How to select peak data and min data from noise in spectrum?

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Hello Guys,
I want to take upside and downside noise signal from my spectrum (the dashed line) just like on this figure. Here, I attach the figure and the excel data. Please can anyone help me with this?.
Thank you, I waiting for your humbly answers

Accepted Answer

Emmanuel J Rodriguez
Emmanuel J Rodriguez on 4 Jul 2022
Edited: Emmanuel J Rodriguez on 4 Jul 2022
This should do it:
%% Import data
x = xlsread('Spectrum.xlsx','Sheet1','A1:A2503');
y = xlsread('Spectrum.xlsx','Sheet1','B1:B2503');
%% Plot data
hold on;
%% Find peaks and dips in the signal
% Peaks
[pks, pks_locs] = findpeaks(y,x); % Finds peaks and their locations
plot(pks_locs, pks, '--k') % Plots a black dashed-line connecting peaks
% Dips
[dip, dip_locs] = findpeaks(-y, x); % Find dips and their locations
plot(dip_locs, -dip, '--k') % Plots a black dashed-line connecting dips
hold off;

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