How can I plot slope including maximum peaks?

Hello, How can I plot slope including peaks point? It should look like exp. I tried envelope but It does not work for my code.

Thank you.

Answer 1

[Star Strider]

If you have the Signal Processing Toolbox, use the findpeaks function to define the peaks and their locations. You can then use those values directly in your exponential regression.

EDIT —

Try this:

y = [12 14 2 8 9 4 6 7 9 5 6];
x = 1:length(y);
ym = mean(y);
yz = y - ym;                                                            % Create Symmetry About Mean
[pospks, poslocs] = findpeaks(yz);                                      % Positive Peaks & Locations
[negpks, neglocs] = findpeaks(-yz);                                     % Negative Peaks & Locations
pkvct = [pospks negpks];                                                % Combine In One Vector FOr Sorting

[locs,idx] = sort([poslocs neglocs]);                                   % Sort
pks = pkvct(idx);

objfcn = @(b,x) b(1).*exp(b(2).*x);                                     % Exponential Objective Function

[B,resnorm] = fminsearch(@(b) norm(pks - objfcn(b,locs)), rand(2,1));   % Fit Data (EStimate Parameters)

figure(1)
plot(x, y, '-g')
hold on
% plot(locs, pks+ym, 'pg')
plot(locs, objfcn(B,locs)+ym, '-r')
hold off
text(5, 13, sprintf('y(x) = %.3f + e^{%.3f\\cdotx} + %.3f', B, ym))

[Ezgi Ertunç]

Thank you for answer. My graph is changing when I run the Matlab.

[Star Strider]

My pleasure.

If my Answer helped you solve your problem, please Accept it!

Answer 2

[Image Analyst]

Why would you try envelope()? diff() would give the slope

slopes = diff(y)