JPS6424607A - Crystal oscillator - Google Patents

Abstract

PURPOSE:To prevent the production of noise due to shock by arranging a positioning elastic body between a crystal resonator and a constant temperature oven in a crystal oscillator containing the crystal resonator in the constant temperature oven and arrang ing the crystal resonator in a floating state in the constant temperature oven so as to adopt elastic coupling structure for the crystal resonator and the constant tempera ture oven and to cause stray capacitance between the both. CONSTITUTION:A capacitance C3 is formed between a metallic cover 9 of the crystal resonator 1 and the constant temperature oven 2. That is, one terminal of capacitors C1, C2 between the metallic cover 9 and an exciting electrode 11 is connected to both ends of the crystal resonator 1 and the other terminals are connected in common to a terminal of a capacitor C3 as shown in an equivalent circuit. The other terminal of the capacitor C3 has an AC ground potential through a hot-wire 14 wound on a metallic cylinder 13. The combined capacitance C is expressed as (C1+C2).C3/(C1+C2+ C3). Then the capacitance C3 is smaller than the capacitances C1 and C2 and is nearly constant against external shock. Thus, the capacitance C3 is dominant in the reactance Xc of the combined capacitance C and the effect of the change in the capacitances C1, C2 is reduced.