spectrum.m

用dsp解压mp3程序的算法

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% spectrum.m - Compute magnitude spectrum of signal in data file
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load -ascii xn.dat;          % load data in data file xn.dat
N = length(xn);              % size of data in array xn
Xk=fft(xn,N);                % perform N-point DFT of signal
magX=20*log10(abs(Xk));      % compute magnitude spectrum in dB
plot(magX);                  % plot the magnitude spectrum
axis([1 N/2 -inf inf]);      % from DC to Nyquist
title('Magnitude spectrum');
xlabel('Frequency index'),
ylabel('Magnitude, dB');