JPS5959038U - frequency synthesizer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Brief explanation of drawings]

1 to 3 are block diagrams for explaining a conventional frequency synthesizer, FIG. 4 is a block diagram for explaining an embodiment of this invention, and FIG. 5 is a waveform diagram for explaining the operation of this invention. , FIG. 6 is a block diagram showing another embodiment of this invention. 101: Phase comparator, 102: Low pass filter, 103
: VCo, 105: Reference oscillator, 301: Variable frequency divider, 402 Near-tub down counter, 407: Control means for controlling the variable frequency divider. -1-■-

Claims (1)

[Claims for Utility Model Registration] A. A reference oscillator that generates a signal with a reference frequency f, and B.
The oscillation frequency f depends on the magnitude of the control voltage. A voltage controlled oscillator in which the output signal of the voltage controlled oscillator changes, C a variable frequency divider that can divide the output signal of this voltage controlled oscillator and change its frequency division ratio, D A phase comparator that compares the phases of output signals and generates the above control voltage; E An up/down counter that repeatedly counts up and down with a duty ratio corresponding to a set value; F Up and down counts of this up/down counter. A frequency synthesizer comprising: control means for changing the division ratio of the variable frequency divider according to the state of the frequency divider;