JP2015065511A - Crystal oscillator with constant temperature bath - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal oscillator with a constant temperature bath, in which the output frequency signal can be stabilized furthermore while reducing variation due to individual difference of the components.SOLUTION: In a crystal oscillator with a constant temperature bath, a gain calculation section 7 inputs an instruction voltage from a temperature control circuit 5 to an electrical heating element 6 while branching, and generates a correction voltage for compensating the variation of the output frequency corresponding to the instruction voltage thus inputted, based on the characteristics of output frequency for a preset instruction voltage, and an addition section 8 adds the correction voltage to a frequency adjustment voltage being inputted to a quarts resonator 1. The crystal oscillator with a constant temperature bath adjusts the load of the oscillation circuit so as to compensate the variation of output frequency depending on the outside temperature, by using the instruction voltage as an index of the outside temperature.

Description

  The present invention relates to a crystal oscillator with a thermostat, and more particularly, to a crystal oscillator with a thermostat capable of further stabilizing an output frequency signal and reducing variations due to individual differences in parts.

[Description of Prior Art: FIG. 4]
A crystal oscillator with a thermostatic chamber (OCXO) is a thermostatic chamber that keeps the temperature constant and encloses a crystal resonator, and is not easily affected by external temperature changes. Is output.
A configuration example of a general crystal oscillator with a thermostat will be described with reference to FIG. FIG. 4 is a schematic cross-sectional explanatory diagram showing a configuration example of a general crystal oscillator with a thermostatic bath.

As shown in FIG. 4, the crystal oscillator with a thermostatic chamber has, for example, a crystal resonator 13 stored in the thermostatic chamber 12 and a heating element 14 such as a heater resistor mounted on the lower surface of the substrate 11. 15 and is enclosed by a cover 16.
Further, the substrate 11 is provided with an oscillation circuit, a temperature sensitive element such as a thermistor, and a temperature control circuit.
In FIG. 4, OCXO using the lead type crystal resonator 13 is shown. However, there is a surface mount type.

  In the conventional crystal oscillator with a thermostat, the temperature control circuit controls the current supplied to the heating element 14 based on the temperature in the vicinity of the thermostat detected by the temperature sensing element, so that the temperature inside the thermostat is kept constant. I try to keep it.

[Temperature control in a conventional crystal oscillator with a thermostat: Fig. 5]
Next, temperature control in the conventional crystal oscillator with a thermostat will be described with reference to FIG. FIG. 5 is a configuration block diagram of a conventional crystal oscillator with a thermostatic bath.
As shown in FIG. 5, the conventional crystal oscillator with a thermostatic bath includes a crystal resonator 41, an oscillation circuit 42, a voltage variable capacitance element 43, a temperature sensing element 44, a temperature control circuit 45, and a heating element 46. It has.

The crystal oscillator 41 oscillates a frequency signal based on the input voltage.
The oscillation circuit 42 amplifies the frequency signal from the crystal resonator 41 and outputs it as an oscillation output, and feeds back a voltage for fine adjustment of the frequency to the input side of the crystal resonator via the voltage variable capacitance element 43. .
The voltage variable capacitance element 43 adjusts the oscillation frequency by adjusting the load of the oscillation circuit 42 according to the voltage applied to both ends.

The temperature sensing element 44 is composed of a thermistor or the like having a characteristic that the resistance value changes according to the temperature, and outputs an electric signal according to the temperature. A signal for instructing the temperature (temperature-sensing element instruction temperature signal) is output.
Based on the temperature sensing element command temperature signal from the temperature sensing element 44, the temperature control circuit 45 outputs a heat generation command voltage for controlling the current supplied to the heating element 46 so as to achieve the command temperature, thereby reducing the heat generation amount. Perform the temperature control to be adjusted.
The heating element 46 is composed of a heater resistor or the like, and generates heat according to an input current.

  In other words, a conventional crystal oscillator with a thermostatic chamber stabilizes the oscillation frequency of the crystal resonator by keeping the temperature inside the thermostatic chamber in which the crystal resonator is housed constant. Is not directly controlled according to the temperature to adjust the output frequency.

  For this reason, in the conventional crystal oscillator with a thermostat, the relationship between the thermostat temperature to be controlled and the oscillation frequency greatly depends on the mechanical structure of the crystal oscillator with a thermostat, and individual differences also increase.

[Example of frequency temperature characteristics of conventional crystal oscillator with thermostat: Fig. 6]
An example of the frequency temperature characteristics of a conventional crystal oscillator with a thermostat will be described with reference to FIG. FIG. 6 is a characteristic diagram showing an example of an outside air temperature-frequency characteristic of a conventional crystal oscillator with a thermostatic bath.
FIG. 6 shows the outside air temperature that is the temperature outside the crystal oscillator with constant temperature bath (around the product) and the amount of frequency fluctuation based on 25 ° C.
Although it is desirable that the output frequency be a constant value even when the external temperature varies, as shown in FIG. 6, the output frequency often has a slope with respect to the external temperature.

[Temperature characteristics of thermosensitive element: Fig. 7]
Next, the temperature characteristics of the temperature sensing element in the conventional crystal oscillator with a thermostat will be described with reference to FIG. FIG. 7 is a characteristic diagram showing the temperature characteristics of the thermosensitive element in a conventional crystal oscillator with a thermostatic bath.
As shown in FIG. 7, the characteristic of the temperature sensing element indicating temperature signal with respect to the outside air temperature varies ± 10 ppb (10 × 10 ^ -9) with 25 ° C. as a reference.
This variation contributes to the frequency-temperature characteristics of the temperature controlled crystal oscillator shown in FIG. 6, but when the amount of variation of the temperature sensing element indication temperature signal is converted to voltage, it corresponds to a change of ± 3 mV, which is extremely small. Therefore, it is difficult to detect and control the fluctuation amount.

[Related technologies]
In addition, as a technique regarding the crystal oscillator with a thermostatic bath, JP 2010-213102 A “Piezoelectric Oscillator and Ambient Temperature Measurement Method of This Piezoelectric Oscillator” (Dai Vacuum, Patent Document 1), JP 2011-205166 A “Constant Temperature Type Piezoelectric Oscillator and Method for Producing the Same” (Seiko Epson Corporation, Patent Document 2), Japanese Unexamined Patent Application Publication No. 2011-004382 “Constant Temperature Type Crystal Oscillator” (Nippon Radio Industry Co., Ltd., Patent Document 3), Japanese Unexamined Patent Publication 2011 No. 0797963, “Constant Temperature Crystal Oscillator” (Nippon Radio Industry Co., Ltd., Patent Document 4).

Patent Document 1 describes that, in a crystal oscillator with a thermostatic chamber, the ambient temperature of the oscillator is measured based on heat generation power consumption, and the oscillation frequency is adjusted using a varicap diode.
Patent Document 2 describes a constant temperature piezoelectric oscillator that compensates an oscillation frequency by applying a frequency deviation of frequency temperature characteristics to a voltage variable capacitance element.

Patent Document 3 describes a constant temperature crystal oscillator in which a heat insulating groove is provided between a linear resistor and a lead wire and a heating resistor so that the linear resistor can accurately detect the ambient temperature.
In Patent Document 4, in a constant temperature crystal oscillator, an open portion is formed on the outer peripheral portion of a heat conducting plate mounted on a circuit board at a point-symmetrical position around the crystal resonator, and the open portion is formed on all of the open portions. A configuration is described in which the same number of power transistors and one or more overheat resistors are arranged.

JP 2010-213102 A JP 2011-205166 A JP 2011-004382 A JP 2011-077963 A

  As described above, in the conventional crystal oscillator with a thermostat, the frequency-temperature characteristics greatly depend on the mechanical structure of the crystal oscillator with a thermostat, so there is a large individual difference between the components, and the temperature sensor output is controlled. Since this is difficult, there is a problem that it is difficult to further stabilize the output frequency.

  In Patent Documents 1 to 4, based on the heat generation instruction voltage applied to the heat generator, a correction voltage that compensates for the frequency temperature characteristics of the crystal oscillator with a thermostatic bath is generated and added to the frequency adjustment voltage. It is not described to compensate for frequency fluctuations by adjusting the load.

  The present invention has been made in view of the above circumstances, and can easily adjust the oscillation frequency with a simple process to obtain a more stable output frequency signal. It is an object to provide a crystal oscillator with a thermostatic bath that improves the reliability of the entire product.

  The present invention for solving the problems of the conventional example described above includes a quartz resonator stored in a thermostatic chamber, an oscillation circuit for amplifying and outputting the output of the quartz resonator, a temperature chamber disposed near the thermostatic chamber, A temperature sensing element that outputs a signal according to the temperature, a temperature control circuit that outputs an instruction voltage based on the signal from the temperature sensing element, and a heating element that generates heat according to the instruction voltage from the temperature control circuit It is a crystal oscillator with a tank, and the instruction voltage from the temperature control circuit is branched and inputted, and the fluctuation of the output frequency corresponding to the inputted instruction voltage is calculated based on the characteristic of the output frequency with respect to the preset instruction voltage. A gain calculation unit that generates a correction voltage to be compensated and an addition unit that adds the correction voltage to the frequency adjustment voltage input to the crystal resonator are provided.

  Further, according to the present invention, in the crystal oscillator with a thermostatic bath, the characteristics of the output frequency with respect to the instruction voltage are based on the characteristics of the output frequency with respect to the outside air temperature and the characteristics of the instruction voltage with respect to the outside air temperature. It is characterized by being generated.

  Further, according to the present invention, in the crystal oscillator with a thermostatic bath, the gain calculation unit calculates a difference between a voltage with a frequency fluctuation amount of 0 and an input instruction voltage as a correction voltage in the characteristics of the output frequency with respect to the instruction voltage. Is output as.

  Further, the present invention is characterized in that, in the above-described crystal oscillator with a thermostatic bath, the gain calculation unit is constituted by a digital circuit including an A / D converter, an arithmetic circuit, and a D / A converter.

  Further, the present invention is characterized in that, in the above-described crystal oscillator with a thermostatic bath, the gain calculation unit is configured by an arithmetic element such as an operational amplifier.

  Moreover, the present invention is characterized in that in the above-mentioned crystal oscillator with a thermostatic bath, the oscillation circuit is constituted by a digital circuit.

  The present invention is also characterized in that, in the crystal oscillator with a thermostatic bath, the oscillation circuit is configured by an analog circuit, and includes a voltage variable capacitance element that applies a feedback signal from the oscillation circuit to the input side of the crystal resonator. It is said.

  According to the present invention, the crystal resonator stored in the thermostatic chamber, the oscillation circuit that amplifies and outputs the output of the crystal resonator, and the temperature sensing device that is disposed in the vicinity of the thermostatic chamber and outputs a signal corresponding to the temperature. A temperature controlled crystal oscillator comprising: an element; a temperature control circuit that outputs an instruction voltage based on a signal from the temperature sensing element; and a heating element that generates heat in response to the instruction voltage from the temperature control circuit. Gain calculation that generates a correction voltage that compensates for fluctuations in the output frequency corresponding to the input command voltage based on the characteristics of the output frequency with respect to the command voltage set in advance by branching the command voltage from the control circuit Unit and a temperature-controlled crystal oscillator with an addition unit that adds the correction voltage to the frequency adjustment voltage input to the crystal unit. Voltage to outside temperature Using as an index, the load of the oscillation circuit can be adjusted according to the outside air temperature so as to compensate the fluctuation of the output frequency according to the outside air temperature, the frequency temperature characteristic is further stabilized, and the electronic circuit constituting the circuit Since the characteristics including individual differences of parts are compensated for, there is an effect that variation of products can be reduced.

  Further, according to the present invention, the characteristic of the output frequency with respect to the instruction voltage is generated based on the characteristic of the output frequency with respect to the outside air temperature and the characteristic of the instruction voltage with respect to the outside air temperature in the crystal oscillator with constant temperature bath. Since the above-mentioned crystal oscillator with a thermostatic chamber is used, the outside temperature-frequency characteristics of the crystal oscillator with a thermostatic chamber can be compensated with high accuracy by using an indicator voltage that fluctuates with a moderate slope with respect to the outside temperature as an index of the outside temperature. Thus, there is an effect that the output frequency signal can be further stabilized.

  Further, according to the present invention, the gain calculation unit outputs the difference between the voltage with the frequency fluctuation amount of 0 and the input instruction voltage as a correction voltage in the output frequency characteristic with respect to the instruction voltage. Since the attached crystal oscillator is used, there is an effect that the fluctuation of the output frequency can be accurately compensated by a simple process.

It is a block diagram of the structure of a crystal oscillator with a thermostatic bath according to an embodiment of the present invention. It is a characteristic view which shows an example of an external temperature-heat generation instruction voltage characteristic. It is a characteristic view which shows the heat generation instruction voltage-frequency characteristic. It is a schematic cross-section explanatory drawing which shows the structural example of the general crystal oscillator with a thermostat. It is a block diagram of a conventional crystal oscillator with a thermostat. It is a characteristic view which shows the example of the conventional outside temperature-frequency characteristic. It is a characteristic view which shows the temperature characteristic of the temperature sensing element in the conventional crystal oscillator with a thermostat.

Embodiments of the present invention will be described with reference to the drawings.
[Outline of the embodiment]
The crystal oscillator with a thermostat according to the embodiment of the present invention is preliminarily based on the characteristics of the frequency fluctuation amount of the crystal oscillator with a thermostat with respect to the outside temperature and the characteristics of the heat generation instruction voltage from the temperature control circuit with respect to the outside temperature. Then, the characteristics of the heat generation instruction voltage-frequency fluctuation amount are obtained, the heat generation instruction voltage is branched and input to the gain calculation unit, and the gain calculation unit reduces the frequency fluctuation amount based on the characteristics. The frequency adjustment voltage input is corrected, the load on the oscillation circuit is controlled according to the outside air temperature, and the frequency temperature characteristics can be compensated accurately with simple processing, further stabilizing the output frequency. In particular, since the frequency characteristics including the individual differences of the components are compensated, the variation of products can be reduced.

[Configuration of Crystal Oscillator with Thermostatic Bath According to Embodiment: FIG. 1]
A configuration of a crystal oscillator with a thermostatic bath according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of a crystal oscillator with a thermostatic bath according to an embodiment of the present invention.
As shown in FIG. 1, a crystal oscillator with a thermostat (crystal oscillator with a thermostat) according to an embodiment of the present invention includes a crystal resonator 1, an oscillation circuit 2, a voltage variable capacitance element 3, and a temperature sensitivity. An element 4, a temperature control circuit 5, a heating element 6, a gain calculation unit 7, and an addition unit 8 are provided.

Of these configurations, the portions excluding the gain calculation unit 7 and the addition unit 8 are the same as those in the prior art, and a detailed description thereof will be omitted.
The frequency signal oscillated by the crystal resonator 1 is amplified by the oscillation circuit 2 and output as an oscillator output. The oscillation circuit 2 inputs a voltage for fine adjustment via the voltage variable capacitance element 3 to the crystal resonator 1. Feedback to the side.

At the same time, the temperature sensing element 4 detects the temperature in the vicinity of the thermostatic chamber as in the prior art, and outputs a temperature sensing element instruction temperature signal (indication temperature signal) based on the detected temperature. The temperature control circuit 5 Based on the above, a heat generation instruction voltage is output to the heat generator 6.
The heat generation instruction voltage corresponds to the instruction voltage in the claims.
Here, the configuration in which the oscillation circuit 2 is an analog circuit is shown, but the oscillation circuit 2 may be a digital circuit and the feedback circuit including the voltage variable capacitance element 3 may be eliminated.

The characteristic part of the crystal oscillator with a thermostat is specifically described.
The gain calculation unit 7 branches and inputs the heat generation instruction voltage output from the temperature control circuit 5 and adjusts the gain to generate a correction voltage for correcting the frequency adjustment voltage applied to the crystal resonator. It is.
The gain calculation unit 7 includes an analog circuit or a digital circuit. In the case of an analog circuit, the gain calculation unit 7 includes an arithmetic element such as an operational amplifier. In the case of a digital circuit, the gain calculation unit 7 includes an A / D converter, an arithmetic circuit, and a D / A converter. Is done.
The adder 8 adds the correction voltage to the frequency adjustment voltage and outputs it to the crystal unit 1.

[Outline of frequency adjustment in this crystal oscillator with temperature chamber]
The gain calculation unit 7 generates a correction voltage based on the relationship between the preset heat generation instruction voltage and the corresponding frequency fluctuation amount so as to compensate for fluctuations in the output frequency according to the outside air temperature.
Specifically, in this crystal oscillator with a thermostat, the characteristics of the fluctuation amount of the output frequency with respect to the outside temperature (outside temperature-frequency characteristics) and the characteristics of the heat generation instruction voltage with respect to the outside temperature (outside temperature-heating instruction voltage characteristics) ) Is obtained, and the frequency variation characteristic (heat generation instruction voltage-frequency characteristic) with respect to the heat generation instruction voltage characteristic is obtained from the two relations, and the frequency fluctuation amount is set to 0 (zero) based on the heat generation instruction voltage-frequency characteristic. A correction voltage is generated as follows.
Then, by adding the correction voltage to the frequency adjustment voltage applied to the voltage variable capacitor 3, the load in the oscillation circuit 2 is adjusted to compensate for the frequency fluctuation.

  That is, in the crystal oscillator with a thermostatic bath, the heat generation instruction voltage is used as an index representing the outside air temperature, and the load of the oscillation circuit 2 is adjusted to the outside air temperature by correcting the frequency adjustment voltage according to the heat generation instruction voltage. In accordance with this, it is dynamically controlled.

  As a result, the crystal oscillator with a thermostat can control the temperature in the vicinity of the thermostat to be constant, and can adjust the output frequency by adjusting the load of the oscillation circuit according to the temperature. Thus, a more stable output frequency signal can be obtained.

[Outside air temperature vs. heat generation instruction voltage characteristics: Fig. 2]
An example of the outside air temperature-heat generation instruction voltage characteristic in the crystal oscillator with a thermostat will be described with reference to FIG. FIG. 2 is a characteristic diagram showing an example of an outside air temperature-heat generation instruction voltage characteristic.
As shown in FIG. 2, the heat generation instruction voltage is a control voltage for the heating element 6, and the outside air temperature increases linearly in the range of 0 to 3 V in the temperature range of −40 ° C. to + 85 ° C.
That is, the heat generation instruction voltage is expressed by a linear function having an appropriate slope with respect to the outside air temperature, and is easy to use as an index representing temperature.
When the reference temperature is 25 ° C., the corresponding heat generation instruction voltage is about 2.3V.

[Heat generation instruction voltage vs. frequency characteristics: Fig. 3]
Next, the heat generation instruction voltage-frequency characteristic, which is a feature of the thermostat crystal oscillator, will be described with reference to FIG. FIG. 3 is a characteristic diagram showing a heat generation instruction voltage-frequency characteristic.
In the crystal oscillator with a thermostat, the heat generation instruction voltage-frequency characteristic is obtained based on the outside air temperature-frequency characteristic shown in FIG. 6 and the outside air temperature-heat generation instruction voltage characteristic shown in FIG.
That is, as shown in FIG. 3, the heat generation instruction voltage-frequency characteristic is a plot in which the heat generation instruction voltage and the frequency fluctuation amount corresponding to the same outside air temperature are associated with each other, and the frequency fluctuation amount is 0 (zero). The heat generation instruction voltage is 2.3V.

[Generation of correction voltage: FIG. 3]
Next, generation of a correction voltage in the gain calculation unit 7 will be described with reference to FIG.
Since the relationship between the voltage applied to the crystal unit 1 and the oscillation frequency is already known in the thermostat with this thermostat, the inverse characteristic of the heat generation instruction voltage-frequency characteristic shown in FIG. What is necessary is just to apply to the crystal oscillator 1.

By using the heat generation instruction voltage as an index of the outside air temperature, the constant temperature bath crystal oscillator can compensate for the output frequency that varies depending on the outside air temperature.
In particular, the heat generation instruction voltage-frequency characteristic of FIG. 3 has a moderate slope and is easily controlled quantitatively, and enables highly accurate compensation.

The generation of the correction voltage based on the heat generation instruction voltage-frequency characteristic of FIG. 3 will be specifically described.
Based on FIG. 3, the gain calculation unit 7 obtains the difference between the input heat generation instruction voltage and the heat generation instruction voltage (reference voltage, here 2.3 V) at which the frequency fluctuation amount is 0 (zero). The difference is output as a correction voltage.
For example, when the inputted heat generation instruction voltage is 2.0 V, the frequency fluctuation amount is about +4.5 [ppb], and fluctuates to the plus side. Therefore, the gain calculator 7 outputs a difference −0.3V from 2.3V at which the frequency fluctuation amount is 0 (zero) as a correction voltage.
As a result, the output frequency is changed to the minus side.

Similarly, for example, when the input heat generation instruction voltage is 2.8 V, the frequency fluctuation amount is −7 [ppb], and the correction voltage is +0.5 V.
In this case, the output frequency is changed to the plus side.

  When the gain calculation unit 7 is composed of an operational amplifier, the difference between the difference is obtained by inputting the heat generation instruction voltage to the + (plus) terminal and the reference voltage (here 2.3V) to the-(minus) terminal. A correction voltage is output.

  Further, when the gain calculation unit 7 is configured by a digital circuit, the A / D converter A / D converts the heat generation instruction voltage to obtain a heat generation instruction voltage value, and the arithmetic circuit calculates from the heat generation instruction voltage. A correction voltage value is calculated by subtracting a reference voltage value stored in advance, and the D / A conversion unit D / A converts the correction voltage value and outputs a correction voltage.

  Then, the addition unit 8 adds the correction voltage to the frequency adjustment voltage and applies the correction voltage to the crystal unit 1, whereby the load of the oscillation circuit 2 can be controlled according to the outside air temperature, and the temperature of the output frequency. The characteristics can be compensated with high accuracy.

In FIG. 4 of the cited document 1, the voltage is adjusted by branching the voltage applied to the heater unit 2a and applying the voltage to the varicap diode 43 via the resistor 41. A gain calculation unit such as an oscillator is not provided, and it is difficult to adjust the capacitance with high accuracy to compensate for fluctuations in the output frequency.
Further, in Cited Document 1, since the gain calculation unit is not provided, the dependence on the varicap diode is high, and the influence of the individual difference of the varicap diode becomes large as in the conventional case, resulting in variations among products. End up.

On the other hand, in this constant temperature chamber crystal oscillator, when the oscillation circuit 2 is composed of an analog circuit, the outside air temperature-frequency characteristic in FIG. 6 becomes the characteristic in the configuration including the voltage variable capacitance element 3. 3 is generated, and the correction voltage is generated.
Therefore, even if there is a variation in the characteristics of the voltage variable capacitance element 3, the present crystal oscillator with a thermostat can absorb the individual differences, stabilize the output frequency, and reduce the variation in the product.

[Effect of the embodiment]
According to the crystal oscillator with a thermostatic bath according to the embodiment of the present invention, the heat generation instruction voltage-frequency characteristic based on the outside air temperature-frequency characteristic and the outside air temperature-heat generation instruction voltage characteristic is set in the gain calculation unit 7 in advance. The heat generation instruction voltage from the temperature control circuit 5 is branched and input to the gain calculation unit 7 so that the gain calculation unit 7 makes the fluctuation of the output frequency close to 0 based on the heat generation instruction voltage-frequency characteristics. Since a correction voltage for correcting the frequency adjustment voltage is generated and the addition unit 8 adds the correction voltage to the frequency adjustment voltage and outputs the correction voltage to the crystal resonator, in addition to the temperature control using the heating element 6 By using a heat generation instruction voltage having an appropriate linearity with respect to the outside air temperature as an indicator of the outside air temperature, the load of the oscillation circuit 2 is accurately adjusted in accordance with the temperature to be used as a component such as a voltage variable capacitance element. Outside temperature-frequency without much dependence Can compensate for the characteristic, there is an advantage of being able to further stabilize the output frequency.

  In particular, according to the crystal oscillator with a thermostat, even if the characteristics of the voltage variable capacitance element 3 vary, the outside air temperature-frequency characteristics including that are compensated by the heat generation instruction voltage-frequency characteristics shown in FIG. Therefore, it is possible to absorb individual differences of the voltage variable capacitance element 3 and to improve the quality of the entire product.

  Further, according to the crystal oscillator with a thermostatic bath, the gain calculation unit 7 can be configured by an operational amplifier or a digital circuit, and can be flexibly handled according to specifications.

  INDUSTRIAL APPLICABILITY The present invention is suitable for a crystal oscillator with a thermostatic bath that can further stabilize the output frequency signal and reduce variations due to individual differences among components.

  DESCRIPTION OF SYMBOLS 1,13,41 ... Crystal oscillator, 2,42 ... Oscillation circuit, 3,43 ... Voltage variable capacitance element, 4,44 ... Temperature sensing element, 5,45 ... Temperature control Circuit, 6, 14, 46 ... Heating element, 7 ... Gain calculator, 8 ... Adder, 11 ... Substrate, 12 ... Thermostatic chamber, 15 ... Base, 16. .cover

Claims (7)

A quartz oscillator stored in a thermostat; an oscillation circuit that amplifies and outputs the output of the crystal oscillator; a thermosensitive element that is disposed in the vicinity of the thermostat and outputs a signal according to temperature; and A temperature controlled circuit that outputs an instruction voltage based on a signal from a temperature sensing element, and a crystal oscillator with a thermostat equipped with a heating element that generates heat according to the instruction voltage from the temperature control circuit,
An instruction voltage from the temperature control circuit is branched and input, and a correction voltage that compensates for a variation in the output frequency corresponding to the input instruction voltage based on a characteristic of an output frequency with respect to a preset instruction voltage is provided. A gain calculation unit to generate;
A crystal oscillator with a thermostat, comprising: an addition unit that adds the correction voltage to a frequency adjustment voltage input to the crystal resonator.   2. The characteristic of the output frequency with respect to the instruction voltage is generated based on the characteristic of the output frequency with respect to the outside air temperature and the characteristic of the instruction voltage with respect to the outside air temperature in the crystal oscillator with constant temperature bath. Crystal oscillator with thermostatic bath as described.   The gain calculation unit outputs a difference between a voltage with a frequency variation amount of 0 and an input instruction voltage as a correction voltage in the characteristic of the output frequency with respect to the instruction voltage. Crystal oscillator with constant temperature bath.   4. The oven-controlled crystal oscillator according to claim 1, wherein the gain calculation unit is composed of a digital circuit including an A / D converter, an arithmetic circuit, and a D / A converter.   4. The oven controlled quartz crystal oscillator according to any one of claims 1 to 3, wherein the gain calculation unit is composed of an operational amplifier.   The crystal oscillator with a thermostatic bath according to any one of claims 1 to 5, wherein the oscillation circuit is constituted by a digital circuit.   6. The thermostatic chamber according to claim 1, further comprising: a voltage variable capacitance element configured to apply an feedback signal from the oscillation circuit to an input side of a crystal resonator. Attached crystal oscillator.

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