TAS5756M: SDOUT(GPIOx) Echo reference and 2.1Channel Question

Jerry Chu

Part Number: TAS5756M
Other Parts Discussed in Thread: TAS5711

Hi Expert,

I saw the below description for SDOUT, but as I know, the echo reference needs the real output signal. Is it ok for echo reference?

I want to design 2.1 channel system, can I use TAS5756M + TAS5711(PBTL)? Thanks!

over 8 years ago

0 Alex Bhandari-Young over 8 years ago

TI__Mastermind 25895 points

Hi Jerry,

Andy can take a look at this question for you and should be posting shortly.

Regards,

Alex

0 Alex Bhandari-Young over 8 years ago in reply to Alex Bhandari-Young

TI__Mastermind 25895 points

Hi Jerry,

Sorry for the delay on this. In your 2.1 system the TAS5711 in PBTL driving your sub-woofer will be driven using the SDOUT of the TAS5756 if I understood your question correctly. You will not be able to do echo cancellation in the 2.1 system you described because in an echo cancellation system you need the SDOUT for echo reference. Does this answer your question?

Regards,

Alex

0 Jerry Chu over 8 years ago in reply to Alex Bhandari-Young

Genius 4915 points

Hi Alex,

I need the echo reference for the AEC application. So, if it's a 2.1 solution, stereo and subwoofer both are need the DOUT for echo reference?

As the below block, the DOUT seems bypass DIN data only, not the real output data. Is it right?

0 Alex Bhandari-Young over 8 years ago in reply to Jerry Chu

TI__Mastermind 25895 points

Hi Jerry,

1) This is application specific so I would need more details about the cancellation algorithm and your setup to be able to help with that question.

2) Have you taken a look at the section of hybridflow of this app note? specifically hybridflow 2, which is used for 2.1 applications provides more details on how SDOUT works www.ti.com/.../slau577a.pdf

If you take a look at the hybridflow structures you can see SDOUT can be taken at three different points in the process flow, including after DSP processing so it is not true that SDOUT is only taken from data in.

In my last response I was under the impression that you were driving the subwoofer through the SDOUT line of the 5756. Is this correct?

Regards,

Alex

0 Jerry Chu over 8 years ago in reply to Alex Bhandari-Young

Genius 4915 points

Hi Alex,
If I chose HybridFlow3 and select SDOUT for Post-DSP. The SDOUT should be L+R(HPF)/L+R(LPF) I2S signal.
Does it possible to output L+R/L+R without filtering signal? Thanks!