基于光子技术的微波频率测量的仿真研究

Simulation Research of Microwave Frequency Measurement Based on Photonic Technology

提出了一种基于相位调制与强度调制相结合的瞬时频率测量仿真方法。单一的连续波光源通过耦合器被分为两部分,未知信号通过调制器进入两臂并与光载波形成双边带信号,之后分别进入两段长距离的单模光纤中,在光纤中利用色散所致的射频功率衰落效应,能获得单调变化的频率—幅度映射关系,进一步通过光电探测的射频信号输出功率比来得到幅度比较函数fACF。该方案结构简易,能够快速精准地测量出未知信号的频率,测量范围可以达到0. 5~53GHz,测量误差小于200MHz。另外,本文还进一步分析与实现测频范围与测频精确度的优化。

A novel simulation technique of instantaneous frequency measurement based on phase modulation and intensity modulation is proposed. A single continuous-wave light source is divided into two parts by a coupler. An unknown signal passes through the modulators and enters both arms and forms two double-sideband signals with the optical carrier,and then the generated signals enter two long-distance single-mode fibers,respectively. The use of dispersion-induced RF power fading effects in the optical fiber can obtain a monotonically-varying frequency-to-amplitude mapping relationship,and further obtain an amplitude comparison function fACFthrough the ratio of the photodetected RF signal output power. The scheme is simple in structure and can quickly and accurately measure the frequency of unknown signals. The measurement range can reach 0. 5 to 53 GHz and the measurement error is less than200 MHz. In addition,this paper further analyzes and improves the frequency measurement range and accuracy of frequency measurement.