Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Reexamination Certificate
2001-02-09
2003-09-09
Dougherty, Thomas M. (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
Reexamination Certificate
active
06617756
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a piezo-oscillator, and more particularly, to a small piezo-oscillator having excellent aging characteristics.
BACKGROUND TECHNIQUE
In recent years, as communications equipment is reduced in size, a reference signal source used for the equipment is required to be small in size, and a quartz oscillator shown in
FIG. 5
for example has been proposed.
FIG.
5
(
a
) is a sectional view of a structure of a conventional quartz oscillator, and FIG.
5
(
b
) is a circuit diagram of the conventional quartz oscillator.
As shown in FIG.
5
(
a
), the quartz oscillator
100
includes an integrated amplifier circuit
101
, a quartz vibrator
102
, a ceramic container
103
having a recess for accommodating the amplifier circuit
101
and the quartz vibrator
102
therein, and a metal lid
104
. After the amplifier circuit
101
is mounted in on a bottom surface of the recess of the ceramic container
103
, the quartz vibrator
102
is mounted such as to cover an upper surface of the amplifier circuit
101
, and the ceramic container
103
is sealed by the lid
104
such as to cover these members.
The quartz vibrator
102
and other electron parts are mounted in the common accommodation container in this manner, thereby realizing a compact quartz oscillator
100
.
However, with the above structure, it is impossible to check a drive level dependence characteristics (DLD characteristics, hereinafter) such as variation in oscillation frequency with respect to drive level variation of the quartz vibrator
102
.
That is, the DLD characteristics may be varied due to variation in producing procedure and producing conditions or the like.
Since the DLD characteristics affects the stability of frequency and characteristics and reproducibility of the quartz vibrator
102
, it is indispensable to check the vibrator after it was completed.
A common method for checking the DLD characteristics of the quartz vibrator
102
is to change the drive level of the quartz vibrator
102
incorporated in the oscillator, and to check deviation of oscillation frequency with respect to variation of the drive level.
In the case of the quartz oscillator
100
, since the quartz vibrator
102
and the amplifier circuit
101
are accommodated in the same container, the quartz vibrator
102
alone can not be checked. It seems possible to control a voltage value of a power source Vcc to be supplied to the oscillator circuit of the quartz oscillator
100
, thereby adjusting the amplification action of the amplifier circuit
101
to control the drive level of the quartz vibrator
102
.
However, since the quartz oscillator
100
output stable frequency signal even if the supplied power source voltage is varied, at least one of a constant-voltage circuit
105
and a constant-current circuit
106
is provided in the oscillator circuit as shown in FIG.
5
(
b
) in many cases.
Therefore, in the case of the quartz oscillator
100
having such a structure, even if the power source voltage value is controlled, since the drive level of the quartz vibrator
102
is not varied, there is a problem that DLD characteristics can not be checked.
The present invention has been accomplished to solve the above problems of the conventional constant-voltage oscillator, and it is an object of the invention to provided a small quartz oscillator in which the DLD characteristics can be measured after it is packaged even if a constant-voltage circuit or constant-current circuit is included in the circuit.
DISCLOSURE OF THE INVENTION
To achieve the above object, according to the invention described in a first aspect, there is provided a piezo-oscillator comprising an oscillator circuit including a piezo-vibrator and an amplifier circuit, and a constant-voltage circuit, in which a power source and the oscillator circuit are connected through the constant-voltage circuit to supply a constant voltage to the oscillator circuit, wherein when a voltage of the power source is equal to or higher than a predetermined value, a function of the constant-voltage circuit is invalidated.
According to a second aspect, there is provided a piezo-oscillator comprising a piezo-oscillator including a piezo-vibrator, an amplifier circuit and a constant-current circuit, wherein when a voltage of the power source is equal to or higher than a predetermined value, a function of the constant-current circuit is invalidated.
According to a third aspect, there is provided a piezo-oscillator comprising an oscillator circuit including a piezo-vibrator and an amplifier circuit, a constant-voltage circuit and frequency control voltage section, in which a power source and the oscillator circuit are connected through the constant-voltage circuit to supply a constant voltage to the oscillator circuit, wherein when a voltage to be supplied to the frequency control voltage section is equal to or higher than a predetermined value, a function of the constant-voltage circuit is invalidated.
According to a fourth aspect, there is provided a piezo-oscillator comprising a piezo-oscillator including a piezo-vibrator, an amplifier circuit, a constant-current circuit and a frequency control voltage section, wherein when a voltage to be supplied to the frequency control voltage section is equal to or higher than a predetermined value, a function of the constant-current circuit is invalidated.
According to a fifth aspect, in addition to the first or the third aspect, within in a voltage range in which the function of the constant-voltage circuit is invalidated, the power source voltage is controlled, and a drive level of the piezo-vibrator is controlled by changing a voltage to be supplied to the amplifier circuit.
According to a sixth aspect, in addition to the second or the fourth aspect, within in a voltage range in which the function of the constant-voltage circuit is invalidated, the power source voltage is controlled, and a drive level of the piezo-vibrator is controlled by changing a voltage to be supplied to the amplifier circuit.
According to a seventh aspect, in addition to the fifth or the sixth aspect, it is possible to confirm drive level dependency characteristics of the piezo-vibrator by controlling a drive level of the piezo-vibrator.
According to an eighth aspect, there is provided a piezo-oscillator comprising an oscillator circuit including a piezo-vibrator and an amplifier circuit for supplying electric power to the oscillator circuit through a constant-voltage circuit or a constant-current circuit, wherein the constant-voltage circuit or the constant-current circuit is provided with a current bypass switch, a function of the constant-voltage circuit or the constant-current circuit is invalidated by controlling the switch from outside.
REFERENCES:
patent: 4142161 (1979-02-01), Gray
patent: 4193046 (1980-03-01), Chiba
patent: 5126695 (1992-06-01), Abe
patent: 6304152 (2001-10-01), Takahashi et al.
patent: H6-164241 (1994-06-01), None
patent: H8-204450 (1996-08-01), None
patent: 9-36661 (1997-02-01), None
patent: 1-300604 (1999-12-01), None
Dougherty Thomas M.
Toyo Communication Equipment Co., Ltd.
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