A Broadband Agile Low Phase Noise Frequency Synthesis Generator

Abstract

The invention belongs to the technology of frequency synthesis generators, and specifically provides a frequency synthesis generator with broadband agility and low phase noise, including: a high-stable crystal oscillator, a down-conversion mixing phase-locked loop module, a preset traction module and a control module, wherein the down-conversion mixing The frequency phase-locked loop module adopts the structure of coarse frequency conversion and fine frequency conversion twice, so as to achieve higher frequency output and low phase noise in a small volume; at the same time, the pre-set traction module completes the traction and coarse tuning of the VCO, thereby Wrong locking is avoided; moreover, the locking speed of the phase-locked loop is obviously improved, and agility is realized. To sum up, the object of the present invention is to provide a frequency synthesis generator with wideband agility and low phase noise, which can realize low phase noise, small step, wide bandwidth and agility.

Description

technical field [0001] The invention belongs to the technology of frequency synthesis generators, in particular to frequency synthesis generators with wide-band agility and low phase noise. Background technique [0002] Radar technology is developing rapidly, and as one of its core technologies, the requirements for frequency synthesis generators are getting higher and higher. With the gradual increase of frequency, low phase noise and spurs have become more and more difficult to achieve, and the structure of the traditional built-in reference crystal oscillator and single phase-locked loop has gradually failed to meet the technical requirements. Due to the characteristics of radar technology itself, in addition to the requirements for low phase noise and low spurs, frequency synthesis generators are often required to achieve wide bandwidth, small steps, high stability, and fast transitions. [0003] In order to achieve small steps and low spurs, an effective way is to use ...

AI Technical Summary

Problems solved by technology

[0003] In order to achieve small steps and low spurs, an effective way is to use DDS (Direct Digital Synthesizer, Direct Digital Synthesizer) to drive the phase-locked loop; but such a structure is limited by the noise floor of the phase-locked loop itself. It is difficult to achieve low enough phase noise; in addition, with such a structure, the frequency hopping time is still determined by the phase-locked loop, so the frequency hopping speed of DDS cannot be reflected, and fast hopping is still impossible

In order to obtain a sufficiently low phase noise, the general method is to use a high-frequency crystal oscillator as a reference to reduce the frequency multiplication N of the phase-locked loop. However, for crystal oscillators, it is difficult to achieve satisfactory stability at too high a frequency; for To obtain a fast enough jump speed, the general measure is to relax the loop filter, but an overly wide loop filter will lead to insufficient suppression of spurs, and even lead to link instability

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