Patent ID: 6897743

Claim:
An electronic apparatus comprising: a display portion; and first and second quartz crystal oscillators comprised of first and second quartz crystal oscillating circuits each having a quartz crystal resonator, an amplifier, a plurality of resistors, and a plurality of capacitors, a mode of vibration of the quartz crystal resonator of the first quartz crystal oscillating circuit being different from that of the quartz crystal resonator of the second quartz crystal oscillating circuit; wherein the quartz crystal resonator of one of the first and second quartz crystal oscillating circuits comprises a quartz crystal tuning fork resonator capable of vibrating in a flexural mode of an inverse phase and having a fundamental mode of vibration and a second overtone mode of vibration, the quartz crystal tuning fork resonator being electrically connected to an amplification circuit having an amplifier and a feedback resistor and to a plurality of capacitors and a drain resistor of a feedback circuit having the quartz crystal tuning fork resonator, and the quartz crystal tuning fork resonator having a quartz crystal tuning fork base, a plurality of quartz crystal tuning fork tines connected to the quartz crystal tuning fork base, and a groove having stepped portions formed in at least one of opposite main surfaces of each of the quartz crystal tuning fork tines; wherein a merit value M 1 of the fundamental mode of vibration of the quartz crystal tuning fork resonator is greater than a merit value M 2 of the second overtone mode of vibration thereof so the second overtone mode of vibration thereof is suppressed and a high frequency stability for the fundamental mode vibration thereof is obtained, the merit values M 1 and M 2 being defined by the ratios Q 1 /r 1 and Q 2 /r 2 , respectively, where Q 1 and Q 2 represent a quality factor of the fundamental mode of vibration and the second overtone mode of vibration, respectively, of the quartz crystal tuning fork resonator and r 1 and r 2 represent a capacitance ratio of the fundamental mode of vibration and the second overtone mode of vibration, respectively, of the quartz crystal tuning fork resonator; wherein a ratio of an absolute value of negative resistance −RL 1 of the fundamental mode of vibration of the amplification circuit and a series resistance R 1 of the fundamental mode of vibration is greater than that of an absolute value of negative resistance −RL 2 of the second overtone mode of vibration of the amplification circuit and a series resistance R 2 of the second overtone mode of vibration; and wherein an output signal of the quartz crystal oscillating circuit comprising the quartz crystal tuning fork resonator is a clock signal for operation of the electronic apparatus to display time information at the display portion, the clock signal having an oscillation frequency of the fundamental mode of vibration of the quartz crystal tuning fork resonator.