dear chassaing

thanks for reply.

1] i am not aware of your book, i will try get it , and give tips how to get it in meantime.   it will be more helpfull if you send me ,examples related to my problem.

2] we are using TIs quad combo CODEC TMC38C17.(you will get more info on TIs web).

3] we did following experiment in our R&D.

    a] samples collected and played back success fully on from and to TMC38c17 respectively.

      the flow is :        telephone->codec->dsp->memorystore->codec->telephone.

      b]  samples collected from PC micro phone and played back on PC speaker.

        the flow is :  mic->pc memory->speaker.

         now the problem is , i want play samples collected from PC microphone on phone through TMC38c17.

      needed flow is:  mic->PC memory->DSP board memory(RAM)->codec->telephone.

16bit linear data to Alaw.

this experiment we did in our lab, but the out put at telephone is noisy.

i want to know what rea the steps i need to play microphone out put from PC to play on telephone.

thanking you in advance

Raja Jitendra Nayaka

Bangalore

 chassaing wrote:

Hi:

Are you familiar with my book: "DSP Applications Using C and the TMS320C6x
DSK"? Included are dozens of examples. Also a student (graduate-level)
project on u-Law for speech companding.

You should use/test your algorithm with the on-board codec. Is the 38C17
the on-board codec (I am not familiar with it). I have included examples
using the AD535 on board the C6x DSK as well as examples using the PCM3003
stereo codec. TI sells a $50 (U.S.) Audio Daughter Card based on the
PCM3003.

I assume that you have other examples tested successfully using your board
with the 38C17 codec.

You can contact me directly if I can be of help.

Rulph Chassaing

----- Original Message -----
From: "raja nayaka"
To: "Jeff Brower"
Cc:
Sent: Wednesday, December 18, 2002 2:08 AM
Subject: Re: [c6x] microphone out put> thanks for reply
> we are using TMS320C6211 DSP based customized board for communication
purpose.
> the codec connected is TMC38C17.
> we could able to record and play back the sample thru and from codec
directly(without wave file).
> how ever, when we feed wave out samples (converted to a A-law sample using
lin-to-Alaw function) from pc to codec we are not able to hear the speech
(other than noise)
> our required flow is: microphone->PC->DSP borad->codec->speech
> tahnking you
> Raja Jitendra nayaka
> Scientist
> ITI Ltd ,
> Bnagalore
> Jeff Brower wrote:Raja Nayaka-
>
> > i want to collect audio samples from pc via microphone and convert it
into PCM
> >
> > A-law.(i.e. paly wave file on codec)..please give me suggetion , what
are the steps i need to do so?...
> >
> > once i used wave file and converted it in to A-law using some linear to
Alaw function.
> >
> > and fed to codec...the final out put was full of noise...
>
> Try some basic debug: what if you just fed .wav file to codec? Did you
hear it? If
> so, then codec was not programmed correctly to accept A-law format data.
>
> [note] You might get much better answers from the group if you mention
which C6x
> board you are using ! Then everyone would know which codec, then you might
actually
> get a suggestion for configuring the codec...
>
> Jeff Brower
> DSP sw/hw engineer
> Signalogic
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