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[Fwd: Re: 64kbps PCM]

Started by Jeff Brower October 26, 2002
K Seshu Babu-

If you look at section 12.4.1, Companding Internal Data, in TMS320C6000
Peripherals
(SPRU190D) you will see that what Chen is recommending will not work with the
AD535
codec directly. You will have to use a second McBSP port to compress 16-bit
data to
u-Law. Do this:

-read 16-bit data from AD535 on McBSP0

-compress on McBSP1 using DLB mode (internal
loopback), with XCOMPAND and RCOMPAND set
same

Then you have 8-bit u-Law data for processing. If McBSP1 is needed for other
peripheral, then you're stuck using a software function.

Jeff Brower
DSP sw/hw engineer
Signalogic -------- Original Message --------
Subject: Re: [c6x] 64kbps PCM
Date: Fri, 25 Oct 2002 23:03:53 -0500
From: Jeff Brower <>
Organization: Signalogic
To: ZW Chen < wrote:
>
> :
> >From:Jeff Brower <>
> >Reply-To:
> >To: K Seshu Babu <>
> >Subject: Re: [c6x] 64kbps PCM
> >
> >K Seshu Babu-
> >
> >> With DSK6711(16-bit codec) can we convert 16-bit PCM to
> >> 8-bit.Is their any method to do it without harming sample value too much
> >
> >Try u-Law, standard telephony method to compress samples to 8-bit. I don't
think
> the
> >feature is built into the AD535 codec on the DSK board, so you might try
simple
> >software formula.
>
> no,Brower, 6711 McBsp has that function,i can convert linear sample to u-law
or
> A-law automatically

Yes the McBSP has many great features. Next time, please help K Seshu Babu or
other
person who needs the help! Thanks.

Jeff Brower
DSP sw/hw engineer
Signalogic