The phase-locked loop circuit consisting of MM74HC4046M CMOS chip and the loop-coil detector form the LC vibration circuit,that converts the LC vibration wave into square waves for microprocessor processing.

• 由MM74HC4046M构成的锁相环电路与环形检测线圈一起构成LC震荡电路,并将LC震荡波形转换为单片机可使用的方波;