Sughrue, Mion, Zinn, Macpeak & Seas, PLLC
Frequency synthesizer having a speed-up circuit
 It is an object of the present invention to provide a frequency synthesiser with a lock speed-up arrangement in a simple and effective form. In accordance with the invention there is provided a frequency synthesiser including a voltage controlled oscillator, a phase detector which receives a base frequency signal and a feedback signal derived from the output of the voltage controlled oscillator and a filter circuit connecting the output of phase detector to a frequency control voltage input of the voltage controlled oscillator, the filter circuit having a reference voltage connection, and a speed-up circuit for applying a voltage signal to the reference voltage connection when a frequency change is demanded. 
NEC Corporation
H H
H03L H03L
inventional inventional
Nigel Justin
Tolson Clark