How do I filter a signal, using FIR filters.
8 次查看(过去 30 天)
显示 更早的评论
I've got this code, what filter, and how should i use it to only show me in the end the component with the 300Hz frequency? Using a fir filter
```
t = 0:1/8000:1023/8000;
w = 0:8000/1024:4000;
x = 0.5*sin(2*pi*50*t) + 0.5*square(2*pi*130*t) + 0.3*sawtooth(2*pi*250*pi) + 0.2*sin(2*pi*300*t);
h =
y = filter(h,1,x);
figure;
subplot(2,1,1), plot(t,x);
z = abs(fft(x)) / 512;
subplot(2,1,2), plot(w, z(1:513));
figure;
subplot(2,1,1), plot(t,y);
z = abs(fft(y)) / 512;
subplot(2,1,2), plot(w, z(1:513));
```
0 个评论
采纳的回答
Scott MacKenzie
2022-3-26
You could perhaps use a butterworth bandpass filter: (Note: Requires Signal Processing Toolbox)
t = 0:1/8000:1023/8000;
w = 0:8000/1024:4000;
x = 0.5*sin(2*pi*50*t) + 0.5*square(2*pi*130*t) + 0.3*sawtooth(2*pi*250*pi) + 0.2*sin(2*pi*300*t);
% h =
% y = filter(h,1,x);
% create bandpass butterworth filter @ 300 Hz
fCutoff1 = 250;
fCutoff2 = 350;
[b, a] = butter(6, [fCutoff1 fCutoff2]/(8000/2), 'bandpass');
% filter the signal
y = filter(b, a, x);
figure;
subplot(2,1,1), plot(t,x);
z = abs(fft(x)) / 512;
subplot(2,1,2), plot(w, z(1:513));
figure;
subplot(2,1,1), plot(t,y);
z = abs(fft(y)) / 512;
subplot(2,1,2), plot(w, z(1:513));
2 个评论
Scott MacKenzie
2022-3-26
编辑:Scott MacKenzie
2022-3-26
I just used order six as it seemed to do a reasonable job in excluding neighboring frequencies. At order 3, for example, you get this:
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/941884/image.jpeg)
更多回答(0 个)
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Digital Filter Analysis 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!