Logarithmic scale using PSD function

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)

Answer 1

[Patrick Kalita]

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')

[Graeme]

That's it. Thanks very much!

Answer 2

[the cyclist]

Guessing you need the semilogx, semilogy, or loglog command.

Answer 3

[Graeme]

I had thought of that, but again that does not work. When i try:

semilogx(Hpsd)

i get the following error:

??? Error using ==> semilogx
Conversion to double from dspdata.psd is not possible.