MATLAB: How to find the peaks (both x and y location)

findpeaksparameterpeaksplotSignal Processing Toolbox

Hello.
For instance, if I was plotting Scope (x) and Temperature (y), why can't I use the following code: [pks,locs] = findpeaks(Temperature)?
Matlab tells me that there is the following error: Error using findpeaks>parse_inputs (line 131) Expected a string for the parameter name, instead the input type was 'double'.
Error in findpeaks (line 71) [X,Ph,Pd,Th,Np,Str,infIdx] = parse_inputs(Xin,varargin{:});
It gives me the peaks when I simply use findpeaks(Temperature), but I need the corresponding x values to compute as well.
Could anyone please help me out? Thank you for your time!

Best Answer

Can you run the example in the help without getting any error:
% Create the sample data
x = linspace(0,1,1000);
Pos = [1 2 3 5 7 8]/10;
Hgt = [4 4 4 2 2 3];
Wdt = [2 6 3 3 4 6]/100;
for n = 1:length(Pos)
    Gauss(n,:) =  Hgt(n)*exp(-((x - Pos(n))/Wdt(n)).^2);
end
PeakSig = sum(Gauss);
plot(x,Gauss,'--',x,PeakSig)
% Use findpeaks with default settings to find the peaks of the signal and their locations.
[pks,locs] = findpeaks(PeakSig,x)
% Plot the peaks using findpeaks and label them.
findpeaks(PeakSig,x)
text(locs+.02,pks,num2str((1:numel(pks))'))
% Sort the peaks from tallest to shortest.
[psor,lsor] = findpeaks(PeakSig,x,'SortStr','descend');
findpeaks(PeakSig,x)
text(lsor+.02,psor,num2str((1:numel(psor))'))
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