Frequency synthesis method and its circuit based on phase-locked loop frequency fast locking

Abstract

The invention discloses a frequency synthesis method and circuit based on rapid frequency locking of a phase-locked loop. The method comprises the following steps that when a locking time slot starts, data are allocated to a phase-locked loop unit; a loop filter is charged; the phase-locked loop unit outputs an locking instruction when the output frequency of a voltage-controlled oscillator reaches the range of configuration data of the phase-locked loop unit; a power source is disconnected according to the locking instruction. According to the frequency synthesis method and circuit, when the locking time slot starts, the loop filter is charged in advance, the power source is disconnected by means of a locking instruction signal, and locking time of the phase-locked loop is shortened.

Description

technical field [0001] The present invention relates to a wireless communication circuit, and more specifically relates to a frequency synthesis method based on phase-locked loop frequency fast locking and a circuit thereof. Background technique [0002] In order to improve spectrum efficiency, most modern wireless communication systems use frequency division / time division multiplexing technology. The channels used by wireless transceivers for communication will be switched in real time according to channel occupancy and channel quality. Channel switching is realized by changing the output frequency of the frequency synthesizer. The frequency synthesizer provides programmable local carrier signals to the frequency conversion circuit in the transceiver circuit, which is the core of wireless communication equipment. The currently used frequency synthesis method is mainly realized by using a phase-locked loop plus a voltage-controlled oscillator. [0003] In the phase-locked ...

AI Technical Summary

Problems solved by technology

This solution needs to pre-measure the statistical characteristics of the single-point voltage in the locked frequency band of the voltage-controlled oscillator and store it in the memory; read the pre-stored voltage when configuring the data for the phase-locked loop, and pre-charge through the digital-to-analog converter. The charging time is determined by the analog The digital converter detects and feeds back to the controller to form a closed-loop control; this solution has high requirements for circuit consistency and temperature stability, the software response is delayed, and the circuit is more complicated and the cost is higher

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