Hello,
I'm using MT Phase Locked Loop VI(PLL VI hereafter) in LabVIEW with NI USRP2920(Kind of IQ converter) to measure carrier frequency and phase of input signal.
The PLL VI works fine when relatively low frequency signals like 500Hz are input, but when it comes to high frequency like 30kHz, the accuracy of frequency and phase estimation in PLL VI is significantly degraded. In my implementation, MT Baseband PLL is selected as an instance.
Can anyone describe why this things happen?
If it is difficult to measure high frequency with this PLL VI, does anyone know appropriate way to measure input IQ signal's carrier frequency and phase?
Thank you for reading through.
P.S.
In my implementation, FDMA is adopted. So, above "carrier" means kind of subcarrier which is downconverted to the baseband as IQ.
