Modulation type dual-mode oscillator intended for micro-chip realization

Dual-mode oscillator is an oscillator based on simultaneous excitation of resonator modes. SC-cut resonators with B- and C- modes excitation are used as dual-mode most often. Each resonator mode has its own frequency vs. temperature dependence. When a resonator is being excited on two modes simultaneously, the mode frequency ratio is uniquely determined by temperature. This unique relation allows one to use C- and B- mode frequency ratio as a resonator proper thermosensor. This thermosensor has full spatial coincidence with a vibrated resonator plate and, therefore, it is an ideal resonator temperature measuring device. Due to quartz nature such sensor is very precise and stable. From the above reasoning dual-mode resonator is an ideal base for thermocompensated (TCXO) and ovenized (OCXO) oscillators, in the cases when we need to measure the quartz plate proper temperature with maximum accuracy. The concepts of dual-mode oscillators design have been discussed in this work. Considerable attention has been given to the constant B-mode excitation level keeping under external factors effects and resonator motional resistance variation. The micro-chip realizable dual-mode oscillator circuit is given. To demonstrate the validity of ideas the interim prototype of micro-chip dual-mode oscillator have been investigated. The main result of this work is that we show that dual-mode oscillators could be realized as a small-size micro device.