IMPROVEMENTS RELATING TO PLL FREQUENCY SYNTHESISERS

摘要

The invention is a phase loop system comprising a first phase comparison and filter means which generates a first frequency change signal according to phase difference between a reference signaland a first loop signal; a first oscillator which generates a first variable frequency signal in response to the first frequency change signal; a second phase comparison and filter means which generates a second frequency change signal according to phase difference between the first variable frequency signal and a second loop signal; a second oscillator which generates a second variable frequency signal as anoutput signal in response to the second frequency change signal, and a loop signal arrangement which receives the second variable frequency signal and forms the first loop signal through at leasta first frequency divider and forms the second loop signal through at least a second frequency divider.