Soft dB SPM PLL User Guide - Manual (Page 9)

SPM - PLL User’s Manual 9
4 PLL User Interface
PLL interface: Main Tab
4.1 Phase Detector Time Cst (s)
This control adjusts the time constant of the phase detector. We suggest keeping time constant to 20us
(fast set-up), which allows a bandwidth of about 8 kHz. Note that the auto-adjustment functions for the
PI gains of both controllers (amplitude and phase) automatically set the time constant to 20us. This
way, the bandwidth of the controller is only limited by the PI gains and the LP filter.
4.2 Resonator Sweep
The Resonator Sweep button performs a frequency scan of the resonator. A sweep over a limited
frequency range is used to measure the frequency response. The following figure presents the
measurement interface: