Matrix dimensions must agree error

Hi all,

Ive got some code from my tutor thats meant to be filtering a medical signal (ecc) by multiplication in the frequency domain, all goes well till Y5=X5.*HBR; , there it says matrix dimensions must agree, been rattling my head about this for a while but cant figure out where the conflict is, tutor wont help either.

fs=500; 
n=2;
Wn=40/250;
[B, A] = butter(n,Wn);
printsys(B, A, 'z' );
x1=eye(1,1000); % create an impulse
plot(x1)
pause
hb=filter(B, A, x1); % calculate the impulse response of the Butterworth filter
plot(hb)
pause
freqz(B, A, 1024, fs)% create frequency response plots
set(gca, 'XScale', 'log')
pause
medical = 'medical signal.dat'; %this needs to be the location of the waveform
xmed = load(medical);
plot(xmed) % display the noisy waveform
pause
X5=fft(xmed)/length(xmed); % calculate the FFT of the signal
f=fs/length(X5)*(0:length(X5)-1);
plot(f, abs(X5)); % display the signal spectrum
pause
 
HBC = fft(hb)/length(hb); % calculate the FFT of the filter impulse response
HBR = HBC.' ; % convert the result to a row vector
f=fs/length(HBR)*(0:length(HBR)-1);
plot(f, abs(HBR)); % display the magnitude of the filter frequency response
pause
 
Y5 = X5.'HBR; % multiply the signal fft by the filter frequency response
plot(f,Y5) % display the frequency response of the result
pause
 
y5=ifft(Y5)*(length(Y5))^2; % convert the result back into the time domain
plot(y5) % display the filtered waveform
pause

Any suggestions on whats causing the matrixes to conflict?

Cheers

[KSSV]

This lineL

Y5 = X5.'HBR; % multiply the signal fft by the filter frequency response

is not correct. You need to change it.

Learn about debugging and check the dimensions where you are getting error.

Answer 1

[Prudhvi Peddagoni]

Hi,

You can keep breakpoints in the code and check the values in different variables.

Hope this helps.

[Jordan Reece Duggan]

It did thanks!