The wired input module receives signals via one or more of the following methods: USB flash drive, TF card, USB interface, Type-C, and Type-B. The wired input module receives audio signals and then inputs them to the audio processing module 2. The wireless input module is a Bluetooth module, used to receive audio signals based on Bluetooth technology.

[0015] It is understood that the parameters of the components (e.g., resistors, capacitors) in this application can be calibrated using limited experiments, and will not be elaborated here.

[0016] It is understood that, in order to better describe the solution of this application, the audio processing circuit is divided into multiple modules (i.e., Bluetooth module, audio processing module 2, FM transmitter module 3, and power supply module 4). In actual products, these modules are located on at least one circuit board.

[0017] The Bluetooth module includes a Bluetooth master control chip and its supporting circuitry, used to receive audio signals based on Bluetooth technology.

[0018] Figure 6 The diagram illustrates the Bluetooth module. U1 is the Bluetooth main control chip, Y1 is the crystal oscillator, C9, C12, C4, C1, C2, and C11 are capacitors, D1IN4148 is a diode for voltage reduction, and D1ANTBNE is the Bluetooth antenna.

[0019] Optionally, the Bluetooth master control chip can be selected from existing technologies, and no limitation is made here. The matching circuit of the Bluetooth master control chip is set according to the requirements of the Bluetooth master control chip, and will not be described in detail here.

[0020] Optionally, the audio processing module 2 includes a first processing submodule. In this case, the first processing submodule directly processes the audio signal received by the Bluetooth module.

[0021] Optionally, the audio processing module 2 includes a first processing submodule and a second processing submodule. In this case, the second processing submodule amplifies the audio signal received by the Bluetooth module, and the first processing submodule processes the signal output by the second processing submodule to improve sound quality. It is understood that the first processing submodule does not directly obtain signals from the Bluetooth module in this situation.

[0022] FM transmitter module 3 includes an FM (Frequency Modulation) transmitter chip and its associated circuitry. The associated circuitry is configured according to the requirements of the FM transmitter chip and will not be detailed here. The FM transmitter chip is used for FM frequency modulation and transmitting the modulated signal.

[0023] Power supply module 4 uses DC-DC, such as Figure 5 As shown. A DC-DC converter is a device that converts electrical energy from one voltage value to another in a DC circuit. It employs microelectronics technology, assembling small surface-mount integrated circuits and microelectronic components into a single unit. The power supply module 4 provides 5V DC power to the Bluetooth module, the audio processing module 2, and the FM transmitter module 3.

[0024] It is understandable that other DC-DC converters can be selected from existing technologies, and no restrictions are imposed here.

[0025] In one embodiment, the wireless input module is a Bluetooth module, which is used to receive audio signals based on Bluetooth technology; the audio processing module 2 includes: a first processing submodule; The first processing submodule includes: a signal frequency division unit, a frequency division adjustment unit, and an amplification and merging unit; The signal frequency division unit is electrically connected to the power supply module 4 and the Bluetooth module, and is used to divide the audio signal received by the Bluetooth module. The frequency division adjustment unit includes at least one of a treble adjustment subunit, a bass adjustment subunit, and a midrange adjustment subunit, wherein the treble adjustment subunit is used to adjust the high-frequency signal divided by the signal frequency division unit, the bass adjustment subunit is used to adjust the low-frequency signal divided by the signal frequency division unit, and the midrange adjustment subunit is used to adjust the mid-frequency signal divided by the signal frequency division unit. The amplification and merging unit includes an amplification and merging chip U5 and a voltage divider subunit. The amplification and merging chip U5 is electrically connected to the frequency division adjustment unit, the FM transmission module 3 and the power supply module 4, and is used to amplify and merge the signal output by the frequency division adjustment unit to output to the FM transmission module 3. The voltage divider subunit includes: a first resistor R19, pin 8 of the amplification and merging chip U5 is electrically connected to the first end of the first resistor R19, and the second end of the first resistor R19 is electrically connected to the power supply module 4. The 8th pin of the amplification and merging chip U5 is used to provide a reference power supply (i.e., VDD).

[0026] This embodiment uses a signal frequency division unit to divide the audio signal received by the Bluetooth module, and then uses a frequency division adjustment unit to adjust the signals of each frequency divided by the signal frequency division unit. This achieves audio signal optimization at the front end of the FM transmitter module 3, resulting in higher quality audio signals received by the car radio and significantly improved sound quality, thus enhancing the user experience. Furthermore, independent adjustment of high-frequency, mid-frequency, and low-frequency signals improves adjustment accuracy and ensures that the signal sent by the FM transmitter module 3 to the car radio better meets the user's personalized needs, further enhancing the user experience.

[0027] The amplifier-merging chip U5 can be selected from chips that can amplify signals and merge the amplified signals at the same time, such as the HG5532 operational amplifier chip.

[0028] The first resistor, R19, is a resistor.

[0029] The signal frequency division unit is used to divide the audio signal received by the Bluetooth module into high-frequency signal, low-frequency signal and intermediate-frequency signal.

[0030] like Figure 2 As shown, in one embodiment, the audio processing module 2 further includes a second processing submodule; The second processing submodule includes: a second resistor R29, a third resistor R30, a first capacitor C59, a second capacitor C99, a third capacitor C61, a fourth capacitor C47, a fifth capacitor C45, a sixth capacitor C46, ​​a seventh capacitor C44, and an operational amplifier U3; The first terminal of the fourth capacitor C47 is electrically connected to the signal division unit to input the signal of the first channel to the signal division unit, and the second terminal of the fourth capacitor C47 is electrically connected to pin 1 and pin 2 of the operational amplifier U3. The two ends of the fifth capacitor C45 are electrically connected to pin 3 of the operational amplifier U3 and the first channel output terminal of the Bluetooth module, respectively. The first end of the third resistor R30 is electrically connected to pin 3 of the operational amplifier U3. The first end of the third capacitor C61 and pin 4 of the operational amplifier U3 are both grounded. The second end of the third resistor R30, the second end of the third capacitor C61, and the first end of the second resistor R29 are electrically connected to pin 5 of the amplifier-integrator chip U5. Pin 5 of the operational amplifier U3 is electrically connected to the second end of the second resistor R29 and the first end of the seventh capacitor C44. The second end of the seventh capacitor C44 is electrically connected to the second channel output terminal of the Bluetooth module. Pin 5 of the amplifier-integrator chip U5 provides power (i.e., VCC). The first terminal of the sixth capacitor C46 is electrically connected to the signal division unit to input the signal of the second channel to the signal division unit, and the second terminal of the sixth capacitor C46 is electrically connected to the 6th pin and the 7th pin of the operational amplifier U3. The 8th pin of the operational amplifier U3 is electrically connected to the 8th pin of the amplification and merging chip U5, the first end of the first capacitor C59, and the first end of the second capacitor C99. The second ends of the first capacitor C59 and the second end of the second capacitor C99 are both grounded.

[0031] This embodiment uses a second processing submodule to amplify the audio signal received by the Bluetooth module and then output it to the signal frequency division unit for frequency division. This achieves two-stage processing by the second processing submodule and the first processing submodule. Compared with the single-stage processing of the first processing submodule, the two-stage processing optimizes the audio signal at the front end of the FM transmitter module 3.

[0032] Optionally, the first channel can be the right channel and the second channel can be the left channel. It is also possible that the second channel can be the right channel and the first channel the left channel.

[0033] In this system, the 5V DC power output from the power supply is stepped down by a diode to power the Bluetooth main control chip. Once the Bluetooth main control chip is operating normally, it outputs audio signals from the first channel output pin (the pin that outputs the first channel signal) and the second channel output pin (the pin that outputs the second channel signal). The audio signal output from the first channel output pin is coupled and filtered by the fifth capacitor C45 to eliminate redundant ripples. The audio signal output from the second channel output pin is coupled and filtered by the seventh capacitor C44 to eliminate redundant ripples. Operational amplifier U3 amplifies the coupled and filtered signal, then outputs the first channel signal from pin 1 of operational amplifier U3 to the fourth capacitor C47, where it is coupled and filtered to eliminate redundant ripples. Finally, the first channel signal is output from pin 7 of operational amplifier U3 to the sixth capacitor C46, ​​where it is coupled and filtered to eliminate redundant ripples. Compared to the audio signal received by the Bluetooth module, the signal output in this embodiment has better quality.

[0034] It is understood that in this embodiment, the audio signal received by the Bluetooth module directly enters the second processing submodule, and the first processing submodule only receives signals from the second processing submodule for processing, and the first processing submodule no longer receives signals from the Bluetooth module.

[0035] The second resistor R29 and the third resistor R30 are both resistors. The first capacitor C59, the second capacitor C99, the third capacitor C61, the fourth capacitor C47, the fifth capacitor C45, the sixth capacitor C46, ​​and the seventh capacitor C44 are all capacitors.

[0036] like Figure 3 and Figure 4 As shown, in one embodiment, the signal frequency division unit includes: an eighth capacitor C49, a ninth capacitor C50, a tenth capacitor C23, an eleventh capacitor C66, a first frequency division resistor R31, and a second frequency division resistor R33. The first terminal of the eighth capacitor C49, the first terminal of the first frequency divider resistor R31, and the first terminal of the tenth capacitor C23 are electrically connected to the first channel output terminal of the Bluetooth module to divide the first channel of the audio signal received by the Bluetooth module. The second terminal of the eighth capacitor C49 serves as the first high-frequency terminal, the second terminal of the first frequency divider resistor R31 serves as the first low-frequency terminal, and the second terminal of the tenth capacitor C23 serves as the first mid-frequency terminal. The first terminal of the ninth capacitor C50, the first terminal of the second frequency divider resistor R33, and the first terminal of the eleventh capacitor C66 are electrically connected to the second channel output terminal of the Bluetooth module to divide the second channel of the audio signal received by the Bluetooth module. The second terminal of the ninth capacitor C50 serves as the second high-frequency terminal, the second terminal of the second frequency divider resistor R33 serves as the second low-frequency terminal, and the second terminal of the eleventh capacitor C66 serves as the second mid-frequency terminal. The capacitance of the tenth capacitor C23 and the eleventh capacitor C66 are both higher than the capacitance of the eighth capacitor C49, and the capacitance of the tenth capacitor C23 and the eleventh capacitor C66 are both higher than the capacitance of the ninth capacitor C50.

[0037] This embodiment achieves frequency division through the eighth capacitor C49, the ninth capacitor C50, the tenth capacitor C23, the eleventh capacitor C66, the first crossover resistor R31, and the second crossover resistor R33, thus providing a basis for independent frequency division adjustment of treble, midrange, and bass.

[0038] It is understandable that in the scheme using audio processing module 2, the first end of the eighth capacitor C49, the first end of the first frequency division resistor R31, and the first end of the tenth capacitor C23 are electrically connected to the operational amplifier U3 of audio processing module 2. The first ends of the eighth capacitor C49, the first end of the first frequency division resistor R31, and the first end of the tenth capacitor C23 are no longer electrically connected to the first channel output of the Bluetooth module. Furthermore, the first ends of the ninth capacitor C50, the first end of the second frequency division resistor R33, and the first end of the eleventh capacitor C66 are electrically connected to the second channel output of the Bluetooth module to perform frequency division on the second channel output by the operational amplifier U3 of audio processing module 2. Frequency division on the second channel of the audio signal received by the Bluetooth module is no longer performed.

[0039] Because capacitors have the function of passing high frequencies and blocking low frequencies, high-frequency signals are blocked by the first frequency divider resistor R31 and the second frequency divider resistor R33, and only pass through the eighth capacitor C49 and the ninth capacitor C50. Low-frequency signals are blocked by the eighth capacitor C49 and the ninth capacitor C50, and only pass through the first frequency divider resistor R31 and the second frequency divider resistor R33. The signal of the input signal frequency divider unit is divided again by the tenth capacitor C23 and the eleventh capacitor C66.

[0040] According to the capacitor frequency formula F = 1 / (2πCXc), when the capacitive reactance is constant, the larger the capacitance, the lower the frequency it passes through; that is, capacitance and frequency are inversely proportional. Since the capacitances of the tenth capacitor C23 and the eleventh capacitor C66 are both higher than the capacitance of the eighth capacitor C49, and the capacitances of the tenth capacitor C23 and the eleventh capacitor C66 are both higher than the capacitance of the ninth capacitor C50, the frequency of the signal flowing through the tenth capacitor C23 and the eleventh capacitor C66 will be lower than the frequency of the signal flowing through the eighth capacitor C49 and the ninth capacitor C50, and higher than the frequency of the signal flowing through the first frequency divider resistor R31 and the second frequency divider resistor R33. This frequency falls between high and low frequencies, i.e., the intermediate frequency.

[0041] The eighth capacitor C49, the ninth capacitor C50, the tenth capacitor C23, and the eleventh capacitor C66 are all capacitors. The first frequency divider resistor R31 and the second frequency divider resistor R33 are resistors.

[0042] like Figure 3 As shown, in one embodiment, the above-mentioned treble adjustment subunit includes: a first treble adjustable resistor RP2-A, a second treble adjustable resistor RP2-B, a twelfth capacitor C51, a thirteenth capacitor C52, a fourteenth capacitor C58, and a fifteenth capacitor C57. The first terminal of the first adjustable tweeter RP2-A is electrically connected to the first tweeter terminal of the signal crossover unit. The second terminal of the first adjustable tweeter RP2-A is electrically connected to the first terminal of the twelfth capacitor C51. The adjustable terminal of the first adjustable tweeter RP2-A is electrically connected to the first input terminal of the amplifier-integrator chip U5. The first output terminal of the amplifier-integrator chip U5 is electrically connected to the first terminal of the fourteenth capacitor C58, the second terminal of the twelfth capacitor C51, and the first input terminal of the FM transmitter module 3. The second terminal of the fourteenth capacitor C58 is electrically connected to the first input terminal of the amplifier-integrator chip U5. The first tweeter terminal outputs the signal of the first channel. The first terminal of the second adjustable tweeter RP2-B is electrically connected to the second tweeter terminal of the signal crossover unit. The second terminal of the second adjustable tweeter RP2-B is electrically connected to the first terminal of the thirteenth capacitor C52. The adjustable terminal of the second adjustable tweeter RP2-B is electrically connected to the second input terminal of the amplifier-integrator chip U5. The second output terminal of the amplifier-integrator chip U5 is electrically connected to the first terminal of the fifteenth capacitor C57, the second terminal of the thirteenth capacitor C52, and the second input terminal of the FM transmitter module 3. The second terminal of the fifteenth capacitor C57 is electrically connected to the second input terminal of the amplifier-integrator chip U5. The second tweeter terminal outputs the signal of the second channel.

[0043] This embodiment achieves independent adjustment of the treble through the first adjustable treble resistor RP2-A and the second adjustable treble resistor RP2-B, which helps to improve the adjustment accuracy and makes the signal sent by the FM transmitter module 3 to the car radio more in line with the user's personalized needs, further improving the user experience.

[0044] The twelfth capacitor C51, the thirteenth capacitor C52, the fourteenth capacitor C58, and the fifteenth capacitor C57 are all capacitors.

[0045] Both the first adjustable treble resistor RP2-A and the second adjustable treble resistor RP2-B are resistors with adjustable resistance values.

[0046] Optionally, the first adjustable tweeter resistor RP2-A and the second adjustable tweeter resistor RP2-B can be of the same specification. This helps to achieve the same tweeter adjustment accuracy for both the first and second channels.

[0047] It is understandable that the specifications of the first adjustable treble resistor RP2-A and the second adjustable treble resistor RP2-B may be different.

[0048] Optionally, the first treble adjustable resistor RP2-A and the second treble adjustable resistor RP2-B can be set as dual potentiometers to achieve synchronous adjustment of the high-frequency signals of all channels.

[0049] Optionally, the first treble adjustable resistor RP2-A and the second treble adjustable resistor RP2-B can be adjusted independently.

[0050] In another embodiment of this application, if no treble adjustment subunit is provided, the first treble end of the signal frequency division unit is electrically connected to the first input end of the amplification and merging chip U5, and the second treble end of the signal frequency division unit is electrically connected to the second input end of the amplification and merging chip U5.

[0051] like Figure 3 As shown, in one embodiment, the above-mentioned treble adjustment subunit further includes: a fourth resistor R38 and a fifth resistor R37; The first end of the fourth resistor R38 is connected to the adjustable end of the first high-frequency adjustable resistor RP2-A, and the second end of the fourth resistor R38 is electrically connected to the first input end of the amplifier and merging chip U5. The first end of the fifth resistor R37 is connected to the adjustable end of the second treble adjustable resistor RP2-B, and the second end of the fifth resistor R37 is electrically connected to the second input end of the amplifier and merging chip U5.

[0052] This embodiment improves the accuracy of amplification adjustment by using the fourth resistor R38 in conjunction with the first treble adjustable resistor RP2-A, and the fifth resistor R37 in conjunction with the second treble adjustable resistor RP2-B.

[0053] The fourth resistor R38 and the fifth resistor R37 are both resistors.

[0054] The amplifier-integrator chip U5 amplifies the signal. According to the operational amplifier principle formula, its amplification factor = 1 + feedback resistor / input resistance. In this embodiment, the feedback resistor of the second channel's treble signal circuit is the second adjustable treble resistor RP2-B, and the input resistance is the sum of the second adjustable treble resistor RP2-B and the fifth resistor R37. In this embodiment, the feedback resistor of the first channel's treble signal circuit is the first adjustable treble resistor RP2-A, and the input resistance is the sum of the first adjustable treble resistor RP2-A and the fourth resistor R38. When we manually adjust the first adjustable treble resistor RP2-A, the audio signal amplification factor at the first output terminal of the amplifier-integrator chip U5 will adjust accordingly, and the treble of the first channel will change accordingly. When we manually adjust the second adjustable treble resistor RP2-B, the audio signal amplification factor at the second output terminal of the amplifier-integrator chip U5 will adjust accordingly, and the treble of the second channel will change accordingly.

[0055] It is understood that both the fourth resistor R38 and the fifth resistor R37 are resistors that balance the relationship between the input and output. In another embodiment of this application, the amplifier-integrator chip U5 integrates the functional package of the fourth resistor R38 and the fifth resistor R37, eliminating the need for separate configurations of the fourth resistor R38 and the fifth resistor R37. In this case, the adjustable terminal of the first treble adjustable resistor RP2-A is electrically connected to the first input terminal of the amplifier-integrator chip U5, and the adjustable terminal of the second treble adjustable resistor RP2-B is electrically connected to the second input terminal of the amplifier-integrator chip U5.

[0056] like Figure 3 As shown, in one embodiment, the bass adjustment subunit includes: a sixteenth capacitor C53, a seventeenth capacitor C54, an eighteenth capacitor C56, a nineteenth capacitor C55, a first bass adjustable resistor RP1-A, and a second bass adjustable resistor RP1-B. The first input terminal of the amplifier-integrator chip U5 is electrically connected to the adjustable terminal of the first bass adjustable resistor RP1-A, the first terminal of the sixteenth capacitor C53, and the first terminal of the seventeenth capacitor C54. The first bass terminal of the signal crossover unit is electrically connected to the second terminal of the sixteenth capacitor C53 and the first terminal of the first bass adjustable resistor RP1-A. The first output terminal of the amplifier-integrator chip U5 is electrically connected to the second terminal of the seventeenth capacitor C54 and the second terminal of the first bass adjustable resistor RP1-A. The first bass terminal outputs the signal of the first channel. The second input terminal of the amplifier-integrator chip U5 is electrically connected to the adjustable terminal of the second bass adjustable resistor RP1-B, the first terminal of the eighteenth capacitor C56, and the first terminal of the nineteenth capacitor C55. The second bass terminal of the signal crossover unit is electrically connected to the second terminal of the eighteenth capacitor C56 and the first terminal of the second bass adjustable resistor RP1-B. The second output terminal of the amplifier-integrator chip U5 is electrically connected to the second terminal of the nineteenth capacitor C55 and the second terminal of the second bass adjustable resistor RP1-B. The second bass terminal outputs the signal of the second channel.

[0057] This embodiment achieves independent bass adjustment through the first bass adjustable resistor RP1-A and the second bass adjustable resistor RP1-B, which helps improve the adjustment accuracy and makes the signal sent to the car radio by the FM transmitter module 3 more in line with the user's personalized needs, further improving the user experience.

[0058] The sixteenth capacitor C53, the seventeenth capacitor C54, the eighteenth capacitor C56, and the nineteenth capacitor C55 are all capacitors.

[0059] The first bass-adjustable resistor RP1-A and the second bass-adjustable resistor RP1-B are both resistors with adjustable resistance values.

[0060] Optionally, the first bass adjustable resistor RP1-A and the second bass adjustable resistor RP1-B have the same specifications. This helps to achieve the same bass adjustment accuracy for both the first and second channels.

[0061] Understandably, the specifications of the first bass adjustable resistor RP1-A and the second bass adjustable resistor RP1-B can also be different.

[0062] Optionally, the first bass adjustable resistor RP1-A and the second bass adjustable resistor RP1-B can be set as a dual potentiometer to achieve synchronous adjustment of the low-frequency signals of all channels.

[0063] Optionally, the first bass adjustable resistor RP1-A and the second bass adjustable resistor RP1-B can be adjusted independently.

[0064] In another embodiment of this application, if a bass adjustment subunit is not provided, the first bass end of the signal crossover unit is electrically connected to the first input end of the amplification and merging chip U5, and the second treble end of the signal crossover unit is electrically connected to the second input end of the amplification and merging chip U5.

[0065] like Figure 3 As shown, in one embodiment, the bass adjustment subunit further includes: a sixth resistor R34, a seventh resistor R36, an eighth resistor R35, and a ninth resistor R39; The first end of the seventh resistor R36 is electrically connected to the first input end of the amplifier-integrator chip U5. The second end of the seventh resistor R36 is electrically connected to the adjustable end of the first bass adjustable resistor RP1-A, the first end of the sixteenth capacitor C53, and the first end of the seventeenth capacitor C54. The first end of the sixth resistor R34 is electrically connected to the first output end of the amplifier-integrator chip U5. The second end of the sixth resistor R34 is electrically connected to the second end of the seventeenth capacitor C54 and the second end of the first bass adjustable resistor RP1-A. The first end of the ninth resistor R39 is electrically connected to the second input end of the amplifier-integrator chip U5. The second end of the ninth resistor R39 is electrically connected to the adjustable end of the second bass adjustable resistor RP1-B, the first end of the eighteenth capacitor C56, and the first end of the nineteenth capacitor C55. The first end of the eighth resistor R35 is electrically connected to the second output end of the amplifier-integrator chip U5. The second end of the eighth resistor R35 is electrically connected to the second end of the nineteenth capacitor C55 and the second end of the second bass adjustable resistor RP1-B.

[0066] This embodiment improves the accuracy of amplification adjustment by using the sixth resistor R34 and the seventh resistor R36 in conjunction with the first bass adjustable resistor RP1-A, and by using the eighth resistor R35 and the ninth resistor R39 in conjunction with the second bass adjustable resistor RP1-B.

[0067] The sixth resistor R34, the seventh resistor R36, the eighth resistor R35, and the ninth resistor R39 are all resistors.

[0068] The amplifier-integrated chip U5 amplifies the signal. According to the operational amplifier principle formula, its amplification factor = 1 + feedback resistor / input resistance. In this embodiment, the feedback resistor of the bass signal circuit of the second channel is the sum of the second adjustable bass resistor RP1-B and the eighth resistor R35, and the input resistance is the sum of the second adjustable bass resistor RP1-B, the ninth resistor R39, and the second crossover resistor R33. In this embodiment, the feedback resistor of the bass signal circuit of the first channel is the sum of the first adjustable bass resistor RP1-A and the sixth resistor R34, and the input resistance is the sum of the first adjustable bass resistor RP1-A, the seventh resistor R36, and the first crossover resistor R31. When we manually adjust the first adjustable bass resistor RP1-A, the audio signal amplification factor at the first output terminal of the amplifier-integrated chip U5 will be adjusted accordingly, and the bass of the first channel will change accordingly. When we manually adjust the second adjustable bass resistor RP1-B, the audio signal amplification factor at the second output terminal of the amplifier-integrated chip U5 will be adjusted accordingly, and the bass of the second channel will change accordingly.

[0069] like Figure 4 As shown, in one embodiment, the above-mentioned mid-range adjustment subunit includes: a twentieth capacitor C70, a twenty-first capacitor C71, a twenty-second capacitor C67, a twenty-third capacitor C68, a twenty-fourth capacitor C69, a twenty-fifth capacitor C43, a first mid-range adjustable resistor RP3-A, and a second mid-range adjustable resistor RP3-B. The first midrange terminal of the signal frequency division unit is electrically connected to the first terminal of the twenty-third capacitor C68 and the first terminal of the first midrange adjustable resistor RP3-A. The first input terminal of the amplifier-combiner chip U5 is electrically connected to the second terminal of the twenty-third capacitor C68, the first terminal of the twenty-fourth capacitor C69, and the adjustable terminal of the first midrange adjustable resistor RP3-A. The first terminal of the twenty-fifth capacitor C43 is electrically connected to the second terminal of the twenty-fourth capacitor C69 and the second terminal of the first midrange adjustable resistor RP3-A. The second terminal of the twenty-fifth capacitor C43 is electrically connected to the first output terminal of the amplifier-combiner chip U5. The second midrange terminal of the signal frequency division unit is electrically connected to the first terminal of the twentieth capacitor C70 and the first terminal of the second midrange adjustable resistor RP3-B. The second input terminal of the amplifier-combiner chip U5 is electrically connected to the second terminal of the twentieth capacitor C70, the first terminal of the eleventh capacitor C71, and the adjustable terminal of the second midrange adjustable resistor RP3-B. The first terminal of the twelfth capacitor C67 is electrically connected to the second terminal of the eleventh capacitor C71 and the second terminal of the second midrange adjustable resistor RP3-B. The second terminal of the twelfth capacitor C67 is electrically connected to the second output terminal of the amplifier-combiner chip U5.

[0070] This embodiment achieves independent adjustment of the midrange frequency through the first adjustable midrange resistor RP3-A and the second adjustable midrange resistor RP3-B, which helps to improve the adjustment accuracy and makes the signal sent to the car radio by the FM transmitter module 3 more in line with the user's personalized needs, further improving the user experience.

[0071] The twentieth capacitor C70, the twenty-first capacitor C71, the twenty-second capacitor C67, the twenty-third capacitor C68, the twenty-fourth capacitor C69, and the twenty-fifth capacitor C43 are all capacitors.

[0072] Both the first and second mid-range adjustable resistors RP3-A and RP3-B are resistors with adjustable resistance values.

[0073] Optionally, the first midrange adjustable resistor RP3-A and the second midrange adjustable resistor RP3-B have the same specifications. This helps to achieve the same midrange adjustment accuracy for both the first and second channels.

[0074] It is understandable that the specifications of the first mid-range adjustable resistor RP3-A and the second mid-range adjustable resistor RP3-B may also be different.

[0075] Optionally, the first mid-range adjustable resistor RP3-A and the second mid-range adjustable resistor RP3-B can be set as a dual potentiometer to achieve synchronous adjustment of the mid-frequency signal of all channels.

[0076] Optionally, the first midrange adjustable resistor RP3-A and the second midrange adjustable resistor RP3-B can be adjusted independently.

[0077] In another embodiment of this application, if no mid-range adjustment subunit is provided, the first mid-range terminal of the signal frequency division unit is electrically connected to the first input terminal of the amplification and merging chip U5, and the second mid-range terminal of the signal frequency division unit is electrically connected to the second input terminal of the amplification and merging chip U5.

[0078] like Figure 4 As shown, in one embodiment, the above-mentioned mid-range adjustment subunit further includes: a tenth resistor R1 and an eleventh resistor R5; The first end of the tenth resistor R1 is electrically connected to the first input terminal of the amplifier and merging chip U5, and the second end of the tenth resistor R1 is electrically connected to the second end of the twenty-third capacitor C68, the first end of the twenty-fourth capacitor C69, and the adjustable end of the first mid-range adjustable resistor RP3-A. The first end of the eleventh resistor R5 is electrically connected to the second input end of the amplifier-merger chip U5, and the second end of the eleventh resistor R5 is electrically connected to the second end of the twentieth capacitor C70, the first end of the eleventh capacitor C71, and the adjustable end of the second mid-range adjustable resistor RP3-B.

[0079] This embodiment improves the accuracy of amplification adjustment by using the cooperation of the tenth resistor R1 with the first mid-range adjustable resistor RP3-A and the eleventh resistor R5 with the second mid-range adjustable resistor RP3-B.

[0080] Both the tenth resistor R1 and the eleventh resistor R5 are resistors.

[0081] like Figure 4 As shown, in one embodiment, the above-mentioned mid-range adjustment subunit further includes: a twelfth resistor R6 and a thirteenth resistor R7; The two ends of the twelfth resistor R6 are electrically connected to the second end of the twenty-fourth capacitor C69 and the first output end of the amplifier-merger chip U5, respectively. The two ends of the thirteenth resistor R7 are electrically connected to the second end of the twenty-first capacitor C71 and the second output end of the amplifier and merging chip U5, respectively.

[0082] This embodiment improves the accuracy of amplification adjustment by using the twelfth resistor R6 in conjunction with the first mid-range adjustable resistor RP3-A, and the thirteenth resistor R7 in conjunction with the second mid-range adjustable resistor RP3-B.

[0083] Both the twelfth resistor R6 and the thirteenth resistor R7 are resistors.

[0084] The amplifier-integrated chip U5 amplifies the signal. According to the operational amplifier principle formula, its amplification factor = 1 + feedback resistor / input resistance. In this embodiment, the feedback resistance of the midrange signal circuit of the second channel is the sum of the second adjustable midrange resistor RP3-B and the twelfth resistor R6, and the input resistance is the sum of the second adjustable midrange resistor RP3-B and the tenth resistor R1. In this embodiment, the feedback resistance of the midrange signal circuit of the first channel is the sum of the first adjustable midrange resistor RP3-A and the thirteenth resistor R7, and the input resistance is the sum of the first adjustable midrange resistor RP3-A and the eleventh resistor R5. When we manually adjust the first adjustable midrange resistor RP3-A, the audio signal amplification factor at the first output terminal of the amplifier-integrated chip U5 will be adjusted accordingly, and the midrange of the first channel will change accordingly. When we manually adjust the second adjustable midrange resistor RP3-B, the audio signal amplification factor at the second output terminal of the amplifier-integrated chip U5 will be adjusted accordingly, and the midrange of the second channel will change accordingly.

[0085] In one embodiment, the treble adjustment subunit synchronously adjusts the high-frequency signals of all channels, the bass adjustment subunit synchronously adjusts the low-frequency signals of all channels, and the midrange adjustment subunit synchronously adjusts the mid-frequency signals of all channels.

[0086] This embodiment uses a treble adjustment subunit to synchronously adjust the high-frequency signals of all channels, a bass adjustment subunit to synchronously adjust the low-frequency signals of all channels, and a midrange adjustment subunit to synchronously adjust the midrange signals of all channels. While enabling individual adjustment of treble, midrange, and bass, it achieves synchronous adjustment of all channels, simplifying the adjustment operation, meeting personalized needs, and maintaining consistency across all channels.

[0087] like Figure 3 As shown, in one embodiment, the first processing submodule further includes: a twenty-sixth capacitor C62 and a twenty-seventh capacitor C63; The first end of the 26th capacitor C62 is electrically connected to the first output end of the amplifier-combiner chip U5, and the second end of the 26th capacitor C62 is electrically connected to the first input end of the FM transmitter module 3. The first end of the 27th capacitor C63 is electrically connected to the second output end of the amplifier-merger chip U5, and the second end of the 27th capacitor C63 is electrically connected to the second input end of the FM transmitter module 3.

[0088] In this embodiment, the signal output from the first output terminal of the amplifier-combiner chip U5 is filtered by the twenty-sixth capacitor C62, and the signal output from the second output terminal of the amplifier-combiner chip U5 is filtered by the twenty-seventh capacitor C63, thereby improving the quality of the signal input to the FM transmitter module 3.

[0089] Both capacitors C62 (twenty-sixth capacitor) and C63 (twenty-seventh capacitor) are capacitors.

[0090] In one embodiment, the audio processing module 2 described above uses a DSP chip.

[0091] Specifically, this means replacing the first processing submodule with a DSP chip.

[0092] DSP chip, which is a digital signal processor.

[0093] like Figure 7 As shown, in one embodiment, the FM transmitter module 3 includes: a frequency modulation transmitter submodule, a twenty-eighth capacitor C5, a twenty-ninth capacitor C6, a fourteenth resistor R22, and a fifteenth resistor R23; The first end of the 29th capacitor C6 is electrically connected to the first output end of the audio processing module 2 to receive the signal of the first channel. The second end of the 29th capacitor C6 is electrically connected to the first end of the 15th resistor R23. The second end of the 15th resistor R23 is electrically connected to the first input end of the FM transmitter submodule. The first end of the 28th capacitor C5 is electrically connected to the second output end of the audio processing module 2 to receive the signal of the second channel. The second end of the 28th capacitor C5 is electrically connected to the first end of the 14th resistor R22. The second end of the 14th resistor R22 is electrically connected to the second input end of the FM transmitter submodule.

[0094] In this embodiment, the signal of the second channel input to the audio processing module 2 is filtered to eliminate ripple through the twenty-eighth capacitor C5 and the fourteenth resistor R22, and the signal of the first channel input to the audio processing module 2 is filtered to eliminate ripple through the twenty-ninth capacitor C6 and the fifteenth resistor R23, which further improves the quality of the signal used for FM tuning and further improves the sound quality of the audio played by the car radio.

[0095] The FM transmitter submodule includes an FM transmitter chip and its associated circuitry.

[0096] Both capacitors C5 (the 28th capacitor) and C6 (the 29th capacitor) are capacitors.

[0097] The fourteenth resistor R22 and the fifteenth resistor R23 are both resistors.

[0098] exist Figure 7 In the diagram, U2 is the FM transmitter chip, FMANT is the transmitting antenna, C10, C32, C17, C12, C13, C65, C18, C64, C3, and C7 are capacitors, L1 and L2 are inductors, Q1 is an NPN transistor, and R16, R24, and R21 are resistors. The +5V is connected to power supply module 4.

[0099] It is understandable that the FM transmitter submodule can also be selected from existing technologies, and no limitation is made here.

[0100] like Figure 8 As shown, in one embodiment, this application also proposes an in-vehicle player, the in-vehicle player comprising: an audio processing circuit, the audio processing circuit comprising: The signal acquisition module 1 is a wireless input module and / or a wired input module. The wireless input module receives audio signals based on wireless technology, and the wired input module is used to receive audio signals based on wired technology. Audio processing module 2 is used to process the audio signal received by signal acquisition module 1 to improve sound quality; FM transmitter module 3 is used to transmit the audio signal output by the audio processing module 2 in frequency modulation. The power supply module 4 is used to supply power to the signal acquisition module 1, the audio processing module 2 and the FM transmission module 3.

[0101] This embodiment optimizes the audio signal at the front end of the FM transmitter module 3 through the audio processing module 2, resulting in higher quality audio signals received by the car radio and significantly improved sound quality of the audio played by the car radio, thus enhancing the user experience.

[0102] Figure 8 The diagram illustrates the block diagram of the car audio player. LED (display screen) is used to set the display for information display. BT-ANT is the Bluetooth antenna. RGB lights are indicator lights for adjusting the level. AC6926A is the Bluetooth main control chip. Y_24M (crystal) is the crystal oscillator. Mid-high-low frequency adjustment / operational amplifier is audio processing module 2. FM_QN8027 is the FM transmitter chip. DC / DC is power supply module 4. TYPE-C is the interface. USB is a universal serial bus standard interface. 12-24V (Power) is the external power supply interface. MIC is the microphone, and KEY / encoder are the buttons and encoder.

[0103] In one embodiment, this application also proposes a Bluetooth playback system, the Bluetooth playback system comprising: an audio processing circuit, the audio processing circuit comprising: The signal acquisition module 1 is a wireless input module and / or a wired input module. The wireless input module receives audio signals based on wireless technology, and the wired input module is used to receive audio signals based on wired technology. Audio processing module 2 is used to process the audio signal received by signal acquisition module 1 to improve sound quality; FM transmitter module 3 is used to transmit the audio signal output by the audio processing module 2 in frequency modulation. The power supply module 4 is used to supply power to the signal acquisition module 1, the audio processing module 2 and the FM transmission module 3.

[0104] This embodiment optimizes the audio signal at the front end of the FM transmitter module 3 through the audio processing module 2, resulting in higher quality audio signals received by the car radio and significantly improved sound quality of the audio played by the car radio, thus enhancing the user experience.

[0105] The Bluetooth playback system also includes mobile devices and a car radio. The mobile device sends audio signals to the Bluetooth module via Bluetooth. The car radio receives audio signals transmitted by the FM transmitter module 3.

[0106] In one embodiment, this application also provides a means of transportation, the means of transportation including: an audio processing circuit, the audio processing circuit including: The signal acquisition module 1 is a wireless input module and / or a wired input module. The wireless input module receives audio signals based on wireless technology, and the wired input module is used to receive audio signals based on wired technology. Audio processing module 2 is used to process the audio signal received by signal acquisition module 1 to improve sound quality; FM transmitter module 3 is used to transmit the audio signal output by the audio processing module 2 in frequency modulation. The power supply module 4 is used to supply power to the signal acquisition module 1, the audio processing module 2 and the FM transmission module 3.

[0107] This embodiment optimizes the audio signal at the front end of the FM transmitter module 3 through the audio processing module 2, resulting in higher quality audio signals received by the car radio and significantly improved sound quality of the audio played by the car radio, thus enhancing the user experience.

[0108] Transportation includes, but is not limited to: cars and buses.

[0109] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0110] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An audio processing circuit, characterized in that, The audio processing circuit includes: A signal acquisition module, wherein the signal acquisition module is a wireless input module and / or a wired input module, wherein the wireless input module receives audio signals based on wireless technology, and the wired input module is used to receive audio signals based on wired technology; An audio processing module is used to process the audio signal received by the signal acquisition module to improve the sound quality; an FM transmission module is used to transmit the audio signal output by the audio processing module in frequency modulation. A power supply module is used to supply power to the signal acquisition module, the audio processing module, and the FM transmission module; The audio processing module includes: a first processing submodule; The first processing submodule includes: a signal frequency division unit, a frequency division adjustment unit, and an amplification and merging unit; The frequency division adjustment unit includes a mid-range adjustment subunit; The mid-range adjustment subunit includes: a 20th capacitor, a 21st capacitor, a 22nd capacitor, a 23rd capacitor, a 24th capacitor, a 25th capacitor, a first mid-range adjustable resistor, and a second mid-range adjustable resistor; The first midrange terminal of the signal frequency division unit is electrically connected to the first terminal of the twenty-third capacitor and the first terminal of the first midrange adjustable resistor. The first input terminal of the amplifier and merging chip is electrically connected to the second terminal of the twenty-third capacitor, the first terminal of the twenty-fourth capacitor, and the adjustable terminal of the first midrange adjustable resistor. The first terminal of the twenty-fifth capacitor is electrically connected to the second terminal of the twenty-fourth capacitor and the second terminal of the first midrange adjustable resistor. The second terminal of the twenty-fifth capacitor is electrically connected to the first output terminal of the amplifier and merging chip. The second midrange terminal of the signal frequency division unit is electrically connected to the first terminal of the twentieth capacitor and the first terminal of the second midrange adjustable resistor. The second input terminal of the amplifier and merging chip is electrically connected to the second terminal of the twentieth capacitor, the first terminal of the twentieth capacitor, and the adjustable terminal of the second midrange adjustable resistor. The first terminal of the twentieth capacitor is electrically connected to the second terminal of the twentieth capacitor and the second terminal of the second midrange adjustable resistor. The second terminal of the twentieth capacitor is electrically connected to the second output terminal of the amplifier and merging chip. The mid-range adjustment subunit also includes: a tenth resistor and an eleventh resistor; The first end of the tenth resistor is electrically connected to the first input terminal of the amplifier and merging chip, and the second end of the tenth resistor is electrically connected to the second end of the twenty-third capacitor, the first end of the twenty-fourth capacitor, and the adjustable end of the first mid-range adjustable resistor. The first end of the eleventh resistor is electrically connected to the second input terminal of the amplifier and merging chip, and the second end of the eleventh resistor is electrically connected to the second end of the twentieth capacitor, the first end of the eleventh capacitor, and the adjustable end of the second mid-range adjustable resistor. The mid-range adjustment subunit also includes: a twelfth resistor and a thirteenth resistor; The two ends of the twelfth resistor are electrically connected to the second end of the twenty-fourth capacitor and the first output terminal of the amplifier-merger chip, respectively; the two ends of the thirteenth resistor are electrically connected to the second end of the twenty-first capacitor and the second output terminal of the amplifier-merger chip, respectively.

2. The audio processing circuit according to claim 1, characterized in that, The wireless input module is a Bluetooth module, which is used to receive audio signals based on Bluetooth technology; the signal frequency division unit is electrically connected to the power supply module and the Bluetooth module, and is used to divide the audio signal received by the Bluetooth module. The frequency division adjustment unit further includes at least one subunit of a treble adjustment subunit and a bass adjustment subunit, wherein the treble adjustment subunit is used to adjust the high-frequency signal divided by the signal frequency division unit, the bass adjustment subunit is used to adjust the low-frequency signal divided by the signal frequency division unit, and the mid-frequency adjustment subunit is used to adjust the mid-frequency signal divided by the signal frequency division unit. The amplification and merging unit includes an amplification and merging chip and a voltage divider subunit. The amplification and merging chip is electrically connected to the frequency division adjustment unit, the FM transmission module and the power supply module, and is used to amplify and merge the signal output by the frequency division adjustment unit to output to the FM transmission module. The voltage divider subunit includes: a first resistor, the 8th pin of the amplification and merging chip is electrically connected to the first end of the first resistor, and the second end of the first resistor is electrically connected to the power supply module, wherein the 8th pin of the amplification and merging chip is used to provide a reference power supply.

3. The audio processing circuit according to claim 2, characterized in that, The audio processing module further includes: a second processing submodule; The second processing submodule includes: a second resistor, a third resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, and an operational amplifier; The first terminal of the fourth capacitor is electrically connected to the signal division unit to input the signal of the first channel to the signal division unit, and the second terminal of the fourth capacitor is electrically connected to the first pin and the second pin of the operational amplifier. The two ends of the fifth capacitor are electrically connected to pin 3 of the operational amplifier and the first channel output of the Bluetooth module, respectively. The first end of the third resistor is electrically connected to pin 3 of the operational amplifier. The first end of the third capacitor and pin 4 of the operational amplifier are both grounded. The second end of the third resistor, the second end of the third capacitor, and the first end of the second resistor are electrically connected to pin 5 of the amplifier-integrator chip. Pin 5 of the operational amplifier is electrically connected to the second end of the second resistor and the first end of the seventh capacitor. The second end of the seventh capacitor is electrically connected to the second channel output of the Bluetooth module. The fifth pin of the amplifier-integrator chip provides power. The first terminal of the sixth capacitor is electrically connected to the signal division unit to input the second channel signal to the signal division unit, and the second terminal of the sixth capacitor is electrically connected to pin 6 and pin 7 of the operational amplifier. The 8th pin of the operational amplifier is electrically connected to the 8th pin of the amplification and merging chip, the first end of the first capacitor, and the first end of the second capacitor. The second ends of the first capacitor and the second end of the second capacitor are both grounded.

4. The audio processing circuit according to claim 2, characterized in that, The signal frequency division unit includes: an eighth capacitor, a ninth capacitor, a tenth capacitor, an eleventh capacitor, a first frequency division resistor, and a second frequency division resistor; The first end of the eighth capacitor, the first end of the first frequency divider resistor, and the first end of the tenth capacitor are electrically connected to the first channel output terminal of the Bluetooth module to divide the first channel of the audio signal received by the Bluetooth module. The second end of the eighth capacitor serves as the first high-frequency end, the second end of the first frequency divider resistor serves as the first low-frequency end, and the second end of the tenth capacitor serves as the first mid-frequency end. The first end of the ninth capacitor, the first end of the second frequency divider resistor, and the first end of the eleventh capacitor are electrically connected to the second channel output terminal of the Bluetooth module to divide the second channel of the audio signal received by the Bluetooth module. The second end of the ninth capacitor serves as the second high-frequency end, the second end of the second frequency divider resistor serves as the second low-frequency end, and the second end of the eleventh capacitor serves as the second mid-frequency end. The capacitance of the tenth capacitor and the eleventh capacitor are both higher than the capacitance of the eighth capacitor, and the capacitance of the tenth capacitor and the eleventh capacitor are both higher than the capacitance of the ninth capacitor.

5. The audio processing circuit according to claim 2, characterized in that, The treble adjustment subunit includes: a first treble adjustable resistor, a second treble adjustable resistor, a twelfth capacitor, a thirteenth capacitor, a fourteenth capacitor, and a fifteenth capacitor; The first end of the first adjustable tweeter is electrically connected to the first tweeter end of the signal frequency division unit, the second end of the first adjustable tweeter is electrically connected to the first end of the twelfth capacitor, the adjustable end of the first adjustable tweeter is electrically connected to the first input end of the amplifier and merging chip, the first output end of the amplifier and merging chip is electrically connected to the first end of the fourteenth capacitor, the second end of the twelfth capacitor and the first input end of the FM transmitter module, and the second end of the fourteenth capacitor is electrically connected to the first input end of the amplifier and merging chip. The first tweeter end outputs the signal of the first channel. The first end of the second adjustable tweeter is electrically connected to the second tweeter of the signal crossover unit, the second end of the second adjustable tweeter is electrically connected to the first end of the thirteenth capacitor, the adjustable end of the second adjustable tweeter is electrically connected to the second input end of the amplifier-combiner chip, the second output end of the amplifier-combiner chip is electrically connected to the first end of the fifteenth capacitor, the second end of the thirteenth capacitor and the second input end of the FM transmitter module, and the second end of the fifteenth capacitor is electrically connected to the second input end of the amplifier-combiner chip. The second tweeter outputs the signal of the second channel.

6. The audio processing circuit according to claim 5, characterized in that, The treble adjustment subunit also includes: a fourth resistor and a fifth resistor; The first end of the fourth resistor is connected to the adjustable end of the first high-frequency adjustable resistor, and the second end of the fourth resistor is electrically connected to the first input end of the amplifier and merging chip. The first end of the fifth resistor is connected to the adjustable end of the second treble adjustable resistor, and the second end of the fifth resistor is electrically connected to the second input end of the amplifier and merging chip.

7. The audio processing circuit according to claim 2, characterized in that, The bass adjustment subunit includes: a sixteenth capacitor, a seventeenth capacitor, an eighteenth capacitor, a nineteenth capacitor, a first bass adjustable resistor, and a second bass adjustable resistor; The first input terminal of the amplifier-merging chip is electrically connected to the adjustable terminal of the first bass adjustable resistor, the first terminal of the sixteenth capacitor, and the first terminal of the seventeenth capacitor. The first bass terminal of the signal division unit is electrically connected to the second terminal of the sixteenth capacitor and the first terminal of the first bass adjustable resistor. The first output terminal of the amplifier-merging chip is electrically connected to the second terminal of the seventeenth capacitor and the second terminal of the first bass adjustable resistor. The first bass terminal outputs the signal of the first channel. The second input terminal of the amplifier-merging chip is electrically connected to the adjustable terminal of the second bass adjustable resistor, the first terminal of the eighteenth capacitor, and the first terminal of the nineteenth capacitor. The second bass terminal of the signal crossover unit is electrically connected to the second terminal of the eighteenth capacitor and the first terminal of the second bass adjustable resistor. The second output terminal of the amplifier-merging chip is electrically connected to the second terminal of the nineteenth capacitor and the second terminal of the second bass adjustable resistor. The second bass terminal outputs the signal of the second channel.

8. The audio processing circuit according to claim 7, characterized in that, The bass adjustment subunit also includes: a sixth resistor, a seventh resistor, an eighth resistor, and a ninth resistor; The first end of the seventh resistor is electrically connected to the first input terminal of the amplifier-integrator chip, the second end of the seventh resistor is electrically connected to the adjustable terminal of the first bass-adjustable resistor, the first end of the sixteenth capacitor and the first end of the seventeenth capacitor, the first end of the sixth resistor is electrically connected to the first output terminal of the amplifier-integrator chip, and the second end of the sixth resistor is electrically connected to the second end of the seventeenth capacitor and the second end of the first bass-adjustable resistor. The first end of the ninth resistor is electrically connected to the second input end of the amplifier-integrator chip. The second end of the ninth resistor is electrically connected to the adjustable end of the second bass-adjustable resistor, the first end of the eighteenth capacitor, and the first end of the nineteenth capacitor. The first end of the eighth resistor is electrically connected to the second output end of the amplifier-integrator chip. The second end of the eighth resistor is electrically connected to the second end of the nineteenth capacitor and the second end of the second bass-adjustable resistor.

9. The audio processing circuit according to claim 2, characterized in that, The treble adjustment subunit synchronously adjusts the high-frequency signals of all channels, the bass adjustment subunit synchronously adjusts the low-frequency signals of all channels, and the midrange adjustment subunit synchronously adjusts the mid-frequency signals of all channels.

10. The audio processing circuit according to claim 2, characterized in that, The first processing submodule further includes: a twenty-sixth capacitor and a twenty-seventh capacitor; The first end of the 26th capacitor is electrically connected to the first output terminal of the amplifier-combiner chip, and the second end of the 26th capacitor is electrically connected to the first input terminal of the FM transmitter module. The first end of the 27th capacitor is electrically connected to the second output terminal of the amplifier-merger chip, and the second end of the 27th capacitor is electrically connected to the second input terminal of the FM transmitter module.

11. The audio processing circuit according to claim 1, characterized in that, The audio processing module uses a DSP chip.

12. The audio processing circuit according to claim 1, characterized in that, The FM transmitter module includes: an FM transmitter submodule, a 28th capacitor, a 29th capacitor, a 14th resistor, and a 15th resistor; The first end of the 29th capacitor is electrically connected to the first output end of the audio processing module to receive the signal of the first channel; the second end of the 29th capacitor is electrically connected to the first end of the 15th resistor; and the second end of the 15th resistor is electrically connected to the first input end of the FM transmitter submodule. The first end of the 28th capacitor is electrically connected to the second output end of the audio processing module to receive the signal of the second channel. The second end of the 28th capacitor is electrically connected to the first end of the 14th resistor. The second end of the 14th resistor is electrically connected to the second input end of the FM transmitter submodule.

13. A car audio player, characterized in that, The in-vehicle player includes the audio processing circuit as described in claim 1.

14. A Bluetooth playback system, characterized in that, The Bluetooth playback system includes the audio processing circuit as described in claim 1.

15. A means of transportation, characterized in that, The vehicle includes: the audio processing circuit as described in claim 1.

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