matlab高通滤波器出错

设计了一个3dB，截止频率4bpm的高通滤波器
报错：出错 gaotong (line 23)
b  = firpm(N, Fo, Ao, W, {dens});

版本是2017b

1. function Hd = gaotong
   
2. %GAOTONG Returns a discrete-time filter object.
   
3. 
   
4. % MATLAB Code
   
5. % Generated by MATLAB(R) 9.3 and Signal Processing Toolbox 7.5.
   
6. % Generated on: 09-Feb-2023 13:12:43
   
7. 
   
8. % Equiripple FIR Lowpass filter designed using the FIRPM function.
   
9. 
   
10. % All frequency values are in Hz.
    
11. Fs = 10;  % Sampling Frequency
    
12. 
    
13. Fpass = 3;            % Passband Frequency
    
14. Fstop = 0.6;           % Stopband Frequency
    
15. Dpass = 0.057501127785;  % Passband Ripple
    
16. Dstop = 0.0001;          % Stopband Attenuation
    
17. dens  = 16;              % Density Factor
    
18. 
    
19. % Calculate the order from the parameters using FIRPMORD.
    
20. [N, Fo, Ao, W] = firpmord([Fpass, Fstop]/(Fs/2), [1 0], [Dpass, Dstop]);
    
21. 
    
22. % Calculate the coefficients using the FIRPM function.
    
23. b  = firpm(N, Fo, Ao, W, {dens});
    
24. Hd = dfilt.dffir(b);
    
25. 
    
26. % [EOF]

复制代码

scj12345 发表于 2023-2-10 14:39
我把Fpass设成了0

Fpass 需要低于Fstop并没有错（对于低通滤波器），但在笫1层的程序中似乎不是应该修改Fpass，而是应该修改Fstop
LZ原设计中是设置低通滤波器的通带为3Hz，LZ把阻带频率设成过渡带的带宽Fstop = 0.6。实际上应把阻带设为
Fstop = 3.6，这样运行笫1层程序就没问题了

Fpass 需要低于Fstop吧

卿猫小咪 发表于 2023-2-10 14:23
Fpass 需要低于Fstop吧

我把Fpass设成了0

1. % All frequency values are in Hz.
   
2. Fs = 10;  % Sampling Frequency
   
3. 
   
4. N     = 10;   % Order
   
5. Fstop = 0.06;  % Stopband Frequency
   
6. Fpass = 0;    % Passband Frequency
   
7. Wstop = 3;    % Stopband Weight
   
8. Wpass = 1;    % Passband Weight
   
9. dens  = 20;   % Density Factor
   
10. 
    
11. % Calculate the coefficients using the FIRPM function.
    
12. b  = firpm(N, [0 Fstop Fpass Fs/2]/(Fs/2), [0 0 1 1], [Wstop Wpass], ...
    
13.            {dens});
    
14. Hd = dfilt.dffir(b);
    
15. 
    
16. % [EOF]

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错误使用 firpminit (line 62)
Frequencies must be non-decreasing.

出错 firpm (line 135)
[nfilt,ff,grid,des,wt,ftype,sign_val,hilbert,neg] = firpminit(order, ff, aa, varargin{:});

出错 gaotong (line 21)
b  = firpm(N, [0 Fstop Fpass Fs/2]/(Fs/2), [0 0 1 1], [Wstop Wpass], ...

我这边看是没问题的呢

scj12345 发表于 2023-2-10 14:39
我把Fpass设成了0

Fpass 需要低于Fstop并没有错（对于低通滤波器），但在笫1层的程序中似乎不是应该修改Fpass，而是应该修改Fstop
LZ原设计中是设置低通滤波器的通带为3Hz，LZ把阻带频率设成过渡带的带宽Fstop = 0.6。实际上应把阻带设为
Fstop = 3.6，这样运行笫1层程序就没问题了