ADAU1442 Clocks

Hi all,

I've got a setup in which a DSP (ADAU1442) is connected to 3 ADC (1974) as input and another DSP as output. Currently the ADAU1442 is master of the TDM stream to the ADC's bus slave to the TDM stream in the output. However, I noticed some artifacts, probably due to the internal clk difference of ADAU 1442 (XTAL) and the output. Is it possible to make the sync on the TDM signal of the output and use this same clock to connect to the ADC? Any advice on this is highly appreciated! Thanks in advice!

Best regards,

Guy

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  • Hi again Alan,

    Thanks again for the answer. I do have sigma studio and I was able to make the artifact go away by using the ASRC! Really impressive :-) However, I do not yet fully understand the routing because it seems that I have connected the input signal from the ADC directly to the TDM output. It's good to know that it works but I have to find how I must avoid bypassing the DSP :-) For this test, I only used 1 input and 1 output. Originally, the output signal was "dancing" (slightly shifting wrt the input signal)

    So what I did in Sigma Studio, in the "Routing Matrix" tab is this:

    I changed "Serial Output Select Pair 8" from "DSP to Serial Output Pair 0" to "ASRC Output Pair 0"

    I changed "ASRC Output Rate Select Pair 0" from "No Rate" to "Serial Output Pair 8"

    I think this is correct, so know I guess I use ASRC Output Pair 0 with the clock of Serial Output Pair 8.

    Finally, I have changed "ASRC input Select Pair 0" to "Serial Input Pair 4". Now I see the signal from the input but the DSP is bypassed. I don't know how I have to select the DSP. I'm not sure it it's important but both input as output format is TDM8.

    Best regards,

    Guy

Reply
  • Hi again Alan,

    Thanks again for the answer. I do have sigma studio and I was able to make the artifact go away by using the ASRC! Really impressive :-) However, I do not yet fully understand the routing because it seems that I have connected the input signal from the ADC directly to the TDM output. It's good to know that it works but I have to find how I must avoid bypassing the DSP :-) For this test, I only used 1 input and 1 output. Originally, the output signal was "dancing" (slightly shifting wrt the input signal)

    So what I did in Sigma Studio, in the "Routing Matrix" tab is this:

    I changed "Serial Output Select Pair 8" from "DSP to Serial Output Pair 0" to "ASRC Output Pair 0"

    I changed "ASRC Output Rate Select Pair 0" from "No Rate" to "Serial Output Pair 8"

    I think this is correct, so know I guess I use ASRC Output Pair 0 with the clock of Serial Output Pair 8.

    Finally, I have changed "ASRC input Select Pair 0" to "Serial Input Pair 4". Now I see the signal from the input but the DSP is bypassed. I don't know how I have to select the DSP. I'm not sure it it's important but both input as output format is TDM8.

    Best regards,

    Guy

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