Hi guys,

I premise that I am not an expert in signal processing at all!

I'm analyzing a linear, time invariant hydrological system where I know 
the input (x) and the output (y) signal at unevenly spaced times.

I need to compute its non parametric transfer function defined as the 
quotient of the spectral density of the output divided by the spectral 
density of the input.

Does anyone know if a (user friendly) code/matlab function exists that 
can compute accurately the TF?

Thank you very much for your help!

Paolo

 Try
  
        help tf