硅谐振式压力微传感器闭环系统

硅谐振压力微传感器在自激振荡回路中采取电阻热激励、电阻拾振时得到的信号,由于有用信号本身的量级小,因而含有严重的同频干扰信号(耦合激励信号),信噪比SNR (Signal Noise Ratio)仅为10^-3数量级.为了提高信噪比,滤除同频干扰,多级放大之后的处理中将锁相环PLL(Phase-Locked Loop)工作原理和分频技术相结合,由锁相环输出作为传感器的激励和鉴相相关信号,搭建硅谐振压力微传感器闭环自激振荡回路.结果表明:采用锁相分频技术的微传感器闭环系统能可靠运行,信噪比低的问题得到了很好解决.

Closed-loop system of silicon resonant pressure micro-sensor

When the silicon resonant pressure micro-sensor works in the self-oscillation close-loop system with thermal-excited and resistor detected, its output has a problem of dreadfully weak signal of micro-sensor. SNR( signal noise ratio) is as low as 10~ -3 , for the system used frequency-equaled signal to excite micro-sensor to get its syntony, as well caused the damaging coupling disturbance. PLL(phase-locked loop) principle and frequency-divided technique were used to design the double closed-loop control circuit of micro-sensor to avoid those. Micro-sensor worked in the outside loop and PLL made the inside loop. The frequency output of micro-sensor had frequency-equaled exciting signal and duple frequency true signal, after multilevel power amplification multiplied duple frequency output of PLL to achieve frequency dividing, adjusting the system state parameters made closed-loop available and phase locking. Results show that the closed-loop system of micro-sensor works effectively based PLL principle and frequency-divided technique and the low SNR gets developed.