Thermally compensated crystal oscillators

The paper describes a new approach to the problem of ¿frequency-versus-temperature¿ stability. The principle involved is particularly suitable for the special requirements of mobile and portable communications equipment. In contrast to oven-controlled crystal oscifiators the technique requires neither the expenditure of power nor the use of thermostats in any form. Frequency stability is achieved by a temperature-sensitive phase-shifting network incorporated in the oscillator circuit. A stability approaching 1 part in 106 is obtained over a wide temperature range.