Frequency Modulation for Tuning Forks on FPGA

[wade_bryant3-24]

Hi,

I am relatively new LabVIEW and FPGA user. I am trying create frequency modulation on the FPGA to maintain a 90 degree phase shift between the input and output signals. Currently, I am having trouble in trying to calculate the phase difference between two analog signals. The two analog signals are coming from analog inputs on the FPGA card. At the end of frequency modulation, there is a VCO that will output a signal that is shifted 90 degrees relative to the input signal. That output signal will drive the tuning fork at resonance. I am not familiar with the FPGA card and LabVIEW so it would be very helpful if someone could tell me how to calculate the phase difference between two analog signals. 

Thanks,

Jason Bryant

[wade_bryant3-24]

Basically how do you calculate the phase difference between two analog signals?

[Catherine-B · Accepted solution]

Hi wade_bruant3-24,

Below are a few links to examples of how to calculate the phase difference of two analog signals. Both examples show how to do this on a real-time or windows operating system, rather than on the FPGA itself since the functions used cannot be run on the FPGA.  

https://decibel.ni.com/content/docs/DOC-21131

https://decibel.ni.com/content/docs/DOC-18286

[wade_bryant3-24]

Thanks a lot!