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PCM3168A: Low Group Delay Audio CODEC Solutions for Acoustic Noise Cancellation

nestor lee
Intellectual 985 points
Part Number: PCM3168A
Other Parts Discussed in Thread: PCM1864

Hi TI Experts，

We have a customer designing ANC(Acoustic Noise Cancellation) Modules. And they run their ANC algorithms in DSP, and use audio CODEC to sample microphone inputs(4-ch) and outputs 2-ch anti noise waveforms to amplifier.

Their algorithms need the group delay parameter in CODEC to be as low as possible(ADC group delay + DAC group delay < 50uS would be perfect). I checked some datasheets, and found that in PCM3168A it describes -- for ADC  Group delay time (dual) is 17/fs, and for DAC, Group delay time (quad) is 19/fs.  So if we run this CODEC at fs = 192kHz, the total group delay would be (17+19)/192k = 187 uS. Am I right calculating group delays?

Are there any lower group delay solutions from TI? Customer can accept using ADC + DAC chips.

Thanks.

  • 0
    TI__Expert 5645 points
    Hi Nestor,
    Our colleague will look into the above query and also recommend the part which meets the spec for group delay. Thanks.

    Best regards,
    Ravi
  • 0 in reply to Ravi Patil
    TI__Guru 57800 points

    Hi, Nestor,

    The calculation for the ADC+CAD group delay you made is correct. Unfortunately the group delay of our audio codec devices is very similar to the PCM3168A. From an ADC standpoint, we have a 4-channel audio ADC, the PCM1864, which features a low-latency filter whose group delay is 10/Fs.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer