Low-phase noise microwave local oscillation generating device and method

Abstract

The invention provides a low-phase noise microwave local oscillation generating device. After a broadband microwave oscillator feedback signal passes by a broadband microwave signal conditioning circuit, down mixing is carried out on the broadband microwave oscillator feedback signal and a local oscillation signal of a certain frequency of a high-purity down-conversion local oscillation group to convert the broadband microwave oscillator feedback signal from a microwave frequency band with higher frequency into a radio frequency band with lower frequency, and then the broadband microwave oscillator feedback signal is mixed with low-noise radio frequency local oscillation, phase discrimination is carried out on a mixed output middle frequency signal and a reference signal from a fractional frequency-division phase-locked loop, and a phase discrimination output is added to a control end of a broadband microwave oscillator after passing by a loop integrator, so that necessary low-phase noise microwave local oscillation is output. The low-phase noise microwave local oscillation generating device provided by the invention overcomes the technical bottleneck that in a sampling mixing method adopted in traditional frequency synthesis, near carrier phase nose for synthesizing the local oscillation signal is constrained by sampling local oscillation phase noise, and a phase noise index of the microwave synthesis local oscillation signal is further improved.

Description

technical field

[0001] The invention relates to the technical field of testing, in particular to a low-phase-noise microwave local oscillator generation device, and also to a low-phase-noise microwave local oscillator generation method. Background technique

[0002] Microwave test instruments have high requirements on the frequency resolution, phase noise and spurious indicators of the local oscillator source. Therefore, in the broadband microwave signal frequency synthesis circuit, the local oscillator circuit usually adopts a multi-loop phase-locked structure, such as figure 1 As shown, the traditional scheme generally includes a low-noise reference source circuit, an integer or fractional frequency division phase-locked loop circuit, a low-noise sampling oscillator circuit, a sampling mixing circuit, a sampling intermediate frequency conditioning circuit, a phase detector, a loop integrator, a broadband Microwave oscillators, broadband microwave signal conditioning circui...

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