The Design And Implemention Of IF Tracking Telemetry And Command Communication Module Based On FPGA

Currently, Chinese Satellite Tracking Telemetry and Command (TT&C) equipments are mainly composed of traditional hardware, and only perform single TT&C task. Because of the differences for operation frequency, coding system, range system and modulation system, the traditional TT&C equipments are not universal, and would increase the development burden. The new spaceflight TT&C system aims at digital system, the intermediate frequency digital transmitter which base on software radio theory has the characteristics of universal, flexible and low bit-error rate, and it is an important part of modern radio communication system. Therefore, the research on intermediate frequency digital system which adopted in TT&C system would have important significance.The main content of this paper is intermediate frequency digital communication module. It is illuminated that the basic operation principle and pivotal techniques, including Digital Downconversion (DDC), sampling rate alteration and FM modem technique, considering of the characteristics of spacecraft TT&C system, we design a general hardware platform for intermediate frequency signal processing based on FPGA. This platform is mainly composed of A/D, D/A, FPGA minimal system, interface circuit and power supply conversion circuit,the main function of the hardware circuits mainly convert the IF analog signals to digital signals,and then send to FPGA.Second,the telemetry digital signals processed by FPGA is converted into analog signals,and then it is sended to UFC after amplification.The main functions of this platform are implemented on FPGA,the main achievement od the features include DDC、 decimation filter、 carrier acquisition and tracking、 BPSK subcarrier demodulation and telemetetry FM modulation.It is illuminated that design principles、 module interface and simulationresults in detail.Compared with traditional analog communication equipments, the newly designed circuit has perfect performance through testing. The new circuit has the characteristics of high-resolution, high-reliability, high anti-Interference ability and flexibility, and overcame the temperature excursion and gain instability. Through the optimization and upgrading the software, it may implement the requirements of multifarious TT&C task, it has a comprehensive application future.