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6711 DSK Audio sample code

Started by Chacko Thomas December 13, 2002
Hi,
I am new to 6711 DSK.
I am using Audio sample code to read/write audio
samples to AD535. Every thing works fine when I
compile the original code and run it. When I tried to
pass the signal through a low pass IIR filter, I get a
noise dominated output. I inserted the IIR code in the
Process() function in audio sample code.
Does any one face similar problem and have a solution?
Can any one help me to resolve this issue?
I appreciate any suggestion.

Thanks
Thomas.

__________________________________________________



Hi Chacko
If you are using the single sample read/write version, it could be that your
code is taking too much time - depending on compiler optimizations etc. This
could sound like bursty noise.
Also, it may be some overload problem depending on the IIR implementation and
the coeff. you use. Again this sounds like noise in some cases. Have you tested
it with zeros in the feedback loop so you have no poles to make it unstable? IF
you used FP this problem should go away depending on how close your poles are to
the unit circle. I had some other problems with the DSK, they mostly went away when I reset the
CPU each time before I loaded new code. You should also wait after reset since
it takes some time and codecomposer can crash if you click too fast. You have
to be a little gentle with the CC. During some crashes, when I was testing
audio code, everything seemed to work, but wither there was no audio, or there
was some pulsing noise. All these problems were due to crashes of the
system....
I am assuming of course that you have no bugs in the code!

Hope this helps!
J.

Chacko Thomas <> wrote:Hi,
I am new to 6711 DSK.
I am using Audio sample code to read/write audio
samples to AD535. Every thing works fine when I
compile the original code and run it. When I tried to
pass the signal through a low pass IIR filter, I get a
noise dominated output. I inserted the IIR code in the
Process() function in audio sample code.
Does any one face similar problem and have a solution?
Can any one help me to resolve this issue?
I appreciate any suggestion.

Thanks
Thomas.

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