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Altera_Forum's avatar
Altera_Forum
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16 years ago

White Noise Spectrum

I have use a simple LFSR to generare random number to generate white noise. Set of random number are pass through to FFT(power in db vs freq). However, the freq response is increasing at low freq. Th...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

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thepancake:

Quote

"if you'd rather see the tapering near the half sample rate, flip the sign of every other sample. in this case i think you'll have a DC offset."

I have no idea abt it. Can you explain in details?

thanks a lot

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you can invert the spectrum by multiplying every other output sample by -1.

for example if your ouputs are 1, 2, 3, 4 you will get 1, -2, 3, -4, then

_|\/|_ turns into /|__|

which would make your spectrum taper off near fs/2 rather than near DC.