doc ffft

Documentation of the ffft function.

helpFun('ffft')

 Fast Finite Fourier Transform

 Y = FFFT(X)

 Description
     Fourier transform of an input signal.

 Input parameters
     X [double(:inf x 1)] is the input signal.

 Output parameters
     Y [double(:inf x 1)] is the Fourier-transformed signal

 Example
     % Sampling frequency
     Fs = 1000;
     % Sampling period
     dt = 1/Fs;
     % Length of signal
     L = 6000;
     % Time vector
     t = (0:L-1)'*dt;
     % Signal
     S = 0.7*sin(2*pi*50*t) + sin(2*pi*120*t);
     xgtt = S + 2*randn(size(t));
     % Apply the fft function of Matlab
     NFFT = 2^nextpow2(L);
     FASsignal=fft(xgtt,NFFT)*dt;
     % Apply the fft function of OpenSeismoMatlab
     FASsignal3=ffft(xgtt)*dt;
     % Difference between results
     max(abs(FASsignal-FASsignal3))

__________________________________________________________________________
 Copyright (c) 2018-2022
     George Papazafeiropoulos
     Major, Infrastructure Engineer, Hellenic Air Force
     Civil Engineer, M.Sc., Ph.D.
     Email: gpapazafeiropoulos@yahoo.gr
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