how to know the frequency on the fft plot
7 次查看(过去 30 天)
显示 更早的评论
if I'm doing fft of my signal, and ploting it
plot(abs(fft(x)).
Now how do I match an index on the graph to a specific frequency? I came to the formula of -
f = (FPS/N)*(i-1)
f - the frequency I am looking for
FPS - the Frames Per Second of the original signal in the time domain
N - total number to recorded frames in the time domain
i - index on x-axis on my abs(fft(x)) plot.
does that correct?
0 个评论
回答(1 个)
Walter Roberson
2015-7-31
Yes, except that it only works for the first half of the fft.
See http://www.mathworks.com/help/matlab/ref/fft.html and notice how they only plot the first half with a formula for "f" that works out the same as the one you have.
0 个评论
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Transforms 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!