Frequency synthesizer capable of achieving low phase noise, low stray and quick change

Abstract

The invention provides a frequency synthesizer capable of achieving low phase noise, low stray and quick change. An innovative phase noise prediction method is adopted, devices are reasonably selected, and the low phase noise is achieved; by means of phase-locked loop frequency presetting and microwave switch switching, frequency is quickly changed; meanwhile, a special isolation structure is adopted, reasonable distribution of the signal amplitude in a cavity structure is utilized, and accordingly low stray of the frequency synthesizer is guaranteed. The frequency synthesizer achieving multi-frequency output meets the requirements of the low phase noise, low stray and quick change.

Description

technical field [0001] The invention relates to the field of frequency synthesizers, in particular to a microwave frequency synthesizer with low phase noise, low stray and quick change. Background technique [0002] Frequency synthesizer is the core component of electronic equipment such as radar and communication, and its main technical indicators include phase noise, spurious suppression, frequency hopping speed, etc. The level of the phase noise of the frequency synthesizer directly determines the magnitude of the sideband signal amplitude of the transmitted spectrum. The sidelobe of the high sideband signal after pulse compression will cover up the weak target detection and reduce the distance detection performance of the radar; When the dispersion level is high, pairs of false signals will be generated in the received echo, and the width of the main lobe will be widened to reduce the distance resolution of the radar; modern radars face complex electromagnetic environmen...

AI Technical Summary

Problems solved by technology

In practical engineering applications, good phase noise can be obtained by using traditional direct digital frequency synthesis, but a large number of frequency mixing and frequency multiplication links are required, nonlinear components are introduced, the circuit is complex, and the spurious index is difficult to control; the PLL method can obtain High spurious suppression, but the frequency hopping speed is usually on the order of 100??s, which is difficult to meet the requirements of frequency agility; if the direct digital synthesis method is used, the frequency hopping speed can meet the requirements, but the spurious index is difficult to control

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