FFT: Amplitude 3D Spectrum of a time series

I have a synchronously sampled time series. I wish to plot the 3D spectra of the time series (time (seconds), frequency (Hz), amplitude (dB)).

Does matlab have a built in tool for this? I cant see how to get it out of periodogram etc.

thank you

T = 1000;
t = 1: T;
ts = randn(T,1);
Fs = 50; %the sampling frequency.
Ns = 10; %the frequency resolution.
xa=[0 Fs];

%I want to find the amplitude. 
amp = ?? %amp is a matrix size (Ns x T)

imagesc(t,xa,(20*log10(amp)));
title('\bf Time series Spectrum');
xlabel('\bf Time');
ylabel('\bf Frequency (Hz)');
colorbar; %the color is the amplitude (in dB)

Answer 1

[Honglei Chen]

You should be able to use spectrogram for this.

http://www.mathworks.com/help/signal/ref/spectrogram.html