Research On Photonic Generation Of Frequency-modulated Continuous-wave And Performance Test Of ROF System

As a combination of optical communication technology and microwave technology,microwave photonics has the advantages of both and is widely used in all aspects of social life,especially in the field of radar detection and high-speed wireless communication.One of the key technologies of a frequency-domain radar detection system is the high-bandwidth frequency-modulated continuous-wave(FM/CW)signal generation;while the realization of high-speed wireless communication benefits from the application of Radio over Fiber(ROF)technology.The main topics of this thesis are the generation of high central frequency and high bandwidth FM/CW signal with optical methods and the network performance test research of wireless communication system based on ROF technology.First,the detection principle,characteristics and classification of frequency-domain radar system are introduced and the frequency-modulated continuous wave generation technology based on optical method is studied.Then,an approach of high frequency and high bandwidth FM/CW signal generation based on gain switching and a multi-radar head distributed system model are proposed.After that,the corresponding simulation and experimental verification are made according to the proposed method.In our experiment,a continuous-wave with frequency of 20 GHz,which decuples that of the input was generated,and a frequency-modulated continuous-wave signal with bandwidth of 500 MHz and central frequency of 10GHz was achieved.What's more,the required modulation signal power is only 5dBm and the optical signal-to-noise ratio is more than 30dB.On the other hand,the composition and necessity of performance test of wireless communication ROF system are illustrated and three important test parameters are pointed out,namely,transmission bandwidth,delay and packet loss rate.Then,the hierarchical model of the communication network system is briefly described,and the performance parameters of an actual ROF system are tested.After analyzing the inaccuracy of the software-based testing,the FPGA-based test mechanism is proposed.The framework of the system design is described in detail and the design are verified in both simulation and experiment.