JP2005159797A - Quartz oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of the structure of the constant temperature bath of a constant temperature bath type quartz oscillator, of which the heat is sensed with a temperature sensor in the constant temperature bath and the current of a heater is controlled according to its change for temperature control, however, the change of the external temperature is not transferred quickly while much heat is released from a support. <P>SOLUTION: The support is improved for less release of heat. A quartz oscillator is realized whose structure takes releasing of heat from the support into account for temperature control. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to temperature control of a thermostatic crystal oscillator.

  A crystal oscillator using a crystal resonator and combined with an oscillation circuit is widely used as a signal source and a clock source for electronic devices and communication devices. In order to obtain a higher stable frequency, the temperature is stabilized at a high temperature in a thermostatic chamber together with a crystal resonator or an oscillation circuit.

  Furthermore, stabilization of the frequency is required.

Japanese Patent Application No. 2001-196859 Japanese Patent Laid-Open No. 7-50523

  The problem to be solved by the present invention is that the crystal resonator and the oscillation circuit are housed in a thermostatic bath, but this thermostatic bath is usually fixed to the base with 3 to 4 screws, and the screws are made of metal. Heat escapes from this, affecting the temperature change of the thermostatic chamber. Therefore, in order to increase the accuracy of the thermostatic chamber, the thermostatic chamber must be enlarged in order to use thermal insulation for thermal stabilization. FIG. 4 shows a structure of a conventional thermostatic oven type oscillator, which includes a substrate 10 on which a thermostatic chamber is mounted on a base 1, and the thermostatic chamber 2 is mounted on a plurality of support bases. ing. The support base is often made of screws or metal. The heat of the thermostatic chamber is conducted from the plurality of support bases, and the change in the heat in the thermostatic chamber becomes large, making it difficult to control the heat. If the thermal control is repeated many times, the frequency changes and the characteristics are impaired. In FIG. 4, the heat insulating material and the outer case are omitted.

Patent Document 1 states that “the printed circuit board is fixed with screws and spacers made of a highly heat-insulating material”, and an example in which a material with high heat insulating properties is used for the spacer is shown. Further, Patent Document 2 states that “the inside is an airtight structure” and “a thin heat insulating material can be used to adjust the equivalent heat transfer resistance of the casing”, but it shows an airtight structure for heat insulation.

  The main feature of the present invention is that, in a crystal oscillator using a thermostatic chamber, the temperature sensor is provided in the support tool at one place between the thermostat bath and the base supporting the thermostatic bath. And

In the present invention, since the supporting portion for supporting the thermostatic chamber is one, the heat escape is reduced, the heat transfer from the outside is reduced, and the thermostatic bath can be kept at a stable temperature, so that the stable frequency is maintained. Is obtained. In addition, by attaching a temperature sensor to the support and sensing the temperature change, it is possible to predict a future temperature change from the temperature difference from the outside and control the temperature of the thermostatic bath, so that a more stable frequency can be obtained. There are advantages.
The temperature sensor detects the heat leaking outside, and does not feel temperature change in a stable state, but when the outside air temperature falls, the balance with the heat leaking from the thermostatic chamber is lost, so the temperature of the support tool By monitoring this state, it is possible to predict the temperature drop of the thermostatic bath. Furthermore, in order to balance the heat, a heat source such as a heater is installed on the support to make it difficult for heat from the thermostatic chamber to be released.
Since the present invention has only one support tool and the influence of heat from the outside is controlled only by the support tool, the temperature can be monitored and used for temperature control of the thermostatic layer.

  In consideration of the balance of heat transmitted to the support according to the present invention, it is possible to predict the temperature in the thermostat in the future, and thus it is possible to provide a thermostatic crystal oscillator having a more stable frequency than the conventional one.

FIG. 1 is a front view of a crystal oscillator illustrating the present invention. On the base 1, there are a crystal resonator and an oscillation circuit placed in a thermostat 2, and supported by a support 3. The thermostatic chamber 2 is usually composed of an object to be heated (a crystal oscillator or an oscillation circuit) and a sensor, and the periphery thereof is wound with a heater wire 5. A heat insulating material is wound around the thermostatic chamber 2 to prevent escape of heat. In this figure, the heat insulating material is omitted. The support 3 is made of a material that is difficult to transmit heat. Conventionally, 2 to 4 metal screws are used to support the thermostat and are supported on the base 1 or the like, but in the present invention, the thermostat is supported by one support. Recently, examples have been proposed in which screws and supports such as polycarbonate, which are more difficult to transmit heat, are used, but the more support points, the more the heat escape does not stop.
Although not shown in FIG. 1, the thermostat 2 is covered with a heat insulating material and covered with a case.
The transistor in FIG. 1 is a temperature control transistor and is also used as a heat source.

  The support 3 is preferably made of a material with less heat conduction, and the smaller the contact area, the better. Although the heat escaped to the outside air around the thermostatic chamber is not shown, it is covered with a heat insulating material so as not to escape. And since there is only one place from the support, heat can escape only from there.

  As another example, a temperature sensor is attached to the support. The temperature sensor senses the heat transmitted from the thermostat and knows the state where the heat escapes through the support. Thereby, the heat leaking to the support can be found by the temperature sensor in the thermostat and the temperature sensor of the support, and can be used for temperature control of the thermostat thereafter. In particular, information from the temperature sensor of the support can be used to predict the heat state in the thermostat.

  FIG. 2 is a partial view showing an example in which a temperature sensor is attached to a support tool showing the embodiment. The support 5 is on the base 1 and supports the thermostatic chamber 2. By attaching the temperature sensor 6 to the support 3, the leaking heat is sensed and transmitted to the control circuit.

As another embodiment, a temperature sensor and a heating element are attached to the support.
As an application of Example 2, by preparing the support 5 heat source for the heat leaking from the thermostatic chamber, it is possible to keep the temperature of the thermostatic bath 2 constant by making a state where heat is not leaked. become.

FIG. 3 is a partial view showing the embodiment, and the thermostatic chamber 2 and the base 1 are supported by a support 5, and an example in which a heater 7 is attached to the support 5 as a heat source together with a temperature sensor 6 is shown. ing. By installing a heater, the outside air temperature decreases and the amount of heat leaking from the thermostat increases, reducing the temperature of the thermostat, but the heat source of the support is used to compensate for the leaked heat, and heat control in the thermostat is reduced. I can do it.
The heat source is not limited to a heater, and may be a transistor, a posistor, or a resistor.
The thermostatic chamber refers to a unit in which a thermal cylinder, a heat insulating material, and a case are integrated. In the present invention, a thermal cylinder into which a crystal resonator is placed is expressed as a thermostatic chamber. In the drawing of the present invention, the heat insulating material wound around the thermostat is omitted.

  The present invention can be used for a highly stable thermostatic crystal oscillator and can be applied to other uses where the temperature needs to be kept constant by the thermostatic chamber.

FIG. 1 is a front view showing an embodiment of the present invention. FIG. 2 is a partial view showing an example in which a temperature sensor is attached to a support. FIG. 3 is a partial view showing an example in which a temperature sensor and a heat source are attached to a support. FIG. 4 is a front view showing the structure of a conventional thermostatic oven crystal oscillator.

Explanation of symbols

1 base 2 thermostatic chamber 3 support 4 heater 6 sensor 7 heat source

Claims (2)

In a crystal oscillator using a thermostatic chamber,
A crystal oscillator comprising a thermostat and a base supporting the thermostat at one place, and a temperature sensor is provided on the support. The crystal oscillator according to claim 1, wherein the temperature sensor and a heat source are provided on the support.

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