SU43933A1 - Quartz oscillator - Google Patents

Description

In order to simplify and reduce the cost of radio stations operating in the shortwave, and especially in the ultrashortwave range, it is advisable to have stable oscillations of the shortest possible wave in the master oscillator, while maintaining sufficient useful power. When quartz stabilization is technically impossible to use plates thinner than 0.5 mm due to their mechanical fragility. Therefore, in order to obtain stable oscillations in the master oscillator of a shorter wave, it is advisable to excite quartz in the harmonics of the fundamental oscillation of quartz in thickness. However, there are also great difficulties on this path, which consists in the fact that quartz plates, when excited in thickness harmonics in ordinary oscillation circuits, are not very active. One of the main causes of this phenomenon is the ever-increasing (with the acceleration of the wave) the adverse effect of the static capacity of quartz, as well as the tanks, adventured parallel to the quartz.

In the proposed quartz oscillator, it is possible (as experience has shown) to easily obtain stable oscillations of considerable power at waves below 50 m. To do this, a circuit is automatically inserted into the self-excited circuit of the lamp generator.

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From a quartz plate and a self-induction coil connected in parallel or in series, the natural frequency of this circuit, formed by the static capacity of quartz and by induction itself, is close to the natural frequency (or harmonic) of oscillations of the quartz plate.

In oscillator circuits, the contour formed from quartz connected in parallel or in series and self-induction plays a double role.

1. Since the self-induction together with the static capacity of quartz is tuned to a frequency close to the natural frequency (or harmonic) of the quartz plate, then the detrimental static capacity of the quartz is compensated.

2. The contour formed by the static capacity of quartz, together with self-induction, is an irregular (in terms of self-excitation) impedance at the natural frequency (or harmonic) of the quartz plate. As a result, self-excitation at the natural frequency (or harmonic) of quartz in addition to quartz is impossible.

When the piezoelectric conductivity of quartz appears, self-excitation conditions at the quartz frequency are satisfied. Thus, a purely oscillation mode of the circuit is performed.