DEVICE AND METHOD FOR OPERATING A LOOP FREQUENCY SYNTHESIZER WITH PHASE LOCKED SENSITIVE TO RADIO FREQUENCY CHANNEL SPACING

摘要

The method involves using a PLL (300) as part of a frequency synthesiser for an RF transceiver unit. The spacing between channels in a frequency band is determined and used to control a PLL. The PLL controls a VCO (204) and has a reference divider (201) signal and loop divider signal (209) which are fed into a phase detector (202). The phase detector output feeds a loop filter (203) and the loop filter output drives the VCO. The loop filter has a bandwidth controller (301) which varies the loop bandwidth.