Study On Method And Technique Of Multi-path Signal Demodulation

Adopted the method of combining theory analysis with circuit experiment, this paper studies key techniques on undistortedly demodulating multi-path local signals from the input FM signal, and gets two kinds of demodulation plans.In the first plan, we, for the first time, suggest an idea which can accomplish demodulation in two parts. The first part is FM signal demodulation circuit and the second part is multi-path signal divided circuit. We have mainly researched two FM signal demodulation techniques called Frequency Spectrum Separation and Phase Lock Loop in the first part. In the second part, we have studied the divided technique of multi-path signal by use of Analog/Digital Change circuit. The feasibility of this plan has been proved through debugging the whole circuit.In the second plan, we introduce the advanced AYR MCU technique to demodulate the input FM signal for the first time. We have mainly researched the hardware circuit and the suitable software. The demodulating program is made up of two major processes: measurement cycle and consult table. This plan has also been successfully debugged in AYR MCU explore system.Finally, this paper compares the two demodulation plans and suggests we should choose one of them to apply to multi-path signal transfer system according to actual demand.