You can use "findpeaks" function in MATLAB to final the local maxima (peaks) of the input signal vector. The below documentation link gives the detailed description about "findpeaks" function.
The below example code snippet extracts the peak from the signal and plot them before and after peak extraction. In the code I have extracted the peaks from the signal and subtracted it from the original signal. So the peak values are now replaced by zeros.
fs=1000; %Sampling frequency
t=0:1/fs:1; %time vector
y=10*sin(2*pi*10*t); % Input Signal
figure(1)
plot(t,y) % Plot the signal before peak extraction
[pks,locs] = findpeaks(y); % returns a vector with the local maxima (peaks) of the input signal y and the indices at which the peaks occur.
x=zeros(size(y));
x(locs)=y(locs);
z=y-x; %Cleaned Signal
figure(2)
plot(t,z) % Plot the signal after peak extraction
You can use "FFT" function in MATLAB to find the spectrum of the signal. The below is the documenation link for the "FFT" function.
