Design And Study Of Detecting Circuit Based On Film Bulk Acoustic Sensor

With the development of electronic science and technology, the sensor is the most effective for a variety of information access in-depth research, information gathering, processing tools. With the development of radio frequency wireless communication technology and semiconductor integrated circuit manufacturing, the sensor forward miniaturized, intelligent, integrated transition. Film bulk acoustic wave (FBAR) micro-mass sensor shown impressive application prospects, because that its unique advantages, the semiconductor integrated circuit technology compatible with the characteristics shown impressive application prospects. FBAR micro-quality sensors in environmental monitoring, biomedical and other fields have achieved good results, and has a huge market value.FBAR micro quality sensor detects the main pathway is used obtained by measuring its phase amplitude or frequency changes. This thesis focuses on the need of the FBAR micro-mass sensor design, the method of measuring frequency to be measured detection. The paper briefly describes the working principle of the FBAR devices, and the principles of the sensor signal processing circuit is made on this basis.In order be able to detect the the FBAR micro-mass sensor is designed with the external environment change, FBAR the voltage-controlled oscillation circuit. Through the principle of the equivalent model of the analysis combined with the basic principle of the voltage controlled oscillation FBAR using capacitive feedback oscillation, its oscillation frequency to a stable output. And harmonic oscillation output signal simulation, time-domain simulation, simulation results show that the design of the oscillator to a stable output signal. In order to reduce the interference of the external environment, the use of the structure of a duplexer, a FBAR micro-mass sensor is collected as a signal output, a the FBAR micro mass sensor as a reference source, and the oscillation signal of the two channels is fed to the mixer to obtain the difference frequency signal, difference frequency signal can reflect the change in resonant frequency of the external environmental factors on the sensor. To fed the back-end FPGA-based digital circuit design, it should design shaping circuit. In digital circuits, the first combination subject to analysis of the method of measurement and comparison of several frequencies used. and paves the theoretical basis for the design of the digital circuit. Using the top-down design philosophy, the frequency measurement circuit is divided into a number of functional modules using Verilog HDL language to write the corresponding code for each sub-circuit, and use of EDA tools Quartus9.0design and simulation of the various sub-modules completed the design and implementation of the circuit, to achieve the expected accuracy envisaged. Integrated analog circuits and digital circuitsexcellent complete the design at the beginning of the performance indicators.This paper belongs to the part of the FBAR. The Micro-quality sensor research laid the foundation for future the FBAR micro mass sensor system is further developed.