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Hi guyz

This is my first DSP project and its a undergrad thesis project, so forgive my stupid question.


Im implementing an adaptive LMS algorithm to cancel background noise from a speech. my primary
mic picks up a noisy speech and the secondary mic will pick up the reference noise. in my PCM
3003 theres only one input port. how can i connect two mics into the PCM. since this is real
time so can i do this project using just the DSK and the PCM or should i need something else
like DSP/BIOS and RTDX.

your help is very much appriciated. 

Thanks...

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Naamhin-

> This is my first DSP project and its a undergrad thesis project, so forgive my stupid
question.
>
> Im implementing an adaptive LMS algorithm to cancel background noise from a speech. my
primary mic picks up a noisy
> speech and the secondary mic will pick up the reference noise. in my PCM 3003 theres only
one input port. how can i
> connect two mics into the PCM.
>
> your help is very much appriciated.

Are you saying your PCM3003 daughtercard has only one connector?  The standard card should have
two (2) I/O connectors
(the card contains a stereo codec).  Here are a couple of pics I found:

  http://www.ict.com.tw/dsp/TI/dspstarterkit/pcm3003.gif

  http://www.cs.princeton.edu/~gewang/ee464/1.jpg

Maybe you don't actually have a PCM3003.  Better check carefully the labeling on the
daughtercard.

> since this is real time so can i do this project using just the DSK and the PCM or
> should i need something else like DSP/BIOS and RTDX.

For speech application, using sampling rate of 8 kHz, the combinatino of DSK C6711 + PCM3003
and DSP/BIOS is
sufficient.  RTDX may not be much help, as it's very slow in transferring data to/from the host
PC.

-Jeff
------------------------------------

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I can't help with your hardware problem, but regarding your adaptive LMS algorithm, I
recently experimented with an adaptive LMS algorithm and it worked great when the noise signal
came from the same source as the noise contaminating the speech.  However, as soon as I
time-delayed the noise signal (even by only a few samples), the adaptive noise filtering
performance was significantly degraded, particularly at high frequencies because the noise in
the contaminated speech at x(n) was not very correlated to the pure noise signal at x(n-m).  As
the delay increased, the noise got worse and produced a comb filter sound.  Let me know if you
have better success with adaptive LMS filtering when your noise pickup mic is displaced (time
delay) from your speech pickup mic.

Thanks,
Gene

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Hi guyz
>
>This is my first DSP project and its a undergrad thesis project, so forgive my stupid
question. 
>
>Im implementing an adaptive LMS algorithm to cancel background noise from a speech. my
primary mic picks up a noisy speech and the secondary mic will pick up the reference noise. in
my PCM 3003 theres only one input port. how can i connect two mics into the PCM. since this is
real time so can i do this project using just the DSK and the PCM or should i need something
else like DSP/BIOS and RTDX.
>
>your help is very much appriciated. 
>
>Thanks...
>
>------------------------------------
>

Thanks for your reply.

The image given in the Princeton link is exactly what i have. When i said i have one input in
my PCM3003, i meant i have only one input port. But i need two inputs, one for my primary mic
and one for secondary mic. So how can i use the PCM3003 for two inputs. Is there any daughter
card with multiple inputs? 

Naamhin.

>

------------------------------------

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Naamhin-

> Thanks for your reply.
>
> The image given in the Princeton link is exactly what i have. When i said i have one input
in my PCM3003, i meant i
> have only one input port. But i need two inputs, one for my primary mic and one for
secondary mic. So how can i use
> the PCM3003 for two inputs. Is there any daughter card with multiple inputs?

What are you missing?  The picture clearly shows two (2) connectors.  Each one is a stereo jack
(i.e. 2 signals).  So
that's a total of four -- 2 inputs, 2 outputs.

Is this not enough to handle a primary and secondary mic?

I don't get what is your issue.  You have everything that you need.  You should get to work on
the code!

-Jeff

PS. Don't strip out the previous text from the message.  If you do that then other students
can't follow the thread,
especially if they come along in the future and are searching the archives.  If you do this, I
can't help you anymore.
------------------------------------

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