NI-4461+Signal Analysis

[G_BHASKAR]

Hi,
As brought out by you the tutorial at following link
http://zone.ni.com/devzone/cda/tut/p/id/4278    provides the formula for  calculating the frequency Response.

H(f) =cross power spectrum(A,B) / Power Spectrum(A)

where
cross power spectrum  =FFT(B)XFFT*(A)    and   power spectrum  =FFT(A)XFFT*(A)
                                                 N^2                                                                 N
i have two questions

1) is FFT(B)XFFT*(A)  the convolution of FFT(B) and FFT*(A)  ?

2) The  cross power spectrum results in a complex array.Similarly the power spectrum results in a complex array.Now how do I divide one complex array by another complex array?

Sorry I am going a bit mathematical.But the option at present is to implement it in code.

Thanks
Bhaskar

[PBear]

Hi Bhaska,

To my knowledge, this is not a covolution and simply a multiplication. As far as performing the mathmatics in code, I would recommend posting to either the Measurement Studio board or on a C developers forum such as on MSDN. I say this as this thread has turned from a DAQ/Hardware thread into a software implementation of mathmatical principles and you would get better support going those routes.

In the meantime, I suggest searching many of the online mathematics resources available on the web.

[G_BHASKAR]

Hi Patrick,

Thanks for all the support.U may be right in saying that this a DAQ Hardware/Labview forum.Maybe I'll have to search somewhere else for signal processing implementations.

Thanks
Bhaskar