绘制连续信号频谱及反变换的matlab程序

function [f,sf]=T2F(t,st) %This is a function using the FFT function to calculate a signal's Fourier %Translation %input is the time and the signal vectors,the length of time must be %greater than 2 %Output is the frequency and the signal spectrum dt=t(2)-t(1); T=t(end); df=1/T; N=length(st); f=-N/2*df:df:N/2*df-df; sf=fft(st); sf=T/N*fftshift(sf);