Spectrum detection system

Abstract

A spectrum detection system, including a frequency-sweeping light source, a phase modulator, an optical filter, a photodetector, a power divider, an electric amplifier, a combiner, an electric filter, and an oscilloscope; wherein, the frequency-sweeping light source, the phase modulator , an optical filter, a photodetector and an electric amplifier together form a ring-shaped photoelectric oscillator resonant cavity; when the Fourier domain mode-locking condition is met, the photoelectric oscillator resonant cavity can generate a broadband adjustable frequency sweep signal. In the present invention, the signal to be measured is coupled to the Fourier domain mode-locked photoelectric oscillator, the signal to be tested beats in the loop and the oscillation signal in the photoelectric oscillator, and the time domain of the output signal is observed by an oscilloscope after being filtered by an electric filter waveform. The frequency information of the signal to be tested can be obtained by using the frequency-to-time mapping of the signal to be measured by the Fourier domain mode-locked photoelectric oscillator, and the appearance time of the waveform observed by the oscilloscope.

Description

technical field [0001] The invention relates to the technical field of microwave photonics, in particular to a spectrum detection system. Background technique [0002] In radar and other electronic warfare systems, the ability to accurately measure intercepted unknown microwave signals is critical. Modern electronic technology can achieve high-precision frequency detection, but the frequency of the signal to be tested may be distributed in a wide frequency band, and the frequency bandwidth is limited when using purely electronic methods, and the measurement is susceptible to electromagnetic interference . [0003] The above-mentioned disadvantages of electronic technology can be avoided by adopting the method of photonics. In principle, photonics-based microwave signal frequency detection schemes can be roughly divided into three categories, namely, based on photonics channelization technology, based on frequency-to-power mapping, and based on frequency-to-time mapping. F...

AI Technical Summary

Problems solved by technology

Frequency measurement based on photonics channelization technology can achieve large bandwidth, but its frequency measurement error is very large, usually greater than 1GHz, which cannot meet the application requirements of most electronic warfare systems; the method based on frequency-to-power mapping can achieve relatively more High-precision frequency detection, but this method can only detect single-frequency microwave signals, and cannot simultaneously detect multiple point-frequency signals, so its application is limited

The method based on frequency-to-time mapping can realize the detection of multi-point frequency signals, but at the same time, the frequency resolution of this method is limited by the accuracy of the optical time gate in the system, which is on the order of hundreds of MHz

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