High-phase detection frequency frequency-agile locked-phase loop circuit

Abstract

The invention discloses a high-phase detection frequency frequency-agile locked-phase loop circuit. The high-phase detection frequency frequency-agile locked-phase loop circuit comprises a reference circuit, a DDS (direct digital frequency synthesis) small-step circuit, a phase-locked loop reference source circuit and a phase-locked loop and output circuit; the reference circuit generates two paths of signals, wherein one path of signals is provided for the DDS small-step circuit so that small-step output signals can be outputted, the other path of signals provides mixed signals for the phase-locked loop reference source circuit; the phase-locked loop reference source circuit mixes the small-step output signals and the mixed signals so as to output reference signals for the phase-locked loop and output circuit; and the phase-locked loop and output circuit filters and amplifies the reference signals so as to output final frequency signals. Compared with a traditional direct analog frequency synthesis mode, a mode according to which phase-locked loop reference frequency is changed through DDS small step, can greatly simplify a scheme and eliminate the defects of complexity, large size and high cost of a traditional frequency-agile circuit scheme, and the reliability and stability of products can be greatly improved.

Description

technical field [0001] The invention relates to the communication field, in particular to a frequency-agile phase-locked loop circuit with high phase-detection frequency. Background technique [0002] There are three main types of existing frequency synthesis techniques, namely direct frequency synthesis, phase-locked frequency synthesis and direct digital frequency synthesis (DDS). The direct frequency synthesis scheme is complicated, the frequency step of the synthesizer is large, and the spurious level is difficult to control, but its phase noise is excellent and the frequency switching time is extremely short. The phase noise of the phase-locked frequency synthesizer is average, and the frequency step cannot be made too small, but the scheme is relatively simple, the spurious level is easy to control, and the frequency switching time is greatly affected by the loop bandwidth. The direct digital frequency synthesizer can produce very small frequency steps, the phase nois...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a high-frequency frequency-agile phase-locked loop circuit, which realizes frequency agility by changing the reference frequency of the phase-locked loop in small steps of DDS, compared with the traditional direct analog frequency The synthesis method greatly simplifies the scheme, overcomes the shortcomings of traditional agile frequency conversion circuit schemes such as complexity, large size, and high cost, and greatly improves product reliability and stability.

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