Creating Notch Filters Cheby1 and Butterworth

Question

Terry Carney 2021-5-14

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/830278-creating-notch-filters-cheby1-and-butterworth

回答： Terry Carney 2021-5-15

data2.txt

I'm trying to create both a Chebychev Type 1 and Butterworth Notch filter. The filters have to produce a min attenuation of 60dB at 10Hz, with a rippe of .01dB. However, my output does not look like a typical notch filter after filtering, using cheby1 for example. What am I doing wrong?

clear;close all;
%Setting up signal:
fs = 200; %Sample Frequency
Ts = 1/fs; %Sample Period
t = 0:Ts:9.9950;
x = load("data2.txt");
plot(t,x);
b = cheby1(2,.01,.1)
x2 = filtfilt(b,1,x)
fvtool(b,1)
figure(1)
plot(t,x2)