A vehicle-mounted audio amplifier performance detection system

Abstract

The utility model provides a vehicle -mounted audio frequency amplifier performance detection system relates to electronic measurement technical field, including signal input output difference circuit, first AD conversion circuit, microphone detection circuit, second AD conversion circuit, temperature detection circuit, current collection amplification circuit, MCU main chip circuit and external display part circuit, signal input output difference circuit is used for accessing the front stage input and rear stage output audio frequency analog signal of the amplifier under test, and carries out the noise reduction and sampling processing, microphone detection circuit handles the audio signal of external microphone collection, temperature detection circuit obtains temperature analog signal, current collection amplification circuit handles current signal, and each circuit is handled by MCU main chip after AD conversion, obtains electrical parameter, and displays in external part. The system is through the integration of multiple signal conditioning channel and high accuracy AD conversion, realizes the synchronous fast accurate measurement.

Description

Technical Field

[0001] This utility model relates to the field of electronic measurement technology, specifically to a vehicle-mounted audio amplifier performance testing system. Background Technology

[0002] The in-vehicle audio amplifier is a core component of a car audio system, and its performance directly affects the final sound quality. To ensure product quality, manufacturers must conduct comprehensive performance testing on in-vehicle audio amplifiers before they leave the factory. Traditional testing methods mainly rely on multiple discrete testing instruments, such as using a digital multimeter to measure voltage and current, using an audio analyzer to measure frequency response and distortion, using a sound level meter to measure sound pressure, and using a thermometer to measure temperature.

[0003] This testing system, composed of multiple discrete instruments, has significant drawbacks: First, the system is complex to set up, with cumbersome connections between instruments, consuming a large amount of workspace; second, during the testing process, multiple instruments need to be powered and operated separately, resulting in cumbersome procedures, low testing efficiency, and hindering rapid, batch testing on the production line; third, data synchronization and integration between different instruments are also difficult, making it hard to achieve a comprehensive and integrated evaluation of the performance of the vehicle audio amplifier. Utility Model Content

[0004] The technical problem to be solved by this utility model is that the existing technology is difficult to achieve a comprehensive and integrated evaluation of the performance of vehicle audio amplifiers. In order to overcome the above-mentioned defects of the existing technology, this utility model provides a vehicle audio amplifier performance testing system and method.

[0005] This utility model provides a vehicle-mounted audio amplifier performance testing system, comprising: The signal input-output differential circuit is electrically connected to the preamp input and the postamp output of the vehicle audio amplifier under test, respectively. The first analog-to-digital converter circuit is electrically connected to the signal input-output differential circuit and is used to convert the processed audio analog signal into an audio digital signal. The microphone detection circuit is electrically connected to the microphone and is used to receive and amplify the audio signal collected by the external microphone. The second analog-to-digital converter circuit is electrically connected to the microphone detection circuit and is used to convert the processed microphone audio signal into an audio digital signal. The temperature detection circuit is electrically connected to an internal NTC resistor or an external temperature probe. The current acquisition and amplification circuit is electrically connected to an external current clamp to acquire and amplify the current signal from the external current clamp. The MCU main chip circuit is electrically connected to the first analog-to-digital conversion circuit, the second analog-to-digital conversion circuit, the temperature detection circuit, and the current acquisition and amplification circuit, respectively, to receive digital or analog signals and process them to obtain the corresponding physical parameters. The external display circuit is electrically connected to the MCU main chip circuit and is used to receive and display the physical parameters processed by the MCU main chip circuit.

[0006] Compared with existing technologies, the vehicle-mounted audio amplifier performance testing system disclosed in this application has the following advantages: By integrating multiple dedicated signal conditioning channels such as signal input / output differential circuits, microphone detection circuits, temperature detection circuits, and current acquisition and amplification circuits, and in conjunction with a high-precision analog-to-digital converter, the system is centrally processed and calculated by a unified MCU main chip, achieving synchronous, rapid, and accurate measurement of key performance parameters of the amplifier. This completely changes the predicament of traditional testing, which involves scattered equipment, cumbersome operation, and asynchronous data, greatly improving testing efficiency and the accuracy of results. It is especially suitable for rapid on-site diagnosis and comprehensive performance evaluation in vehicle environments.

[0007] In one possible implementation, the signal input / output differential circuit includes eight differential circuits, wherein the input terminals of four of the differential circuits are electrically connected to the four audio input channels of the audio amplifier under test, and the input terminals of the other four differential circuits are electrically connected to the four audio output channels of the audio amplifier under test.

[0008] Compared with existing technologies, by designing eight independent differential circuits, which are respectively connected to the four input channels and four output channels of the vehicle audio amplifier, the system achieves full-channel synchronous and parallel testing capability for multi-channel audio systems. This not only significantly improves testing efficiency and avoids the cumbersome operation of repeatedly switching channels in traditional methods, but also ensures that the input and output signals are compared on the same time reference. This provides a reliable guarantee for accurately analyzing key performance parameters of the amplifier, such as gain, frequency response, distortion, and channel consistency, and is particularly suitable for the comprehensive testing needs of current mainstream multi-channel vehicle audio systems.

[0009] In one possible implementation, the microphone detection circuit includes an amplifier U11; The positive input terminal of amplifier U11 is electrically connected to the positive terminal of the microphone via capacitor C35, and the negative terminal of the microphone is grounded. The positive input terminal of amplifier U11 is also grounded via resistor R57. Furthermore, the positive input terminal of amplifier U11 is electrically connected to the first terminal of capacitor C33 via resistor R51, and the second terminal of capacitor C33 is grounded. The positive terminal of the microphone is electrically connected to the first terminal of capacitor C33 via resistor R52, and the first terminal of capacitor C33 is electrically connected to the power supply via resistor FB5. The negative input terminal of amplifier U11 is grounded via resistor R59. The negative input terminal of amplifier U11 is also electrically connected to the output terminal of amplifier U11 via resistor R56. The output terminal of amplifier U11 is electrically connected to the second analog-to-digital converter circuit via series resistors R53 and R50. A voltage regulator circuit is connected in parallel across the resistor R50. The voltage regulator circuit includes a capacitor C32, a resistor R48, a resistor R49, and a Zener diode D4. The connection point of the resistors R53 and R50 is electrically connected to the negative terminal of the Zener diode D4. The positive terminal of the Zener diode D4 is connected in series with the resistor R49, the resistor R48, and the capacitor C32 and electrically connected to the other end of the resistor R50.

[0010] Compared with existing technologies, by constructing an amplification structure with bias and feedback using a high-precision amplifier U11, and combining it with a power supply filtering and signal conditioning network composed of capacitor C33 and resistors R51 / R52 / FB5, the anti-interference capability and signal-to-noise ratio of the microphone signal are effectively improved. In particular, an innovative parallel voltage regulator circuit composed of Zener diode D4 and resistors and capacitors is introduced at the output end, which can accurately limit the voltage amplitude sent to the subsequent ADC. This can prevent signal overshoot from damaging sensitive devices and ensure the dynamic range and linearity of the sampled signal under different sound pressure environments, thus laying a reliable hardware foundation for realizing high-precision sound pressure measurement and FFT spectrum analysis.

[0011] In one possible implementation, the temperature detection circuit includes an NTC detection circuit for detecting the temperature of the internal power amplifier board and an external temperature probe detection circuit for detecting the temperature of the external power amplifier heatsink or speaker. The NTC detection circuit includes resistors NTC1 and NTC2. One end of resistor NTC1 is grounded, and the other end of resistor NTC1 is electrically connected to the power supply through resistor R26. A capacitor C12 is connected in parallel across resistor NTC1, and the connection point between resistor NTC1 and resistor R26 is electrically connected to the MCU main chip circuit. One end of resistor NTC2 is grounded, and the other end of resistor NTC2 is electrically connected to the power supply through resistor R27. A capacitor C13 is connected in parallel across resistor NTC2, and the connection point between resistor NTC1 and resistor R27 is electrically connected to the MCU main chip circuit. The external temperature probe detection circuit includes an external temperature probe, the negative terminal of which is grounded, the positive terminal of which is electrically connected to the main chip circuit through a resistor R29, one end of which is electrically connected to the main chip circuit through a capacitor C14, a bidirectional trigger diode E1 connected in parallel across the two ends of the external temperature probe, and the positive terminal of which is electrically connected to the power supply through a resistor R28.

[0012] Compared with existing technologies, this system adopts a composite detection design that combines internal and external components. Internally, two independent NTC detection circuits (NTC1 and NTC2) perform multi-point synchronous temperature monitoring of key locations on the power amplifier board, ensuring the comprehensiveness and reliability of internal temperature data. Externally, a dedicated temperature probe detection circuit is used, and a bidirectional trigger diode E1 is innovatively introduced as the core overvoltage protection component. This effectively suppresses static electricity or surge impacts that may be introduced due to long-distance connections to external probes. Thus, while achieving accurate monitoring of the temperature of external heat sinks or speakers, the system greatly improves the durability and anti-interference capability of the entire detection system in complex automotive electrical environments.

[0013] In one possible implementation, the current acquisition and amplification circuit includes a high-current detection circuit for detecting large currents and a low-current detection circuit for detecting small currents. The input terminal of the high current detection circuit is electrically connected to the input terminal of the external current clamp, and the output terminal of the high current detection circuit is electrically connected to the MCU main chip circuit. The input terminal of the low current detection circuit is electrically connected to the output terminal of the high current detection circuit, and the output terminal of the low current detection circuit is electrically connected to the MCU main chip circuit.

[0014] Compared with existing technologies, by adopting a dual-channel collaborative detection architecture with large and small currents, seamless and accurate measurement of the wide dynamic range current of the vehicle audio amplifier is achieved. The small current detection channel cleverly obtains the signal from the output of the front-end large current channel and performs secondary amplification processing, enabling it to accurately capture the milliampere-level standby static current. This allows for high-precision acquisition of both large and small currents simultaneously without the need for range switching. This eliminates the data interruption problem caused by range switching in traditional detection and significantly improves the efficiency and accuracy of current measurement, perfectly adapting to the full-condition testing needs of vehicle audio systems from standby to full-load operation.

[0015] In one possible implementation, the external display circuit is an LCD screen for displaying parameter information processed by the MCU main chip circuit, and the LCD screen is electrically connected to the MCU main chip circuit.

[0016] Compared with existing technologies, by using an LCD display as an external display unit, the multi-dimensional parameters (such as sound pressure, temperature, frequency response, voltage and current) processed by the MCU main chip can be presented in a high-contrast and visual manner. It not only supports real-time display of various data formats such as waveforms, spectrum, and values, but also provides on-site technicians with an intuitive human-machine interface, which greatly facilitates the rapid reading and comprehensive analysis of various performance indicators of the vehicle audio amplifier, and effectively improves the efficiency of testing and the accuracy of interpretation.

[0017] In one possible implementation, the MCU main chip circuit is electrically connected to an RS-485 communication circuit for providing data transmission and external communication, and the MCU main chip circuit is electrically connected to a USB circuit for communication with a PC.

[0018] Compared with existing technologies, a flexible and reliable dual communication interface is constructed through RS-485 communication circuit and USB circuit: the RS-485 interface, with its strong anti-common-mode interference capability and long-distance transmission characteristics, ensures that the detection system can stably and reliably interact with remote equipment in complex electromagnetic vehicle environments; while the USB interface provides a convenient bridge for high-speed data upload, in-depth analysis and system firmware upgrade between the field and the PC. Attached Figure Description

[0019] Figure 1 This is a system block diagram of a vehicle-mounted audio amplifier performance testing system according to the present invention; Figure 2 This is a circuit diagram of the signal input / output differential circuit and the first analog-to-digital conversion circuit in a vehicle-mounted audio amplifier performance testing system according to this utility model; Figure 3 This invention relates to a circuit diagram of a second analog-to-digital converter circuit, a microphone detection circuit, a temperature detection circuit, a current acquisition and amplification circuit, and a power supply circuit in a vehicle-mounted audio amplifier performance testing system. Figure 4 This is a circuit diagram of the MCU main chip circuit, external display circuit, communication interface circuit and USB interface circuit in a vehicle-mounted audio amplifier performance testing system of this utility model. Detailed Implementation

[0020] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0021] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0022] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0023] See Figures 1-4 As shown in the figure, this application discloses a vehicle audio amplifier performance testing system, including: The signal input-output differential circuit is used to receive the audio analog signals from the preamp input and the postamp output of the vehicle audio amplifier under test, respectively, and to perform noise reduction and sampling detection processing on the signals. The first analog-to-digital converter circuit is electrically connected to the signal input-output differential circuit and is used to convert the processed audio analog signal into an audio digital signal. The microphone detection circuit is used to receive and amplify the audio signals collected by the external microphone. The second analog-to-digital converter circuit is electrically connected to the microphone detection circuit and is used to convert the processed microphone audio signal into an audio digital signal. Temperature detection circuit, used to receive signals from NTC resistor or external temperature probe to obtain temperature analog signals; The current acquisition and amplification circuit is used to acquire the current signal from the external current clamp and amplify it. The MCU main chip circuit is electrically connected to the first analog-to-digital conversion circuit, the second analog-to-digital conversion circuit, the temperature detection circuit, and the current acquisition and amplification circuit, respectively, to receive various digital or analog signals and process them to obtain sound pressure, temperature, frequency response, distortion, voltage, and current parameters. The external display circuit is electrically connected to the MCU main chip circuit and is used to receive and display various parameters processed by the MCU main chip circuit.

[0024] By integrating multiple dedicated signal conditioning channels, including signal input / output differential circuits, microphone detection circuits, temperature detection circuits, and current acquisition and amplification circuits, and using a high-precision analog-to-digital converter, the system achieves synchronous, rapid, and accurate measurement of key amplifier performance parameters through a unified MCU main chip. This completely changes the traditional testing methods, which suffer from scattered equipment, cumbersome operation, and asynchronous data, greatly improving testing efficiency and the accuracy of results. It is especially suitable for rapid on-site diagnosis and comprehensive performance evaluation in vehicle environments.

[0025] See Figure 2 As shown, in this embodiment, the signal input / output differential circuit includes eight differential circuits, wherein the input terminals of four differential circuits are electrically connected to the four audio input channels of the audio amplifier under test, and the input terminals of the other four differential circuits are electrically connected to the four audio output channels of the audio amplifier under test.

[0026] By designing eight independent differential circuits, which are respectively connected to the four input channels and four output channels of the vehicle audio amplifier, the system achieves full-channel synchronous and parallel testing capability for multi-channel audio systems. This not only significantly improves testing efficiency and avoids the tedious operation of repeatedly switching channels in traditional methods, but also ensures that the input and output signals are compared on the same time reference. This provides a reliable guarantee for accurately analyzing key performance parameters such as amplifier gain, frequency response, distortion, and channel consistency, and is particularly suitable for the comprehensive testing needs of current mainstream multi-channel vehicle audio systems.

[0027] See Figure 3 As shown, the microphone detection circuit includes amplifier U11. The positive input terminal of amplifier U11 is electrically connected to the positive terminal of the microphone through capacitor C35, and the negative terminal of the microphone is grounded. The positive input terminal of amplifier U11 is grounded through resistor R57. The positive input terminal of amplifier U11 is electrically connected to the first terminal of capacitor C33 through resistor R51, and the second terminal of capacitor C33 is grounded. The positive terminal of the microphone is electrically connected to the first terminal of capacitor C33 through resistor R52. The first terminal of capacitor C33 is electrically connected to the power supply through resistor FB5. The negative input terminal of amplifier U11 is grounded through resistor R59. The negative input terminal of amplifier U11 is electrically connected to the output terminal of amplifier U11 through resistor R56. The output terminal of amplifier U11 is electrically connected to the second analog-to-digital converter circuit through series resistors R53 and R50. A voltage regulator circuit is connected in parallel across resistor R50. The voltage regulator circuit includes capacitor C32, resistor R48, resistor R49, and Zener diode D4. The connection terminals of resistors R53 and R50 are electrically connected to the negative terminal of Zener diode D4. The positive terminal of Zener diode D4 is connected in series with resistor R49, resistor R48, and capacitor C32 to the other end of resistor R50.

[0028] By employing a high-precision amplifier U11 to construct an amplification structure with bias and feedback, and combining it with a power supply filtering and signal conditioning network composed of capacitor C33 and resistors R51 / R52 / FB5, the anti-interference capability and signal-to-noise ratio of the microphone signal are effectively improved. In particular, an innovative parallel voltage regulator circuit composed of Zener diode D4 and resistors and capacitors is introduced at the output end, which can accurately limit the voltage amplitude sent to the subsequent ADC. This not only prevents signal overshoot from damaging sensitive devices, but also ensures the dynamic range and linearity of the sampled signal under different sound pressure environments, thus laying a reliable hardware foundation for realizing high-precision sound pressure measurement and FFT spectrum analysis.

[0029] See Figure 3 As shown, in this embodiment, the temperature detection circuit includes an NTC detection circuit for detecting the temperature of the internal power amplifier board and an external temperature probe detection circuit for detecting the temperature of the external power amplifier heatsink or speaker. The NTC detection circuit includes resistors NTC1 and NTC2. One end of resistor NTC1 is grounded, and the other end is electrically connected to the power supply through resistor R26. A capacitor C12 is connected in parallel across resistor NTC1, and the connection point between resistor NTC1 and resistor R26 is electrically connected to the MCU main chip circuit. One end of resistor NTC2 is grounded, and the other end is electrically connected to the power supply through resistor R27. A capacitor C13 is connected in parallel across resistor NTC2, and the connection point between resistor NTC1 and resistor R27 is electrically connected to the MCU main chip circuit. The external temperature probe detection circuit includes an external temperature probe, with the negative terminal of the external temperature probe grounded. The positive terminal of the external temperature probe is electrically connected to the main chip circuit through resistor R29. One end of resistor R29, which is electrically connected to the main chip circuit, is grounded through capacitor C14. A bidirectional trigger diode E1 is connected in parallel across the two ends of the external temperature probe. The positive terminal of the external temperature probe is electrically connected to the power supply through resistor R28.

[0030] The system employs a combined internal and external detection design. Internally, two independent NTC detection circuits (NTC1 and NTC2) perform multi-point synchronous temperature monitoring of key locations on the power amplifier board, ensuring the comprehensiveness and reliability of internal temperature data. Externally, a dedicated temperature probe detection circuit is used, and a bidirectional trigger diode E1 is innovatively introduced as the core overvoltage protection component. This effectively suppresses static electricity or surge impacts that may be introduced due to long-distance connections to external probes. Thus, while achieving accurate monitoring of the temperature of external heat sinks or speakers, the system greatly improves the durability and anti-interference capability of the entire detection system in complex automotive electrical environments.

[0031] See Figure 3 As shown, in this embodiment, the current acquisition and amplification circuit includes a high-current detection circuit for detecting large currents and a low-current detection circuit for detecting small currents. The input terminal of the high current detection circuit is electrically connected to the input terminal of the external current clamp, and the output terminal of the high current detection circuit is electrically connected to the MCU main chip circuit. The input terminal of the low current detection circuit is electrically connected to the output terminal of the high current detection circuit, and the output terminal of the low current detection circuit is electrically connected to the MCU main chip circuit.

[0032] By adopting a dual-channel collaborative detection architecture for large and small currents, seamless and accurate measurement of the wide dynamic range current of the vehicle audio amplifier is achieved. The small current detection channel cleverly obtains the signal from the output of the front-end large current channel and performs secondary amplification processing, enabling it to accurately capture the milliampere-level standby static current. This allows for high-precision acquisition of both large and small currents simultaneously without the need for range switching. This eliminates the data interruption problem caused by range switching in traditional detection and significantly improves the efficiency and accuracy of current measurement, perfectly adapting to the full-condition testing needs of vehicle audio systems from standby to full-load operation.

[0033] See Figure 4 As shown, in this embodiment, the external display circuit is an LCD screen used to display parameter information processed by the MCU main chip circuit, and the LCD screen is electrically connected to the MCU main chip circuit.

[0034] By using an LCD display as an external display unit, the multi-dimensional parameters (such as sound pressure, temperature, frequency response, voltage and current) processed by the MCU main chip can be presented in a high-contrast and visual manner. It not only supports real-time display of various data formats such as waveforms, spectrum, and values, but also provides an intuitive human-machine interface for on-site technicians. This greatly facilitates the rapid reading and comprehensive analysis of various performance indicators of the vehicle-mounted audio amplifier, effectively improving the efficiency of testing and the accuracy of interpretation.

[0035] See Figure 4 As shown, in this embodiment, the MCU main chip circuit is electrically connected to an RS-485 communication circuit for providing data transmission and external communication, and the MCU main chip circuit is electrically connected to a USB circuit for communication with a PC.

[0036] By using RS-485 communication circuits and USB circuits, a flexible and reliable dual communication interface is constructed: the RS-485 interface, with its strong anti-common-mode interference capability and long-distance transmission characteristics, ensures that the detection system can stably and reliably exchange data with remote equipment in complex electromagnetic vehicle environments; while the USB interface provides a convenient bridge for high-speed data upload, in-depth analysis, and system firmware upgrades between the field and the PC.

[0037] In this embodiment, a testing method for a vehicle-mounted audio amplifier performance testing system includes the following steps: The input and output audio signals of the audio amplifier under test are obtained through a signal input-output differential circuit, and the pre-processed analog audio signals are converted into digital signals through analog-to-digital conversion. The sound pressure signal collected by the external microphone is obtained through the microphone detection circuit; The voltage and current signals of the external temperature probe are obtained through the temperature detection circuit; The current signal of the external current clamp is obtained through a current acquisition and amplification circuit; The MCU main chip circuit receives and processes all the above signals, calculates the frequency response, distortion, sound pressure, temperature, voltage, and current parameters, and displays the calculated performance parameters through the external display circuit.

[0038] By synchronously acquiring and processing audio input and output signals, sound pressure signals, temperature signals, and current signals, the MCU main chip uniformly calculates and generates key performance parameters such as frequency response, distortion, sound pressure, temperature, voltage, and current. This enables a comprehensive evaluation of the amplifier's electrical performance, acoustic characteristics, and thermal state in a single test, significantly improving detection efficiency and spatiotemporal consistency of data. It completely overcomes the technical difficulties of traditional methods, which require separate measurements using different devices and make data correlation and comparison difficult.

[0039] The step of receiving and processing all the above signals in the MCU main chip circuit includes selecting test items through user operation function keys and switching the corresponding test circuits by the MCU.

[0040] The user can select test items by using function keys and the MCU will automatically switch the corresponding test circuit, simplifying the operation process and significantly improving the testing efficiency.

[0041] In this embodiment, the detected performance parameters are also transmitted to an external device via a communication interface circuit.

[0042] The detection data is transmitted to external devices in real time through the communication interface, enabling remote monitoring, massive storage and in-depth analysis of the detection data, which greatly enhances the data value of the detection results and the scalability of the system.

[0043] In the description of the embodiments of this application, it should be noted that the terms "inner" and "outer" and other terms indicating direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0044] In the description of this application, the references to terms such as "an embodiment," "some embodiments," "in this embodiment," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0045] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A vehicle-mounted audio amplifier performance testing system, characterized in that, include: The signal input-output differential circuit is electrically connected to the preamp input and the postamp output of the vehicle audio amplifier under test, respectively. The first analog-to-digital converter circuit is electrically connected to the signal input-output differential circuit and is used to convert the processed audio analog signal into an audio digital signal. The microphone detection circuit is electrically connected to the microphone and is used to receive and amplify the audio signal collected by the external microphone. The second analog-to-digital converter circuit is electrically connected to the microphone detection circuit and is used to convert the processed microphone audio signal into an audio digital signal. The temperature detection circuit is electrically connected to an internal NTC resistor or an external temperature probe. The current acquisition and amplification circuit is electrically connected to an external current clamp to acquire and amplify the current signal from the external current clamp. The MCU main chip circuit is electrically connected to the first analog-to-digital conversion circuit, the second analog-to-digital conversion circuit, the temperature detection circuit, and the current acquisition and amplification circuit, respectively, to receive digital or analog signals and process them to obtain the corresponding physical parameters. The external display circuit is electrically connected to the MCU main chip circuit and is used to receive and display the physical parameters processed by the MCU main chip circuit.

2. The vehicle-mounted audio amplifier performance testing system according to claim 1, characterized in that, The signal input / output differential circuit includes eight differential circuits, wherein the input terminals of four of the differential circuits are electrically connected to the four audio input channels of the audio amplifier under test, and the input terminals of the other four differential circuits are electrically connected to the four audio output channels of the audio amplifier under test.

3. The vehicle-mounted audio amplifier performance testing system according to claim 1, characterized in that, The microphone detection circuit includes an amplifier U11; The positive input terminal of amplifier U11 is electrically connected to the positive terminal of the microphone through capacitor C35, the negative terminal of the microphone is grounded, the positive input terminal of amplifier U11 is grounded through resistor R57, the positive input terminal of amplifier U11 is electrically connected to the first terminal of capacitor C33 through resistor R51, the second terminal of capacitor C33 is grounded, the positive terminal of the microphone is electrically connected to the first terminal of capacitor C33 through resistor R52, the first terminal of capacitor C33 is electrically connected to the power supply through resistor FB5, the negative input terminal of amplifier U11 is grounded through resistor R59, the negative input terminal of amplifier U11 is electrically connected to the output terminal of amplifier U11 through resistor R56, and the output terminal of amplifier U11 is electrically connected to the second analog-to-digital conversion circuit through series resistors R53 and R50. A voltage regulator circuit is connected in parallel across the resistor R50. The voltage regulator circuit includes a capacitor C32, a resistor R48, a resistor R49, and a Zener diode D4. The connection point of the resistors R53 and R50 is electrically connected to the negative terminal of the Zener diode D4. The positive terminal of the Zener diode D4 is connected in series with the resistor R49, the resistor R48, and the capacitor C32 and electrically connected to the other end of the resistor R50.

4. The vehicle-mounted audio amplifier performance testing system according to claim 1, characterized in that, The temperature detection circuit includes an NTC detection circuit for detecting the temperature of the internal power amplifier board and an external temperature probe detection circuit for detecting the temperature of the external power amplifier heatsink or speaker. The NTC detection circuit includes resistors NTC1 and NTC2. One end of resistor NTC1 is grounded, and the other end of resistor NTC1 is electrically connected to the power supply through resistor R26. A capacitor C12 is connected in parallel across resistor NTC1, and the connection point between resistor NTC1 and resistor R26 is electrically connected to the MCU main chip circuit. One end of resistor NTC2 is grounded, and the other end of resistor NTC2 is electrically connected to the power supply through resistor R27. A capacitor C13 is connected in parallel across resistor NTC2, and the connection point between resistor NTC1 and resistor R27 is electrically connected to the MCU main chip circuit. The external temperature probe detection circuit includes an external temperature probe, the negative terminal of which is grounded, the positive terminal of which is electrically connected to the main chip circuit through a resistor R29, one end of which is electrically connected to the main chip circuit through a capacitor C14, a bidirectional trigger diode E1 connected in parallel across the two ends of the external temperature probe, and the positive terminal of which is electrically connected to the power supply through a resistor R28.

5. The vehicle-mounted audio amplifier performance testing system according to claim 1, characterized in that, The current acquisition and amplification circuit includes a high-current detection circuit for detecting large currents and a low-current detection circuit for detecting small currents. The input terminal of the high current detection circuit is electrically connected to the input terminal of the external current clamp, and the output terminal of the high current detection circuit is electrically connected to the MCU main chip circuit. The input terminal of the low current detection circuit is electrically connected to the output terminal of the high current detection circuit, and the output terminal of the low current detection circuit is electrically connected to the MCU main chip circuit.

6. The vehicle-mounted audio amplifier performance testing system according to claim 1, characterized in that, The external display circuit is an LCD screen used to display parameter information processed by the MCU main chip circuit, and the LCD screen is electrically connected to the MCU main chip circuit.

7. The vehicle-mounted audio amplifier performance testing system according to claim 1, characterized in that, The MCU main chip circuit is electrically connected to a communication interface circuit for providing data transmission and external communication. The communication interface circuit is an RS-485 communication circuit. The MCU main chip circuit is also electrically connected to a USB circuit for communication with a PC.

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