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ADAU1442 time multiplexed audio

Question asked by IanH on May 13, 2010
Latest reply on May 14, 2010 by JeradL

Hi,

I have an application where I am sending/receiving audio from a E1 comms link in TDM8 format. Since the E1 comms link is a 256bit packet at 8kHz rate I need to assemble/reassemble my audio stream into a 24-bit 24kS/s stream.

 

A 24kS/s stream is represented in the TDM8 packet as three 24-bit samples all arriving/sent in the same packet (9 bytes total).

 

For sending, I was going to use

the form az + az-1 + az-2

 

i.e convert to 24kh and then use single sample delays to create 3 outputs and then output in my TDM8 stream.

 

But receiving is much more difficult to me to visualise.

 

The input port can be delayed in reverse order to align the three samples but I uncertain how I would convert three samples received at the same time into three sequential samples and upscaled to 48kS/s (all internal processing is at 48kS/s)?

 

I'm not too concerned about delays in the system. I've looked at the Feedback module but don't think that will do it. I wondered about using some form of counter to use as a index to insert into a stream.

 

 

Anyone got any idea of an approach to this?

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