JP5673044B2 - Temperature compensated piezoelectric oscillator, frequency correction system, frequency drift correction method - Google Patents

Description

  The present invention relates to a temperature-compensated piezoelectric oscillator, and more particularly to a temperature-compensated piezoelectric oscillator that generates information for correcting frequency fluctuations due to temperature drift at startup in a temperature-compensated oscillator used in an electronic device. .

A temperature-compensated piezoelectric oscillator (hereinafter referred to as TCXO) is required to have high frequency stability with respect to a change in temperature while being reduced in size and weight. In particular, in TCXO used in GPS, since it is necessary to immediately capture a GPS satellite at the time of power activation, high frequency stability at the time of activation is required.
10 is a cross-sectional view showing the package structure of the TCXO disclosed in Patent Document 1, FIG. 11 is a block diagram showing the circuit configuration inside the IC chip, and FIG. 12 is a view showing the temperature characteristics of the piezoelectric vibrator. It is. In the package structure of FIG. 10, the IC chip 37 shown in FIG. 11 is mounted on the sheet substrate 35 having the external terminals 36, and is connected to the transducer terminals 32 provided on the transducer base substrate 31 via the connection members 34. A piezoelectric vibrator 30 is mounted in the vibrator base substrate 31. Here, as shown in FIG. 11, the IC chip 37 is based on a temperature sensor 38 that detects the ambient temperature, a memory 39 that stores data related to a temperature compensation voltage for each temperature, and data of the temperature sensor 38 and the memory 39. A temperature compensation voltage generation circuit 40 that generates a temperature compensation voltage and a VCXO (Volt Control Crystal Oscillator) 41 are provided. That is, the temperature compensation mechanism 42 and the piezoelectric oscillator 43 are included. For example, as shown in FIG. 12, the piezoelectric vibrator 30 has a temperature characteristic such as a cubic curve 44 having an inflection point near room temperature (25 ° C.) as an AT cut. The temperature sensor 38 is composed of, for example, a diode, and detects the voltage value of the diode that changes according to the ambient temperature as a temperature change. The temperature compensation voltage generated based on the temperature information obtained by the temperature sensor 38 generates a temperature compensation characteristic 45 that cancels the temperature characteristic of the piezoelectric vibrator 30 and compensates the frequency of the piezoelectric oscillator 43 with high accuracy.

JP 2008-136169 A

However, in the conventional TCXO, active elements such as an oscillation circuit and an output circuit operate at the time of startup, so that the heat generation temperature of the IC chip 37 covered with the mold resin becomes higher than the ambient temperature, but the piezoelectric vibrator 30 Operates at a temperature lower than that of the IC chip 37, the temperature sensor 38 in the IC chip 37 detects a temperature higher than the actual temperature of the piezoelectric vibrator 30, and as a result, the originally required temperature compensation amount shifts. There is a problem that the oscillation frequency drifts immediately after startup, for example, for about 30 seconds.
The present invention has been made in view of such problems, and outputs frequency drift correction data, time information, and temperature information immediately after startup to the external device side, and based on these information on the external device side. An object of the present invention is to provide a temperature-compensated piezoelectric oscillator capable of correcting drift at startup.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
[Mode 1] A piezoelectric vibrator, a temperature sensor, and a temperature compensation voltage generation circuit that generates a temperature compensation voltage for compensating a frequency temperature characteristic of the piezoelectric vibrator based on an output voltage of the temperature sensor, and the temperature A temperature compensated piezoelectric oscillator in which the oscillation frequency is controlled based on a compensation voltage, the temperature information storage circuit storing temperature information detected by the temperature sensor, and the frequency drift characteristics of the temperature compensated piezoelectric oscillator are approximated A frequency drift correction data storage unit that stores approximate coefficient data of a curve, an elapsed time information output unit that outputs elapsed time information from the time when the temperature-compensated oscillator is activated, the temperature information to an external device, the And an interface control circuit for outputting the approximate coefficient data and the elapsed time information.
The temperature compensated oscillator according to the present invention further includes a temperature information storage circuit, a frequency drift correction data storage unit, an elapsed time information output means, and an interface control circuit in addition to the conventional temperature compensated oscillator, and is connected to the interface control circuit. The temperature information, approximate coefficient data, and elapsed time information are passed to the external device, and the frequency drift at startup is corrected based on the information on the external device side. Thereby, the frequency drift at the time of starting can be corrected in elapsed time units.
[Mode 2] The curve approximating the frequency drift characteristic is a product of a first quadratic function term having temperature as a variable, a second quadratic function having temperature as a variable, and a logarithmic function having time as a variable. It is expressed by the sum of the term consisting of
An approximate expression of the frequency drift characteristic can be expressed as {A ′ (temp−t ₀ ) ² + A} × Ln (time) + { B ′ (temp−t ₀ ) ² + B}. That is, the part {A ′ (temp−t ₀ ) ² + A} is the second quadratic function, the part { B ′ (temp−t ₀ ) ² + B} is the first quadratic function, and Ln (time) Is a logarithmic function with time as a variable. Therefore, the external device side can immediately correct the frequency by receiving the temperature information, the approximation coefficient data, and the elapsed time information and substituting them into the above approximate expression for calculation.
[Mode 3] The frequency drift correction data storage unit stores a first frequency drift correction data storage unit that stores first approximate coefficient data until a predetermined time elapses after activation, and the predetermined time has elapsed. And a second frequency drift correction data storage section for storing second approximate coefficient data later.
The frequency drift characteristic of an actual temperature-compensated piezoelectric oscillator shows a rapid frequency change in the time lapse from about 2 seconds immediately after startup, and a gradual frequency change after that. Therefore, the present invention includes an approximation coefficient that approximates a frequency drift in a region where the frequency changes sharply in an initial startup state, and an approximation coefficient that approximates a frequency drift in a region where the frequency changes slowly. Thereby, the characteristic close | similar to an actual frequency drift characteristic can be produced | generated.
[Mode 4] A correction data switching time storage unit that stores a time for switching from the first frequency drift correction data storage unit to the second frequency drift correction data storage unit is provided, and the interface control circuit is connected to the external device. On the other hand, the switching time is output.
The first and second approximation coefficient data have a point of intersection when a predetermined time has elapsed since the start. Therefore, in the present invention, the first and second frequency drift correction data storage units are switched based on the time output from the interface control circuit at the intersection. Thereby, approximate coefficient data whose approximate coefficient data is close to the actual frequency drift characteristic can be obtained.
[Mode 5] The approximation coefficient data is expressed as a frequency deviation with respect to a nominal value of an oscillation frequency of the piezoelectric vibrator.
The approximation coefficient data calculated based on the information received from the oscillator on the device side is information for correcting the oscillation frequency. Therefore, since the frequency drift characteristic obtained by calculation is calculated as a frequency deviation, the nominal value of the oscillation frequency is multiplied by the frequency drift characteristic (ppb: part per billion) obtained from the calculation. Obtained. Thereby, the drift at the time of starting can be correct | amended accurately by calculating based on a frequency correction type | formula.
[Mode 6] A frequency correction system including the temperature compensated piezoelectric oscillator according to any one of modes 1 to 5 and an external device, wherein the external device is the temperature compensated piezoelectric oscillator. Control means for calculating frequency drift characteristics based on the approximate coefficient data output from the interface control circuit, and signals output from the temperature compensated piezoelectric oscillator based on the frequency drift characteristics calculated by the control means And a correction circuit that corrects the frequency.
The frequency correction system is a temperature-compensated oscillator according to the present invention, control means for calculating a frequency drift characteristic based on a frequency correction expression based on information output from the temperature-compensated oscillator, and correcting an oscillation frequency based on the frequency drift characteristic. And an external device including a correction circuit. In other words, the external device can immediately correct the oscillation frequency simply by receiving the information given from the temperature compensated oscillator as a variable and calculating according to the determined formula. Thereby, the control on the external device side is easy and can be simplified.
SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
[Application Example 1] A piezoelectric vibrator, a temperature sensor, and a temperature compensation voltage generation circuit that generates a temperature compensation voltage for compensating the frequency temperature characteristic of the piezoelectric vibrator based on an output voltage of the temperature sensor, A temperature-compensated piezoelectric oscillator whose oscillation frequency is controlled based on a temperature-compensated voltage, the temperature information storage circuit storing the temperature information detected by the temperature sensor, and the frequency drift characteristics of the temperature-compensated piezoelectric oscillator are approximated A frequency drift correction data storage unit that stores approximate coefficient data of the curve, an elapsed time information output unit that outputs elapsed time information from the time when the temperature compensated oscillator is started, and the temperature information for an external device, And an interface control circuit that outputs the approximate coefficient data and the elapsed time information.

  The temperature compensated oscillator according to the present invention further includes a temperature information storage circuit, a frequency drift correction data storage unit, an elapsed time information output means, and an interface control circuit in addition to the conventional temperature compensated oscillator, and is connected to the interface control circuit. The temperature information, approximate coefficient data, and elapsed time information are passed to the external device, and the frequency drift at startup is corrected based on the information on the external device side. Thereby, the frequency drift at the time of starting can be corrected in elapsed time units.

  Application Example 2 A curve approximating the frequency drift characteristic is a term composed of a product of a quadratic function having temperature as a variable, a quadratic function having temperature as a variable, and a logarithmic function having time as a variable. It is represented by the approximate expression containing these.

An approximate expression of the frequency drift characteristic can be expressed as {A ′ (temp−t ₀ ) ² + A} × Ln (time) + {B ′ (temp−t ₀ ) ² + B}. That is, {A ′ (temp−t ₀ ) ² + A} is a quadratic function of coefficient A, {B ′ (temp−t ₀ ) ² + B} is a quadratic function of coefficient B, and Ln (time) Is a logarithmic function with time as a variable. Therefore, the external device side can immediately correct the frequency by receiving the temperature information, the approximation coefficient data, and the elapsed time information and substituting them into the above approximate expression for calculation.

  Application Example 3 First Frequency Drift Correction Data Storage Unit that Stores First Approximation Coefficient Data Between the Frequency Drift Correction Data Storage Unit and a Predetermined Time Elapse from Start-up And a second frequency drift correction data storage unit for storing the second approximate coefficient data after being performed.

  The frequency drift characteristic of an actual temperature-compensated piezoelectric oscillator shows a rapid frequency change in the time lapse from about 2 seconds immediately after startup, and a gradual frequency change after that. Therefore, the present invention includes an approximation coefficient that approximates a frequency drift in a region where the frequency changes sharply in an initial startup state, and an approximation coefficient that approximates a frequency drift in a region where the frequency changes slowly. Thereby, the characteristic close | similar to an actual frequency drift characteristic can be produced | generated.

  Application Example 4 The present invention includes a correction data switching time storage unit that stores a time for switching from the first frequency drift correction data storage unit to the second frequency drift correction data storage unit.

  The first and second approximation coefficient data have a point of intersection when a predetermined time has elapsed since the start. Therefore, in the present invention, the first and second frequency drift correction data storage units are switched at this intersecting point. Thereby, approximate coefficient data whose approximate coefficient data is close to the actual frequency drift characteristic can be obtained.

  Application Example 5 The approximate coefficient data is expressed as a frequency deviation with respect to a nominal value of the oscillation frequency of the piezoelectric vibrator.

  The approximation coefficient data calculated based on the information received from the oscillator on the device side is information for correcting the oscillation frequency. Therefore, since the frequency drift characteristic obtained by calculation is calculated as a frequency deviation, the nominal value of the oscillation frequency is multiplied by the frequency drift characteristic (ppb: part per billion) obtained from the calculation. Obtained. Thereby, the drift at the time of starting can be correct | amended accurately by calculating based on a frequency correction type | formula.

A temperature compensated piezoelectric oscillator according to any one of Application Example 6 Application Example 1 to 5, a frequency correction system and a said external device, the external device, the temperature-compensated piezoelectric Control means for calculating frequency drift characteristics based on the approximate coefficient data output from the interface control circuit of an oscillator, and output from the temperature compensated piezoelectric oscillator based on the frequency drift characteristics calculated by the control means And a correction circuit for correcting the frequency of the received signal.

  The frequency correction system is a temperature-compensated oscillator according to the present invention, control means for calculating a frequency drift characteristic based on a frequency correction expression based on information output from the temperature-compensated oscillator, and correcting an oscillation frequency based on the frequency drift characteristic. And an external device including a correction circuit. In other words, the external device can immediately correct the oscillation frequency simply by receiving the information given from the temperature compensated oscillator as a variable and calculating according to the determined formula. Thereby, the control on the external device side is easy and can be simplified.

Application Example 7 A frequency drift correction method for a temperature compensated piezoelectric oscillator including a temperature information storage circuit, a frequency drift correction data storage unit, an elapsed time information output unit, and an interface control circuit, wherein the temperature information storage circuit Storing the temperature information detected by the temperature sensor, storing the approximate coefficient data of a curve in which the frequency drift correction data storage unit approximates the frequency drift characteristic of the temperature compensated piezoelectric oscillator, and the elapsed time information output means, and outputting an elapsed time information from the time when the temperature compensated oscillator is activated, the interface control circuit, the temperature information to external devices, the approximate coefficient data, and the elapsed time And a step of outputting information.

  The present invention has the same effects as application example 1.

(A) is the figure which plotted the frequency drift characteristic in normal temperature (25 degreeC), (b) is a figure showing the temperature dependence in drift approximation coefficient A and B, (c) is the temperature of a piezoelectric vibrator. It is a figure which shows a characteristic, (d) is the figure which graphed the frequency drift characteristic in each temperature. It is a block diagram which shows the structure of the frequency correction system using TCXO which concerns on the 1st Embodiment of this invention. It is a flowchart explaining operation | movement of the frequency correction system which concerns on the 1st Embodiment of this invention. It is a figure which shows the mode of the change of the frequency deviation in each elapsed time. It is a block diagram which shows the structure of the frequency correction system using TCXO which concerns on the 2nd Embodiment of this invention. It is a flowchart explaining operation | movement of the frequency correction system which concerns on the 2nd Embodiment of this invention. It is a figure which shows the mode of the change of the frequency deviation in each elapsed time. It is a block diagram which shows the structure of the frequency correction system using TCXO which concerns on the 3rd Embodiment of this invention. It is a flowchart explaining operation | movement of the frequency correction system which concerns on the 3rd Embodiment of this invention. 10 is a cross-sectional view showing a package structure of TCXO disclosed in Patent Document 1. FIG. It is a block diagram which shows the internal circuit structure of the IC chip used for the conventional TCXO. It is a figure which shows the temperature characteristic of a piezoelectric vibrator.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .

FIG. 1A is a graph showing the frequency drift characteristics of TCXO at room temperature (25 ° C.). Graph 26 represents the frequency drift characteristics of TCXO, and graph 27 represents the frequency drift approximate characteristics based on the calculated values. FIG. 1B is a diagram showing the temperature dependence of the drift approximation coefficients A and B. FIG. 1C is a diagram showing temperature characteristics of the piezoelectric vibrator. FIG. 1D is a graph showing the frequency correction formula for each temperature.
The frequency correction formula is expressed as follows.
{A ′ (temp−t ₀ ) ² + A} × Ln (time) + {B ′ (temp−t ₀ ) ² + B} (1)
Here, A and B are drift approximation coefficients, A ′ and B ′ are drift approximation coefficients A and B, which are temperature coefficients, t ₀ is a room temperature of 25 ° C., temp is a measurement temperature, and time is a predetermined time. Information. Approximation coefficient data of a curve approximating the actual frequency drift characteristics and approximation coefficient data indicating the temperature dependence of the drift characteristics (hereinafter referred to as frequency drift correction data) are stored in a memory circuit, and externally stored. The device side reads the current temperature information, time lapse information, and frequency drift correction data from the TCXO, and calculates the frequency drift characteristic based on the equation (1). Theoretically, when TCXO is started at 25 ° C., the heat generation temperature of the IC chip slightly rises above the temperature of the piezoelectric vibrator, and a temperature difference is generated between the IC chip and the piezoelectric vibrator. This temperature difference affects the temperature compensation operation, and the frequency gradually increases with time. Such a frequency drift characteristic is calculated using the calculation formula (1).

  FIG. 2 is a block diagram showing the configuration of the frequency correction system using the TCXO according to the first embodiment of the present invention. The frequency correction system 100 of the present invention includes a TCXO 50 and a GPS receiver 12, and the TCXO 50 outputs a voltage corresponding to a temperature change, the piezoelectric vibrator 1 whose frequency changes in a cubic curve with respect to the temperature. Temperature sensor 2, temperature compensation voltage generation circuit 3 for generating a temperature compensation voltage for correcting the frequency temperature characteristic of the piezoelectric vibrator 1 based on this voltage, and voltage control type for oscillating a frequency controlled based on the temperature compensation voltage The TCXO 50 includes an oscillator (hereinafter referred to as VCXO) 5, and the TCXO 50 converts the temperature information detected by the temperature sensor 2 into a digital signal by the A / D converter 6 and stores it. And approximation coefficient data of a curve approximating the frequency drift characteristic of TCXO50, and an approximation coefficient indicating the temperature dependence of the frequency drift characteristic A frequency drift correction data storage unit 7 for storing data, an elapsed time information output means 46 including an N frequency divider 9 for outputting elapsed time information from the time when the TCXO 50 is activated, and a counter 10, and a GPS receiver ( And an interface control circuit 11 that outputs temperature information, frequency drift correction data, and elapsed time information to an external device 12.

The circuits other than the piezoelectric vibrator 1 connected to the terminal 4 are integrated in the IC chip 22. The GPS receiver 12 includes a correction circuit 15 that corrects the frequency of the oscillation signal 21, an RF unit 14 that performs communication with a GPS satellite, a baseband signal processing LSI (BB-LSI) 16, temperature information, and frequency. A CPU (Central Processing Unit) 17 for calculating the frequency drift characteristic according to the equation (1) based on the drift correction data and the elapsed time information, a memory 18, a clock 19, data 20, and an oscillation signal 21 is connected to the TCXO 50.
That is, the TCXO 50 according to the present embodiment adds the temperature information storage circuit 8, the frequency drift correction data storage unit 7, the elapsed time information output means 46, and the interface control circuit 11 to the conventional temperature compensated oscillator, and performs interface control. Temperature information, frequency drift correction data, and elapsed time information are passed to the GPS receiver 12 connected to the circuit 11, and the GPS receiver 12 side corrects the frequency drift when the TCXO 50 is activated based on the information. Thereby, the frequency drift at the time of starting of TCXO50 can be correct | amended per elapsed time unit.

FIG. 3 is a flowchart for explaining the operation of the frequency correction system according to the first embodiment of the present invention, and FIG. 4 is a diagram showing a change in frequency deviation at each elapsed time.
First, the CPU 17 of the GPS receiver 12 reads elapsed time information at time T1 (time 0 seconds immediately after activation) in FIG. 4 via the interface circuit 11 (S1). Then, the frequency drift correction data stored in the frequency drift correction data storage unit 7 and the temperature information stored in the temperature information storage circuit 8 are read out via the interface circuit 11 (S2). Next, elapsed time information at a predetermined time T2 is read through the interface circuit 11 (S3). Then, calculation is performed by substituting each value into the frequency correction formula of the formula (1) (S4), and the oscillation frequency of the oscillation signal 21 is corrected by the correction circuit 15 based on the calculation result (S5). The GPS receiver 12 captures a GPS satellite based on the corrected frequency (S6).

  FIG. 5 is a block diagram showing a configuration of a frequency correction system using a TCXO according to the second embodiment of the present invention. Since the frequency correction system 110 of the present invention is the same as that of FIG. 2 except for the configuration of the TCXO 51, the same reference numerals as those in FIG. The TCXO 51 of the present invention includes a first frequency drift correction data storage unit 23 that stores first approximate coefficient data until a predetermined time elapses after activation as a frequency drift correction data storage unit, and a predetermined time elapses. And a second frequency drift correction data storage unit 24 for storing the second approximation coefficient data after being processed. That is, as shown in FIG. 7, the approximation coefficient 26 that approximates the frequency drift in the initial startup state has poor approximation accuracy at a loose portion (point B), and an error from the actual frequency drift of the TCXO 51 becomes large. In view of this, the present embodiment includes an approximation coefficient 26 that approximates the frequency drift in the initial startup state, and an approximation coefficient 27 that approximates the frequency drift of the slowly changing region. Thereby, characteristics closer to the actual frequency drift characteristics can be generated. Even if the frequency drift characteristic does not fit well on one approximate curve, the optimum fitting curve can be obtained where the drift is steep and gentle, so it is possible to correct the frequency drift after startup more precisely. It becomes.

  FIG. 6 is a flowchart for explaining the operation of the frequency correction system according to the second embodiment of the present invention, and FIG. 7 is a diagram showing how the frequency deviation changes at each elapsed time. First, the CPU 17 of the GPS receiver 12 reads elapsed time information at time T1 (time 0 seconds immediately after activation) in FIG. 7 through the interface circuit 11 (S11). The interface circuit 11 receives the frequency drift correction data stored in the first frequency drift correction data storage unit 23 and the second frequency drift correction data storage unit 24 and the temperature information stored in the temperature information storage circuit 8. (S12). Next, it is checked whether or not GPS satellite acquisition has started before time T2 (point A) in FIG. 7 (S13). If GPS satellite acquisition has started before time T2, (Yes in S13), the elapsed time information is read out via the interface circuit 11 (S14). Then, calculation is performed by substituting each data into the frequency information expression of the frequency correction expression (1) (S15), and the correction circuit 15 corrects the oscillation frequency of the oscillation signal 21 with the value (S16). The GPS receiver 12 captures a GPS satellite based on the corrected frequency (S17). On the other hand, when the acquisition of the GPS satellite is started after time T2 (point A) in step S13 (No in S13), the frequency drift correction data of the oscillator is transferred from the first frequency drift correction data storage unit 23 to the second frequency. Switching to the drift correction data storage unit 24 and reading (S18), the process proceeds to step S14.

  FIG. 8 is a block diagram showing the configuration of a frequency correction system using a TCXO according to the third embodiment of the present invention. Since the frequency correction system 120 of the present invention is the same as that of FIG. 5 except for the configuration of the TCXO 52, the same reference numerals as those in FIG. The TCXO 52 of the present invention includes a correction data switching time storage unit 25 that stores time information for switching between the first frequency drift correction data storage unit 23 and the second frequency drift correction data storage unit 24. That is, the first and second approximation coefficient data 26 and 27 have a point A that intersects when a predetermined time has elapsed from the time of activation. Therefore, in the present embodiment, the first frequency drift correction data storage unit 23 and the second frequency drift correction data storage unit 24 are switched at the intersection A. As a result, approximate coefficient data closer to the actual frequency drift characteristic can be obtained.

  FIG. 9 is a flowchart for explaining the operation of the frequency correction system according to the third embodiment of the present invention. First, the CPU 17 of the GPS receiver 12 reads the elapsed time information at time T1 (time 0 seconds immediately after activation) in FIG. 7 through the interface circuit 11 (S21). The interface circuit 11 receives the frequency drift correction data stored in the first frequency drift correction data storage unit 23 and the second frequency drift correction data storage unit 24 and the temperature information stored in the temperature information storage circuit 8. (S22). Next, the switching time data stored in the correction data switching time storage unit 25 is read (S23). Then, after a predetermined time has elapsed, the elapsed time information is read (S24), the elapsed time and the switching time are compared (S25), and if the elapsed time is smaller than the switching time (Yes in S25), the frequency drift correction data of the oscillator is obtained. The data is read from the first frequency drift correction data storage unit 23 and calculated by substituting each data into the frequency information formula of the frequency correction formula (1) (S26). When the elapsed time is larger than the switching time in step S25 (No in S25), the frequency drift correction data of the oscillator is read from the second frequency drift correction data storage unit 24, and each frequency information expression of the frequency correction expression (1) is set. Data is substituted and calculated (S29). Then, the correction circuit 15 corrects the oscillation frequency of the oscillation signal 21 with the value (S27). The GPS receiver 12 captures a GPS satellite based on the corrected frequency (S28).

  DESCRIPTION OF SYMBOLS 1 Piezoelectric vibrator, 2 Temperature sensor, 3 Temperature compensation voltage generation circuit, 4 terminals, 5 VCXO, 6 A / D converter, 7 Frequency drift correction data storage part, 8 Temperature information storage circuit, 9 N frequency divider, 10 Counter, 11 Interface control circuit, 12 GPS receiver, 13 Antenna, 14 RF unit, 15 Correction circuit, 16 BB-LSI, 17 CPU, 18 Memory, 19 Clock signal line, 20 Data line, 21 Oscillation signal line, 22 IC chip , 23 First frequency drift correction data storage unit, 24 Second frequency drift correction data storage unit, 25 Correction data switching time storage unit, 26 First frequency correction data, 27 Second frequency correction data, 30 Piezoelectric vibration Child, 31 vibrator base substrate, 32 vibrator terminal, 33 resin mold, 34 connecting member, 35 Sheet substrate, 36 External terminal, 37 IC chip, 38 Temperature sensor, 39 Memory, 40 Temperature compensation voltage generation circuit, 41 VCXO, 42 Temperature compensation mechanism, 43 Piezoelectric oscillator, 44 Variation amount of piezoelectric vibrator, 45 Temperature compensation mechanism Temperature compensation amount, 46 elapsed time information output means, 50 TCXO of the first embodiment, 51 TCXO of the second embodiment, 52 TCXO of the third embodiment, 100 first frequency correction system, 110 second Frequency correction system, 120 Third frequency correction system

Claims (7)

A piezoelectric vibrator, a temperature sensor, and a temperature compensation voltage generation circuit that generates a temperature compensation voltage for compensating a frequency temperature characteristic of the piezoelectric vibrator based on an output voltage of the temperature sensor,
A temperature compensated piezoelectric oscillator in which an oscillation frequency is controlled based on the temperature compensated voltage,
A temperature information storage circuit for storing temperature information detected by the temperature sensor;
A frequency drift correction data storage unit storing approximation coefficient data of a curve approximating the frequency drift characteristic of the temperature compensated piezoelectric oscillator;
Elapsed time information output means for outputting elapsed time information from the time when the temperature compensated oscillator is started,
An interface control circuit that outputs the temperature information, the approximation coefficient data, and the elapsed time information to an external device. Said frequency drift characteristic approximating the curve is first and term of the quadratic function, terms of a second quadratic function and the logarithmic function number of the product that the time is for a variable that the temperature as a variable that the temperature as a variable When, the temperature-compensated piezoelectric oscillator according to claim 1, characterized by being represented by the sum of.   The frequency drift correction data storage unit stores a first frequency drift correction data storage unit that stores first approximate coefficient data until a predetermined time elapses from the start, and a second after the predetermined time has elapsed. The temperature-compensated piezoelectric oscillator according to claim 1, further comprising: a second frequency drift correction data storage unit that stores the approximate coefficient data. A correction data switching time storage unit that stores a time for switching from the first frequency drift correction data storage unit to the second frequency drift correction data storage unit ;
The temperature-compensated piezoelectric oscillator according to claim 3, wherein the interface control circuit outputs the switching time to the external device .   5. The temperature compensated piezoelectric oscillator according to claim 1, wherein the approximation coefficient data is expressed as a frequency deviation with respect to a nominal value of an oscillation frequency of the piezoelectric vibrator. A frequency correction system comprising the temperature compensated piezoelectric oscillator according to any one of claims 1 to 5 and an external device,
The external device is based on the frequency drift characteristic calculated by the control means for calculating the frequency drift characteristic based on the approximate coefficient data output from the interface control circuit of the temperature compensated piezoelectric oscillator, and the control means. And a correction circuit for correcting the frequency of the signal output from the temperature-compensated piezoelectric oscillator. A temperature drift compensation method for a temperature compensated piezoelectric oscillator comprising a temperature information storage circuit, a frequency drift correction data storage unit, an elapsed time information output means, and an interface control circuit,
The temperature information storage circuit storing temperature information detected by a temperature sensor;
The frequency drift correction data storage unit storing approximation coefficient data of a curve approximating a frequency drift characteristic of the temperature compensated piezoelectric oscillator;
The elapsed time information output means outputs the elapsed time information from the time when the temperature compensated oscillator is started; and
The interface control circuit includes the step of outputting the temperature information, the approximation coefficient data, and the elapsed time information to an external device.

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