17 lines
462 B
Matlab
17 lines
462 B
Matlab
function [f,val] = FFT_time2freq( t, val )
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% [f,val] = FFT_time2freq( t, val )
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%
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% See also DFT_time2freq
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dt=t(2)-t(1); % timestep
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L=numel(val); % signal length
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NFFT = 2^nextpow2(L); % next power of 2 (makes fft fast)
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%very fine freq resolution... NFFT = NFFT+100000;
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val = fft( val, NFFT)*dt;
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f = 1/(2*dt) * linspace(0,1,NFFT/2+1);
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val = 2*val(1:NFFT/2+1); % single-sided spectrum
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%correct phase for time-shifted signals
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val = val .* exp(-1j*2*pi*f * t(1));
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