We have a Analog Devices A2B bus evaluation kit which is based on ADAU1452 and as far as I understood features also one of these programmable audio dsps.
Now we have realized a design with SigmaStudio which uses the Voice Activity Detection block (which was already available inside the SigmaStudio Library).
I use the envelope output of the VAD block and connect it to VAD Flag unit and use its output as the detected speed acitivty flag. Is this correct?
Somewhere I read I should use the modulation index output. But that output is all the time zero. The Envelope output is not zero and changes according to input audio stream. But I do not understand why the modulation index is always zero.
Where can I read the algorithm implemented in this block?