fft for unequal step size data

I have encountered the same problem as you got long back.

"I have a signal that is about 3000 points long and sampled using different sampling frequencies. The smallest sample time is about 1.2e-24 seconds while the largest sample time is 0.1 seconds. The sample time rarely stays the same and varies like crazy between the two extremes. This signal is output of a Simulink block diagram which essentially uses a variable time step solver.

Can someone suggest a method by which to find the FFT of this signal ? The FFT block in the DSP blockset demands a constant sample time.

*sample time = reciprocal of sampling frequency." from your previous discussion on matlab center , i have found out that clean algorithm can solve the purpose of unequal time series . but not able to find matlab code for clean algo. can anybody provide me the code. or any other option for the same.

please help

Thanx in advance.

KG sharma