Engineering Development Of Electrical Demodulating Circuit For Four-mode Differential Laser Gyro

This paper presented an engineering-oriented electronic signal-demodulating system for four-mode differential laser gyro(FMDLG). The electric demodulating method is briefly described. The disadvantages of the analog-device-based demodulating system are analyzed, followed which is a digital demodulating system based on FPGA. Some IC chips are chosen to meet the engineering requirements during the system's hardware and software design. A series of experiments prove its correct demodulation under engineering conditions.Emphasis is laid on the engineering design of the digital demodulating system. An A/D converter MAX1425 is chosen to construct the sampling module for its appropriate sampling speed and good temperature resistance. The core of the system's hardware is formed by a high-speed and high-integrated FPGA chip EP2C20Q240C8. The PCB of this system is optimally designed to meet the engineering requirements, thus a high-integrated hardware entity is accomplished. The input channel is designed according to MAX1425's transmission features.A digital demodulating module is actualized considering the FMDLG signal characters. Some important modules are debugged and simulated. The system's performances of bandwidth and temperature resistance are tested through experiments under different engineering conditions. The results show it a high-integrated system with adequate bandwidth and good temperature resistance, and it has met the engineering requirements to the FMDLG's signal-demodulating system.