www.gusucode.com > GPS仿真Matlab编程源码程序 > GPS仿真Matlab编程源码程序/plotspec.m
% plotspec(x,Ts) plots the spectrum of the signal x % Ts = time (in seconds) between adjacent samples in x function plotspec(x,Ts) N=length(x); % length of the signal x t=Ts*(1:N); % define a time vector ssf=(-N/2:N/2-1)/(Ts*N); % frequency vector fx=fft(x(1:N)); % do DFT/FFT fxs=fftshift(fx); % shift it for plotting subplot(2,1,1), plot(t,x) % plot the waveform xlabel('seconds'); ylabel('amplitude') % label the axes subplot(2,1,2), plot(ssf,abs(fxs)) % plot magnitude spectrum xlabel('frequency'); ylabel('magnitude') % label the axes %verify parseval equalize power using %sum(abs(fxs).^2)/N %sum(abs(x).^2) % use axis([0,2,-1.1,1.1]) for specsquare.eps