An oscillator includes a first resonator element, a circuit element configured to oscillate the first resonator element to generate an oscillation signal, a first package which includes a substrate, and has a housing space configured to house the first resonator element and the circuit element at one principal surface side of the substrate, a second resonator element which is disposed at another principal surface side of the substrate, and an oscillation frequency of which is controlled based on the oscillation signal, and a leg part which is disposed at the another principal surface side of the substrate, and which is arranged so as to surround the second resonator element in a plan view of the substrate.

A crystal oscillator device is disclosed. The crystal oscillator device includes a casing; a crystal piece; a pair of excitation electrodes; a transmission antenna electrically coupled to one of the excitation electrodes; a reception antenna configured to receive a radio wave from the transmission antenna; and an alarm generator configured to generate an alarm based on a signal whose amplitude is equal to or less than a reference value, the signal being received by the reception antenna.

A crystal oscillator device is disclosed. The crystal oscillator device includes a crystal piece provided in a casing; a pair of excitation electrodes provided for the crystal piece; a coil provided on the crystal piece; a magnetic flux generating member configured to generate magnetic flux passing through the coil; and an alarm generator configured to generate an alarm based on a signal whose amplitude is equal to or less than a reference value, the signal being generated in the coil.

A crystal oscillator includes a crystal resonator; an inverting amplifier configured to be coupled between a pair of excitation electrodes of the crystal resonator; and a control circuit configured to initiate an alarm and raise gain of the inverting amplifier in a case where an index value for representing oscillation amplitude of the crystal resonator in an oscillation state is equal to or lower than a reference value.

There is configured an oscillator characterized by including an outer package having a housing space, an inner package housed in the housing space, a resonator element housed in the inner package, a heater element housed in the housing space, and fixed to the inner package, an oscillation circuit configured to oscillate the resonator element, a conducting member configured to electrically couple the inner package and the heater element to each other, and a first bonding wire configured to couple the heater element and the outer package to each other, and configured to electrically couple the conducting member and the outer package to each other.

A circuit device includes a phase comparator that performs phase comparison between an input signal based on an oscillation signal and a reference signal, a processor that performs a digital signal process on phase comparison result data which is a result of the phase comparison so as to generate frequency control data, and an oscillation signal generation circuit that generates the oscillation signal having an oscillation frequency which is set on the basis of the frequency control data. The processor performs the digital signal process by using data used when a hold-over state is ended in a case where the hold-over state occurs due to the absence or the abnormality of the reference signal, and then the hold-over state is ended.

A vibration element includes a crystal blank, a pair of excitation electrodes, and pair of extraction electrodes. The crystal blank is an AT cut crystal blank including a mesa part and an outer circumferential part which is thinner than the mesa part and surrounds the mesa part. The pair of excitation electrodes is provided on the two major surfaces of the mesa part. The pair of extraction electrodes include pad parts which are provided at the end parts of the crystal blank in the longitudinal direction on one major surface of the outer circumferential part and are connected to the pair of excitation electrodes. The length in the longitudinal direction of the crystal blank is less than 1000 μm. When the resonance frequency is F (MHz) and t=1670/F, the distance “y” (μm) between each of the pad parts and the mesa part satisfies 0.048F+1.18<y/t<0.097F+0.36.

An oven controlled crystal oscillator includes a crystal oscillator, a temperature control circuit, and a control integrated circuit. The crystal oscillator includes a crystal resonator and an oscillator circuit. The temperature control circuit includes a heater resistor, a thermistor, a first resistor, a second resistor, a third resistor, a differential amplifier, a thermosensor, and a fourth resistor. The thermosensor is disposed in parallel to the first resistor. The thermosensor has one end to which the supply voltage is supplied. The fourth resistor has one end connected to another end of the thermosensor and another end that is grounded. The control integrated circuit includes a digital variable resistor and a controller. The digital variable resistor is connected to the thermosensor in parallel. The controller adjusts a resistance value of the digital variable resistor based on a digital control signal input from outside.

A resonator element includes an SC-cut quartz crystal substrate having a thickness t, and an excitation electrode disposed on a principal surface of the quartz crystal substrate, the principal surface being square or rectangular in shape, a side of which has a length L, 28≦L/t≦60 is satisfied.

A clock oscillator includes a first resonator, a second resonator, and a frequency synthesis module, where an output frequency of the first resonator is higher than an output frequency of the second resonator, the frequency synthesis module is configured to generate a synthesis frequency based on the output frequency of the first resonator and the output frequency of the second resonator, and the synthesis frequency is used as a clock frequency output by the clock oscillator. The clock oscillator uses both of the two resonators with the different output frequencies as clock signal sources, and generates a synthesized clock signal by using the frequency synthesis module.