Acquire sine wave from DAQ

Question

Hi
I am using DAQ to acquire sine wave from function generator to determine the fringes, phase and wavelength.
How can I build this VI?
Thank you

Answer 1

Mostly like the phase is being reported
from 0 to 180 or 0 to -180.  There is a VI to unwrap the phase.
I took a look at your code and I am a
bit confused about what you are trying to do. 
Right now it looks like you are gathering 100k samples at a sampling frequency
of 200k in a finite acquisition.
In your code, each iteration of the For
loop takes 100k samples and finds the number of peaks.  The Extract Single Tone Information.vi finds
the tone with the largest amplitude in the 100k samples and returns the
amplitude and phase.  The phase in this
case returns the absolute (start) phase of your detected sine tone, that can
also be viewed as the phase relative the beginning of your signal (in this case
the beginning of the 100k samples).
On the next iteration, the code takes a
new set of 100k samples and calculates the same information (again the phase is
based on the start of this new set of 100k samples).
What is your ultimate goal?  To continuously acquire data, find peaks and their
phase relative to the first sample collected? To acquire a finite set of data,
and find the phase of each peak relative to the first sample?  Get the relative phase between two different
peaks?  What are you using the phase
information for?  Are you using the phase
to count the number of cycles?  What kind
of signal is coming from your signal generator?
To compare the phase to the first sample
you will need to use some comparison vi’s as mentioned in another post.  Shift registers can be used to keep a “running”
total of the phase from the first sample.
Jared T.