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Dual ADAU1701 with selectable A or D input

SigmaDSP & SigmaStudio JoeSonic Aug 22, 2012 00:00 4 replies Original on forum ↗
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JoeSonic Question
Aug 22, 2012 00:00

Hello,

for a 3-way self powered loudspeaker system I need a couple of functions which I do not understand yet. We are using single ADAU1701 with analog inputs in various products but this seems to be a bit more complicated.

I need to split the signal flow onto two ADAU1701 because at 192kHz the program will be too long.

The first DSP should be the "input-chip". I should be able to switch between analog inputs and a digital input from a S/PDIF receiver with sample rate converter. How do I do the switching of the PLL in this case? I think I need to change the clock source, right? How will this look in the SigmaStudio File?

The first DSP contains a 3-way frequency crossover and some EQs and selectors. The 3 signals from the crossover need to be send digitally to the second DSP, where some EQs are used and limiters for all three ways, before the signals are send to the onboard DACs.

Can you give me some hints how to build something like a daisy chain for this?

The ADAU1701 are used in self-boot mode.

Thank you very much,

Hanno

Audio Signal Processors

input_selector

SigmaDSP Audio Processors

adau1701

daisy_chain

Bill.PE Reply
Aug 22, 2012 00:00

If you need a digital audio input with variable sample rates, then I believe you need to use the a part with ASRC (asynchronous sample rate convertors). The only part with ASRC and a A/D is the the new ADAU1772 as far as I know. I have not use this part yet.

ADIApproved Reply
Aug 22, 2012 00:00

Does your S/PDIF receiver have an internal sample rate converter? Can it be a slave to an external master clock source? If so, then that makes the system much less complicated.

JoeSonic Reply
Sep 5, 2012 00:00

Actually I didn't find a good S/PDIF receiver/ASCR yet. Perhaps, what I could start with is using the S/PDIF interface of the ADAU1701 evaluation board (I have the larger one).

I haven't understood yet, how to configure and build the signal flow for only receiving S/PDIF data and converting into analog stereo output. This would be a good starting point, I think.

ADIApproved Reply
Sep 6, 2012 00:00

Page 8 of the user guide should be able to help you set up S/PDIF. http://www.analog.com/static/imported-files/user_guides/UG-072.pdf