Search On Photonics-Assisted Broadband RF Receiver Based On Optical Undersampling

Broadband Radio Frequency (RF) receiver is the key equipment in electronic warfare. An ideal RF receiver should be able to measure multi-frequency RF signal in broadband with a high interception probability and sensitivity. Traditional electronic RF receiver cannot meet the requirement of current electronic warfare since the limitation by electronic bottleneck. As the rapid development of high speed digital signal processing (DSP), compressive sampling are raised and introduced into broadband RF sensing. In the meantime, microwave photonics is an interdiscipline developing well in recent years, which combines the advantages of microwave techniques’precise control ability and photonics techniques’broadband feature. Compressive sampling and microwave photonics offer new solution to the high performance requirement of broadband RF receiver by current electronic warfare.This thesis focuses on using microwave photonics and optical undersampling to measure the broadband RF signal, the main works are as follows:Firstly, a broadband multi-frequency RF sensing system model is investigated based on compressive sensing. The compressive measurement method and recovery algorithm are well analyzed and simulated. The results show that a broadband signal ranging from0～5GHz with3carrier is reconstructed. The total sampling rate is1.23GS/s.24channels are needed. The compression ratio is8. However, the number of the carrier, the compressive ratio, the complexity of the system and the efficiency of the recovery algorithm need to be further improved.Secondly, to overcome the drawbacks of the numerical model above, an optimized multi-frequency RF measurement scheme is proposed based on optical undersampling. Firstly, the system’s setup and optical coding principal are presented. Secondly, the coding process are well analyzed. Then an efficient recovery algorithm is proposed and discussed. At last, an integral experiment platform is set up to verify the proposed scheme. The experiment results show that, in this scheme, using only one optical link and one ADC whose analog bandwidth is42.6MHz, precise measurement of40RF tones ranging from0～1GHz are achieved without large computational load. The system’s compression ratio is23.5and the resolution is2kHz.The experiment result is a world leading achievement.