SignalProcessing.UnwrapPhase vs. Unwrap Phase VI

[MPLynch]

I noticed that the SignalProcessing.UnwrapPhase method, according to documentation, "Unwraps the phase array by eliminating discontinuities whose absolute values exceed 2*Pi radians."  However, the Unwrap Phase VI in normal Lab View uses Pi, not 2*Pi.  Is this a mistake in documentation?  Is there another Measurement Studio method which mimics the VI?

Thanks!

[StevieZ · Accepted solution]

MPLynch,

You are correct. There is disparity between the two functions and this is not a documentation mistake. However, this situation is easily rectified...

The forumula that is used for the UnwrapPhase in LabVIEW is

x[i] = x[i] - Floor((x[i] - x[i-1])/(2.0*Pi)+0.5)*(2.0*Pi), for each i in x

You can make a function that will mimic this formula and use that instead of the SignalProcessing.UnwrapPhase method if you need two to match.

Regards,

Steven Zittrower

Applications Engineer

National Instruments

http://www.ni.com/support

[MPLynch]

Thanks a lot for the help.

In case it wasn't blatantly obvious, I'm a bit new to the world of signal processing.  Really appreciate the nudge in the right direction.