MATLAB: Peak value on plot graph

peakpeakfinder

y=a1(:,1); 
chan1= y-mean(a1); 
fs=128;
d=1/fs; 
t=[0:length(chan1)-1]*d;
fs=fft(chan1,128); 
pp=fs.*conj(fs)/128; 
ff=(2:9)/128/d; 
figure(4); 
plot(ff,pp(2:9)); 
title('Power Spectrum');
xlabel('Frequency(Hz)');
ylabel('Power Spectrum Density(µv)');
grid on;
Peak.jpg
How to find peak value on y-axis without using Data Cursor tools. Thanks in advance.

Best Answer

If you have R2017b or later, you can use the islocalmax function.
If you have the Signal Processing Toolbox, you can use the findpeaks function.
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