[Hilo] [PCM] what are the advantages of using PCM instead of analog signals?
Answer: For using the digital audio path (PCM) you have to add one chip to convert digital to analog then you can plug your mic and speaker.
If you decide to use the PCM
|MODULE| -------DIGITAL PATH----------| PCM DECODER|------- ANALOG SIGNALS---- |SPEAKER/MIC|
Compare to the ANALOG solution
|MODULE| -------ANALOG PATH---- ----|SPEAKER/MIC|
One possible advantage for DIGITAL solution is that when the PCB of the customer is really noisy (by other RF antenna for example, or by a poor power supply quality) you can use the DIGITAL path to make the connection between the module and the decoder (90% of the distance between both) then use the PCM decoder and come back in analog as much closer as possible to the MIC/SPEAKER.
It can increase the quality of the audio in this case but it has a cost because you have to add on PCM decoder.
However, same can be done with the Analog solution by adding two GND plans on the PCB and adding a lot of via all the long of the analog path. So the analog path will be protected like in a jail between two GND plans and VIA between GND plans.
This solution is cost saving.
The real advantage of the DIGITAL is if you want to make a processing on the audio flow.
|MODULE| -------DIGITAL PATH----------| CPU or DSP |------- ANALOG SIGNALS---- |SPEAKER/MIC|
Inside the CPU/DSP you can add some filters or mixe the audio with another one and so on.
Analog path and digital path are exclusive.
You can use one of them but not both at the same time. (See AT+VIP)