4. FAQ

1. No waveform on the right channel of the “ain_record.pcm” file in BGA packaging platform.

   Answer: Check if there is a reference signal introduced into the ADCR channel on the hardware pcb.

2. There is echo in the intercom (the other person involved can hear their own voice).

   Answer: Check if the recording waveform of the left and right channels in “ain_record.pcm” is too large and distorted. Check if the mic and spk are damaged, if there is interference in the analog circuit. If all of these issues have been ruled out, consider the algorithm and algorithm parameters.

3. The gain value of my ADCR has been set to 1, and the gain set for Audio Output is not large, but the right channel of the “ain_record.pcm” is very distorted despite being attenuated.

   Answer: Check the sound data sent by the other person via the network, save it as a file, and view the waveform on a PC.

4. The sound heard on the machine side is problematic, such as fluctuations in volume and lost words.

   Answer: Assuming the machine is intercomming with a mobile app, the sound played by the machine is sent from the mobile phone. This is generally a problem with the mobile phone. The results of AEC processing in all intercoms are manifested at the other end. In other words, our processing results are manifested on the mobile phone side. As long as the person on the mobile phone cannot hear their own voice and the other person’s voice is not lost or stuttered (which may be due to network or processor overload), then our AEC processing results are okay.

5. In order to prevent distortion of the right channel waveform of the “ain_record.pcm” on the QFN packaging platform, the gain of the Audio Output volume was reduced, resulting in the speaker not being loud enough. What should I do?

   Answer: The premise for the normal operation of the AEC algorithm is that there is no distortion (including peak attenuation, mic issues, spk issues, and distortion caused by interference). Because the QFN connects the ADCR to the DACR internally and the ADC gain does not have the function of reducing volume, the only solution in this situation is to reduce the Audio Output and increase the amplification coefficient of the power amplifier to solve this contradiction. On the BGA platform, the wiring on the PCB connects the ADCR to the DACR, so resistor dividers can be adjusted to avoid this situation.

6. The following test methods are not effective: using mobile phone playback to replace speaking for testing; machine and mobile phone placed together with one person speaking simultaneously.

7. There is serious howling during intercom debugging.

   Answer: Determine whether the distance between the speaker and mic is too close. If there is still howling when they are far apart, the gain value of the mic can be appropriately reduced.