Hi. My task is to analyze acceleration signal for driving comfort. I have to multiply this acceleration signal with appropriate weighting function using values from a chart. This chart has values of weighting function values for "different third octave frequency". So, for this I am converting acceleration signal(71376 values in one column vector)from time to frequency domain by FFT.my code:
% x is the my acceleration signal
% carrying out FFT on acceleration data%
%just retaining the positive frequencies%
xdft = xdft(1:length(x)/2+1);
%generating suitable frequency scale%
freq = linspace(0,Fs/2,length(x)/2+1);
Now this works for me. I get picks at non zero frequency value in my graph.But I do not know if it's giving me correct transformation form time domain to frequency domain. Can somebody guide me how to check it?
Second thing is I need "one third octave frequency". So how can i get it form the frequency scale which I am generating in "freq = linspace(0,Fs/2,length(x)/2+1);" ?
Next thing is when I make fft in "xdft = fft(x-mean(x))/N;" , subtracting Mean form each value means detrending or centering data? Thanks in advance.