LOCKPROOF LOW LEVEL OSCILLATOR USING DIGITAL COMPONENTS

摘要

LOCKPROOF LOW LEVEL OSCILLATOR USING DIGITAL COMPONENTS Three series connected inverters (38, 40, 42) are attached to a tank circuit (18) which includes an inductance (12, 14) and a capacitance (16, 17). Negative feedback from the third inverter (42) to the first inverter (38) biases the inverters at the midpoint between the bistable low and high logic level states. Positive feedback from the second inverter (90) to the tank circuit induces oscillation in the tank circuit. The negative feedback is decoupled at the resonant frequency and the energy delivered to the tank circuit from the positive feedback maintains a low level oscillation in the tank circuit. Negative feedback around the three inverter digital circuit prevents lockup in the event of power loss or momentary short.