Downsampling from 192kHz ADC to 96kHz System Sampling Rate ADAU 1452-66
Hello,
the ADCs 192kHz rate must be converted to the general ADAU rate of 96kHz. The ADAU provides the master clock for the peripheral devices. Could operate the inputs with 96kHz and drop every second sample be a possible solution?
Marc
Hello,
You can run your ADCs at 192 and use the ASRCs on the ADAU1452 to downsample to 96.
Hello MarcE,
Dropping every other sample will cause some audio issues. The 192kHz sampled audio will contain energy at frequencies above the Nyquist frequency of a 96kHz sample rate. So those will alias into the 96kHz audio.
Another option you have since the ADC is synchronous to the DSP, is to run the serial input port at 192kHz. Then run the core at 192kHz and use the down-sample cells to create a lower sample rate processing thread in the DSP. Then you can run the serial output port at 96kHz and that will work. It may make the rest of the system a bit more tricky and it will use up more MIPS to do this.
Using the ASRCs will simplify things a lot and since it is implemented in hardware it will not use up any MIPS in the DSP for down-sampling.
Dave T
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