Passband Modulation
Newbie level 4
i have some polymers characterized by transmission terahertz time domain spectroscopy (THz-TDS).
ive now the time domain data in Excel, with column A being (Delay ps), column B (Reference), column C (Amplitube nA) as follows.
**broken link removed**
i would like to have "FFT phase of column C" minus "FFT phase of column B", and then plot the phase (after deduction) as a function of frequency.
i am told this could be done by adding
plot(freq,angle(fft(X
,3)))-angle(fft(X,2))))
after
[X,TXT,RAW] = xlsread('yourfile.xls');
xdft = fft(X,2)); xdft = fft(X,2));
% sampling interval -- assuming equal sampling
DT = X(2,1)-X(1,1);
% sampling frequency
Fs = 1/DT;
DF = Fs/size(X,1);
freq = 0F:Fs/2;
xdft = xdft(1:length(xdft)/2+1);
phi = angle(xdft);
anyway it does not work
the command window shows
??? Error using ==> plot Vectors must be the same lengths.
Error in ==> Untitled at 12 plot(freq,angle(fft(X,3)))-angle(fft(X,2))))
ive now the time domain data in Excel, with column A being (Delay ps), column B (Reference), column C (Amplitube nA) as follows.
**broken link removed**
i would like to have "FFT phase of column C" minus "FFT phase of column B", and then plot the phase (after deduction) as a function of frequency.
i am told this could be done by adding
plot(freq,angle(fft(X
,3)))-angle(fft(X,2)))) after
[X,TXT,RAW] = xlsread('yourfile.xls');
xdft = fft(X
,2)); xdft = fft(X,2));% sampling interval -- assuming equal sampling
DT = X(2,1)-X(1,1);
% sampling frequency
Fs = 1/DT;
DF = Fs/size(X,1);
freq = 0
F:Fs/2;xdft = xdft(1:length(xdft)/2+1);
phi = angle(xdft);
anyway it does not work
the command window shows
??? Error using ==> plot Vectors must be the same lengths.
Error in ==> Untitled at 12 plot(freq,angle(fft(X
,3)))-angle(fft(X,2))))