JP2011234094A - Piezoelectric oscillator, manufacturing method of piezoelectric oscillator and temperature compensation method of piezoelectric oscillator - Google Patents

Abstract

A piezoelectric oscillator, a piezoelectric oscillator manufacturing method, and a piezoelectric oscillator temperature compensation method are provided.
A piezoelectric vibrator 12 having an activity dip 56 in frequency temperature characteristics, an oscillation circuit 14 that oscillates the piezoelectric vibrator 12 and outputs an oscillation signal 50, and a storage circuit 18 are provided. The circuit 18 calculates an activity dip 56 calculated based on the characteristic information 58 extracted from the information of the approximate expression approximating the information 54 of the frequency temperature characteristic, the information 54 of the frequency temperature characteristic and the information of the approximate expression. And dip information 62 indicating the above is stored.
[Selection] Figure 1

Description

  The present invention relates to temperature compensation of a TSXO (Temperature Sensor Xtal Oscillator) that is a piezoelectric oscillator that entrusts a temperature compensation function to the outside, and a TCXO (Temperature Compensated Xtal Oscillator) equipped with a temperature compensation function.

  A piezoelectric vibrator that performs thickness shear vibration or the like has a frequency temperature characteristic that changes in a cubic function with respect to a temperature change. Therefore, there is a demand for acquiring temperature characteristic information indicating such a cubic curve-like frequency temperature characteristic peculiar to the piezoelectric vibrator and appropriately performing temperature compensation. Therefore, in order to cope with this, in the TSXO that does not require a temperature compensation circuit on the oscillation circuit side, a temperature sensor that outputs temperature information of the mounted piezoelectric vibrator to the user side, and a temperature of the mounted piezoelectric vibrator A memory circuit that stores characteristic information (a temperature sensor voltage indicating a predetermined temperature of the piezoelectric vibrator at a certain ambient temperature and a temperature coefficient) and outputs temperature characteristic information to the user side is mounted (Patent Document 1, Patent Document) 2).

  In a system having a temperature compensation circuit mounted with the above TSXO and connected to the TSXO on the user side, based on the temperature of the piezoelectric vibrator obtained from the temperature sensor and the frequency temperature characteristic information obtained from the memory circuit, In the temperature compensation circuit, the temperature compensation amount is calculated and frequency correction is performed so that the frequency is constant at any temperature.

  Similarly, in a GPS system or the like equipped with a TCXO, based on the information about the temperature of the crystal unit obtained from the temperature sensor and the frequency temperature characteristic obtained from the storage circuit, the TCXO is set so that the frequency is constant at any temperature. The temperature compensation voltage is calculated by the temperature compensation voltage generation circuit, and the temperature compensation voltage is applied to the oscillation circuit in the TCXO that performs temperature compensation by the temperature compensation voltage to apply frequency correction.

Japanese Patent Laid-Open No. 7-122935 JP 2003-324318 A

  By the way, since such TSXO and TCXO are mounted on a terminal having a GPS function or the like, there is a demand for both miniaturization and high accuracy. Since the CI value increases as the piezoelectric vibrator constituting the TSXO or TCXO is made smaller, it is necessary to increase the current value for exciting the piezoelectric vibrator. However, when this current value is increased, an effect dip that shows sudden frequency fluctuations with respect to temperature changes appears in the frequency temperature characteristics due to the influence of unnecessary vibrations other than the basic vibration of thickness shear vibration, and the accuracy of temperature compensation decreases. There was a problem such as.

  The present invention provides a piezoelectric oscillator, a piezoelectric oscillator manufacturing method, and a piezoelectric oscillator temperature compensation method that perform temperature compensation with high accuracy even when there is an activity dip in the frequency-temperature characteristics, focusing on the above-described problems. For the purpose.

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 application examples.
Application Example 1 A piezoelectric vibrator having activity dip in frequency temperature characteristics, an oscillation circuit that oscillates the piezoelectric vibrator and outputs an oscillation signal, and a storage circuit, and the storage circuit includes The characteristic information extracted from the information of the approximate expression approximating the information of the frequency temperature characteristic, and the dip information indicating the activity dip calculated based on the information of the frequency temperature characteristic and the information of the approximate expression are stored. A piezoelectric oscillator characterized by that.

  With the above configuration, the oscillation circuit outputs an oscillation signal including an activity dip in the frequency temperature characteristic of the piezoelectric vibrator, but the frequency temperature characteristic is approximately represented by characteristic information and dip information. Each memory use amount can be suppressed and the memory burden on the memory circuit can be suppressed. And since characteristic information and dip information are output, it becomes a piezoelectric oscillator which can perform temperature compensation of an oscillation signal by acquiring these two information on the user side.

  Application Example 2 The oscillation circuit generates a second approximate expression including the activity dip based on the characteristic information and the dip information, and the second approximate expression and the temperature of the piezoelectric vibrator. The oscillation signal is output to a temperature compensation circuit that performs temperature compensation of the oscillation signal based on the information of the oscillation signal, and the storage circuit outputs information for generating the approximate expression and the dip information to the temperature compensation circuit. The piezoelectric oscillator according to Application Example 1, wherein

  With the above configuration, the temperature compensation circuit outputs an oscillation signal that has been subjected to temperature compensation in accordance with the frequency temperature characteristics including the activity dip of the piezoelectric vibrator. Therefore, even an oscillation circuit using a piezoelectric vibrator having a frequency temperature characteristic including an activity dip can be a piezoelectric oscillator capable of highly accurate temperature compensation.

  Application Example 3 Extracted from information on a piezoelectric vibrator having an activity dip in frequency temperature characteristics, an oscillation circuit that oscillates the piezoelectric vibrator and outputs an oscillation signal, and an approximate expression that approximates the frequency temperature characteristics A storage circuit storing characteristic information, dip information indicating the temperature characteristic of the activity dip calculated based on the frequency temperature characteristic information and the approximate expression information, and the characteristic information and the dip information. A calculation circuit that generates a second approximate expression including the activity dip based on the second approximate expression and the temperature information of the piezoelectric vibrator, and an oscillation signal. A piezoelectric oscillator comprising: a frequency correction circuit that performs temperature compensation of the oscillation signal based on the input temperature compensation amount.

  With the above configuration, the frequency correction circuit outputs an oscillation signal subjected to temperature compensation in accordance with the frequency temperature characteristic including the activity dip of the piezoelectric vibrator. Therefore, a piezoelectric oscillator capable of performing highly accurate temperature compensation even with an oscillation circuit using a piezoelectric vibrator having frequency temperature characteristics including activity dip is provided.

Application Example 4 The information of the approximate expression is generated by approximation by power series expansion of the information of the frequency temperature characteristic, and the characteristic information is information of a coefficient extracted from the information of the approximate expression. The piezoelectric oscillator according to any one of Application Examples 1 to 3.
This eliminates the need to calculate a coefficient on the temperature compensation side, so that the burden on the temperature compensation side can be reduced and the temperature compensation can be easily performed.

Application Example 5 The characteristic information is a point on the approximate curve generated by the information of the approximate expression, and information on the relationship between the temperature and the frequency deviation extracted so that the information of the approximate expression can be generated, or 4. The piezoelectric oscillator according to any one of application examples 1 to 3, wherein the piezoelectric oscillator is information representing a relationship between temperature and frequency.
Thus, it is necessary to calculate the coefficient on the temperature compensation side, but the coefficient can be calculated with high accuracy on the temperature compensation side.

  Application Example 6 A piezoelectric vibrator having an activity dip in frequency temperature characteristics, an oscillation circuit that oscillates the piezoelectric vibrator and outputs an oscillation signal and performs temperature compensation of the oscillation signal by a temperature compensation voltage, A temperature compensation voltage generation circuit that outputs the temperature compensation voltage to an oscillation circuit, and the temperature compensation voltage generation circuit includes characteristic information extracted from information of an approximate expression that approximates information of the frequency temperature characteristic; and Using the frequency temperature characteristic information and the dip information indicating the activity dip calculated based on the information on the approximate expression, information on a second approximate expression including the activity dip is generated, and the second The temperature compensation voltage is calculated based on the information of the approximate expression and the temperature information of the piezoelectric vibrator.

  With the above configuration, the oscillation circuit outputs an oscillation signal subjected to temperature compensation corresponding to the frequency temperature characteristic including the activity dip of the piezoelectric vibrator. Therefore, even an oscillation circuit using a piezoelectric vibrator having frequency temperature characteristics including activity dip can perform temperature compensation with high accuracy. In addition, since the frequency temperature characteristic is approximately represented by the characteristic information and the dip information, the piezoelectric oscillator capable of suppressing the memory usage and the memory load on the storage circuit can be obtained.

  Application Example 7 The dip information is information representing the relationship between temperature and frequency deviation calculated from the difference between the frequency temperature characteristic information and the approximate curve information generated from the approximate expression information. 6. The piezoelectric oscillator according to any one of application examples 1 to 5, wherein the piezoelectric oscillator is provided.

  As a result, the activity dip in the frequency temperature characteristic of the piezoelectric vibrator can be extracted with high accuracy, so that a piezoelectric oscillator capable of performing temperature compensation with high accuracy without the activity dip is obtained.

  Application Example 8 The dip information is calculated from a difference between the frequency temperature characteristic information and the approximate curve information, and extracted from information of a third approximate expression that approximates information representing a relationship between temperature and frequency deviation. 7. The piezoelectric oscillator according to any one of application examples 1 to 6, wherein the temperature coefficient is a measured temperature coefficient.

  As a result, the amount of information of activity dip in the frequency temperature characteristics of the piezoelectric vibrator can be reduced, so it is possible to reduce the memory burden, reduce costs, and perform temperature compensation without the activity dip. A piezoelectric oscillator.

  [Application Example 9] The activity dip is generated in a part of the temperature region of the frequency temperature characteristic, and the dip information is generated in the range of the temperature region. 9. The piezoelectric oscillator according to 8.

  As a result, the amount of activity dip information in the frequency temperature characteristics of the piezoelectric vibrator can be further reduced, so that the memory burden can be reduced and the temperature compensation without the activity dip can be performed at a reduced cost. It becomes a possible piezoelectric oscillator.

  Application Example 10 A method of manufacturing a piezoelectric oscillator having a piezoelectric vibrator having activity dip in frequency temperature characteristics, an oscillation circuit that oscillates the piezoelectric vibrator and outputs an oscillation signal, and a memory circuit, Extracting characteristic information from information of an approximate expression approximating the information of the frequency temperature characteristic, calculating dip information indicating activity dip based on the information of the frequency temperature characteristic and the information of the approximate expression, the characteristic information and A method of manufacturing a piezoelectric oscillator, wherein the dip information is stored in the storage circuit.

  According to the above method, the oscillation circuit outputs an oscillation signal including an activity dip in the frequency temperature characteristic of the piezoelectric vibrator, but the frequency temperature characteristic is approximately represented by the characteristic information and the dip information. Each memory use amount can be suppressed and the memory burden on the memory circuit can be suppressed. Since the characteristic information and the dip information are output, the temperature compensation of the oscillation signal can be performed by acquiring these two pieces of information on the user side.

  Application Example 11 A piezoelectric vibrator having an activity dip in frequency temperature characteristics, an oscillation circuit that oscillates the piezoelectric vibrator and outputs an oscillation signal, and the oscillation signal that is inputted with the oscillation signal and is based on a temperature compensation amount A temperature compensation method for a piezoelectric oscillator having a frequency correction circuit for performing temperature compensation, wherein characteristic information is extracted from information on an approximate expression approximating the frequency temperature characteristic, and the information on the frequency temperature characteristic and the approximate expression Dip information indicating a temperature characteristic of the activity dip is calculated based on the information of the dip, and a second approximate expression including the activity dip is generated based on the characteristic information and the dip information, and the second dip information is generated. A piezoelectric oscillator that calculates a temperature compensation amount based on an approximate expression and temperature information of the piezoelectric vibrator and outputs the temperature compensation amount to the frequency correction circuit Temperature compensation method.

  By the above method, the frequency correction circuit outputs an oscillation signal subjected to temperature compensation corresponding to the frequency temperature characteristic including the activity dip of the piezoelectric vibrator. Therefore, high-precision temperature compensation can be performed even with an oscillation circuit using a piezoelectric vibrator having frequency temperature characteristics including activity dip.

  Application Example 12 A piezoelectric vibrator having an activity dip in frequency temperature characteristics, and an oscillation circuit that oscillates the piezoelectric vibrator and outputs an oscillation signal and performs temperature compensation of the oscillation signal by a temperature compensation voltage. A temperature compensation method for a piezoelectric oscillator comprising: extracting characteristic information from information of an approximate expression that approximates the information of the frequency temperature characteristic; and performing an activity dip based on the information of the frequency temperature characteristic and the information of the approximate expression Dip information is calculated, information on the second approximate expression including the activity dip is generated using the characteristic information and the dip information, and information on the second approximate expression and the temperature of the piezoelectric vibrator A temperature compensation method for a piezoelectric oscillator, wherein the temperature compensation voltage is calculated on the basis of the information and output to the oscillation circuit.

  By the above method, the oscillation circuit outputs an oscillation signal subjected to temperature compensation corresponding to the frequency temperature characteristic including the activity dip of the piezoelectric vibrator. Therefore, even an oscillation circuit using a piezoelectric vibrator having frequency temperature characteristics including activity dip can perform temperature compensation with high accuracy. Further, since the frequency temperature characteristic is approximately represented by the characteristic information and the dip information, the memory usage can be suppressed and the memory load on the storage circuit can be suppressed.

It is a schematic diagram of the piezoelectric oscillator of the first embodiment. It is a schematic diagram at the time of connecting the piezoelectric oscillator of 1st Embodiment to the measuring device. It is a figure which shows the frequency temperature characteristic of a piezoelectric vibrator. It is a schematic diagram of the piezoelectric oscillator of the second embodiment. It is a partial detail drawing of the modification of the piezoelectric oscillator of 2nd Embodiment.

  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. 1 shows a piezoelectric oscillator according to the first embodiment. The piezoelectric oscillator 10 according to the first embodiment is connected to the temperature compensation circuit 32 based on the above-described TSXO or includes the temperature compensation circuit 32. In the piezoelectric oscillator 10 of the first embodiment, terminals such as an oscillation circuit 14, a temperature sensor 16, a storage circuit 18, a serial interface circuit 20, a power supply terminal 28, and a ground terminal 30 are formed by patterning on a semiconductor substrate (not shown). The oscillation circuit 14 and the piezoelectric vibrator 12 are connected to each other. Further, as shown in FIG. 1, the temperature compensation circuit 32 to be connected to the piezoelectric oscillator 10 includes a frequency correction circuit 34, a CPU 36 serving as an arithmetic circuit, a memory 38, and an A / D converter 40. When calculating the characteristic information and dip information from the frequency temperature characteristics of the piezoelectric vibrator 12, the piezoelectric oscillator 10 is connected to a measuring instrument 42 as shown in FIG. 2, and the measuring instrument 42 includes a frequency counter 44 and a PC 46. (Personal computer) and a voltage multimeter 48.

  The piezoelectric vibrator 12 is a piezoelectric material such as quartz, lithium niobate, lithium tantalate, etc. If it is quartz, it is formed by AT-cutting, receives an AC voltage from the oscillation circuit 14, and receives a predetermined amount by thickness shear vibration. It can oscillate at the resonance frequency. The resonance frequency of the crystal resonator using the thickness shear vibration due to the AT cut has a temperature characteristic that becomes a positive cubic curve centering on the reference temperature (25 ° C.).

  The oscillation circuit 14 is, for example, a Colpitts type oscillation circuit using the piezoelectric vibrator 12 as an oscillation source, and outputs an oscillation signal to the temperature compensation circuit 32 or the measuring device 42 via the oscillation signal output terminal 22.

  FIG. 3 shows frequency temperature characteristics of the piezoelectric vibrator, FIG. 3A is an overall view, and FIG. 3B is a detailed view of a portion surrounded by a broken line in FIG. The piezoelectric vibrator 12 used in the present embodiment is downsized and used in a state in which the current value to be driven is set high, so that the activity dip 56 is generated in the frequency temperature characteristic (frequency temperature characteristic information 54). It has become. Therefore, the frequency temperature characteristic of the oscillation signal 50 output from the oscillation circuit is also in a state having the activity dip 56.

  The activity dip 56 refers to a sudden fluctuation phenomenon of the resonance frequency or series resistance that occurs when a temperature change is applied to the piezoelectric vibrator 12, and as a dip at a predetermined temperature position of the frequency temperature characteristic of the piezoelectric vibrator 12. It is what appears.

  However, the frequency temperature characteristics of the piezoelectric vibrator 12 are approximated to characteristic information 58 (approximate curve 60) that changes gently with respect to temperature change of the resonance frequency and dip information 62 (approximate curve 64) that changes abruptly. They can be separated from each other using the formula.

First, frequency temperature characteristic information 54 in which the resonance frequency is measured at a predetermined temperature interval in the range from the set minimum temperature to the set maximum temperature of the piezoelectric oscillator 10 of the present embodiment is generated. Then, the frequency temperature characteristic information 54 is substituted into the following approximate expression (power series), and the characteristic information 58 is generated from the frequency temperature characteristic information 54.

Here, f is a reference frequency, Δf is a deviation between the measured frequency and the reference frequency, and T ₀ is a reference temperature. And each coefficient (A, B, C, D, E) of Numerical formula 1 is calculated using the least squares method. At this time, the dip included in the frequency temperature characteristic is not picked up by the order of Equation 1. Therefore, an approximate curve 60 that does not include a dip as shown in FIG. 3A can be generated from the obtained coefficients (A, B, C, D, E). By representing the characteristic information 58 as a coefficient in this way, the step of calculating the coefficient is not necessary on the temperature compensation side, so that the burden on the temperature compensation side can be reduced and the temperature compensation can be easily performed. it can.

  Note that the characteristic information 58 is a point on the approximate curve 60 generated by the above-described approximate expression information, and uses information indicating the relationship between the temperature and the frequency deviation extracted so that the approximate expression information can be generated. Also good. Or it is good also as information showing the relationship between temperature and a frequency (absolute value). Thus, it is necessary to calculate the coefficient on the temperature compensation side, but the coefficient can be calculated with high accuracy on the temperature compensation side.

  Next, the characteristic information 58 (coefficient) is substituted into the right side of Equation 1, the frequency temperature characteristic information 54 is substituted into the left side of Equation 1, and the dip information 62 is calculated by calculating the difference between the right side and the left side of Equation 1. Is generated.

  The dip information 62 obtained in this way indicates the relationship between the temperature and frequency deviation calculated by the difference between the frequency temperature characteristic information and the approximate curve 60 information generated from the approximate expression information (characteristic information 58). This is information to be represented (plot data in FIG. 3B). By adopting such an information form, the activity dip 56 in the frequency temperature characteristic of the piezoelectric vibrator 12 can be extracted with high accuracy, and therefore temperature compensation without the activity dip 56 is performed with high accuracy. be able to.

  The dip information 62 includes information in the same temperature range as the frequency temperature characteristic information 54. However, in the frequency temperature characteristic, the activity dip 56 is one of the temperature ranges included in the frequency temperature characteristic information 54. Since it is in the temperature region of the part, information other than that temperature region may be deleted. As a result, it is possible to reduce the memory burden of the storage circuit 18 and the like, which will be described later, and to suppress the cost of the piezoelectric oscillator 10.

  The oscillation signal from the oscillation circuit includes information on the second approximate expression obtained by adding the information on the above approximate expression (characteristic information) and the dip information, and information on the temperature of the piezoelectric vibrator 12 (temperature T). Temperature compensation can be performed.

In the first embodiment, the characteristic information 58 and the dip information 62 are output to the temperature compensation circuit 32. Therefore, the dip information 62 is also preferably expressed by the above-described coefficient. The dip information 62 can be approximated by a third approximate expression (power series) shown below.

Therefore, the same calculation as described above is performed. The dip information 62 can be expressed by the coefficients (A, B, C, D, E, F) of Equation 2.
The dip information 62 obtained in this way is calculated by the difference between the frequency temperature characteristic information 54 and the information of the approximate curve 60 generated from the approximate expression information, and is a third one that approximates information representing the relationship between temperature and frequency deviation. It becomes the information of the coefficient extracted from the information of the approximate expression. As a result, the amount of activity dip information in the frequency temperature characteristics of the piezoelectric vibrator 12 can be reduced, so that the memory compensation is reduced, the cost is reduced, and temperature compensation is performed without the activity dip 56. Can do.

  By the way, the activity dip 56 related to the dip information 62 includes, for example, as shown in FIG. 3B, a first temperature range 66 that draws a convex curve upward, and a second temperature range 68 that draws a straight line. And a third temperature range 70 having a downwardly convex curve. Accordingly, the dip information 62 calculates the coefficient of Equation 2 for each of the first temperature range 66, the second temperature range 68, and the third temperature range 70, and the temperature compensation circuit 32 (described later in a second implementation). (Temperature compensation voltage generation circuit) may be configured such that the coefficient of the dip information 62 can be selected in accordance with the temperature at which temperature compensation is performed. As a result, the dip information 62 can generate an approximate curve 64 according to Equation 2.

  Therefore, as a combination of the characteristic information 58 and the dip information 62, (characteristic information 58, dip information 62) = (temperature and frequency deviation, temperature and frequency deviation), (coefficient, coefficient (there are cases depending on the temperature range)), ( Temperature and frequency deviation, coefficient (depending on temperature range), (coefficient, temperature and frequency deviation) can be applied. In any combination, the temperature compensation circuit 32 (a temperature compensation voltage generation circuit according to a second embodiment to be described later) is configured to generate the above-described second approximate expression and output the temperature compensation amount 72. The above calculation is performed by the measuring instrument 42 described later.

  The temperature sensor 16 has a diode structure, allows a forward current to flow, and outputs a detection voltage 52 that varies depending on the temperature from the temperature sensor voltage output terminal 24 to the temperature compensation circuit 32 or the measuring instrument 42. Here, the detection voltage 52 decreases linearly as the temperature rises, and the output detection voltage 52 corresponds to the measured temperature T. The temperature sensor 16 is desirably disposed adjacent to the piezoelectric vibrator 12. Accordingly, the temperature of the piezoelectric vibrator 12 can be accurately measured, and the frequency temperature characteristic information 54, the characteristic information 58, and the dip information 62 can be calculated with high accuracy. As described above, in this embodiment, the temperature of the piezoelectric vibrator 12 corresponds to the detection voltage 52 from the temperature sensor 16. Therefore, the measuring instrument 42 described later calculates frequency temperature characteristic information 54, characteristic information 58, and dip information 62 as information associated with the detection voltage 52 (information having the detection voltage 52 as a domain), and the temperature compensation circuit 32. The temperature compensation amount 72 is calculated by treating the characteristic information 58 and the dip information 62 as information associated with the detected voltage 52.

  The serial interface circuit 20 receives a command from the outside and stores the characteristic information 58 and the dip information 62 in the storage circuit 18 or outputs them to the outside. The serial interface circuit 20 is connected to the storage circuit 18 and is also connected to the temperature compensation circuit 32 and the measuring device 42 via the data input / output terminal 26.

  The storage circuit 18 is formed of an EEPROM or the like, and the characteristic information 58 and the dip information 62 can be stored (written) or output via the serial interface circuit 20. The characteristic information 58 and the dip information 62 are composed of a finite number of data, respectively, but are provided with addresses that can be commonly recognized by the PC 46 in the measuring instrument 42 and the CPU 36 in the temperature compensation circuit 32, respectively. To do. Further, when the dip information 62 is stored as a coefficient, the coefficient calculated for each temperature range described above corresponds to the temperature range so that the coefficient can be properly used in a temperature compensation circuit 32 (a temperature compensation voltage generation circuit described later). Assume that addresses that can be distinguished from each other are provided.

  The temperature compensation circuit 32 receives the oscillation signal from the oscillation circuit 14 and also approximates the temperature characteristic of the oscillation frequency of the oscillation signal 50 output from the oscillation circuit 14 based on the characteristic information 58 and the dip information 62. 2 is generated, the temperature compensation amount 72 is calculated using the second approximate expression and the detection voltage 52 which is the temperature information of the piezoelectric vibrator 12, and the temperature compensated oscillation signal 74 is output. It is.

  The temperature compensation circuit includes a frequency correction circuit, a CPU serving as an arithmetic circuit, a memory, and the like. The frequency correction circuit is a circuit that varies the frequency of the output signal in accordance with the temperature compensation amount output from the CPU. The frequency correction circuit is connected to the oscillation signal output terminal and receives the oscillation signal, and the temperature is controlled under the control of the CPU. The compensated oscillation signal is output.

  The CPU 36 is the core of the temperature compensation circuit, and generates a second approximate expression that approximates the temperature characteristic of the oscillation frequency of the piezoelectric vibrator 12 from the characteristic information 58 and the dip information 62 input from the storage circuit 18. The temperature compensation amount 72 is calculated based on the second approximate expression and the detection voltage 52 (temperature information) input from the temperature sensor 16 and is output to the frequency correction circuit 34.

  The CPU 36 is connected to the data input / output terminal 26, the frequency correction circuit 34, and the temperature sensor 16 via the A / D converter 40. At startup, the CPU 36 outputs serial data for reading the characteristic information 58 and the dip information 62 stored in the storage circuit 18 to the data input / output terminal 26 by a program, and the characteristic information 58 and the dip information 62 in the storage circuit 18 are output. Are output via the serial interface circuit 20 and stored in the memory 38 attached to the CPU 36.

  When the characteristic information 58 stored in the storage circuit 18 is constituted by the temperature and frequency deviation information calculated through the above-described Equation 1, the CPU 36 uses the approximate expression of Equation 1 to indicate the temperature T information, It is assumed that the frequency deviation information corresponding to the temperature T is substituted, and coefficients (A, B, C, D, E) are calculated using the least square method or the like and stored in the memory 38 attached to the CPU 36. When the characteristic information 58 stored in the storage circuit 18 is constituted by coefficient information, the CPU 36 is assumed to have a configuration in which it is stored in the attached memory as it is.

  On the other hand, when the dip information 62 stored in the storage circuit 18 is constituted by the temperature and frequency deviation information calculated by the mathematical formula 1, the CPU 36 stores it in the attached memory 38 as it is, and stores it in the input detection voltage 52. It is assumed that the frequency deviation information related to the information on the temperature (closest temperature) matching the corresponding temperature can be extracted. Further, when the dip information 62 is constituted by the coefficient information calculated by Equation 2, the CPU 36 stores it in the attached memory 38 as it is.

Then, the CPU 36 uses the characteristic information 58 read from the memory 38 and the temperature information (T−T ₀ ) to calculate the component of the characteristic information 58 of the temperature compensation amount 72 according to Equation 1. Further, the CPU 36 calculates the component of the dip information 62 of the temperature compensation amount 72 according to Equation 2 using the dip information 62 read from the memory 38 and the temperature information (T−T ₀ ). Then, the temperature compensation amount 72 is calculated by adding the component of the characteristic information 58 of the temperature compensation amount 72 (the right side of Equation 1) and the component of the dip information 62 of the temperature compensation amount 72 (the right side of Equation 2). Note that the sum of the right side of Formula 1 and the right side of Formula 2 is also the second approximate formula.

  Here, when the input temperature information (detection voltage 52) belongs to any of the first temperature range 66, the second temperature range 68, and the third temperature range 70, the temperature range is related. A coefficient is selected and used. Further, when the input temperature T information (detection voltage) does not belong to any of the above temperature ranges, the temperature compensation amount 72 is calculated using only the component (Equation 1) of the characteristic information 58.

  Further, the CPU 36 converts the detected voltage 52 (temperature information) from the temperature sensor 16 into digital data via the A / D converter 40 and inputs it into the attached memory 38 every predetermined time by a program. Then, the characteristic information 58 and the dip information 62 are read from the memory 38 to generate a second approximate expression, and the detection voltage 52 (temperature information) is further read from the memory 38, and the temperature is calculated from the second approximate expression and the detection voltage 52. A compensation amount 72 is calculated, and the temperature compensation amount 72 is output to the frequency correction circuit 34. Therefore, the CPU 36 calculates the temperature compensation amount 72 every predetermined time and outputs it to the frequency correction circuit 34. As a result, the frequency correction circuit 34 always outputs the oscillation signal 74 after temperature compensation, but the oscillation signal 74 is subjected to temperature compensation every predetermined time.

  As described above, since the CPU 36 requires the characteristic information 58 and the dip information 62, the piezoelectric oscillator 10 needs to store the characteristic information 58 and the dip information 62 to be output to the CPU 36 in the storage circuit 18 in advance. For this reason, the piezoelectric oscillator 10 is connected to the measuring instrument 42, and the frequency temperature characteristic information 54 in the range from the set minimum temperature to the set maximum temperature of the piezoelectric oscillator 10 is generated. Based on this, the characteristic information 58 and the dip information 62 are generated. There is a need to.

  FIG. 2 shows a connection diagram between the piezoelectric oscillator and the measuring instrument. The measuring device 42 calculates characteristic information 58 and dip information 62 required by the temperature compensation circuit 32 and writes them in the storage circuit 18. The measuring instrument 42 includes a frequency counter 44, a PC 46 (personal computer), and a voltage multimeter 48. The frequency counter 44 is connected to the oscillation signal output terminal 22 and can measure the frequency of the oscillation signal 50 output from the oscillation circuit 14 and output it to the PC 46. The voltage multimeter 48 can convert the detection voltage 52 from the temperature sensor 16 into digital data and output it to the PC 46.

  The PC can start a frequency counter or voltage multimeter by key operation, etc., and can input a detection voltage (temperature information) from a temperature sensor and store it in a storage area (not shown) attached to the PC. it can.

  In the present embodiment, the piezoelectric oscillator 10 is disposed in a temperature-adjustable chamber (not shown), and the piezoelectric oscillator 10 is changed within a predetermined temperature range from the set minimum temperature to the set maximum temperature. Frequency temperature characteristic information 54 is generated by measuring the oscillation frequency of the oscillation signal 50 output from the piezoelectric oscillator 10 at each temperature point. It should be noted that the temperature width only needs to correspond to a resolution that can identify the shape of the activity dip 56 in the frequency temperature characteristic information 54.

  Then, the PC 46 generates the characteristic information 58 and the dip information 62 by using the above formula 1 or the formula 2 as described later, converts them into serial data, and stores them in the storage circuit 18 via the serial interface circuit 20. Thereafter, when the piezoelectric oscillator 10 is connected to the temperature compensation circuit 32, the characteristic information 58 and the dip information 62 stored in the storage circuit 18 are input to the CPU 36 (memory 38) of the temperature compensation circuit 32, and the characteristic information 58 and the dip information 62 are stored. The temperature compensation amount 72 is calculated from the second approximation equation and the detection voltage 52 based on the second approximation equation, the temperature compensation amount 72 is output to the frequency correction circuit 34, and the temperature compensated oscillation signal 74 is calculated. Will be output.

  In the present embodiment, the capacities of the characteristic information 58 and the dip information 62 stored in the storage circuit 18 will be described. First, consider the case where the characteristic information 58 and the dip information 62 are each composed of temperature and frequency deviation information. The characteristic information 58 includes, for example, a first temperature point (set minimum temperature, for example, −30 ° C.), a second temperature point (for example, −15 ° C.), a third temperature point (for example, 0 ° C.), Frequency at 4th temperature point (reference temperature, eg: + 25 ° C), 5th temperature point (eg: + 50 ° C), 6th temperature point (eg: + 70 ° C), 7th temperature point (set maximum temperature, eg + 85 ° C) The deviation is extracted and configured by a combination of information on each temperature point and information on the frequency deviation at each temperature point. In addition, the coefficient in Formula 1 is easily computable by employ | adopting the above temperature point.

  The capacity used for each piece of information for each temperature point varies according to the significant number of each piece of information, but in the present embodiment, it is assumed that each is 2 bytes. Then, the capacity used by the characteristic information 58 is 28 bytes based on seven pieces of temperature point information and seven pieces of frequency deviation information corresponding thereto. On the other hand, for the dip information 62, 14 temperature points are used in the temperature range including the activity dip 56 appearing in the frequency temperature characteristic information 54, and 14 frequency deviations corresponding thereto are also used. At this time, if the capacity used by each information is 2 bytes, the capacity used by the dip information 62 is 56 bytes. Therefore, the sum of the characteristic information 58 and the dip information 62 is 84 bytes.

  Next, consider the case where the characteristic information 58 and the dip information 62 are each composed of coefficient information. The characteristic information 58 is the coefficient (five) of the above-described formula 1. Therefore, if 2 bytes are used per information of one coefficient, the capacity used by the characteristic information 58 is 10 bytes. On the other hand, the dip information 62 is the coefficient (six) of the above-described formula 2 and is classified according to the temperature range. As described above, the activity dip 56 related to the dip information 62 generates coefficient information for each of the first temperature range, the second temperature range, and the third temperature range. Then, six coefficients are used in each of the first temperature range and the third temperature range, and two coefficients (E, F) are used because the activity dip is a linear function in the second temperature range. Become. Therefore, if 2 bytes are used per information of one coefficient, the capacity used by the dip information 62 is 28 bytes. Therefore, the total of the characteristic information 58 and the dip information 62 is 38 bytes.

  By the way, when the frequency temperature characteristic information 54 is generated with a temperature range that allows the shape of the activity dip 56 to be recognized, a capacity much larger than the capacity in the above two cases is required. Therefore, it can be seen that the frequency temperature characteristics can be expressed using the characteristic information 58 and the dip information 62 as in the present embodiment, so that the capacity used can be reduced and the memory load on the storage circuit 18 can be reduced. .

  According to the piezoelectric oscillator 10 of the first embodiment, the oscillation circuit 14 outputs the oscillation signal 50 including the activity dip 56 in the frequency temperature characteristic of the piezoelectric vibrator 12. Since it is approximately represented by the characteristic information 58 and the dip information 62, the memory usage can be suppressed and the memory load on the storage circuit 18 can be suppressed. Since the characteristic information 58 and the dip information 62 are output, the temperature compensation of the oscillation signal 50 can be performed by acquiring these two pieces of information on the user side.

  Further, the piezoelectric oscillator 10 of the present embodiment has a configuration connected to the temperature compensation circuit 32 and a configuration including the temperature compensation circuit 32. Therefore, the temperature compensation circuit 32 (frequency correction circuit 34) outputs an oscillation signal 74 that has been subjected to temperature compensation in accordance with the frequency temperature characteristic including the activity dip 56 of the piezoelectric vibrator 12. Therefore, highly accurate temperature compensation can be performed even with the oscillation circuit 14 using the piezoelectric vibrator 12 having the frequency temperature characteristic including the activity dip 56.

  FIG. 4 shows a piezoelectric oscillator according to the second embodiment. As shown in FIG. 4, the piezoelectric oscillator includes an oscillation circuit 104, a temperature sensor 106, a temperature compensation voltage generation circuit 108, a storage circuit 136, a switching circuit 138, a serial interface circuit 140, a power supply by patterning on a semiconductor substrate (not shown). A semiconductor circuit board on which terminals such as a terminal 142 and a ground terminal 144 are formed is provided, and the oscillation circuit 104 and the piezoelectric vibrator 102 are connected.

  The piezoelectric vibrator 102 has the same characteristics as the piezoelectric vibrator 12 of the first embodiment. The oscillation circuit 104 is, for example, a Colpitts type oscillation circuit using the piezoelectric vibrator 102 as an oscillation source. The oscillation circuit 104 has a built-in variable capacitor, and a temperature compensation voltage 164 applied to the variable capacitor or an ideal from the outside. The compensation voltage 156 is input, temperature compensation of the oscillation signal 154 output from the oscillation circuit 104 is performed, and the oscillation signal 154 is output to the oscillation signal output terminal 146.

  The temperature compensation voltage 164 and the ideal compensation voltage 156 are such that when the oscillation circuit 104 including the piezoelectric vibrator 102 is changed from the set minimum temperature to the set maximum temperature, the frequency of the oscillation signal 154 is the reference temperature (25 ° C.). Is a voltage applied to the variable capacitor of the oscillation circuit 104 so as to be the same as the reference frequency in FIG. Therefore, the temperature characteristics of the temperature compensation voltage 164 and the ideal compensation voltage 156 coincide with the frequency temperature characteristics of the piezoelectric vibrator 102, and the activity dip 56 appears in the temperature characteristics. Therefore, according to the temperature characteristics of the ideal compensation voltage 156, the same characteristic information 158 (see the same as the characteristic information 58, see FIG. 3) and the dip information 160 (the same as the dip information 62, as shown in FIG. See). Note that the temperature compensation voltage 164 and the ideal compensation voltage 156 are used in a range in which the change in the frequency of the oscillation signal 154 responds linearly (range in which linear response is performed).

  Similar to the temperature sensor 16 of the first embodiment, the temperature sensor 106 has a diode structure, generates a temperature-compensated voltage by passing a forward current and generating an analog detection voltage that is a potential between the terminals of the diode, which varies with temperature. Can be output to the circuit. The temperature sensor always outputs the detection voltage as long as the power supply voltage is supplied.

  The temperature compensation voltage generation circuit 108 includes a quaternary voltage generation circuit 110, a tertiary voltage generation circuit 112, a secondary voltage generation circuit 114, a primary voltage generation circuit 116, a 0th order voltage generation circuit 118, a DIP voltage generation circuit 120, and an addition. The circuit 122 is configured. Each voltage generating circuit is connected to the memory circuit 136.

The frequency-temperature characteristics of the piezoelectric vibrator 102 of the present embodiment can be approximately expressed by the characteristic information 158 and the dip information 160, as with the piezoelectric vibrator 12 of the first embodiment. Therefore, in order to perform temperature compensation of the oscillation signal 154 having such temperature characteristics, the component related to the characteristic information 158 of the temperature compensation voltage 164 (ideal compensation voltage 156) Vh needs to have the following temperature characteristics. .

Here, Vc ₄ , Vc ₃ , Vc ₂ , Vc ₁ , and Vc ₀ correspond to −A, −B, −C, −D, and −E in Formula 1, respectively. T ₀ is a reference temperature. Information coefficients in the order 4 primary voltage generating circuit 110 (Vc ₄₎ is, information of the coefficient for third order voltage generating circuit 112 (Vc ₃₎ is the secondary voltage generating circuit 114 coefficients (Vc ₂₎ The information is configured such that the primary voltage generation circuit 116 receives information on the coefficient (Vc ₁ ) and the zero-order voltage generation circuit 118 receives information on the coefficient (Vc ₀ ).

When the temperature information of the piezoelectric vibrator 102, that is, the detection voltage 152 is input to each voltage generation circuit other than the zero-order voltage generation circuit 118, the quaternary voltage generation circuit 110 receives the temperature information (T −T ₀ ) and the voltage corresponding to the product of the coefficient (Vc ₄ ) information are output, and the tertiary voltage generation circuit 112 outputs the third power of the temperature information (T−T ₀ ) and the coefficient (Vc _3). ) Is output, and the secondary voltage generation circuit 114 outputs a voltage corresponding to the product of the square of the temperature information (T−T ₀ ) and the coefficient (Vc ₂ ). The voltage generation circuit 116 outputs the product of the temperature information (T−T ₀ ) and the coefficient (Vc ₁ ), and the zero-order voltage generation circuit 118 outputs a voltage corresponding to the value of the coefficient (Vc ₁ ).

  On the other hand, when the dip information 160 is information indicating the relationship between the temperature and the frequency deviation, all of the dip information 160 is input to the DIP voltage generation circuit 120 and temperature information (detection voltage 152) from the temperature sensor 106 is input. ) Is extracted, and the voltage corresponding to this information is output. These voltages are added by the adder circuit 122 to generate a temperature compensation voltage 164 (Vh).

  The storage circuit 136 is formed of an EEPROM or the like, stores characteristic information 158 and dip information 160 input via the serial interface circuit 140, and outputs these information to the temperature compensation voltage generation circuit 108.

Therefore, the memory circuit 136 outputs information on the coefficient A corresponding to the coefficient (Vc ₄ ) to the fourth voltage generation circuit 110 and outputs information on the coefficient B corresponding to the coefficient (Vc ₃ ) to the third voltage generation circuit 112. Then, information on the coefficient C corresponding to the coefficient (Vc ₂ ) is output to the secondary voltage generation circuit 114, information on the coefficient D corresponding to the coefficient (Vc ₁ ) is output to the primary voltage generation circuit 116, and the coefficient ( Information on the coefficient E corresponding to (Vc ₀ ) (offset amount) is output to the zero-order voltage generation circuit 118. If the dip information 160 is temperature and frequency deviation information, the entire dip information 160 is output to the DIP voltage generation circuit 120.

  The characteristic information 158 and the dip information 160 are calculated by the PC 174 described later. When new characteristic information 158 and dip information 160 are input, the storage circuit 136 overwrites the original characteristic information 158 and dip information 160 and stores the new characteristic information 158 and dip information 160. This is output to the temperature compensation voltage generation circuit 108.

  The switching circuit 138 is interposed between the temperature compensation voltage generation circuit 108 and the oscillation circuit 104. The switching circuit 138 has a configuration in which one is connected to the oscillation circuit 104 and the other is connectable to either the temperature compensation voltage generation circuit 108 or the voltage input terminal 148 (voltage generation circuit 170). The switching circuit 138 can be switched and connected to the temperature compensation voltage generation circuit 108 side and the voltage input terminal 148 side by a switching signal 162 input from the serial interface circuit 140.

  The serial interface circuit 140 is connected to the signal input terminal 150, decodes serial data (characteristic information 158, dip information 160, switching signal 162) from the outside, and the decoded information is characteristic information 158 and dip information 160. Outputs the information to the storage circuit 136, and outputs the switching signal 162 to the switching circuit 138 when the decoded information is the switching signal 162.

  In the calculation process of the characteristic information 158 and the dip information 160 in the present embodiment, the piezoelectric oscillator 100 is connected to the measuring instrument 166. The measuring instrument 166 includes a frequency counter 168, a voltage generation circuit 170, a voltage multimeter 172, and a PC 174 (personal computer).

  The frequency counter 168 is connected to the oscillation signal output terminal 146, measures the frequency information of the oscillation signal 154 output from the oscillation circuit 104 at predetermined time intervals, and outputs it to the PC 174. The voltage generation circuit 170 is connected to the voltage input terminal 148 and outputs an ideal compensation voltage 156 that can be adjusted to an arbitrary voltage value to the oscillation circuit 104 via the switching circuit 138. The voltage multimeter 172 measures the value of the ideal compensation voltage 164 output from the voltage generation circuit 170 and outputs information on the ideal compensation voltage 164 to the PC.

  The PC 174 is connected to the signal input terminal 150, calculates the characteristic information 158 and the dip information 160, converts the information or the information of the switching signal 162 into serial data, and outputs the serial data to the serial interface circuit 140.

  The ideal compensation voltage 156 is adjusted by, for example, an operator manually adjusting the frequency of the oscillation signal 154 displayed on the display of the PC 174, and the frequency of the oscillation signal 154 matches the basic frequency by key operation on the PC 174. Information of ideal compensation voltage 156 and temperature information may be input. Further, the voltage generation circuit 170 is connected to the PC 174, and the output of the voltage generation circuit 170 is adjusted so that the frequency of the oscillation signal 154 becomes the reference frequency according to a program installed in the PC 174, and the ideal compensation voltage 156 at this time The information and temperature information may be input. In any case, the PC 174 has a configuration that converts temperature information into a detection voltage 152 output from the temperature sensor 106.

  The characteristic information 158 and the dip information 160 in the present embodiment are changed in a predetermined temperature range from the set minimum temperature to the set maximum temperature for the oscillation circuit including the piezoelectric vibrator 102 as in the first embodiment. Then, the ideal compensation voltage 156 is applied manually or by a program of the PC 174 or the like so that the frequency of the oscillation signal 154 at that time becomes the reference frequency, and the applied voltage information and the temperature information are generated. 156 temperature characteristic information is generated. This temperature characteristic information can be obtained by applying Equation 1.

FIG. 5 shows a partial detailed view of a modification of the piezoelectric oscillator of the second embodiment. Next, a case where the dip information 160 is used as coefficient information according to Equation 2 will be described. Since the DIP voltage generation circuit 120 corresponds to the coefficient shown in Formula 2, as shown in FIG. 5, the fifth voltage generation circuit 124, the fourth voltage generation circuit 126, the third voltage generation circuit 128, and the second voltage generation circuit 130. The primary voltage generation circuit 132 and the zero-order voltage generation circuit 134 are configured such that the input side is connected to the storage circuit 136 in parallel with each other, and the output side is connected to the adder circuit 122. Each voltage generation circuit is connected to the temperature sensor 106 and receives the detection voltage 152. Therefore, the voltage Vh ₁ output from the DIP voltage generation circuit 120 is as follows.

Here, Vc ₅ , Vc ₄ , Vc ₃ , Vc ₂ , Vc ₁ , and Vc ₀ correspond to −A, −B, −C, −D, −E, and −F in Formula 2, respectively. T ₀ is a reference temperature. For this reason, the fifth voltage generation circuit 124 generates information on the coefficient A corresponding to the coefficient (Vc ₅ ), and the fourth voltage generation circuit 126 receives information on the coefficient B corresponding to the coefficient (Vc ₄ ). The circuit 128 has information on the coefficient C corresponding to the coefficient (Vc ₃ ), the secondary voltage generation circuit 130 has information on the coefficient D corresponding to the coefficient (Vc ₂ ), and the primary voltage generation circuit 132 has the coefficient ( The information on the coefficient E corresponding to Vc ₁ ) and the information on the coefficient F corresponding to the coefficient (Vc ₀ ) are input to the zero-order voltage generation circuit 134.

When the voltage information of the piezoelectric vibrator 102, that is, the detection voltage 152 is input to each voltage generation circuit, the fifth-order voltage generation circuit 124 calculates the fifth power of the temperature information (T−T ₀ ) of the piezoelectric vibrator 102. A voltage corresponding to the product of the coefficient (Vc ₅ ) information is output, and the quaternary voltage generation circuit 126 corresponds to the product of the fourth power of the temperature information (T−T ₀ ) and the coefficient (Vc ₄ ) information. The secondary voltage generation circuit 128 outputs a voltage corresponding to the product of the third power of the temperature information (T−T ₀ ) and the coefficient (Vc ₃ ) information, and the secondary voltage generation circuit 130 A voltage corresponding to the product of the square of the temperature information (T−T ₀ ) and the coefficient (Vc ₂ ) is output, and the primary voltage generation circuit 132 outputs the temperature information (T−T ₀ ) and the coefficient (Vc ₁ ). outputs of the product, 0-order voltage generating circuit 134 outputs a voltage corresponding to the value of the coefficient (Vc ₀₎ That.

Here, as described in the first embodiment, the dip information 160 includes, for example, a first temperature range 66 in which the shape of the dip is an upwardly convex shape, a second temperature range 68 that changes in a linear function, A coefficient is obtained for each third temperature range 70 having a downwardly convex shape, and information on the corresponding temperature range is added to each coefficient. Therefore, each voltage generation circuit receives a plurality of coefficients (three in this embodiment) from the storage circuit 136. Further, each voltage generation circuit determines which temperature range the temperature information (detection voltage 152) from the temperature sensor 106 belongs to, and selects a coefficient belonging to the temperature range. Accordingly, each voltage generation circuit selects a coefficient corresponding to the temperature related to the detection voltage 152 from among a plurality of coefficients input in advance from the storage circuit 136, and selects a corresponding voltage based on the selected coefficient and the detection voltage 152. Will be output. Thus, the temperature compensation voltage 164 is generated by adding the voltage (Vh) related to the characteristic information 158 and the voltage (Vh ₁ ) related to the dip information 160, and has the activity dip 56 in the frequency temperature characteristic. However, the temperature compensation of the oscillation signal 154 can be performed satisfactorily. When the input temperature T (detection voltage 152) does not belong to any of the first temperature range 66, the second temperature range 68, and the third temperature range 70, the temperature compensation voltage 164 is , Calculated only by the voltage (Vh) according to the characteristic information 158.

  Therefore, according to the piezoelectric oscillator 100 according to the second embodiment, the oscillation circuit 104 outputs the oscillation signal 154 that has been subjected to temperature compensation in accordance with the frequency temperature characteristic including the activity dip 56 of the piezoelectric vibrator 102. It will be. Therefore, even the oscillation circuit 104 using the piezoelectric vibrator 102 having the frequency temperature characteristic including the activity dip 56 can perform temperature compensation with high accuracy. Further, since the frequency temperature characteristic is approximately expressed using the characteristic information 158 and the dip information 160, the memory usage can be suppressed and the memory load on the storage circuit 136 can be suppressed.

10 ......... Piezoelectric oscillator, 12 ......... Piezoelectric vibrator, 14 ......... Oscillation circuit, 16 ......... Temperature sensor, 18 ......... Storage circuit, 20 ......... Serial interface circuit, 22 ......... Oscillation signal Output terminal, 24 ......... Temperature sensor voltage output terminal, 26 ......... Data input / output terminal, 28 ......... Power supply terminal, 30 ......... Ground terminal, 32 ......... Temperature compensation circuit, 34 ......... Frequency correction Circuit, 36 ......... CPU, 38 ......... Memory, 40 ......... A / D converter, 42 ......... Measurement device, 44 ......... Frequency counter, 46 ......... PC, 48 ......... Voltage multi Meter, 50 ......... Oscillation signal, 52 ... Detection voltage, 54 ......... Frequency / temperature characteristic information, 56 ... Activity dip, 58 ......... Characteristic information, 60 ......... Approximate curve, 62 ... ... Dip information, 64 ... Approximate curve, 66 ......... first temperature range, 68 ......... second temperature range, 70 ......... third temperature range, 72 ......... temperature compensation amount, 74 ......... oscillation signal, 100 ... …… Piezoelectric oscillator, 102 ...... Piezoelectric vibrator, 104 ...... Oscillation circuit, 106 ...... Temperature sensor, 108 ...... Temperature compensation voltage generation circuit, 110 ...... Quaternary voltage generation circuit, 112 …… ... Tertiary voltage generation circuit 114... Secondary voltage generation circuit 116... Primary voltage generation circuit 118... 0th voltage generation circuit 120... DIP voltage generation circuit 122. Adder circuit 124... 5th voltage generator circuit 126... 4th voltage generator circuit 128 128... Tertiary voltage generator circuit 130... Secondary voltage generator circuit 132 132. Generator circuit 134... Zero-order voltage generator circuit 136 136 Memory circuit 138... Switching circuit 140... Serial interface circuit 142... Power supply terminal 144 144 Ground terminal 146 Oscillation signal output terminal 148 Voltage input terminal 150 Signal input terminal, 152... Detection voltage, 154... Oscillation signal, 156... Ideal compensation voltage, 158... Characteristic information, 160... Dip information, 162. ... Temperature compensation voltage, 166 ......... Measurement device, 168 ......... Frequency counter, 170 ......... Voltage generation circuit, 172 ...... Voltage multimeter, 174 ...... PC.

Claims (12)

A piezoelectric vibrator having an activity dip in the frequency-temperature characteristics;
An oscillation circuit that oscillates the piezoelectric vibrator and outputs an oscillation signal;
A storage circuit,
In the memory circuit,
Characteristic information extracted from information of an approximate expression that approximates information of the frequency temperature characteristic;
A piezoelectric oscillator characterized in that dip information indicating an activity dip calculated based on the information on the frequency temperature characteristic and the information on the approximate expression is stored. The oscillation circuit generates a second approximate expression including the activity dip based on the characteristic information and the dip information, and based on the second approximate expression and the temperature information of the piezoelectric vibrator. Output the oscillation signal to a temperature compensation circuit that performs temperature compensation of the oscillation signal,
The piezoelectric oscillator according to claim 1, wherein the storage circuit outputs information for generating the approximate expression and the dip information to the temperature compensation circuit. A piezoelectric vibrator having an activity dip in the frequency-temperature characteristics;
An oscillation circuit that oscillates the piezoelectric vibrator and outputs an oscillation signal;
The characteristic information extracted from the information of the approximate expression approximating the frequency temperature characteristic, and the dip information indicating the temperature characteristic of the activity dip calculated based on the information of the frequency temperature characteristic and the information of the approximate expression are stored. Memory circuit,
A second approximate expression including the activity dip is generated based on the characteristic information and the dip information, and a temperature compensation amount is output based on the second approximate expression and temperature information of the piezoelectric vibrator. An arithmetic circuit to
A piezoelectric oscillator comprising: a frequency correction circuit that receives the oscillation signal and performs temperature compensation of the oscillation signal based on the temperature compensation amount. The information of the approximate expression is generated by approximation by power series expansion of the information of the frequency temperature characteristic,
4. The piezoelectric oscillator according to claim 1, wherein the characteristic information is information of a coefficient extracted from the information of the approximate expression. 5.   The characteristic information is a point on the approximate curve generated by the information of the approximate expression, and information on the relationship between the temperature and the frequency deviation extracted so that the information of the approximate expression can be generated, or between the temperature and the frequency The piezoelectric oscillator according to claim 1, wherein the piezoelectric oscillator is information representing a relationship. A piezoelectric vibrator having an activity dip in the frequency-temperature characteristics;
An oscillation circuit that oscillates the piezoelectric vibrator to output an oscillation signal and performs temperature compensation of the oscillation signal by a temperature compensation voltage;
A temperature compensation voltage generation circuit that outputs the temperature compensation voltage to the oscillation circuit, and
The temperature compensated voltage generation circuit includes:
Using the characteristic information extracted from the information of the approximate expression approximating the information of the frequency temperature characteristic, and the dip information indicating the activity dip calculated based on the information of the frequency temperature characteristic and the information of the approximate expression Generating information of a second approximate expression including the activity dip, and calculating the temperature compensation voltage based on the information of the second approximate expression and the temperature information of the piezoelectric vibrator; Piezoelectric oscillator.   The dip information is information representing a relationship between temperature and frequency deviation calculated by a difference between information on the frequency-temperature characteristic and information on an approximate curve generated from the information on the approximate expression. The piezoelectric oscillator according to any one of claims 1 to 5.   The dip information is a temperature coefficient extracted from the information of the third approximate expression that is calculated by the difference between the frequency temperature characteristic information and the approximate curve information, and approximates the information representing the relationship between the temperature and the frequency deviation. The piezoelectric oscillator according to claim 1, wherein the piezoelectric oscillator is provided. The activity dip is generated in a part of the temperature range of the frequency temperature characteristic,
The piezoelectric oscillator according to claim 7 or 8, wherein the dip information is generated in a range of the temperature region. A piezoelectric vibrator having an activity dip in the frequency-temperature characteristics;
An oscillation circuit that oscillates the piezoelectric vibrator and outputs an oscillation signal;
A method of manufacturing a piezoelectric oscillator having a memory circuit,
Extracting the characteristic information from the information of the approximate expression that approximates the frequency temperature characteristic information,
A method of manufacturing a piezoelectric oscillator, comprising: calculating dip information indicating an activity dip based on information on the frequency temperature characteristic and information on the approximate expression; and storing the characteristic information and the dip information in the storage circuit . A piezoelectric vibrator having an activity dip in the frequency-temperature characteristics;
An oscillation circuit that oscillates the piezoelectric vibrator and outputs an oscillation signal;
A frequency compensation circuit that receives the oscillation signal and performs temperature compensation of the oscillation signal based on a temperature compensation amount, and a temperature compensation method for a piezoelectric oscillator,
Extracting the characteristic information from the information of the approximate expression that approximates the frequency temperature characteristic,
Calculate dip information indicating the temperature characteristic of the activity dip based on the information of the frequency temperature characteristic and the information of the approximate expression,
A second approximate expression including the activity dip is generated based on the characteristic information and the dip information, and a temperature compensation amount is calculated based on the second approximate expression and the temperature information of the piezoelectric vibrator. And outputting to the frequency correction circuit. A piezoelectric vibrator having an activity dip in the frequency-temperature characteristics;
An oscillation circuit that oscillates the piezoelectric vibrator and outputs an oscillation signal and performs temperature compensation of the oscillation signal by a temperature compensation voltage, and a temperature compensation method for a piezoelectric oscillator,
Extracting characteristic information from information of an approximate expression approximating the information of the frequency temperature characteristic, calculating dip information indicating activity dip based on the information of the frequency temperature characteristic and the information of the approximate expression, the characteristic information and Using the dip information, information on a second approximate expression including the activity dip is generated, and the temperature compensation voltage is calculated based on the information on the second approximate expression and the temperature information of the piezoelectric vibrator. And outputting the temperature to the oscillation circuit.