response of type 2 Chebyshev filter
[h2]=cheb2mag(n,omegar,A,sample)
integer ; filter order
real scalar : cut-off frequency
attenuation in stop band
vector of frequencies where cheb2mag is evaluated
vector of Chebyshev II filter values at sample points
Square magnitude response of a type 2 Chebyshev filter.
omegar
= stopband edge, sample
= vector of
frequencies where the square magnitude h2
is desired.
//Chebyshev; ripple in the stopband n=10; omegar=6; A=1/0.2; Samples=0.0001:0.05:10; h2=cheb2mag(n,omegar,A,Samples); plot(Samples,log(h2)/log(10)) xtitle("", "frequencies", "magnitude in dB"); //Plotting of frequency edges minval=(-max(-log(h2)))/log(10); plot2d([omegar;omegar],[minval;0],[2],"000"); //Computation of the attenuation in dB at the stopband edge attenuation=-log(A*A)/log(10); plot2d(Samples',attenuation*ones(Samples)',[5],"000") | ![]() | ![]() |