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ADAU1451 and STA120 AES IC

Question asked by Fountainhead on Feb 10, 2017
Latest reply on Feb 10, 2017 by Fountainhead

Hello All,

 

I'm using an ADAU1451 with 1789 D/A, 1978 A/D, and the STA120 AES decode IC (for an AES input option).

The problem is the STA120 IC Sine wave (generated with AP515 Digital AES on STA120 RX input) won't decode cleanly (FFT shows noise floor jumping instability etc.) in the D/A output. Other sine waves from other sources are fine.

I've tried using the BCLK, LRCLK out as slave and master to/from the ADAU1451 from the STA120 but no change. The only way to make the STA120 signal FFT clean/stable from the ADAU1451 is to use the MCLK from the STA120 as master to the ADAU1451 and everything else mentioned previously. The problem with that is when a digital signal is present, the STA120 MCLK is 12.28 MHz. When the digital signal is removed the MCLK remains 12.28 MHz. But, if the system is powered down and up, the MCLK from the STA120 is 5MHz, which is the lowest default since the MCLK is derived from the incoming signal. I'm not comfortable with this setup...

Does anyone know of a work around ?

 

Thank you in advance,

 

Ray

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