JPH1010174A - Method for measuring CI of crystal unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new method for measuring the CI of a quartz oscillator which can measure CI in a short time, simply and with high accuracy for various quartz oscillators having a wide range of frequencies or CI values. I will provide a. SOLUTION: A crystal oscillation circuit capable of starting a crystal oscillator at a frequency very close to a series resonance frequency of the crystal oscillator is used, and the absolute value of the impedance of the crystal oscillator is measured in the crystal oscillation circuit. Considering the absolute value of this impedance as the CI value of the crystal unit,
Get the I value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
It relates to the I measurement method. More specifically, the present invention provides CI, which is one of the parameters of a quartz oscillator,
Based on the constant excitation voltage, constant excitation current, or constant excitation power,
The present invention relates to a new method for measuring the CI of a quartz resonator, which can easily and accurately measure the CI in a short time by directly reading the voltage or the current value.

[0002]

2. Description of the Related Art Conventionally, the CI
As a measuring method, a resistance displacement method, a free vibration method, or the like is used. The resistance replacement method is a method of measuring the CI of a quartz oscillator as an impedance when the quartz oscillator to be measured is incorporated in a feedback loop of a self-excited oscillation circuit and the quartz oscillator is excited by complete series resonance. It is.

However, in this resistance replacement method, the oscillation frequency must be adjusted and set for each crystal resonator to be measured. Further, if the oscillation frequency deviates from about ± 10 ppm of the resonance frequency, CI Since the measurement accuracy of the crystal oscillator rapidly decreases, there is a problem that it is necessary to perform an extremely difficult and time-consuming operation in order to accurately measure the CI of various crystal units. Also, when measuring the CI of a quartz oscillator having various oscillation frequencies,
There was also a problem that very complicated operations such as switching of the frequency range and setting of the excitation level were required.

In the free oscillation method, a quartz oscillator to be measured is first oscillated in a quartz oscillator circuit by some method, and when the CI is measured, the quartz oscillator is separated from the quartz oscillator circuit, and the oscillation up to that point is performed. This is a method of measuring the decay time of the damped oscillation, which is the lingering sound of, to estimate the CI. However, in the free vibration method, the oscillation is naturally performed at a frequency different from the conventional oscillation frequency, and the excitation level is attenuated from a large value. Therefore, a CI different from the CI during the normal oscillation is measured. Therefore, there is a problem that an accurate CI cannot be measured.

As described above, in the conventional CI measuring method, it is very difficult to measure the CI accurately in a short time and simply. In view of the above, the present invention has been made in order to solve the above-mentioned drawbacks of the prior art, and is intended for various crystal units having a wide range of frequencies or CI values in a short time and easily. It is an object of the present invention to provide a new method of measuring the CI of a crystal unit, which can measure the CI with high accuracy.

[0006]

According to the present invention, there is provided a method for measuring a CI value of a quartz oscillator, the method comprising the steps of: Using a crystal oscillation circuit capable of oscillating at a close frequency, measuring the absolute value of the impedance of the crystal oscillator in the crystal oscillation circuit, and considering the absolute value of the impedance as the CI value of the crystal oscillator,
Provided is a method for measuring the CI of a quartz resonator, characterized by obtaining a value.

Further, according to the present invention, in the above-described measuring method, a crystal oscillation circuit in which the amplifier circuit is a voltage output type or a crystal oscillation circuit in which the amplifier circuit is a current output type are used. (Claim 3) also has such an embodiment. Further, in the above-described measuring method, in order to oscillate the crystal oscillator by the constant excitation voltage, the constant excitation current, or the constant excitation power, regardless of the oscillation frequency of the crystal oscillator, one or more differentiating circuits are provided. Use of a built-in crystal oscillation circuit (claim 4) is also one of the preferred embodiments.

Still further, according to the present invention, in the above-mentioned measuring method, a crystal in which one or a plurality of AGC circuits are incorporated in order to oscillate the crystal oscillator with a constant excitation voltage regardless of the CI of the crystal oscillator. An oscillator circuit is used (claim 5), and a crystal oscillator circuit in which one or a plurality of AGC circuits are incorporated to oscillate a crystal oscillator by a constant excitation current is used (claim 6). AGC is used to oscillate the crystal unit by the excitation power.
In order to use a crystal oscillation circuit in which one or more circuits, one multiplication circuit, and one division circuit are incorporated (claim 7), or to oscillate a crystal resonator with constant excitation power, an AGC circuit is used. A crystal oscillation circuit incorporating one or more circuits, one circuit having an output characteristic inversely proportional to the square of the input signal, and one circuit having an output characteristic proportional to the square of the input signal is used.
And the like are also preferred embodiments thereof.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the method for measuring the CI of a crystal unit according to the present invention is to set the crystal unit to be measured at a frequency very close to its series resonance frequency, for example, when the absolute value of impedance of the crystal unit is ± 10 for series resistance value
Using a crystal oscillation circuit that can oscillate at a frequency within a deviation of within%, the absolute value of the impedance of the crystal oscillator is measured in the crystal oscillation circuit, and the absolute value of the impedance is measured as the CI value of the crystal oscillator. , A CI value can be obtained.

In general, a crystal unit can be represented by an equivalent circuit illustrated in FIG. This FIG. 1 (a)
, Le is the equivalent inductance, Ce is the equivalent capacitance, Re is the equivalent resistance, and Co is the capacitance between the electrodes of the vibrator. Further, a crystal resonator oscillated at a frequency very close to the series resonance frequency can be represented by an equivalent circuit illustrated in FIG.

In FIG. 1B, the absolute value of the impedance Zx of the crystal unit is

[0012]

(Equation 1)

## EQU1 ## Here, ω is the oscillation angular frequency of the crystal resonator. According to the measuring method of the present invention, the absolute value of the impedance of the crystal unit represented by the equation (1) is regarded as an approximate value of the resistance Rx of the crystal unit, that is, an approximate value of CI, thereby obtaining the CI value of the crystal unit. Get the value. The absolute value of the impedance of the crystal resonator becomes an approximate value of Rx with higher accuracy as the oscillation frequency of the crystal resonator approaches the series resonance frequency. In other words, for example, the absolute value of the impedance of the crystal unit is ±
If the deviation is within 10%, a highly accurate CI can be obtained as compared with the CI obtained by the conventional measurement method.

In order for the absolute value of the impedance of the crystal unit to have a deviation of ± 10% or less with respect to the value of the series resistance, the oscillation angular frequency of the crystal unit is actually set to the series resonance angular frequency. Must be within about ± 10 ppm. As a crystal oscillation circuit capable of suppressing the oscillation angular frequency of the crystal unit to a deviation of about ± 10 ppm or less as compared with the series resonance angular frequency, for example, the one shown in FIG. it can.

FIG. 2A exemplifies a Colpitts type crystal oscillation circuit using a voltage output inverting type amplifier circuit, which is a voltage output type crystal oscillation circuit. In FIG. 2A, -Av is an AC voltage gain of the amplifier circuit, Q1 is a crystal oscillator, R1 is an output-side resistance of the amplifier circuit, C1 is an output-side capacitance of the amplifier circuit, and R2 is
Is an input-side resistance of the amplifier circuit, C2 is an input-side capacitance of the amplifier circuit, and fout is an output terminal of the oscillation circuit.

When R2 is much larger than the reactance of C2, R2 can be regarded as infinite. Therefore, the crystal oscillation circuit shown in FIG.
As illustrated in (b), R2 can be omitted. In FIG. 2B, the oscillation angular frequency ωv
Is

[0017]

(Equation 2)

## EQU1 ## In this equation (2),

[0019]

(Equation 3)

Term represents the deviation between the oscillation angular frequency and the series resonance angular frequency, which is ± 10 pp as described above.
m, the output side capacitance C1 and the input side capacitance C2 of the amplifier circuit are actually 10 ⁵ to 10 ⁶ compared with the capacitance Cx of the crystal unit.
Need to be In the crystal oscillation circuit illustrated in FIG. 2B, C1 and C2 can be set to 10 ⁵ to 10 ⁶ as compared with Cx.

Therefore, the deviation between the oscillation angular frequency and the series resonance angular frequency can be suppressed to, for example, within ± 10 ppm by using the crystal oscillation circuit in which the amplifier circuit is a voltage output type. The absolute value of the impedance can be accurately measured, and the CI value of the crystal unit can be obtained with high accuracy. However, in a crystal oscillation circuit in which such an amplification circuit is a voltage output type, in a case where the resistance Rx of the crystal resonator becomes extremely large, for example, 10 times or more as compared with the output side resistance R1 of the amplification circuit, The deviation between the oscillation angular frequency and the series resonance angular frequency cannot be suppressed within ± 10 ppm.

Therefore, as an example of a crystal oscillation circuit that can suppress the oscillation angular frequency of the crystal oscillator to within ± 10 ppm as compared with the series resonance angular frequency when Rx is extremely large as compared with R1, for example, , FIG. 3 (a)
As exemplified in the above, the amplifier circuit may be of a current output type. FIG. 3A illustrates a Colpitts-type crystal oscillation circuit using a current output inverting amplifier circuit, where -gm is the transconductance of the amplifier circuit,
Q1 is a crystal oscillator, R1 is an output-side resistance of an amplifier circuit, C1
Is the output side capacitance of the amplifier circuit, R2 is the input side resistance of the amplifier circuit, C2 is the input side capacitance of the amplifier circuit,
fout is an output terminal of the oscillation circuit.

In the case where R2 is much larger than the reactance of C2 in FIG. 3A, R2 can be regarded as infinity.
As illustrated in (b), R2 can be omitted. In FIG. 3B, the oscillation angular frequency ωi
Is

[0024]

(Equation 4)

## EQU1 ## In this equation (4),

[0026]

(Equation 5)

[0027] represents the deviation between the oscillation angular frequency and the series resonance angular frequency. In this term, Rx does not exist, as can be seen from comparison with the equation (3) in the crystal oscillation circuit in which the amplifier circuit is a voltage output type. That is, in a crystal oscillation circuit in which the amplifier circuit is a current output type, Rx
Is extremely large compared to R1,
The oscillation angular frequency of the crystal unit can be suppressed to within ± 10 ppm of deviation from the series resonance angular frequency without being affected by Rx, so that the absolute value of the impedance of the crystal unit can always be measured accurately. Thus, the CI value of the crystal unit can be obtained with high accuracy.

In a crystal oscillation circuit in which the amplifier circuit is a voltage output type, the deviation between the oscillation angular frequency and the series resonance angular frequency is ± 10 p when Rx, that is, CI is extremely large.
Although it cannot be suppressed to within pm, the CI value can be measured with high accuracy without any problem when the value of Rx is within the normal range. Since the circuit configuration also has a simple configuration, it is possible to reduce the size of the entire measurement apparatus. Therefore, for CI measurement when the value of Rx is small, the crystal oscillation having a simple circuit configuration and a voltage output type amplifier circuit is used. A circuit may be used.

As described above, according to the measuring method of the present invention, the amplifying circuit is a current output type or a voltage output type, and the crystal oscillation circuit can oscillate the crystal unit to be measured at a frequency very close to its series resonance frequency. Is used, the absolute value of the impedance of the crystal oscillator can be easily and accurately measured in the crystal oscillation circuit, and the CI can be easily obtained with high accuracy.

Actually, as a measuring circuit for measuring the absolute value of the impedance of a crystal resonator using such a crystal oscillation circuit, that is, a CI measuring circuit, for example, FIGS. , FIG. 5, FIG. 6, and FIG. FIG. 4A shows an example of a CI measuring circuit in which the amplifier circuit is of a voltage output type and can drive the quartz oscillator at a constant voltage, and drives the quartz oscillator at a constant voltage, that is, at both ends of the quartz oscillator. In order to keep the applied excitation voltage constant and to oscillate the crystal oscillator with the constant excitation voltage, one differentiating circuit and one AGC amplifier circuit are incorporated.

In FIG. 4A, the crystal unit Q1
Is amplified by an AC amplifier circuit Av2 and then rectified by a rectifier circuit Rec2 to become a DC voltage Vq proportional to the excitation voltage vq. This DC voltage V
q is an excitation voltage setting value VV set by the voltage value setting volume VR1 by the differential DC amplifier circuit AV.
The DC voltage VAGC is amplified by comparison with the input DC voltage VAGC, and the input DC voltage VAGC controls the AGC amplifier circuit Gv whose gain is variable. As a result, the DC voltage Vq is always equal to the excitation voltage set value VV. Therefore, when the value of Rx is within the normal range, the excitation voltage vq is always constant without being affected by the value of Rx. Is controlled. Thereby, the crystal oscillator can be oscillated by the constant excitation voltage without adjustment regardless of the CI value. Also,
The voltage vi applied to both ends of the input-side capacitance C2 of the amplifier circuit is AC-amplified by an AC amplifier circuit AV1, then frequency-corrected by a differentiator Di, and rectified by a rectifier Rec1 to obtain a CI of the crystal oscillator. DC voltage V (1 / CI) inversely proportional to Differentiating circuit Di
, The CI of a crystal oscillator having an arbitrary frequency can be measured without adjustment in the same measurement circuit regardless of the magnitude of the oscillation angular frequency ω of the crystal oscillator.

In such a CI measuring circuit,

[0033]

(Equation 6)

The following holds. In this equation, a is a constant. That is, by using the CI measurement circuit shown in FIG. 4A, V (1 /
CI) is measured, and an Rx value, that is, a CI value can be easily and accurately obtained from the V (1 / CI). Further, in the CI measuring circuit of the crystal unit, instead of the excitation voltage vq of the crystal unit Q1 in the CI measuring circuit of FIG.
As exemplified in (b), vq ′ which is an approximate voltage of the excitation voltage vq may be used. The CI measurement circuit in this case is
There is an advantage that the circuit configuration is simpler than the circuit configuration of the CI measurement circuit in FIG.

FIG. 5 shows an example of a CI measuring circuit in which the amplifier circuit is of a voltage output type and the excitation of the crystal unit can be driven with a constant current. In order to keep the current constant and oscillate the crystal unit with a constant excitation current, one differentiating circuit and one AGC amplifier circuit are incorporated. In FIG. 5, the excitation voltage vq of the crystal resonator Q1 is AC-amplified by the AC amplifier circuit Av2, and then rectified by the rectifier circuit Rec2 to become a DC voltage VCI proportional to the CI of the crystal resonator. The voltage vi applied to both ends of the input-side capacitance C2 of the amplifier circuit is equal to the AC amplifier circuit AV.
1, is subjected to frequency correction by a differentiating circuit Di, is rectified by a rectifying circuit Rec1, and is a DC voltage V proportional to an exciting current flowing through the crystal resonator.
i. This DC voltage Vi is applied to the differential DC amplifier circuit A.
The DC voltage VAGC is amplified by comparison with the excitation current setting value VI set by the current value setting volume VR1, and the AGC amplifier circuit Gv whose gain is variable by the input DC voltage VAGC is controlled. As a result, the DC voltage Vi is always equal to the excitation current set value VI, so that the voltage vi is controlled so as to be always a constant value, whereby the quartz oscillator is not adjusted regardless of the magnitude of its CI value. Thus, oscillation can always be performed with a constant excitation current.

In such a CI measuring circuit,

[0037]

(Equation 7)

Holds. In this equation, b is a constant. That is, by using the CI measurement circuit shown in FIG. 5, VCI is measured as a voltage value proportional to Rx, and an Rx value, that is, a CI value can be easily and accurately obtained from this VCI. In the CI measuring circuit of the crystal unit, the excitation voltage of the crystal unit is
Similarly to the CI measurement circuit of FIG. 5B, instead of the excitation voltage vq of the crystal unit Q1 in the CI measurement circuit of FIG. 5, for example, vq ′ which is an approximate voltage of the excitation voltage vq may be used. The circuit configuration of the CI measurement circuit in this case is shown in FIG.
There is an advantage that the configuration becomes simpler than the circuit configuration of the CI measurement circuit.

FIG. 6 shows an example of a CI measuring circuit in which the amplifier circuit is of a voltage output type and the excitation of the crystal unit can be driven at a constant power. In order to keep the constant and to oscillate the crystal unit with constant excitation power, a differentiating circuit, AGC amplifier circuit,
One multiplication circuit and one division circuit are incorporated.

In FIG. 6, the excitation voltage vq of the crystal oscillator Q1 is AC-amplified by an AC amplifier circuit Av2, and then rectified by a rectifier circuit Rec2 to obtain an excitation voltage vq.
Becomes a DC voltage Vv proportional to. The voltage vi applied across the input-side capacitance C2 of the amplifier circuit is
After being subjected to AC amplification by the AC amplification circuit AV1, the frequency is corrected by the differentiation circuit Di, and then rectified by the rectification circuit Rec1 to become a DC voltage Vi proportional to the excitation current flowing through the crystal resonator. The DC voltages Vv and Vi are multiplied by a multiplication circuit Mul to become a DC voltage Vp proportional to the excitation power of the crystal resonator. This DC voltage Vp is
The differential DC amplifier circuit AV compares and amplifies the excitation power setting value VP set by the power value setting volume VR1 to obtain a DC voltage VAGC, and the input DC voltage V
The AGC controls an AGC amplifier circuit Gv whose gain is variable. As a result, the DC voltage Vp becomes the excitation power set value V
Since the value is always equal to P, a value obtained by multiplying the excitation voltage vq of the crystal unit and the voltage vi, that is, a value proportional to the excitation power of the crystal unit, is controlled to be always a constant value. Thus, the crystal oscillator can be always oscillated with a constant excitation power without adjustment, regardless of the magnitude of its CI value. Further, the DC voltage Vv is divided by the DC voltage Vi by the division circuit Dev, and becomes a DC voltage VCI proportional to the CI of the crystal resonator.

In such a CI measuring circuit shown in FIG.

[0042]

(Equation 8)

Holds. In this equation, c is a constant. That is, by using the CI measurement circuit shown in FIG. 6, VCI is measured as a voltage value proportional to Rx, and an Rx value, that is, a CI value can be easily and accurately obtained from this VCI. In the CI measuring circuit of the crystal unit, the excitation voltage of the crystal unit is
Similarly to the CI measurement circuit of FIG. 6B, instead of the excitation voltage vq of the crystal unit Q1 in the CI measurement circuit of FIG. 6, for example, vq ′ which is an approximate voltage of the excitation voltage vq may be used. The CI measurement circuit in this case has a circuit configuration shown in FIG.
There is an advantage that the configuration becomes simpler than the circuit configuration of the CI measurement circuit.

In the CI measuring circuit shown in FIG. 6, the multiplying circuit and the dividing circuit are of an analog type. However, even if a multiplier and a divider of a program type using a microcomputer or the like are incorporated in the measuring circuit. Good.
FIG. 7 illustrates a CI measuring circuit in which the amplifier circuit is a voltage output type and can drive the quartz resonator with constant power driving. The constant power driving, that is, the excitation power of the quartz resonator is kept constant. In order to maintain and oscillate the crystal unit with constant excitation power, a differentiating circuit, an AGC amplifier circuit, a circuit having an output characteristic inversely proportional to the square of the input signal, and a circuit having an output characteristic proportional to the square of the input signal, Each one,
It has been incorporated.

In FIG. 7, a voltage vi applied to both ends of an input-side capacitance C2 of an amplifier circuit is AC-amplified by an AC amplifier circuit AV1, then frequency-corrected by a differentiator Di, and rectified by a rectifier Rec1. Thus, the DC voltage becomes a DC voltage Vi proportional to the excitation current flowing through the crystal resonator. This DC voltage Vi has an output characteristic inversely proportional to the square of the input signal. For example, a circuit 1 / S ² such as an antilog circuit or the like has a DC voltage inversely proportional to the square value Vi ² of the DC voltage Vi as the input signal. Voltage VAG
The signal is converted into C, and the AGC amplifier circuit Gv having a variable gain is controlled by the input DC voltage VAGC. As a result, the excitation power of the crystal oscillator is controlled so as to always be a constant value. When the crystal oscillator is excited with constant power, the Rx of the crystal oscillator is proportional to the square of the excitation voltage vq of the crystal oscillator.
After AC amplified by 2, and rectified by the rectifier circuit Rec2, and a DC voltage Vv, further having an output characteristic which is proportional to the square of the input signal, for example by circuit S ² such as antilog circuit is the input signal converting the DC voltage VCI in proportion to the value Vv ² of the squares of the DC voltage Vv.

In the CI measurement circuit shown in FIG. 7,

[0047]

(Equation 9)

Holds. In this equation, d is a constant. That is, by using the CI measuring circuit shown in FIG. 7, VCI is measured as a voltage value proportional to Rx, and an Rx value, that is, a CI value can be obtained easily and accurately from this VCI. In the CI measuring circuit of the crystal unit, the excitation voltage of the crystal unit is
Similar to the CI measurement circuit of FIG. 7B, instead of the excitation voltage vq of the crystal unit Q1 in the CI measurement circuit of FIG. 7, for example, vq ′ which is an approximate voltage of the excitation voltage vq may be used. The CI measurement circuit in this case has a circuit configuration shown in FIG.
There is an advantage that the configuration becomes simpler than the circuit configuration of the CI measurement circuit.

The C shown in FIGS. 4, 5, 6, and 7
All of the I measurement circuits use a crystal oscillation circuit in which the amplifier circuit is a voltage output type. However, a CI measurement circuit using a crystal oscillation circuit in which the amplification circuit is a current output type similarly has a CI measuring circuit. Needless to say, the measurement can be easily and accurately performed. As described above, although the CI measurement circuit using the crystal oscillation circuit in which the amplification circuit is a current output type has a slightly more complicated circuit configuration than the crystal oscillation circuit in which the amplification circuit is a voltage output type, Even when Rx becomes extremely large compared to R1, CI measurement can be performed with high accuracy without being affected by the value of Rx.
Further, in a CI measurement circuit using a crystal oscillation circuit whose voltage output type is a voltage output type, when the Rx becomes extremely large compared to R1, the measurement accuracy of the CI is slightly lowered, but the amplification circuit is The circuit configuration is simpler than a current output type crystal oscillation circuit. Therefore, in consideration of the use environment of the CI measurement circuit, for example, the type of the crystal unit, the size of the device in which the CI measurement circuit is incorporated, the installation location, and the like, select and use either the voltage output type or the current output type. , CI is preferably measured.

[0050]

As described above in detail, according to the present invention, it is possible to adjust the frequency correction, the setting of the excitation level, etc. in the same measuring circuit for various quartz oscillators having a wide range of frequencies or CI values. A new method for measuring the CI of a quartz resonator that can be automatically performed, and thus can accurately and easily measure the CI in a short time is provided.

[Brief description of the drawings]

FIGS. 1A and 1B are circuit diagrams illustrating equivalent circuits of a crystal unit. FIG. 1A is a circuit diagram of a normal circuit, and FIG. 1B is a circuit diagram of a case where oscillation is performed at a frequency very close to a series resonance frequency. It is.

FIGS. 2A and 2B are circuit diagrams illustrating a Colpitts type crystal oscillation circuit using a voltage output inverting amplifier circuit, where FIG. 2A is a normal circuit configuration diagram, and FIG. And FIG.

FIGS. 3A and 3B are circuit diagrams illustrating a Colpitts-type crystal oscillation circuit using a current output inverting amplifier circuit, wherein FIG. 3A is a normal configuration diagram, and FIG. It is a block diagram in case of being large.

FIG. 4 is a circuit diagram illustrating a CI measuring circuit in which amplifying circuit is a constant voltage excitation using a crystal oscillation circuit of a voltage output type. FIG. 4A shows a case where vq is used as an excitation voltage of a crystal resonator. FIG. 3B is a circuit diagram when an approximate voltage vq ′ of vq is used as the excitation voltage of the crystal resonator.

FIG. 5 is a circuit diagram illustrating a CI measurement circuit in which amplifying circuit is a constant current excitation using a crystal oscillation circuit of a voltage output type.

FIG. 6 is a circuit diagram illustrating a CI measuring circuit which is a constant power excitation using a crystal oscillation circuit whose amplification circuit is a voltage output type.

FIG. 7 is a circuit diagram illustrating a CI measuring circuit which is a constant power excitation using a crystal oscillation circuit in which an amplifier circuit is a voltage output type.

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[Procedure amendment]

[Submission date] July 18, 1996

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 6

[Correction method] Change

[Correction contents]

FIG. 6

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Fig. 7

[Correction method] Change

[Correction contents]

FIG. 7

[Procedure amendment]

[Submission date] July 18, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction contents]

[0019]

(Equation 3)

Claims (8)

[Claims] 1. A method for measuring a CI value of a crystal unit, comprising: using a crystal oscillation circuit capable of causing the crystal unit to oscillate at a frequency very close to a series resonance frequency of the crystal unit. A method of measuring the absolute value of the impedance of a quartz oscillator in a circuit, and obtaining the CI value by regarding the absolute value of the impedance as the CI value of the quartz oscillator. 2. The method according to claim 1, wherein the amplification circuit uses a voltage output type crystal oscillation circuit. 3. The method for measuring CI of a crystal resonator according to claim 1, wherein the amplifier circuit uses a crystal oscillation circuit of a current output type. 4. The measuring method according to claim 2, wherein
Regardless of the oscillation frequency of the crystal unit, use a crystal oscillation circuit incorporating one or more differentiating circuits to oscillate the crystal unit with constant excitation voltage, constant excitation current, or constant excitation power. Characteristic CI measurement method for quartz oscillator. 5. The measuring method according to claim 4, wherein one or a plurality of AGC circuits are incorporated in order to oscillate the crystal oscillator with a constant excitation voltage regardless of the CI of the crystal oscillator. A method for measuring the CI of a quartz oscillator, which is used. 6. The measuring method according to claim 4, wherein the crystal oscillator includes one or more AGC circuits for oscillating the crystal oscillator with a constant excitation current regardless of the CI of the crystal oscillator. A method for measuring the CI of a quartz oscillator, which is used. 7. The measuring method according to claim 4, wherein one or a plurality of AGC circuits, one multiplication circuit, and a division circuit are provided to oscillate the crystal oscillator with constant excitation power regardless of the CI of the crystal oscillator. Characterized by using a crystal oscillation circuit in which one circuit is incorporated.
Measuring method. 8. The measuring method according to claim 4, wherein one or a plurality of AGC circuits are inversely proportional to the square of the input signal in order to oscillate the crystal oscillator with constant excitation power regardless of the CI of the crystal oscillator. A method for measuring the CI of a crystal resonator, comprising using a crystal oscillation circuit in which one circuit having an output characteristic and one circuit having an output characteristic proportional to the square of an input signal are incorporated.