how to find the bottom peaks in the graph?

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Sun Heat 2018-10-1

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评论： Thumree Sarkar 2019-2-6

mat.jpg

how to find decreasing order of peaks in graphs, so that how much graphs goes deeper at higher frequencies (plz refer image.).i have to find the values so that my graph reaches as deeper as possible at higher frequency.

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Sun Heat 2018-10-1

bottom peaks not top peaks of the image file

Thumree Sarkar 2019-2-6

data= - data, then use findpeaks, you will get the bottom peaks.

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Answer 1

madhan ravi 2018-10-1

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编辑：madhan ravi 2018-10-3

[locs,idxs]=findpeaks(-y) %EDITED

If y is the function of the plot -y will give the minimum of the function.

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Sun Heat 2018-10-1

i want multiple peaks but it gives only 64 at 700Mhz. It should also give -36 at 150MHz and many more.

madhan ravi 2018-10-3

Check the edited code now.

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Answer 2

Image Analyst 2018-10-3

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在 MATLAB Online 中打开

Find valleys by sending the inverted vector into findpeaks() and finding the peaks. Then you have to invert again to get the positive values (since you have inverted/negated it):

% Find values and locations:
[negPeakValues, indexesOfValleys] = findpeaks(-signal);
% Invert values to get the original, non-inverted values.
valleyValues = -negPeakValues;