# How can i generate a Pinknoise with a certain duration

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Zakaria Souf on 10 Nov 2018
I am using this function to generate a PinkNoise but I can't figure out, How to make the Noise Only run for a certain duration of Time
if true
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Pink Noise Generation with MATLAB Implementation %
% %
% Author: M.Sc. Eng. Hristo Zhivomirov 07/30/13 %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function y = pinknoise(m, n)
% function: y = pinknoise(m, n)
% m - number of matrix rows
% n - number of matrix columns
% y - matrix with pink (flicker) noise samples
% with mu = 0 and sigma = 1 (columnwise)
% The function generates a matrix of pink (flicker) noise samples
% (columnwise). In terms of power at a constant bandwidth, pink
% noise falls off at 3 dB/oct, i.e. 10 dB/dec.
% difine the length of the noise vector and ensure
% that M is even, this will simplify the processing
m = round(m); n = round(n); N = m*n;
if rem(N, 2)
M = N+1;
else
M = N;
end
% generate white noise sequence
x = randn(1, M);
% FFT
X = fft(x);
% prepare a vector with frequency indexes
NumUniquePts = M/2 + 1; % number of the unique fft points
k = 1:NumUniquePts; % vector with frequency indexes
% manipulate the left half of the spectrum so the PSD
% is proportional to the frequency by a factor of 1/f,
% i.e. the amplitudes are proportional to 1/sqrt(f)
X = X(1:NumUniquePts);
X = X./sqrt(k);
% prepare the right half of the spectrum - a conjugate copy of the left
% one except the DC component and the Nyquist component - they are unique,
% and reconstruct the whole spectrum
X = [X conj(X(end-1:-1:2))];
% IFFT
y = real(ifft(X));
% ensure that the length of y is N
y = y(1, 1:N);
% form the noise matrix and ensure unity standard
% deviation and zero mean value (columnwise)
y = reshape(y, [m, n]);
y = bsxfun(@minus, y, mean(y));
y = bsxfun(@rdivide, y, std(y));
end
end

Hristo Zhivomirov on 7 Apr 2019
Hi Zakaria!
About your question - set m = 1 and n = round(T*fs), where T is the desired duration of the noise signal and fs is the sampling frequency.
All best,
Hristo

R2018a

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