基于双平行强度调制的宽带多普勒频移测量

Wide Range Doppler Frequency Shift Measurement Based on Dual-Parallel Mach-Zehnder Modulator

多普勒频移测量在电子战、雷达系统中有重要的应用。电域测量方法存在带宽受限、抗电磁干扰能力弱的缺陷。提出并实验验证一种光辅助法测量多普勒频移,在光域,采用双平行强度调制器进行光双边带载波抑制调制、光带通滤波、低频光电转换,最后在电域进行低频频谱分析,从而实现多普勒频移测量,有效解决了电域测量方法的缺陷。实验结果表明,在微波/毫米波频率7~40 GHz、多普勒频移1 k Hz^10 MHz实现了误差±46 Hz的多普勒频移测量。

Doppler frequency shift measurement is widely used in electronic warfare and radar system. Measurement in electric domain suffers from narrow range and weak electro-magnetic interference resistance. This paper proposes and experimentally demonstrates an optics-assisted Doppler frequency shift measurement approach, which employs dual-parallel Mach-Zehnder modulator for double sideband carrier modulation, band pass filtering and low-frequency photoelectric conversion in optical domain, then analyses the low-frequency spectrum in electric domain, showing an effectively solution to the disadvantages of measurement in electric domain. Experimental results shows a measurement at 7-40 GHz microwave/millimeter wave of 1 kHz-10 MHz Doppler frequency shift with measurement error of ±46 Hz.