function [power, duration] = frequencySpectrum_noplot(signal, fs, pad)
%%%%%%%%%%%%%%%%%%
%function power = frequencySpectrum(signal, fs, pad)
%
% Task: Display the power spectrum (lin and log scale) of a given signal
%
% Input:
%	- signal: the input signal to process
%	- fs: the sampling rate
%	-pad: boolean if true, signal is padded with 0 to the next power of 2 -> FFT instead of DFT
%
% Output: 
%	- power: the power spectrum
%	
%
% Guillaume Gibert, guillaume.gibert@ecam.fr
% 25/04/2022
%%%%%%%%%%%%%%%%%%

n = length(signal);        % number of samples

if (pad)
	n = 2^nextpow2(n);
end

tic
y = fft(signal, n);% compute DFT of input signal
duration = toc;

power = abs(y).^2/n;    % power of the DFT

[val, ind] = max(power); % find the mx value of DFT and its index

t=0:1/fs:(n-1)/fs; % time range
%pad signal with zeros
if (pad)
	signal = [ signal; zeros( n-length(signal), 1)];
end

f = (0:n-1)*(fs/n);     % frequency range