Instruction Spread Spectrum Communication System Response Module Design

Radio Control Detector Instrument (RCDI) is communication equipments of missiles, and implements information exchange with Ground Radiation Guided Radar (GRGR):On the one hand, receiver module of RCDI receives continuous or single control instructions sending from the GRGR, and then transmit the instructions to control module of the missile; On the other hand, response module of RCDI transmits coordinate information of the missile to the GRGR, so that the GRGR can calculate position of the missile, and form the correct control instructions. The paper mainly researches on receiver modular of RCDI.The paper analyzes the requirements of the entire system, and recommends gold sequences as spreading codes based on features of the source signal and varieties of spreading codes. By analyzing performance of m-sequence and gold sequence, and combining with the system requirements, we finally adopt six bands gold sequence as spread sequence of both GRGR and RCDI. The gold sequence family not only can help GRGR launch and track 12 missiles at the same time, but also meet pseudo-code synchronization requirements between RCDI and GRGR. With help of matlab, the paper completes depth and detailed analysis on generation of spread-spectrum code, and performance of self-correlation and cross-correlation.The paper completes pseudo-code generation module on FPGA platform, and integrated simulation and timing simulation results indicate that the pseudo-code generator can meet the requirements. The paper analyzes the process of spread spectrum modulation module, and completes the module based on FPGA platform, and also studies differentiated encoding, mapping, quantification, interpolation, forming filtering process of BPSK module, and completes simulation of BPSK module based on FPGA.Finally, the paper analyzes despreading technology of spread spectrum signal, and implements simulation and analysis on influence of Doppler shift on despreading in scenario of different code rate, and then determines rate range of baseband signal.