Research On Microwave And Millimeter-wave Agility Sweep Source

Frequency synthesizer is the core component of the electronic system.With the rapid development of electronic systems,key indexes of the system continue to improve,the requirements on improving the performance of frequency synthesizer is getting higher and higher.Therefore,studing the frequency synthesis that applies to many fields is significant and has application value.Based on the study of instantaneous frequency measurement system,this thesis aims to research and design the microwave and millimeter-wave signal source with fast frequency conversion performance.After analyzing advantages and disadvantages of several frequency synthesis techniques,the paper adopts direct digital frequency synthesis(DDS)and direct frequency synthesis(DS)technology to study and design the microwave and millimeter-wave high speed sweep source.According to the high-speed frequency sweep source output frequency and bandwidth requirements of the the X-band and Ka-band,the frequency relations and system performance index was estimated to determine the implementation of the sweep source.The digital circuit part of the sweep source combines the DDS with the FPGA,and DDS output the narrow-band frequency modulation signals under the control of FPGA and 1GHz reference signal.On the basis of different frequency bands,analog circuit part has different frequency multipling method: X band with × 3 × 3 × 8 frequency multiplier chain,Ka band using × 7 × 3 × 4 × 3 frequency multiplier chain.This scheme has the characteristics of high frequency resolution and low phase noise,it can satisfy the instantaneous frequency measurement system of nanosecond test frequency conversion speed.Controlled by the host computer program,the two sweep sources can realize the linear frequency modulation and frequency output by changing the parameters such as the start and end frequency,frequency hopping step and frequency hopping time of the sweep source.Finally,the design of the high-speed sweep source system is tested.The result shows that the output frequency of the X-band sweep source is 9.9-10.5GHz,the minimum frequency-hopping time is 24 ns,the phase noise is lower than-84 d Bc/Hz@1kHz,spurious suppression is better than 34 d Bc,the output power is greater than 5.8dBm;Kaband sweep source output frequency is 34.5-35.5GHz,the minimum frequency-hopping time is 24 ns,phase noise is lower than-80 d Bc/Hz@1kHz,spurious suppression is better than 20 dBc,output power is greater than 1.8d Bm.The results verify that the X-band and Ka-band high-speed sweep source system meet the technical indexes of instantaneous frequency measurement system.