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请教matlab高手！
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作者： 上下求索_quest
01-01 08:00
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请看下面一段关于快速傅利叶变换的程序：
%generate the time index
sampling_rate = 100;
t1 = 0:1/sampling_rate:3-1/sampling_rate;
t2 = 3+1/sampling_rate:1/sampling_rate:6;
t = [t1 t2];
%determine the frequency of the input signal
F1 = 2;
F2 = 8;
temp1 = sin(2*F1*pi*t1);
temp2 = sin(2*F2*pi*t2);
%generate the signals
x1 = [temp1 temp2];
%apply the FFT transform on the input signals
y1 = fft(x1);
%plot the input signal
plot(t, x1); grid on; xlabel('time (seconds)'); ylabel('Magnitude');
%generate the frequency index
f = (0:length(y1)-1)'*sampling_rate/length(y1);
%plot the frequency components of the input signal
plot(f(1:length(f)/2), abs(y1(1:length(y1)/2)));
xlabel('Frequency (Hz)'); ylabel('Abs. Magnitude'); grid on;
请问f = (0:length(y1)-1)'*sampling_rate/length(y1); 这段程序是如何将横轴坐标转变成频率为刻度的？原理应该怎样解释？ |
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回复：请教matlab高手！
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作者： legendbb
01-01 08:00
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%generate the frequency index
f = (0:length(y1)-1)'*sampling_rate/length(y1);
plot(x,y)
x的原始值就是频率，没有另外的转换。 |
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