Patent application number | Description | Published |
20090212878 | Oven-controlled crystal oscillator - An oven-controlled crystal oscillator includes a circuit board, a crystal unit surface-mounted on the circuit board, and a temperature control circuit that maintains operating temperature of the crystal unit constant. The temperature control circuit includes a heating resistor, a power transistor that supplies power to a heating resistor, and a temperature sensitive resistor that detects temperature of the crystal unit. The heating resistor is formed, as a film resistor, on a surface of the circuit board in an area thereof in which the crystal unit is located. The temperature sensitive resistor is provided on the circuit board as a film resistor. | 08-27-2009 |
20100033258 | Secondary vibration damping type crystal oscillator circuit - A secondary vibration damping type crystal oscillator circuit is formed as a Colpitts type, in which a crystal unit is connected between base and collector terminals, a first capacitor is connected between emitter and collector terminals, and a second capacitor is connected between emitter and base terminals of a oscillating transistor. A region between the emitter and collector terminals or between the emitter and base terminals includes a reactance parallel circuit, in which an LC series circuit is connected in parallel to the first or second capacitor. The reactance parallel circuit has resonant characteristics that the reactance parallel circuit is made capacitive at an oscillating frequency in principal vibration mode of the crystal unit as an oscillating frequency, and a resonant frequency of the LC series circuit corresponds to the vibrational frequency in secondary vibration mode that is close to the principal vibration mode. | 02-11-2010 |
20100102892 | CRYSTAL OSCILLATOR - A crystal oscillator includes a crystal unit and a voltage-variable capacitive element that is connected to the crystal unit in series, the crystal oscillator varying an oscillation frequency by applying a control voltage between terminals of the voltage-variable capacitive element and by varying a series equivalence capacitance at a side of the oscillator circuit when observed between terminals of the crystal unit. The crystal oscillator further includes a first resistor and a second resistor for dividing the control voltage. At least one of the first resistor and the second resistor is a temperature sensing resistor, the resistance of which changes depending on a temperature, so as to correct frequency temperature characteristics of the oscillation frequency. | 04-29-2010 |
20100231309 | CONSTANT-TEMPERATURE TYPE CRYSTAL OSCILLATOR - A constant-temperature type crystal oscillator includes: a surface-mount crystal unit, in which a crystal element is housed in a case main body to hermetically encapsulate the crystal element with a metal cover, and which includes a crystal terminal serving as a mounting terminal that is electrically connected to at least the crystal element on an outer bottom face of the case main body; a thermistor that detects an operational temperature of the surface-mount crystal unit; and a circuit substrate, on which elements forming an oscillator circuit and elements forming a temperature control circuit along with the thermistor are installed. The thermistor includes a first and second terminal electrode and a temperature detecting electrode that is electrically independent of the first and second terminal electrode. The temperature detecting electrode is electrically connected to the crystal terminal of the surface-mount crystal unit through a circuit pattern formed on the circuit substrate. | 09-16-2010 |
20120292300 | TEMPERATURE CONTROL CIRCUIT OF OVEN CONTROLLED CRYSTAL OSCILLATOR - A temperature control circuit of an oven controlled crystal oscillator (OCXO) is provided. A first and a second digital potentiometer are correspondingly arranged in a bridge circuit which outputs a voltage to an input terminal of a differential amplifier (OPAMP), wherein the resistance value of the first digital potentiometer is adjustable so as to adjust the temperature of the oven to the peak temperature of the crystal resonator, and the resistance value of the second digital potentiometer is adjustable so as to cancel the temperature gradient of the first digital potentiometer. In the temperature control circuit of OCXO, the heat generation of the heater resistor is controlled by the power transistor based on the control voltage from the differential amplifier. | 11-22-2012 |
20130008883 | TEMPERATURE CONTROL CIRCUIT OF OVEN-CONTROLLED CRYSTAL OSCILLATOR - A temperature control circuit of oven-controlled crystal oscillator includes a heater resistor, a first resistor, a thermistor, a second resistor, a third resistor, a differential amplifier, a PNP-type power transistor, and a PNP-type current-limiting transistor. The thermistor outputs a voltage depending on a temperature. The differential amplifier amplifies a difference between the voltage received by the one input terminal and the voltage received by the other and output as a control voltage. The PNP-type power transistor includes an emitter where the other end of the heater resistor is connected, a base that receives an output of the differential amplifier, and a grounded collector. The PNP-type current-limiting transistor has an emitter where a power voltage is supplied, a base that receives a voltage between the other end of the heater resistor and the emitter of the power transistor, and a collector connected to the base of the power transistor. | 01-10-2013 |
20130249641 | OSCILLATOR CIRCUIT - The oscillator circuit | 09-26-2013 |
20150084705 | TEMPERATURE CONTROL CIRCUIT AND OVEN CONTROLLED CRYSTAL OSCILLATOR - A temperature control circuit of an oven controlled crystal oscillator is a circuit in which a supply voltage is applied to a first terminal of a resistance R | 03-26-2015 |