Self tuning resonant circuit using a microprocessor based system

Three novel techniques for matching the frequency of the driver (voltage controlled oscillator) and the resonant frequency of the detection system were investigated. All three methods rely on automatic adjustment procedures implemented via a microcontroller chip that requires no external memory and minimal peripheral devices. The three self-tuning techniques are: automatic tuning with an analog multiplexer, automatic tuning with a digital-to-analog convertor, and automatic tuning with a variable capacitor in the voltage controlled oscillator circuit. Each of the three methods was implemented and tested individually