Phase lock loop frequency synthesizer with quick lock function

Abstract

The invention discloses a phase lock loop frequency synthesizer with quick lock function, comprising a phase lock loop (101) and a quick lock logic unit (102). The phase lock loop (101) consists of a frequency discrimination phase discriminator (501), a charge pump (502), a voltage control oscillator (503), a programmable multimode frequency divider (504) and a loop filter (511). The quick lock logic unit (102) consists of a logic control circuit (508), a unit gain follower (509) and a phase lock monitor (510). The invention realizes the quick lock of the frequency synthesizer, and the quick lock logic unit has simple structure and low power consumption. The invention is especially suitable for a wireless radio frequency communication system which requires low power consumption and quick lock.

Description

technical field [0001] The invention belongs to the technical field of electronic communication or radio frequency, and specifically refers to a phase-locked loop frequency synthesizer with fast locking function. Background technique: [0002] At present, the phase-locked loop frequency synthesizer is widely used in the fields of electronic communication and wireless radio frequency technology, and has become an indispensable module of modern wireless communication. In modern wireless radio frequency communications such as digital mobile systems that require fast locking of frequency synthesis, vehicle radio frequency receiving systems and frequency hopping systems, fast frequency synthesis is a very important indicator. Because fractional phase-locked loop frequency synthesis can provide large loop bandwidth while achieving narrow channel spacing, compared with integer phase-locked loop, it has the advantage of fast loop locking speed. No worse than integer frequency synth...

AI Technical Summary

Problems solved by technology

The disadvantage of the acceleration mode is that when the loop is switched from the acceleration state to the normal mode state, the voltage control line of the VCO will be greatly disturbed, and because the loop gain or zero and pole changes in the acceleration mode state are not large enough , the loop lock time is still limited

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