Hi, there this is piece of code and I am getting these errors (Undefined function or variable 'dtft'.Error in Lab9 (line 12) X_DTFT = dtft(x,w);) so, can you please help me out with this, Thanks in advance.
N =100; %signal length
M =2^16; %FFT size(M >= N)
n=0:N-1; %discrete time vector
x = (0.8.^ n).* cos (0.5* pi*n); %signal
%Calculate DFT and measure calculation time
tic;X_DFT = fft(x,M);toc;%Calculate DTFT and measure calculation time
w = -pi :2* pi/M:pi -2* pi/M; % freq vector
tic;X_DTFT = dtft(x,w);toc;%Elapsed time is 0.001090 seconds.
%Elapsed time is 0.000066 seconds.
%Plot magnitude and phase of DTFT ( blue solid line ) and DFT (red x)
figure;subplot (2, 1, 1)plot (w/pi , fftshift (abs ( X_DFT )), 'b-');hold on;plot (w/pi,abs(X_DTFT),'rx');hold off ;grid on;title ('Magnitude')xlabel ('Normalized Radian Frequency (\ times \pi rad / sample )');ylabel ('Amplitude');legend ('DFT','DTFT');subplot (2, 1, 2)plot (w/pi , fftshift ( angle ( X_DFT )/pi),'b-');hold on;plot (w/pi , angle (X_DTFT )/pi ,'rx');hold off ;grid on;title ('Phase')xlabel ('Normalized Radian Frequency (\ times \pi rad / sample )');ylabel ('Phase (\ times \pi rad )');legend ('DFT','DTFT');%Elapsed time is 0.001090 seconds.%Elapsed time is 0.000066 seconds.
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