A New Type of Standard Frequency Piezo-Electric Oscillator

In this paper is described a system for producing alternating current of audible frequency of a very high degree of precision. The chief novelty in the system consists in the manner in which the energy necessary to sustain the oscillations of the quartz bar is returned to it. This "feed-back" is accomplished acoustically and the extremely loose coupling thereby secured insures that the generated frequency is practically uninfluenced by inertia effects of electrodes or variations in tube constants. There is also described the installation of the auxiliary apparatus to permit the continuous operation of the oscillator over very long periods of time and to measure the generated frequency with the highest possible precision.