The online Example Program Database on the National Instruments
Developer Zone has a few programs that should help you out with
programming an application involving a Phase Lock Loop (PLL). The
following program jumped out at me as a very simple implementation of a
PLL alorithm in LabVIEW. It uses simulated data, but can probably
be adapted to work with your acquired data. Note - This example
has not been tested by National Instruments, and we take no
responsibility for its correctness or operation.
Developer Zone Example: PLL Demo
Another example program that also might be helpful is the
following. It is intended to be used with the Dynamic Signal
Analysis (DSA) line of Modular Instrument DAQ devices, but still may
Developer Zone Example: Multi Channel Count Lock-In Amplifier with DAQmx
You can search for more similar examples by going to www.ni.com/examples
. I hope this helps!