Hi all, i want to generate white noise phisically to test my filters.
i used the matlab commands (wgn(),sound()) to generate the noise using the sound
card .
But when i tested the fft of the output signal the spectrum is not flat which it
should be.
Is there any other way to generate the white noise using any software or
hardware.
Any response in this regard would be helpful.
Thanks
wajahat.
how to generate white noise///
Started by ●February 19, 2007
Reply by ●February 20, 20072007-02-20
Wahijat-
> Hi all, i want to generate white noise phisically to test my filters.
> i used the matlab commands (wgn(),sound()) to generate the noise using the sound card .
> But when i tested the fft of the output signal the spectrum is not flat which it should be.
> Is there any other way to generate the white noise using any software or hardware.
> Any response in this regard would be helpful.
First, make sure you are averaging the spectrum over several frames so you get an
accurate, stable view. Second, please explain "not flat" -- is it sort of flat with
'round off' at higher frequency area? If so, then you may be looking at the effect
of the anti-alias filters on the sound card in cascade with your DSP code filters.
-Jeff
> Hi all, i want to generate white noise phisically to test my filters.
> i used the matlab commands (wgn(),sound()) to generate the noise using the sound card .
> But when i tested the fft of the output signal the spectrum is not flat which it should be.
> Is there any other way to generate the white noise using any software or hardware.
> Any response in this regard would be helpful.
First, make sure you are averaging the spectrum over several frames so you get an
accurate, stable view. Second, please explain "not flat" -- is it sort of flat with
'round off' at higher frequency area? If so, then you may be looking at the effect
of the anti-alias filters on the sound card in cascade with your DSP code filters.
-Jeff
