Study On Embedded Demodulation System For FBG Sensors

The study on FBG (Fiber Bragg Grating) promotes the development of FBG sensors. Nowadays more and more FBG sensors are widely used in many fields such as structure monitoring, intelligent materials, electric power industry, medicine and chemical engineering, etc.The most important study on practical application is to detect small shifts in Bragg wavelength of FBG sensors. In the past, one choose is to use some optical instruments for detecting, but the high cost and large physics size is their shortcoming, and the other problem is that they can not be obtained directly electric signals which correspond to the change of Bragg wavelength, so they are not suit project application, such as real-time monitor, auto control, etc. Some other problems include the limit of demodulation speed and precision, the lack of various interface type and internet function, the key problem is that after demodulation the process and analysis of signals must use computer and demodulation software. According to all above, it is needed to study and design a FBG demodulation system which is portable and also can provide more interface types, high speed and precision demodulation, etc. So presents an embedded demodulation system for FBG sensors.In this paper, simply introduces FBG and its sensing principle, practical applications of FBG sensors, and FBG demodulation methods, such as grating matching method, non-balance Mach-Zehnder interferometer method, and gives more emphases in tunable Fabry-Perot cavity method, etc. Furthermore, this paper also introduces some knowledge of embedded technology, including definitions of embedded system, the embedded system structure, and the embedded system design flow, etc.This embedded FGB demodulation system based on Samsung's S3C44B0X 16/32-bit RISC microprocessor. Using a ARM7TDMI core, it is designed to provide a cost-effective and high performance solution for hand-held devices and general application. In the system, using the keyboard as its input and the LCD as its output, it also provides general serial ports, USB and Ethernet port, flash memory and SDRAM, etc. Design and implement software of this embedded FBG demodulation system includes porting embedded operation system, Human-Machine interface, and serial, USB, Ethernet communication program, etc.