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How could I measure the delay of an external analog loopback on ADZS-SC584-EZLITE board?

Hi ADI experts,

Now I'm developing ANC solution based on the ADC DAC playback SC589 example codes on ADZS-SC584-EZLITE board.

And I have two questions.

1) How could I measure the delay of an external analog loopback (from RCA audio output to RCA audio input) on ADZS-SC584-EZLITE board?

-> Could I estimate the delay using correlation? 

2) How could I minimize the delay of an external analog loopback (from RCA audio output to RCA audio input) on ADZS-SC584-EZLITE board? 

-> Do I need to modify AUDIO_BUFFER_SIZE to a smaller size in the adc_dac_playback.h file of the ADC DAC playback example?

Thanks for your support!

Kim

  • Hello Kim,

    ADC DAC playback SC589 example code makes use of two buffers to receive the input data. Hence the equivalent net delay is time required to fill/write two buffers.

    So for a block size of 1024 and the sampling rate of 48Khz:
    The time per frame will be (1/48KHz)= 20.83 micro seconds.
    Total net delay will be 20.83 * 1024 * 2= 42.659 msec.

    By reducing the BLOCK Size, latency will also be reduced.

    Best Regards,
    Santhakumari.K