Special tranfer function VI for linear systems and eigenfunc stimuli???

Question

Can someone tell me if there exists a vi function that gives modulus and
phase angle of a sinusoid output of a linear system when knowing the
modulus and phase angle of the sinusoid stimulus and also having the
sampled output in the time domain.
Input = sin (fi*t)
H(f)=tranfer function of the linear system
Output = |H(fi)|*sin (fi*t+angle(H(fi)))
with fi the frequency of the input wave
So I want |H(fi)| and angle(H(fi))
when given Input and the sampled output in the time domain
Thanks in advance.
Message Edited by Support on 07-10-2007 10:20 AM

Answer 1

Look in/at:
C:\PROGRAM FILES\NATIONAL
INSTRUMENTS\LABVIEW\vi.lib\Analysis\0measdsp.llb\Transfer Function.vi
You can also select this function from the menue Signal Processing
==>Measurement
If your sine is not periodic in the sample interval (2^N points preferrably)
you might need other stuff from that same menue like 'auto power
spectrum.vi' and 'power&frequency estimate.vi' to determine the exact
frequency. And you have to interpolate the phase (change: - pi radians per
frequency bin).
Don't forget to 'window' before taking the powerspec.
See also:
C:\PROGRAM FILES\NATIONAL
INSTRUMENTS\LABVIEW\EXAMPLES\ANALYSIS\measure\daqmeas.llb\Network Analyzer
this vi 'does it all' including DAQ.
There are a lot of examples in the help and at zone.ni.com
Keywords: FFT, Fourier,
Signal Processing etc.
wrote in message
news:[email protected]..
> Can someone tell me if there exists a vi function that gives modulus and
> phase angle of a sinusoid output of a linear system when knowing the
> modulus and phase angle of the sinusoid stimulus and also having the
> sampled output in the time domain.
>
> Input = sin (fi*t)
> H(f)=tranfer function of the linear system
> Output = |H(fi)|*sin (fi*t+angle(H(fi)))
>
> with fi the frequency of the input wave
>
> So I want |H(fi)| and angle(H(fi))
> when given Input and the sampled output in the time domain
>
> Thanks in advance.
Message Edited by Support on 07-10-2007 10:21 AM