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Stable SPDIF I/O at 44.1kHz on EVAL-ADAU1452MINIZ EVM?

Question asked by DMR on Apr 14, 2014
Latest reply on Apr 29, 2014 by DMR

I am measuring the SPDIF I/O performance of the ADAU1452MINIZ EVM. My measurement system can record the exact output (with delay) when using SPDIF loopback at 44.1 and 48kHz. I set up the EVM (with SigmaStudio) to use SPDIF TX and RX with simple I/O as described in the user guide. When I set the sampling frequency to 44.1kHz I find that my recorded output from the EVM given a one sample pulse train input (repeats every 500ms) is smeared in time and the peak amplitude varies. (Note that my audio device, an M-Audio ProFire 2626, cannot sync lock to the SPDIF TX at 44.1kHz but can lock at 48kHz.) With the sampling frequency at 48kHz and the EVM the master Fs clock, the recorded output of the impulse train is still smeared by 62 samples, but the peak and smeared samples are always the same. I assume the smearing is due to the ASRC doing its job. Is there a way to get similar stable performance with the EVM at 44.1kHz?

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