Abstract: A piezoelectric oscillator operating in the aperiodic or overtone mode comprising a first piezoelectric resonator having a resonance frequency at which the oscillator is to operate. One side of the first resonator is connected to ground, and the other side is connected through a second piezoelectric resonator to the base of a transistor. The second resonator has in common with the first resonator a mode at the resonance frequency, but its intrinsic quality factor is between 30 and 1000 times smaller than that of the first resonator. A capacitive divider bridge having a middle point is connected between the base of the transistor and ground. A third piezoelectric resonator having in common with said first resonator a mode at said resonance frequency, but whose intrinsic quality factor is of the same order of size as that of the second resonator, is connected between said middle point and the emitter of said transistor.

Abstract: A device having the function of compensating for the acceleration sensitivity of an oscillator of given nominal frequency comprises an acceleration-sensing element such as a filter which is capable of producing a signal having a nominal frequency equal to that of the oscillator to be compensated but, in respect of its nominal frequency, has higher sensitivity to acceleration than the oscillator to be compensated. The phase difference between the frequency of the oscillator and the frequency produced by the filter is compared in a mixer in order to extract the phase modulation induced by the acceleration. A follow-up control amplifier receives the output signal of the phase comparator and produces at its output a signal for correcting the oscillator.

Abstract: A piezoelectric oscillator of the Clapp type for operation in the overtone mode comprises a piezoelectric resonator having a C-mode resonance frequency at which the oscillator is designed to operate, the resonator being connected between the base of a transistor and ground. A capacitive voltage-dividing bridge is also connected between the base of the transistor and ground, the so-called midpoint of the bridge being connected to the emitter of the transistor. A quartz crystal and an inductance coil decoupled by a capacitor are placed between the emitter of the transistor and ground. The inductance coil and the capacitor form a high-pass filter for attenuating frequencies below the resonance frequency. The piezoelectric resonator is tuned to the mode B which is adjacent to the mode C in order to eliminate the unwanted mode B.