请教matlab-help-fft问题
matlab-help-fft有个例子Convert a Gaussian pulse from the time domain to the frequency domain.Define signal parameters and a Gaussian pulse, X.Fs = 100; % Sampling frequencyt = -0.5:1/Fs:0.5;% Time vectorL = length(t); % Signal lengthX = 1/(4*sqrt(2*pi*0.01))*(exp(-t.^2/(2*0.01)));
Plot the pulse in the time domain.plot(t,X)title('Gaussian Pulse in Time Domain')xlabel('Time (t)')ylabel('X(t)')
../../examples/matlab/GaussianPulseExample_01.pngTo use the fft function to convert the signal to the frequency domain, first identify a new input length that is the next power of 2 from the original signal length. This will pad the signal X with trailing zeros in order to improve the performance of fft.n = 2^nextpow2(L);
Convert the Gaussian pulse to the frequency domain.Y = fft(X,n);
Define the frequency domain and plot the unique frequencies.f = Fs*(0:(n/2))/n;P = abs(Y/n);plot(f,P(1:n/2+1))title('Gaussian Pulse in Frequency Domain')xlabel('Frequency (f)')ylabel('|P(f)|')
../../examples/matlab/GaussianPulseExample_02.png为什么P=abs(Y/n),我觉得应该是P=2*abs(Y/n)？ 试了一下，假如函数y=20*sin(2*pi*0.0006*t)+10*cos(2*pi*0.001*t),求得的振幅确实少了一倍啊？？？
咋还研究这个了呢
Edinburgh 发表于 2016-11-29 13:29
咋还研究这个了呢
要搞傅里叶变换啊 xiujuan507 发表于 2016-11-29 14:51
要搞傅里叶变换啊
论坛里很多现成的程序 minoz 发表于 2016-11-30 08:28
论坛里很多现成的程序
matlab-help里的，怎么看都是错的 xiujuan507 发表于 2016-11-30 08:33
matlab-help里的，怎么看都是错的
应该不能很权威的
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