CN117198373A - Method for evaluating and calculating automatic performance of audio IC playing and recording channel - Google Patents
Method for evaluating and calculating automatic performance of audio IC playing and recording channel Download PDFInfo
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- CN117198373A CN117198373A CN202311245524.2A CN202311245524A CN117198373A CN 117198373 A CN117198373 A CN 117198373A CN 202311245524 A CN202311245524 A CN 202311245524A CN 117198373 A CN117198373 A CN 117198373A
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Abstract
The invention discloses a method for evaluating and calculating automatic performance of a playing and recording channel of a production test audio frequency IC, which specifically comprises the following steps: s1, after a hardware board is prepared, pre-storing 1k sine and standard obtained sweep frequency signals in software into a local memory; s2, starting an MCU by software to start a test, wherein 3 large scene coverage play recording channels are tested; s3, testing a playing channel, S4, calculating a numerical value by throwing data obtained by a playing device to an algorithm unit SNR/THD+N again to calculate the numerical value, and applying the numerical value to judge whether the numerical value accords with an expected value, S5, testing a recording channel. The method for evaluating and calculating the automatic performance of the playing and recording passage of the AUDIO IC is capable of realizing AUDIO performance test by using pure software, is convenient and simple for research and development factories, has high execution effect, fast result, high precision calculation accuracy, no AUDIO loss caused by external measuring equipment, and is very fast, convenient and high in consistency by batch screening of AUDIO ICs.
Description
Technical Field
The invention relates to the technical field of audio data processing, in particular to a method for evaluating and calculating automatic performance of a playing and recording channel of a production test audio IC.
Background
The voice chip is a chip facing the audio voice and basic playing scene, after the chip is processed, chip test is carried out, wherein the function and performance test of the audio IC chip are necessary, and the function and performance screening tool of the ATE audio IC is generated due to the requirement of the audio test of the machine, so that the basic screening and verification of the ATE audio chip are accelerated and facilitated, software assists in developing the tool, the test acceptance of key items of the audio IC chip is greatly improved, and the chips which meet the requirement and are not met are screened.
According to the invention, the performance of an audio IC playing channel is automatically calculated, the software controls the playing instruction through presetting standard pure tone and sweep frequency signals, the DSP is started to acquire data from a preset memory and send the data to a DAC/ClassD or ClassAB playing device for playing, the software automatically calculates the performance of the current playing channel by scheduling an algorithm unit SNR/THD+N in the design, and the numerical value of the SNR/THD+N is saved.
Meanwhile, the invention automatically calculates the performance of an audio IC playing and recording loop-back channel, the hardware PCBA connects the playing and recording by a circuit, after the playing and recording hardware are communicated, software controls a DSP to play a preset standard 1k pure tone test signal or a sweep frequency signal by an MCU, a playing device loops back the signal to a recording channel by the hardware connection, the software captures audio data from the recording channel (such as ADC/PDM/IIS and other digital analog channels) after setting the audio format of the recording channel, and the software calls the algorithm unit of SNR/THD+N to calculate the captured data and stores the calculated value.
Disclosure of Invention
(one) solving the technical problems
In order to overcome the defects of the prior art, the invention provides a method for evaluating and calculating the automatic performance of a playing and recording channel of an audio IC to be tested, by automatically calculating the performance of the playing and recording channel of the audio IC, a hardware PCBA is connected with playing and recording by a circuit, after playing and recording hardware are communicated, software controls a DSP to play a preset standard 1k pure tone test signal or a sweep frequency signal by an MCU, a playing device loops the signal back to a recording channel by the hardware connection, the software writes recorded data to the playing channel device by the MCU, controls the DSP to play, and invokes an SNR/THD+N algorithm unit again to calculate, and the whole process is a playback.
(II) technical scheme
In order to achieve the above purpose, the invention is realized by the following technical scheme: a method for producing and measuring automatic performance evaluation calculation of an audio IC playing and recording channel specifically comprises the following steps:
s1, after a hardware board is prepared, pre-storing 1k sine and standard obtained sweep frequency signals in software into a local memory;
s2, starting an MCU by software to start a test, wherein 3 large scene coverage play recording channels are tested;
s3, testing a playing channel, namely sending an instruction to a DSP by the MCU to start audio performance test of the playing channel, opening a playing device after the DSP receives an execution instruction, and sending 1k of sine or sweep frequency data to the playing device for playing by using a DMA from a memory;
s4, the data obtained by the playing device is lost to an algorithm unit SNR/THD+N again to calculate an algorithm, a numerical value is calculated and stored, and the numerical value is applied to judge whether the expected value is met;
s5, testing the recording channel, wherein the MCU sends an instruction to the DSP to start the performance test of the recording channel, the data played by the DSP is directly transmitted to the input end of the recording channel through the IIS and other playing devices through the hardware lead signal, the software can flexibly select and match, and the algorithm unit obtained in the step 4 is circularly called for calculation after the recording channel records the data.
Preferably, the playing device in the step S3 is one of DAC, classD, classAB or IIS link.
Preferably, in step S5, except for directly transmitting the data played by the DSP to the input end of the recording channel through the playing device such as the IIS through the hardware lead signal, or carrying the playing data 1k sine or the scanning DMA to the digital recording unit in a software manner.
Preferably, in calculating the signal-to-noise ratio, it is calculated by the following formula:
SNR＝10*log 10 (Ps/Pn)；
where Ps represents the average power of the signal and Pn represents the average power of the noise;
quantized output signal to noise ratioSNR = 6.02n+1.76db, ideal N-bit converter for a full scale input sine waveInput power is +.>The quantized noise model is:
e(t)＝st,--q/2s≤t≤q/2s；
the noise power is:the quantized output signal-to-noise ratio is therefore:
preferably, the logarithmic scale is used in calculating the signal-to-noise ratio because the power of the signal and noise is expressed in dB.
Preferably, the root mean square quantization noise is measured over the full Nyquist bandwidth range of DC to fs/2.
Preferably, in the step S4, the total harmonic distortion plus noise thd+n is the ratio of the sum root value to the signal root value of all the harmonics and noise components under the specified bandwidth, and the noise term in thd+n measurement must be integrated over the entire measurement bandwidth, and the bandwidth must be specified to obtain a meaningful measurement result.
Preferably, the THD measurement does not include a noise term, while thd+n includes, in narrowband applications, reducing the noise level by filtering, which will reduce thd+n, thereby improving the signal-to-noise ratio SNR.
(III) beneficial effects
The invention provides a method for evaluating and calculating automatic performance of a playing and recording channel of a production test audio frequency IC. Compared with the prior art, the method has the following beneficial effects:
(1) The method for evaluating and calculating the automatic performance of the playing and recording passage of the AUDIO IC for production and measurement can be used for realizing AUDIO performance test by using pure software, can be used in research and development factories, is convenient and simple, has high execution effect, fast results, high precision calculation accuracy, no AUDIO loss caused by external measurement equipment, and is very fast, convenient and high in consistency in batch screening of AUDIO ICs.
(2) According to the method for automatically evaluating and calculating the performance of the audio IC playing and recording channel, the performance of the audio IC playing channel is automatically calculated, software controls a playing instruction through presetting standard pure tone and sweep frequency signals, a DSP is started to acquire data from a preset memory and send the data to playing devices such as DAC/ClassD or ClassAB for playing, and the software automatically calculates the performance of a current playing channel through a method for scheduling an algorithm unit SNR/THD+N in the design and stores the value of the SNR/THD+N.
(3) According to the method for evaluating and calculating the automatic performance of the audio IC playing and recording channel, the performance of the audio IC playing and recording loop-back channel is automatically calculated, the hardware PCBA is connected with playing and recording through a circuit, after playing and recording hardware are communicated, software controls a DSP to play a preset standard 1k pure tone test signal or a sweep frequency signal through an MCU, the playing device loops back the signal to a recording channel through the hardware connection, the software captures audio data from the recording channel (such as ADC/PDM/IIS and other digital analog channels) after setting the audio format of the recording channel, and the software calls an algorithm unit of SNR/THD+N to calculate the captured data and stores the calculated value.
(4) According to the method for automatically evaluating and calculating the performance of the audio IC playing and recording channel, the performance of the audio IC playing and recording channel is automatically calculated, the hardware PCBA is connected with playing and recording through a circuit, after playing and recording hardware are communicated, software controls a DSP to play a preset standard 1k pure tone test signal or a sweep frequency signal through an MCU, a playing device loops the signal back to a recording channel through the hardware connection, the software writes recorded data into a playing channel device through the MCU, controls the DSP to play, and invokes an SNR/THD+N algorithm unit again to calculate, and the whole process is a playback.
Drawings
FIG. 1 is a diagram of a system module connection of the present invention;
FIG. 2 is a flow chart of system software of the present invention;
FIG. 3 is a schematic diagram of a product scheme of the present invention;
FIG. 4 is a schematic diagram of the invention when THD+N is calculated;
FIG. 5 is a schematic diagram of power spectral density in an embodiment of the invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1-5, the embodiments of the present invention provide two technical schemes: the method for automatically evaluating and calculating the performance of the audio IC playing and recording channel comprises the following embodiments:
example 1
A method for producing and measuring automatic performance evaluation calculation of an audio IC playing and recording channel specifically comprises the following steps:
s1, after a hardware board is prepared, pre-storing 1k sine and standard obtained sweep frequency signals in software into a local memory;
s2, starting an MCU by software to start a test, wherein 3 large scene coverage play recording channels are tested;
s3, testing a playing channel, wherein the MCU sends an instruction to the DSP to start the audio performance test of the playing channel, after the DSP receives an execution instruction, the playing device is opened, 1k of sine or sweep frequency data is sent to the playing device from the memory by using the DMA to play, and the playing device is a DAC;
s4, the data obtained by the playing device is lost to an algorithm unit SNR/THD+N again to calculate an algorithm, a numerical value is calculated and stored, and the numerical value is applied to judge whether the expected value is met;
in the embodiment of the present invention, when thd+n is calculated, as shown in the formula in fig. 4, total harmonic distortion plus noise thd+n is the ratio of the sum square root value to the signal square root value of all harmonics and noise components under a specified bandwidth, the noise term in thd+n measurement must be integrated over the whole measurement bandwidth, and the bandwidth must be specified to obtain a meaningful measurement result, THD measurement does not include the noise term, and thd+n includes, in narrowband application, the noise level is reduced by filtering, and the result is reduced thd+n, thereby improving the signal-to-noise ratio SNR.
S5, testing a recording channel, wherein the MCU sends an instruction to the DSP to start performance test of the recording channel, data played by the DSP are directly transmitted to an input end of the recording channel through a playing device such as an IIS (inter-integrated space) and the like through a hardware lead signal, software can be flexibly selected and matched, and the algorithm unit obtained in the step 4 is circularly called for calculation after the recording channel records the data;
in the embodiment of the invention, except that the data played by the DSP are directly transmitted to the input end of the recording channel through the playing device such as the IIS and the like through the hardware lead signal, or the playing data 1ksinewave or the scanning DMA is carried to the digital recording unit in a software mode, the ADC device is obtained through simulation by the bypass.
In the embodiment of the invention, when calculating the signal-to-noise ratio, the signal-to-noise ratio is calculated by the following formula:
SNR＝10*log 10 (Ps/Pn)；
where Ps represents the average power of the signal and Pn represents the average power of the noise;
quantized output snr=6.02n+1.76db, ideal N-bit converter for a full scale input sine waveInput power is +.>The quantized noise model is:
e(t)＝st,--q/2s≤t≤q/2s；
the noise power is:thus quantifying the output signal-to-noiseThe ratio is as follows:
in the embodiment of the invention, the logarithmic scale is used in calculating the signal-to-noise ratio because the power of the signal and noise is expressed in dB, and the root mean square quantization noise is measured in the complete nyquist bandwidth range of DC to fs/2.
Example 2
A method for producing and measuring automatic performance evaluation calculation of an audio IC playing and recording channel specifically comprises the following steps:
s1, after a hardware board is prepared, pre-storing 1k sine and standard obtained sweep frequency signals in software into a local memory;
s2, starting an MCU by software to start a test, wherein 3 large scene coverage play recording channels are tested;
s3, testing a playing channel, wherein the MCU sends an instruction to the DSP to start the audio performance test of the playing channel, after the DSP receives an execution instruction, the playing device is opened, 1k of sine or sweep frequency data is sent to the playing device from the memory by using the DMA to play, and the playing device is an IIS link;
s4, the data obtained by the playing device is lost to an algorithm unit SNR/THD+N again to calculate an algorithm, a numerical value is calculated and stored, and the numerical value is applied to judge whether the expected value is met;
in the embodiment of the present invention, when thd+n is calculated, as shown in the formula in fig. 4, total harmonic distortion plus noise thd+n is the ratio of the sum square root value to the signal square root value of all harmonics and noise components under a specified bandwidth, the noise term in thd+n measurement must be integrated over the whole measurement bandwidth, and the bandwidth must be specified to obtain a meaningful measurement result, THD measurement does not include the noise term, and thd+n includes, in narrowband application, the noise level is reduced by filtering, and the result is reduced thd+n, thereby improving the signal-to-noise ratio SNR.
S5, testing a recording channel, wherein the MCU sends an instruction to the DSP to start performance test of the recording channel, data played by the DSP are directly transmitted to an input end of the recording channel through a playing device such as an IIS (inter-integrated space) and the like through a hardware lead signal, software can be flexibly selected and matched, and the algorithm unit obtained in the step 4 is circularly called for calculation after the recording channel records the data;
in the embodiment of the invention, except that the data played by the DSP are directly transmitted to the input end of the recording channel through the playing device such as the IIS and the like through the hardware lead signal, or the playing data 1ksinewave or the scanning DMA is carried to the digital recording unit in a software mode, the ADC device is obtained through simulation by the bypass.
In the embodiment of the invention, when calculating the signal-to-noise ratio, the signal-to-noise ratio is calculated by the following formula:
SNR＝10*log 10 (Ps/Pn)；
where Ps represents the average power of the signal and Pn represents the average power of the noise;
quantized output snr=6.02n+1.76db, ideal N-bit converter for a full scale input sine waveInput power is +.>The quantized noise model is:
e(t)＝st,--q/2s≤t≤q/2s；
the noise power is:the quantized output signal-to-noise ratio is therefore:
in the embodiment of the invention, the logarithmic scale is used in calculating the signal-to-noise ratio because the power of the signal and noise is expressed in dB, and the root mean square quantization noise is measured in the complete nyquist bandwidth range of DC to fs/2.
In the actual use process, if the original clean signal is not known, the signal parameters need to be estimated at the moment, so that the signal power and the noise power are obtained. Since the autocorrelation function and the power spectral density function are fourier transform pairs, we perform the power spectral density by combining the specific process given in fig. 5 to obtain the power spectral density function, and the general power spectral density is obtained by FFT calculation using a Kaiser window, and the purpose of windowing is to prevent energy leakage.
The average power of the signal is calculated. The direct current DC band is removed, the band with the maximum value max is found, and then the total power Pfund of the whole peak band is calculated as the average power of the signal.
The average power of the noise is calculated. Removing a Direct Current (DC) wave band (setting 0), removing a signal peak value segment (setting 0), removing 2-6 harmonic wave segments (setting 0), calculating a median value (estimaedNoiseDensity) of the rest part, assigning the 0-set part as the estimaedNoiseDensity, and finally calculating the total Noiseof the whole power spectrum as noise average power.
SNR was calculated, r=10log 10 (Pfund/totalNoise).
And all that is not described in detail in this specification is well known to those skilled in the art.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (8)
1. A method for producing and measuring automatic performance evaluation and calculation of an audio IC playing and recording channel is characterized in that: the method specifically comprises the following steps:
s1, after a hardware board is prepared, pre-storing 1k sine and standard obtained sweep frequency signals in software into a local memory;
s2, starting an MCU by software to start a test, wherein 3 large scene coverage play recording channels are tested;
s3, testing a playing channel, namely sending an instruction to a DSP by the MCU to start audio performance test of the playing channel, opening a playing device after the DSP receives an execution instruction, and sending 1k of sine or sweep frequency data to the playing device for playing by using a DMA from a memory;
s4, the data obtained by the playing device is lost to an algorithm unit SNR/THD+N again to calculate an algorithm, a numerical value is calculated and stored, and the numerical value is applied to judge whether the expected value is met;
s5, testing the recording channel, wherein the MCU sends an instruction to the DSP to start the performance test of the recording channel, the data played by the DSP is directly transmitted to the input end of the recording channel through the IIS and other playing devices through the hardware lead signal, the software can flexibly select and match, and the algorithm unit obtained in the step 4 is circularly called for calculation after the recording channel records the data.
2. The method for generating an audio IC playback recording path automatic performance assessment calculation of claim 1, wherein: the playing device in the step S3 is one of DAC, classD, classAB or IIS link.
3. The method for generating an audio IC playback recording path automatic performance assessment calculation of claim 1, wherein: in the step S5, except for directly transmitting the data played by the DSP to the input end of the recording channel through the playing device such as the IIS and the like through the hardware lead signal, or carrying the playing data 1k sine or the scanning DMA to the digital recording unit in a software mode.
4. The method for generating an audio IC playback recording path automatic performance assessment calculation of claim 1, wherein: in calculating the signal-to-noise ratio, it is calculated by the following formula:
SNR＝10*log 10 (Ps/Pn)；
where Ps represents the average power of the signal and Pn represents the average power of the noise;
quantized output snr=6.02n+1.76db, ideal N-bit converter for a full scale input sine waveInput power is +.>The quantized noise model is:
e(t)＝st，--q/2s≤t≤q/2s；
the noise power is:the quantized output signal-to-noise ratio is therefore:
5. the method for generating an audio IC playback recording path automatic performance assessment calculation of claim 4, wherein: the logarithmic scale is used in calculating the signal-to-noise ratio because the power of the signal and noise is expressed in decibels dB.
6. The method for generating an audio IC playback recording path automatic performance assessment calculation of claim 4, wherein: root mean square quantization noise is measured over the full nyquist bandwidth range of DC to fs/2.
7. The method for generating an audio IC playback recording path automatic performance assessment calculation of claim 1, wherein: in the step S4, when thd+n is calculated, the total harmonic distortion plus noise thd+n is the ratio of the sum root value to the signal root value of all the harmonic and noise components under the specified bandwidth, and the noise term in thd+n measurement must be integrated over the entire measurement bandwidth, and the bandwidth must be specified to obtain a meaningful measurement result.
8. The method for generating an audio IC playback recording path automatic performance assessment calculation of claim 7, wherein: the THD measurement does not include a noise term, whereas thd+n includes, in narrowband applications, a reduction in noise level by filtering, which will reduce thd+n, thereby improving signal-to-noise ratio SNR.
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