**IIR Chebyshev Filter Design**

**AIM**

**:-**To design IIR Chebyshev digital filters.

**THEORY: -**IIR filters can be expanded as infinite impulse response filters. In designing IIR filters, cutoff frequencies of the filters should be mentioned. The order of the filter can be estimated using Chebyshev polynomial with the help of cutoff frequencies and the gain at that frequencies. That’s why the filters are named as Chebyshev filters. Filter coefficients can be found and the response can be plotted.

**PROGRAM: -**

wp = 200;

wq = 300;

rp = 2;

sp = 40;

fs = 1000;

wpn = 2 * wp / fs;

wqn = 2 *wq / fs ;

[ n wn ] = cheb1ord(wpn, wqn, rp, sp )

[ b a ] =cheby1(n, rp, wn );

[ h w ] = freqz(b, a, 128 );

plot( w/pi, abs(h) )

**RESULT: -**A Chebyshev LPF is designed and response is plotted.