Based On The Photoelectric Conversion Technology Field Strength Measurement System Design

In the field of electromagnetic measurement and EMC(electromagnetic compatibility), the intensity of signal is the key index to forecast the electromagnetic environment. Consequently, the precision of the field intensity measure is especially important. The error is relate to equipment, technique and condition of the measurement. At present, most field intensity measuring system use cable as data transmission channel. It may influence the accuracy of measurement when electromagnetic environment is bad. A digital field intensity measurement system using fiber as date transmission channel is introduced in this paper. This testing method accomplishes automatic tune and signal detection by the microcontroller.At first, the paper describes the whole design scheme of the field intensity measurement system based on optical-electrical conversion and clarifies the operating principle of each part.Then, after reading the date of many chips, the hardware design of the system is proposed. It includes the frequency modulation circuit for receiving signals, the demodulation circuit for detecting signals, and the FOTS (fibre-optic transmission system) for transmiting date. The flowchart of software design based on the intelligent measurement is showed. And the interface circuit and the communication procedure to the upper computer is also presented in the paper.At last, hardware debugging results of the whole system are displayed. Some questions existed in the software design and hardware debugging are analyzed.