myfft.m

对输入信号进行傅立叶变换

function myfft(Sgn,Fs,L)
%Sgn : Signal
% Fs : Sampling frequency
% L  : Length of signal
T = 1/Fs;                    % Sample time
NFFT = 2^nextpow2(L);        % Next power of 2 from length of y
Y = fft(Sgn,NFFT)/L;
f = Fs/2*linspace(0,1,NFFT/2);
% Plot single-sided amplitude spectrum.
plot(f,2*abs(Y(1:NFFT/2))) 
title('Single-Sided Amplitude Spectrum')
xlabel('Frequency (Hz)')
ylabel('|Y(f)|')
grid on
end