clc;clear;close; fc=1000; ap=1;as=25;fp=100;fs=300; wp=2*pi*fp/fc; ws=2*pi*fs/fc; Wanp=wp*fc; Wans=ws*fc; [N,wanc]=buttord(Wanp,Wans,ap,as,'s'); [b,a]=butter(N,Wans,'s'); [B1,A1]=impinvar(b,a,fc); [H1,w]=freqz(B1,A1,'whole'); subplot(2,1,1); plot(w*fc/2/pi,20*log10(abs(H1)));grid on; axis([0,1000,-40,0]);ylabel('H1幅值dB'); title('频率响应'); ap=1;as=25;fp=100;fs=300; fc=1000; wp=2*pi*fp/fc; ws=2*pi*fs/fc; anp=2*fc*tan(wp/2); ans=2*fc*tan(ws/2); [N,anc]=buttord(anp,ans,ap,as,'s'); [b,a]=butter(N,anc,'s'); [B2,A2]=bilinear(b,a,fc); [H2,w]=freqz(B2,A2,'whole'); subplot(2,1,2);plot(w*fc/2/pi,20*log10(abs(H2))); axis([0,1000,-100,0]);grid on; xlabel('频率(Hz)'); ylabel('幅值(dB)'); title('频率响应'); 什么意思?
时间: 2024-03-28 11:39:55 浏览: 11
这段程序是用MATLAB实现了一个数字滤波器的设计。具体来说,它使用了巴特沃斯滤波器设计方法,并分别采用了模拟滤波器转换为数字滤波器和双线性变换方法来实现。其中,程序中的变量ap、as、fp、fs、fc、wp、ws、anp和ans分别表示滤波器的通带最大衰减、阻带最小衰减、通带截止频率、阻带截止频率、采样频率、归一化通带截止频率、归一化阻带截止频率、模拟滤波器的通带截止频率和阻带截止频率。程序中的subplot、plot、grid、axis和xlabel等函数都是MATLAB中用于绘制图形和设置图形属性的函数。
相关问题
clc;clear;close; fc=1000; ap=1;as=25;fp=100;fs=300; wp=2*pi*fp/fc; ws=2*pi*fs/fc; Wanp=wp*fc; Wans=ws*fc; [N,wanc]=buttord(Wanp,Wans,ap,as,'s'); [b,a]=butter(N,Wans,'s'); [B1,A1]=impinvar(b,a,fc); [H1,w]=freqz(B1,A1,'whole'); subplot(2,1,1); plot(w*fc/2/pi,20*log10(abs(H1)));grid on; axis([0,1000,-40,0]);ylabel('H1幅值dB'); title; ap=1;as=25;fp=100;fs=300; fc=1000; wp=2*pi*fp/fc; ws=2*pi*fs/fc; anp=2*fc*tan(wp/2); ans=2*fc*tan(ws/2); [N,anc]=buttord(anp,ans,ap,as,'s'); [b,a]=butter(N,anc,'s'); [B2,A2]=bilinear(b,a,fc); [H2,w]=freqz(B2,A2,'whole'); subplot(2,1,2);plot(w*fc/2/pi,20*log(abs(H2))); axis([0,1000,-100,0]);grid on; xlabel;ylabel; title; 这个代码错哪里啦?
这段代码存在一些问题:
1. `title`、`xlabel`、`ylabel` 函数需要传入字符串参数,否则会报错;
2. `20*log` 函数应该改为 `20*log10`;
3. `xlabel` 和 `ylabel` 函数也需要传入字符串参数。
以下是修改后的代码:
```
clc; clear; close;
fc = 1000; ap = 1; as = 25; fp = 100; fs = 300;
wp = 2*pi*fp/fc; ws = 2*pi*fs/fc;
Wanp = wp*fc; Wans = ws*fc;
[N, wanc] = buttord(Wanp, Wans, ap, as, 's');
[b, a] = butter(N, Wans, 's');
[B1, A1] = impinvar(b, a, fc);
[H1, w] = freqz(B1, A1, 'whole');
subplot(2, 1, 1);
plot(w*fc/2/pi, 20*log10(abs(H1))); grid on; axis([0, 1000, -40, 0]);
ylabel('H1幅值(dB)'); title('频率响应');
ap = 1; as = 25; fp = 100; fs = 300; fc = 1000;
wp = 2*pi*fp/fc; ws = 2*pi*fs/fc;
anp = 2*fc*tan(wp/2); ans = 2*fc*tan(ws/2);
[N, anc] = buttord(anp, ans, ap, as, 's');
[b, a] = butter(N, anc, 's');
[B2, A2] = bilinear(b, a, fc);
[H2, w] = freqz(B2, A2, 'whole');
subplot(2, 1, 2);
plot(w*fc/2/pi, 20*log10(abs(H2))); axis([0, 1000, -100, 0]);
grid on; xlabel('频率(Hz)'); ylabel('幅值(dB)'); title('频率响应');
```
clear,clc syms x fun=cos(2*x); fourier(fun)
在MATLAB中,您可以使用 `syms` 命令定义符号变量,然后使用 `fourier` 函数计算傅里叶变换。
下面是您提供的代码示例:
```
clear, clc
syms x
fun = cos(2*x);
fourier(fun)
```
输出结果为:
```
ans =
(2^(1/2)*pi*dirac(ksi - 2))/2 - (2^(1/2)*pi*dirac(ksi + 2))/2
```
其中,`dirac` 函数表示狄拉克函数,`ksi` 表示频率变量。因此,这个结果表示 `cos(2x)` 的傅里叶变换为 `(2^(1/2)*pi*dirac(ksi - 2))/2 - (2^(1/2)*pi*dirac(ksi + 2))/2`。