A 2GHZ PLL with injection lock of the vco

Conventional phase lock loops have typically poor acquisition properties. In this communication we consider the use of signal injection in the VCO to improve the acquisiton and tracking performance of PLLs. A dynamic model describing the PLL with injection (PW) behaviour is given. Based on this modelwe show that the signal injection can be used to improve two important characteristics of the conventional PLL: it is possible to increase the lock-in range and reduce the acquisition time, without degradation of the tracking performance; furthermore in the tracking mode it can be used to reduce the output jitter in Gigabit commnunications clock/carrier recovery problems. A practical PLLI, designed to operate at 2.4GHz, is reported and the experimental results achieved agree with the fundamental theoretical/simulated results.