
One zero, LP/HP
References : Posted by Bram
Notes : LP is only 'valid' for cutoffs > samplerate/4
HP is only 'valid' for cutoffs < samplerate/4
Code : theta = cutoff*2*pi / samplerate
LP:
H(z) = (1+p*z^(1)) / (1+p)
out[i] = 1/(1+p) * in[i] + p/(1+p) * in[i1];
p = (12*cos(theta))  sqrt((12*cos(theta))^2  1)
Pi/2 < theta < Pi
HP:
H(z) = (1p*z^(1)) / (1+p)
out[i] = 1/(1+p) * in[i]  p/(1+p) * in[i1];
p = (1+2*cos(theta))  sqrt((1+2*cos(theta))^2  1)
0 < theta < Pi/2 
Comments
Added on : 22/04/03 by newbie attack Comment : What is the implementation of z^(1)?
Added on : 29/06/04 by spam[ AT ]hell[ DOT ]no Comment : z^(1) = 1/z
Added on : 26/07/06 by cam Comment : z^(1) is a single sample delay. The second line of code is the actual filter code. First line is a transfer function.
Added on : 17/05/07 by Gorgr Comment : wt's the meaning of 'p'?
Added on : 21/04/14 by chippo Comment : And what's the meaning of 'z'?

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