Low cost DTCXO structure based on modern microcontroller

The basic requirements for crystal oscillators used as sources of reference oscillations can be formulated as: high frequency stability; low level of noises; small overall dimensions; small power consumption; short setting time; and low cost. When the overall dimensions and consumed power is the determinative factor (for example, in mobile equipment) thermocompensated crystal oscillator with analogue thermal compensation (TCXO) are widely used. The thermal frequency stability can be improved by using of digital methods of thermal compensation. Besides, oscillators with digital thermal compensation (DTCXO) are much more simple in tuning. The situation of high price and high overall dimensions has changed, when the small-sized microcontrollers, having in their structure the majority of units, indispensable for implementation of a digital part of DTCXO, have appeared at yhemarket. The creation of DTCXO with temperature stability up to 0,1 ppm on basis of the standard microcontroller is possible. With allowance that controller cost does not exceed several dollars, solution offered in this article can be considered very perspective