【摘要】 设计了基于FPGA的谐振式微悬臂梁传感器接口电路,将接口电路与谐振式微悬臂梁传感器组成闭环自激振荡系统。为满足接口电路智能化与输出频率稳定性的要求,设计了带有自动扫频功能的锁相环,以此锁相环为核心并结合外围放大、滤波、移相、整形电路构成的接口电路系统,能够自动扫频寻找谐振点并锁定,扫频精度为0.012 Hz左右,谐振频率的波动范围可达0.01 Hz左右,且锁定范围极广。分别测试了谐振点在100 kHz与500 kHz附近的两组传感器,该系统均能很好地自动扫频寻找谐振点并锁定。更多还原

【Abstract】 An FPGA-based interface circuit for resonant micro-cantilever sensors was designed.The resonant micro-cantilever sensor and the interface circuit were combined together to form a close-looped self-exciting resonance system.To meet the requirements of both intelligence and good frequency stability of the system,a phase-locked loop(PLL) with automatic frequency scanning function was employed.The interface circuit,which is composed of PLL,amplifiers,filters,phase shifter and waveform shapers,can scanning search the resonant frequency automatically and lock it rapidly.The frequency scanning precision of the system is 0.012 Hz.The fluctuation range of the resonant frequency is measured as about 0.01 Hz,while a very wide locking range is available.Two groups of sensors with different resonant frequencies of 100 kHz and 500 kHz,respectively,were tested.The testing results indicate that the system can automatically search the resonant frequency and lock it precisely,rapidly and reliably.更多还原