Chebyshev filter cutoff frequency

조회 수: 10 (최근 30일)
Juan Chehin
Juan Chehin 2021년 8월 6일
댓글: Star Strider 2021년 8월 6일
Hello, I have this code corresponding to a chebyshev filter and the graph that matlab returns to me. The question is, is the cutoff frequency that of the black line (2 on the x-axis) or the green line when it intersects the blue line at 0.7?
The problem specifies that "the bands must be limited by half the power frequencies (0.707 of the maximum transfer value, or -3 dB)".
Fs = 4400;
Fn = Fs/2;
n = 3; Rp = 0.5;
Wn = [250 2000]/Fn;
[b a]=cheby1(n,Rp,Wn,'bandpass')
[h,w]=freqs(b,a)
plot(w,abs(h))
  댓글 수: 1
Star Strider
Star Strider 2021년 8월 6일
We’ve been through this several times already.
For a Chebyshev Type I filter, the cutoff frequency is defined as the frequency where the passband crosses the value for the ripple amplitude. Here, it would be -0.5 dB.
If you want the cutoff frequency of this filter to be defined as the -3 dB point, define the ripple amplitude as 3 dB.

댓글을 달려면 로그인하십시오.

답변 (0개)

제품


릴리스

R2014b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by