Electromagnetic compatibility test system and method for vehicle audio system

Abstract

The present invention discloses an electromagnetic compatibility test system and method for an in-vehicle audio system. It includes an audio host, a power amplifier module, a speaker, and an audio analyzer, an eye diagram analyzer, and a control module arranged in a shielded room and connected in sequence. The audio analyzer is used to detect the quality parameters of the audio signal output by the power amplifier module, and judge the first level of the audio signal according to the quality parameters; the eye diagram analyzer is used to detect the eye diagram parameters of the transmission signal on the audio bus, and judge the second level of the transmission signal according to the eye diagram parameters; the control module is used to judge the performance level of the in-vehicle audio system according to the first level and the second level. The present invention adds an eye diagram analyzer to judge the data transmission quality of the audio bus and adds an audio analyzer to judge the output sound quality, which can identify parameter deviations that cannot be judged by the human ear, improve risk identification capabilities, and reduce the cost of later problem investigation, rectification, and repeated verification.

Description

Technical Field

[0001] The invention belongs to the field of automobile technology, and in particular relates to an electromagnetic compatibility test system and method for a vehicle audio system. Background Art

[0002] The existing electromagnetic compatibility test of the in-vehicle audio system is that the tester monitors the test music with human ears, and the sound is received by the mic in the shielding room. The tester is in the control room to make judgments. This test method has the following defects:

[0003] 1. The anti-interference requirements for the radio system in the shielded room are relatively high.

[0004] 2. Human ear monitoring has high uncertainty and cannot be played back. Electromagnetic compatibility problems often have a certain probability and need to be judged through repeated tests. This is inefficient and prone to errors.

[0005] 3. When there is a problem with the audio, it is impossible to locate the specific problem on the audio bus, and which parameters of the audio signal have shifted to cause the fault; and when the tester hears the audio fault in the control room, he records the frequency band where the fault occurs, which is delayed from the frequency band where the actual problem occurs. Summary of the invention

[0006] The purpose of the present invention is to solve the deficiencies of the above-mentioned background technology and to provide a simple and efficient electromagnetic compatibility test system and method for a vehicle audio system.

[0007] The technical solution adopted by the present invention is: an electromagnetic compatibility test system for a vehicle audio system, comprising an audio host, a power amplifier module, a speaker, an audio analyzer, an eye diagram analyzer, and a control module arranged in a shielded room and connected in sequence,

[0008] The audio analyzer input end is connected between the power amplifier module and the speaker, and is used to detect the quality parameters of the audio signal output by the power amplifier module, and determine the first level of the audio signal according to the quality parameters;

[0009] The eye diagram analyzer input end is connected to the audio bus between the audio host and the power amplifier module, and is used to detect the eye diagram parameters of the transmission signal on the audio bus, and determine the second level of the transmission signal according to the eye diagram parameters;

[0010] The control module is used to determine the performance level of the vehicle audio system according to the first level and the second level.

[0011] Furthermore, the quality parameters include multiple ones, each quality parameter is set to multiple different levels, and each level corresponds to a different parameter range.

[0012] Furthermore, the level of each quality parameter is determined according to the size of the quality parameter actually detected and the set level, and the level corresponding to the lowest level parameter among the quality parameters is taken as the first level.

[0013] Furthermore, the eye diagram parameters include multiple ones, each eye diagram parameter is set to multiple different levels, and each level corresponds to a different parameter range.

[0014] Furthermore, the level of each eye diagram parameter is determined according to the size of the eye diagram parameter actually detected and the set level, and the level corresponding to the lowest level parameter among the eye diagram parameters is used as the second level.

[0015] Furthermore, when the first level is lower than the second level, the first level is used as the performance level of the vehicle audio system; when the first level is higher than the second level, the second level is used as the performance level of the vehicle audio system.

[0016] An electromagnetic compatibility test method for a vehicle audio system, the process is:

[0017] An audio analyzer is connected between the power amplifier module and the speaker, and a quality parameter of the audio signal output by the power amplifier module is detected by the audio analyzer, and a first level of the audio signal is determined according to the quality parameter;

[0018] An eye diagram analyzer is connected to the audio bus between the audio host and the power amplifier module, the eye diagram parameters of the signal transmitted on the audio bus are detected by the eye diagram analyzer, and the second level of the transmission signal is determined according to the eye diagram parameters;

[0019] The performance level of the in-vehicle audio system is judged according to the first level and the second level.

[0020] Furthermore, the quality parameters include multiple ones, each quality parameter is set to multiple different levels, and the level corresponding to the lowest level parameter among the quality parameters is used as the first level.

[0021] Furthermore, the eye diagram parameters include multiple ones, each eye diagram parameter is set to multiple different levels, and the level corresponding to the parameter with the lowest level among the eye diagram parameters is used as the second level.

[0022] Furthermore, when the first level is lower than the second level, the first level is used as the performance level of the vehicle audio system; when the first level is higher than the second level, the second level is used as the performance level of the vehicle audio system.

[0023] The beneficial effects of the present invention are:

[0024] 1. The shielding room of the present invention is combined with an eye diagram analyzer and an audio analyzer to eliminate interference factors other than DUT such as a radio system and human ear errors, thereby improving the test reliability.

[0025] 2. The eye diagram analyzer and audio analyzer of the present invention can retain objective test monitoring data, improve the accuracy of test judgment, and can also perform quality judgment, thereby freeing up a certain amount of manpower and improving test efficiency.

[0026] 3. The present invention is conducive to problem location, for example, whether the audio bus input is faulty or the parameters of the power amplifier are offset after analysis, the specific value of the offset and its potential risks.

[0027] 4. The present invention adds an eye diagram analyzer to determine the data transmission quality of the audio bus and adds an audio analyzer to determine the output sound quality, which can identify parameter deviations that cannot be determined by the human ear, improve risk identification capabilities, and reduce the cost of subsequent problem investigation, rectification and repeated verification.

[0028] 5. The present invention sets a plurality of different levels for each parameter to be detected. When making performance judgments, the situation of each parameter can be accurately known, so that targeted equipment can be debugged. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a system principle diagram of the present invention. DETAILED DESCRIPTION

[0030] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] In the electromagnetic compatibility test bench of the vehicle audio system, the vehicle audio host plays the sound source to the power amplifier, and the power amplifier amplifies the weak signal to drive the speaker to make sound. The same problem phenomenon may cause more than one cause, involving the entire link. In the electromagnetic compatibility test of the existing system type, the fault judgment problem is very difficult and repetitive. Therefore, the present invention provides a set of test systems and methods to locate the problem to the specific modules and corresponding parameters in the system, so as to obtain accurate test results and the source of the problem.

[0032] like Figure 1 As shown, the present invention provides an electromagnetic compatibility test system for a vehicle audio system, comprising an audio host, a power amplifier module and a speaker which are arranged in a shielded room and connected in sequence, and an audio analyzer, an eye diagram analyzer and a control module which are arranged in a control room.

[0033] The audio analyzer input end is connected between the power amplifier module and the speaker, and is used to detect the quality parameters of the audio signal output by the power amplifier module, and determine the first level of the audio signal according to the quality parameters;

[0034] The input end of the eye diagram analyzer is connected to the audio bus between the audio host and the power amplifier module, such as the A2B bus, through an optical fiber, and is used to detect the eye diagram parameters of the signal transmitted on the audio bus, and determine the second level of the transmission signal according to the eye diagram parameters;

[0035] The control module is used to determine the performance level of the vehicle audio system according to the first level and the second level.

[0036] In the above scheme, the quality parameters include multiple ones, namely signal voltage, frequency, sensitivity and total harmonic distortion. Each quality parameter is set to four different levels, and each level corresponds to a different parameter range. The details are as follows:

[0037] The voltage ranges corresponding to the four levels of signal voltage from high to low are: level A voltage range is V≥9V, level B voltage range is 7V≤V<9V, level C voltage range is 6V≤V<7V, and level D voltage range is V<6V.

[0038] The frequency ranges corresponding to the four levels from high to low are: Level A frequency range is f≤12.5kHz, Level B frequency range is 12.5kHz<f≤15kHz, Level C frequency range is 15kHz<f≤20kHz, and Level D frequency range is f>20kHz.

[0039] The sensitivity ranges corresponding to the four levels from high to low are: when the frequency f≤1kHz, the sensitivity range of level A is S≥85dB, the sensitivity range of level B is 80dB≤S<85dB, the sensitivity range of level C is 75dB≤S<80dB, and the sensitivity range of level D is S<75Db; when the frequency f>1kHz, the sensitivity range of level A is S≥84dB, the sensitivity range of level B is 77dB≤S<84dB, the sensitivity range of level C is 70dB≤S<77dB, and the sensitivity range of level D is S<70dB.

[0040] The distortion ranges of the four levels of total harmonic distortion from high to low are: Level A distortion range is THD ≤ 3%, Level B distortion range is 3% < THD ≤ 5%, Level C distortion range is 5% < THD ≤ 8%, and Level D distortion range is THD > 8%. The calculation formula for total harmonic distortion THD (%) is:

[0041] THD=100*SQRT[(P 2 +P 3 +P 4 +…+P n )*Z out ] / V t

[0042] Among them, SQRT means square root, P 2 , P 3 , P 4 …P n is the power of each harmonic, Z out is the load impedance, V t is the total RMS output voltage (including fundamental and harmonic terms).

[0043] In the above scheme, the level of each quality parameter is determined according to the size of the quality parameter actually detected and the set level, and the level corresponding to the parameter with the lowest level among the quality parameters is used as the first level. According to the above set levels and corresponding parameter ranges, the levels of the four quality parameters actually collected can be determined, and from the determined four levels, the level corresponding to the parameter with the lowest level is selected as the first level. For example, when three of the four quality parameters are level B and the other is level C, level C is used as the first level.

[0044] In the above scheme, the eye diagram parameters include multiple ones, namely eye height, eye width, hypotenuse slope, zero point distortion, each eye diagram parameter is set to multiple different levels, each level corresponds to a different parameter range. Specifically as follows:

[0045] The range of the four eye diagram parameters of grade A is the set standard range, and the standard range of each eye diagram parameter can be the same or different; the range of the four eye diagram parameters of grade B fluctuates within ±10% of the standard range; the range of the four eye diagram parameters of grade C fluctuates above ±10% of the standard range, and can be automatically restored after the interference is cancelled; the range of the four eye diagram parameters of grade D fluctuates above ±10% of the standard range, and manual operation is required to restore after the interference is cancelled.

[0046] In the above scheme, the level of each eye diagram parameter is determined according to the size of the eye diagram parameter actually detected and the set level, and the level corresponding to the parameter with the lowest level among the eye diagram parameters is used as the second level. According to the above set level and the corresponding parameter range, the levels of the four eye diagram parameters actually collected can be determined, and from the determined four levels, the level corresponding to the parameter with the lowest level is selected as the second level.

[0047] In the above scheme, when the first level is lower than the second level, the first level is used as the performance level of the vehicle audio system; when the first level is higher than the second level, the second level is used as the performance level of the vehicle audio system. For example, when the first level is level B and the second level is level C, the performance level of the vehicle audio system is determined to be level C.

[0048] Based on the above electromagnetic compatibility test system, the present invention also provides an electromagnetic compatibility test method for a vehicle audio system, the process is as follows:

[0049] Implementation steps:

[0050] 1. Build a test bench that meets the requirements of electromagnetic compatibility testing.

[0051] 2. On the basis of the original test system, add an optical conversion device (i.e. light) at the input end of the power amplifier, connect it to the eye diagram analyzer in the control room, monitor the changes on the audio bus, take the A2B bus as an example, monitor its eye diagram, including eye height, eye width, hypotenuse slope, zero-point distortion, etc.

[0052] 3. Connect the audio analyzer in the control room to the speaker end to monitor audio quality parameters, including signal voltage, frequency, sensitivity, total harmonic distortion, etc.

[0053] 4. During the test, monitor the data in the eye diagram analyzer and the audio analyzer, record and save the parameters that deviate from the design requirements, including the corresponding parameters in steps 2 and 3 above, and the interference intensity, frequency, modulation mode, etc. corresponding to the test at this time. According to the test parameters, the performance level of the vehicle audio system can be judged, and the test results and reports can be obtained, freeing up the test manpower.

[0054] For example, when it is determined according to the above method that the performance level of the vehicle audio system is level C, it is possible to determine which one or more data are level C based on the detected data, so that the device can be modulated in a targeted manner.

[0055] The present invention is mainly used for EMS testing to monitor the faults or parameter deviations of the vehicle audio system. It can also be applied to EMI testing to ensure the realization of the audio system functions during the test process and to compare with the actual vehicle application scenario.

[0056] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field.

Claims

1. An electromagnetic compatibility test system for a vehicle audio system. Features: It includes an audio host, a power amplifier module, a speaker, and an audio analyzer, an eye diagram analyzer, and a control module which are arranged in a shielded room and connected in sequence. The audio analyzer input end is connected between the power amplifier module and the speaker, and is used to detect the quality parameters of the audio signal output by the power amplifier module, and determine the first level of the audio signal according to the quality parameters; The eye diagram analyzer input end is connected to the audio bus between the audio host and the power amplifier module, and is used to detect the eye diagram parameters of the transmission signal on the audio bus, and determine the second level of the transmission signal according to the eye diagram parameters; The control module is used to determine the performance level of the vehicle audio system according to the first level and the second level. When the first level is lower than the second level, the first level is used as the performance level of the vehicle audio system; when the first level is higher than the second level, the second level is used as the performance level of the vehicle audio system.

2. The electromagnetic compatibility test system of the vehicle audio system according to claim 1, Features: The quality parameters include multiple ones, each quality parameter is set to multiple different levels, and each level corresponds to a different parameter range.

3. The electromagnetic compatibility test system of the vehicle audio system according to claim 1, Features: The level of each quality parameter is determined according to the size of the quality parameter actually detected and the set level, and the level corresponding to the lowest level parameter among the quality parameters is taken as the first level.

4. The electromagnetic compatibility test system of the vehicle audio system according to claim 1, Features: The eye diagram parameters include multiple ones, each eye diagram parameter is set to multiple different levels, and each level corresponds to a different parameter range.

5. The electromagnetic compatibility test system of the vehicle audio system according to claim 1, Features: The level of each eye diagram parameter is determined according to the size of the eye diagram parameter actually detected and the set level, and the level corresponding to the lowest level parameter among the eye diagram parameters is used as the second level.

6. An electromagnetic compatibility test method for a vehicle audio system. Features: An audio analyzer is connected between the power amplifier module and the speaker, and a quality parameter of the audio signal output by the power amplifier module is detected by the audio analyzer, and a first level of the audio signal is determined according to the quality parameter; An eye diagram analyzer is connected to the audio bus between the audio host and the power amplifier module, the eye diagram parameters of the signal transmitted on the audio bus are detected by the eye diagram analyzer, and the second level of the transmission signal is determined according to the eye diagram parameters; The performance level of the vehicle audio system is judged according to the first level and the second level. When the first level is lower than the second level, the first level is used as the performance level of the vehicle audio system; when the first level is higher than the second level, the second level is used as the performance level of the vehicle audio system.

7. The electromagnetic compatibility test method of the vehicle audio system according to claim 6, Features: The quality parameters include multiple ones, each quality parameter is set to multiple different levels, and the level corresponding to the lowest level parameter among the quality parameters is used as the first level.

8. The electromagnetic compatibility test method of the vehicle audio system according to claim 6, Features: The eye diagram parameters include multiple ones, each eye diagram parameter is set to multiple different levels, and the level corresponding to the lowest level parameter among the eye diagram parameters is used as the second level.

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