Research And Realization Of Signal Processing For Sawtooth Wave Frequency Modulation System

Modern electromagnetic warfare has high requirements for various radio detection systems. The continuous wave FM detecting system has been widely used because of its high accuracy in distance-detecting and the robustness of anti-interference ability.This paper is about the signal processing of the Sawtooth FM detecting system.The paper starts with analyzing the theory of the Sawtooth FM detecting system which focuses on the analysis of target echo features. Time domain sub-sampling principle is chosen to be the solution of speed measurement based on experiment analysis. Also, CZT principle is chosen to be the solution of distance measurement. Systematic simulation on MATLAB has been conducted to verify the theory of signal processing.Secondly, this paper proposes an overall design of the hardware circuit of signal processing and distribution requirements of each module. The PCB board of signal processing circuit is designed in Cadence after that. The hardware circuit is fully tested and debugged to ensure the reliability.Finally, the designs of FPGA signal processing system in QuartusII is conducted. Joint board debugging with the produced signal processing circuit and RF Transceiver is conducted as well. Simulations and field tests indicate that the proposed design can achieve an accuracy of 0.1m in distance measurement and 0.01m/s in speed measurement, which meets the design requirements.