MATLAB: Logarithmic scale using PSD function

psd

I have a problem using the PSD function – basically the output of my code gives the frequency in a linear scale, when i need it in a logarithmic scale. Does anyone know how to alter the PSD/output to give the resulting plot in a logarithmic scale? cl is an array of values. I assume it is something very basic i need to change.
My code is as follows:
Fs = 1/0.005;
h = spectrum.welch;            
Hpsd = psd(h,cl,'Fs',Fs);             
plot(Hpsd)

Best Answer

After creating the plot, set the axes XScale (if you want to replicate a semilogx plot) property to 'log'. For example:
 Fs = 1000;   t = 0:1/Fs:.296;
 x = cos(2*pi*t*200)+randn(size(t));
 h = spectrum.welch;    % Create a Welch spectral estimator.
 Hpsd = psd(h,x,'Fs',Fs);             % Calculate the PSD
 plot(Hpsd)
 set(gca, 'XScale', 'log')
Related Question