04980652 is referenced by 82 patents and cites 3 patents.

In a phase locked loop frequency synthesizer, the frequency of a VCO is switched by changing the division ratio of a variable ratio frequency divider in the feedback path of the loop. At the time of switching, a prepositioning voltage is applied to the VCO to realize fast frequency switching. To correct for nonlinear response of the VCO, the prepositioning voltage is adjusted according to information received from a voltage measuring circuit connected to the VCO control circuit.

Title
Frequency synthesizer having compensation for nonlinearities
Application Number
7/400665
Publication Number
4980652
Application Date
August 31, 1989
Publication Date
December 25, 1990
Inventor
Toshio Nojima
Yokosuka
JP
Yasushi Yamao
Yokosuka
JP
Shigeki Saito
Yokohama
JP
Yoshiaki Tarusawa
Yokohama
JP
Agent
Cushman Darby & Cushman
Assignee
Nippon Telegraph and Telephone Corporation
JP
IPC
H03L 7/189
View Original Source