Optical-assisted broadband microwave instantaneous frequency measurement method and device

Abstract

The invention discloses an optical-assisted broadband microwave instantaneous frequency measurement method and device. Continuous light emitted by a laser firstly enters a carrier suppression type single sideband modulation module to be modulated by a received radio frequency signal to be measured, and a generated optical signal of a single sideband is divided into two branches through a coupler; the upper branch optical sideband enters a Mach-Zehnder interferometer to obtain two port outputs of complementary filtering; optical frequency shift fs from MHz to hundred MHz magnitude is realized after the optical sideband of the lower branch passes through the acousto-optic modulator; the outputs of the two branches are combined and enter the two low-speed photoelectric detectors, and a radio frequency signal with a fixed carrier frequency fs is generated through beat frequency; and an amplitude comparison function is obtained by comparing the amplitudes of the two radio frequency signals, so that the frequency of the microwave signal to be measured is speculated. According to the method, interference of direct current and low-frequency noise is avoided, the whole process is irrelevant to changes of light source power and microwave power, and instantaneous frequency measurement can be achieved in a broadband range.

Description

technical field [0001] The invention relates to the fields of microwave detection, microwave photonics and radar, especially optically assisted broadband microwave instantaneous frequency measurement technology. Background technique [0002] Modern warfare has turned into electronic warfare to some extent, in which radar has played a huge role. If the frequency parameters of the signal emitted by the enemy's radar can be quickly obtained, it can become one of the key factors that determine the outcome of the battle . Although the traditional electronic instantaneous frequency measurement receiver can measure the instantaneous frequency of the signal with a duration of 5 ns or less (B. Zhang, X. Wang, and S. Pan, "Photonics-based instantaneous multi-parameter measurement of a linear frequency modulation microwave signal,” Journal of Lightwave Technology, vol.36, no.13, pp.2589–2596, 2018; M. Pagani et al., “Low-error and broadband microwave frequency measurement in a silicon...

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Problems solved by technology

[0004] But in general, the frequency-to-microwave power mapping scheme requires high-speed photodetectors, which greatly increases the cost of the system; and the frequency-to-optical power mapping scheme passes Direct analysis of the obtained DC component is difficult to avoid DC and low-frequency noise interference

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