Clear Filters
Clear Filters

How to deal with this error??

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Good mind
Good mind on 4 May 2017
Commented: Star Strider on 7 May 2017
A model of the surface EMG signal is created by filtering a white gaussian noise, using a shaping filter H(f). this filter has low cut-off freq=60hz and high cut-off freq=120hz. this is my code but i don't know how to deal with Undefined function 'designfilt' for input arguments of type 'char'.
clear all;
subplot(322);
load nnoise.m;
plot(nnoise,'k');
% design shaping filter
bpFilt = designfilt('bandpassfir',...
'CutoffFrequency1',60,'CutoffFrequency2',120, ...
'SampleRate',2000);
subplot(323);
W = filter(bpFilt,nnoise);
plot(W,'k');title ('EMG');
  2 Comments
Adam
Adam on 4 May 2017
Do you have the Signal Processing toolbox? If not then you will not have this function.
Good mind
Good mind on 4 May 2017
So what is the solution? how can i get it

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Accepted Answer

Star Strider
Star Strider on 4 May 2017
The designfilt function was introduced in the R2014a version of the Signal Processing Toolbox.
If you have an earlier version of the Signal Processing Toolbox, this filter will work, since all the functions were introduced prior to R2006a:
Fs = 2000;
notch_frq = [50 60 120 130];
mags = [0 1 0];
devs = [0.05 0.01 0.05];
[n,Wn,beta,ftype] = kaiserord(notch_frq,mags,devs,Fs);
n = n + rem(n,2);
hh = fir1(n,Wn,ftype,kaiser(n+1,beta),'scale');
figure(1)
freqz(hh, 1, 2^17, Fs)
Use the filtfilt function to do the actual filtering of your signal.
See the documentation on the various functions to understand how to use them.
  13 Comments
Good mind
Good mind on 7 May 2017
Mr. Strider I would like to thank you very much. you alerted me to important informations. I hope that everyone will benefit from these discussions, especially beginners.
2^17 is from where?
Star Strider
Star Strider on 7 May 2017
As always, it is my pleasure to help.
The ‘2^17’ is the length of the Fast Fourier Transform that freqz uses to compute the transfer function. I apologise for not explaining that earlier.

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