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Altera_Forum's avatar
Altera_Forum
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16 years ago

Pre-Emphasis with IIR Filter

Hello! I want to do a classic Pre-Emphasis with VHDL. Normally this is implemented with an IIR-Filter. I tried to do this in VHDL with the following formula I found in the web: y(i)=x(i)-(x(i-1...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

I just modelled your equation in Matlab : 


x = ;  %impulse input
k = .95;
 
y(1)=0;
for i = 2:1000
   y(i)=x(i)-(x(i-1)*k);
end
 
fx = fftshift(fft(x));
fy = fftshift(fft(y));
plot(abs(fx));hold
plot(abs(fy),'r')

output is simply reduced by .95 at all frequencies