cheb2mag

response of type 2 Chebyshev filter

Calling Sequence

[h2]=cheb2mag(n,omegar,A,sample)

Arguments

:n integer ; filter order : :omegar real scalar : cut-off frequency : :A attenuation in stop band : :sample vector of frequencies where cheb2mag is evaluated : :h2 vector of Chebyshev II filter values at sample points :

Description

Square magnitude response of a type 2 Chebyshev filter.

omegar = stopband edge, sample = vector of frequencies where the square magnitude h2 is desired.

Examples

//Chebyshev; ripple in the stopband
n=10;omegar=6;A=1/0.2;`sample`_=0.0001:0.05:10;
h2=cheb2mag(n,omegar,A,`sample`_);
`plot`_(`sample`_,`log`_(h2)/`log`_(10),'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`_(`sample`_',attenuation*`ones`_(`sample`_)',[5],"000")

See Also

• cheb1mag response of Chebyshev type 1 filter