Frequency synthesizer

Abstract

The invention discloses a frequency synthesizer. The frequency synthesized comprises a first counter, a second counter, a controllable oscillator and a controller. The controller obtains a first time when the first counter completes N counts, calculates a target count value of the second counter in the first time according to a target frequency when outputs frequency signals, determines a target count interval of the second counter in the first time according to the target count value and then compares an actual count value completed by the second counter in the first time with the target count interval; according to the comparative result, the controller adjusts the output frequency of the controllable oscillator towards a direction close to the target frequency until the output frequency signals of the controllable oscillator reaches a target frequency meeting the precision requirements. The frequency synthesizer can reduce the requirements on loop stability and bandwidth and the design difficulties of internal modules and achieve the configurability of the precision of the output frequency signals.

Description

technical field [0001] The invention relates to the technical field of frequency synthesis, in particular to a frequency synthesizer. Background technique [0002] A frequency synthesizer is a device that uses one or more standard signals to generate a large number of discrete frequency signals through various technical approaches. Currently, a phase-locked loop frequency synthesis method (PLLFS, Phase-Locked Loop Frequency Synthesis) is widely used. [0003] Phase-locked loop frequency synthesis is an indirect frequency synthesis method. It uses phase-locked technology to generate a large number of frequency sources with high stability and high purity. Its basic structure is as follows: figure 1 . Reference frequency signal f ref Usually by the input frequency signal f in Generated by a frequency divider, where, f in = M·f ref , the phase detector (PD) on the reference frequency signal f ref And the frequency signal f output by the voltage controlled oscillator (VCO)...

AI Technical Summary

Problems solved by technology

[0004] However, the existing phase-locked loop frequency synthesizer has higher requirements on loop stability and bandwidth, and each module of the loop will affect the spectral purity of the output frequency signal, which leads to the limitation of each module of the loop. The design requirements are high, and the accuracy of the frequency signal output by the phase-locked loop frequency synthesizer is fixed, so it cannot be configured according to the requirements

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