High-frequency piezoelectric oscillator
View Patent ↗In the high-frequency piezoelectric oscillator, capacitors C 1 , C 2 as a part of a load capacitor are connected between a base of a transistor TR 1 and the ground. The connection point of the capacitors C 1 , C 2 is connected to an emitter of the transistor TR 1 , and is grounded via an emitter resistor R 1 . A base bias circuit consisting of resistors RB 1 and RB 2 is connected to the base of the transistor TR 1 . A piezoelectric vibrator, an inductor, and a resistor are connected in parallel, and connected between the base of the transistor TR 1 . A capacitor is connected to the parallel circuit and grounded. A collector of the transistor and a power supply line are connected together.
1. A high-frequency piezoelectric oscillator including a piezoelectric vibrator having a piezoelectric element that is excited in a predetermined frequency, and an oscillation amplifier that oscillates the piezoelectric element by flowing current to the piezoelectric element, wherein
an inductor and a resistor are insertion connected in parallel respectively to the piezoelectric vibrator of the high-frequency piezoelectric oscillator, and resonance frequency of a parallel resonance circuit consisting of the inductor and the resistor is set to the vicinity of the oscillation frequency of the high-frequency piezoelectric oscillator thereby to increase negative resistance applied to a series arm of the piezoelectric element and suppress unwanted oscillation due to the inductor.
2. A high-frequency piezoelectric oscillator including a piezoelectric oscillator having a piezoelectric vibrator that is excited in a predetermined frequency, and an oscillation amplifier that oscillates the piezoelectric vibrator by flowing current to a piezoelectric element, wherein
a circuit having an inductor and a variable capacitance diode connected in series and a resistor are insertion connected in parallel respectively to the piezoelectric vibrator of the high-frequency piezoelectric oscillator, resonance frequency of a parallel resonance circuit consisting of the inductor and the resistor is set to the vicinity of the oscillation frequency of the high-frequency piezoelectric oscillator, thereby to increase negative resistance applied to a series arm of the piezoelectric element and externally fine adjust the capacitance of the variable capacitance diode so as to optimize oscillation and make it possible to control frequency.
3. A high-frequency piezoelectric oscillator including a piezoelectric oscillator having a piezoelectric vibrator that is excited in a predetermined frequency, and an oscillation amplifier that oscillates the piezoelectric vibrator by flowing current to a piezoelectric element, wherein
a first inductor and a resistor are connected in parallel respectively to the piezoelectric vibrator of the high-frequency piezoelectric oscillator, the connection point is grounded via a circuit having a second inductor and a variable capacitance diode connected in series, and resonance frequency of a parallel resonance circuit consisting of the first inductor and the resistor is set to the vicinity of the resonance frequency of the high-frequency piezoelectric oscillator, thereby to increase negative resistance applied to a series arm of the piezoelectric element and externally fine adjust the capacitance of the variable capacitance diode so as to optimize oscillation and make it possible to control frequency.
4. A high-frequency piezoelectric oscillator according to any one of claims 1 to 3 , wherein
the following relationships are fulfilled:
R
1
+
R
L
=
0
·
ω
L
1
+
1
ω
·
C
1
+
X
L
=
0
when
X
0
=
1
ω
C
0
×
1
(
1
-
ω
0
2
ω
2
)
=
1
ω
C
0
×
1
(
ω
0
2
ω
2
-
1
)
z
0
=
R
0
X
0
2
R
0
2
+
X
0
2
+
j
X
0
R
0
2
R
0
2
+
X
0
2
r
α
=
R
0
X
0
2
R
0
2
+
X
0
2
,
…
X
α
=
X
0
R
0
2
R
0
2
+
X
0
2
.
Z
L
=
-
r
α
R
c
+
X
α
X
c
-
j
(
X
α
R
c
+
X
c
r
α
)
r
α
-
R
c
+
j
(
X
α
-
X
c
)
,
…
A
=
r
α
-
R
c
,
…
B
=
X
α
-
X
c
,
…
C
=
R
c
2
+
X
c
2
,
…
D
=
r
α
2
+
X
α
2
R
L
=
r
α
×
C
-
R
c
×
D
A
2
+
B
2
,
…
X
L
=
X
c
×
D
-
X
α
×
C
A
2
+
B
2
,
(
I
)
where −Rc represents the negative resistance, Cc represents circuit capacitance, C 0 represents interelectrode capacitance of the piezoelectric vibrator, X 0 represents reactance of a parallel circuit of the inductor L 0 , R 0 represents resistance of the resistor, −Xc represents circuit capacitance of the circuit, rα represents parallel connection resistance of the X 0 and R 0 , Xα represents reactance, RL represents negative resistance of the series arm of the oscillator, XL represents reactance, and (I) represents an oscillation condition.
5. A high-frequency piezoelectric oscillator according to claim 1 , wherein
ω 1 <ω T <ω 2 (Exp. 1) is fulfilled, when
ω T represents unwanted resonance non-angular frequency, C o represents interelectrode capacitance of the vibrator, Rc represents an absolute value of negative resistance of an additional resistor and an oscillation circuit that are connected in parallel to the C o , L o represents an inductor that is connected in parallel to the C o , and ω 0 represents parallel resonance angular frequency of the C o and L o , where
(Exp. 2) to (Exp. 4) is fulfilled
…
ω
1
=
ω
0
2
+
K
-
K
(
K
+
4
ω
0
2
)
2
,
(
Exp
.
2
)
…
ω
2
=
ω
0
2
+
K
+
K
(
K
+
4
ω
0
2
)
2
,
…
K
=
M
C
0
2
R
0
2
,
…
M
=
R
0
R
c
-
1
M
>
0
,
R
0
>
R
c
…
.
T
=
.
2
-
.
1
=
K
2
4.
0
2
+
K
=
.
0
2
Q
0
M
(
4
Q
0
+
M
)
(
Exp
.
3
)
T: unwanted resonance non-angular bandwidth
…
Q
=
R
0
.
0
L
0
=
.
0
C
0
R
0
(
Exp
.
4
)
the (Exp. 1) represents unwanted resonance non-angular bandwidth, (Exp. 2) represents a condition for fulfilling the (Exp. 1), and (Exp. 3) represents an unwanted band,
(Exp. 5) is fulfilled, where
…
R
L
=
r
.
×
C
-
R
c
×
D
A
2
+
B
2
…
X
L
=
X
.
×
C
-
X
c
×
D
A
2
+
B
2
.
…
r
.
=
R
0
X
0
2
R
0
2
+
X
0
2
,
…
X
.
=
X
0
R
0
2
R
0
2
+
X
0
2
,
…
X
0
=
1
…
C
0
(
.
0
2
.
2
-
1
)
,
…
X
c
=
1
…
C
c
…
A
=
r
.
-
R
c
,
…
B
=
X
.
-
X
c
,
…
C
=
R
c
2
+
X
c
2
,
…
D
=
r
.
2
+
X
.
2
(
Exp
.
5
)
Q represents resonance frequency which is a ratio of a real number to reactance shown by the ω 0 in the (Exp. 4), RL represents the negative resistance for oscillating the series arm consisting of L 1 /C 1 /R 0 of the oscillator, XL represents reactance, Cc represents circuit capacitance of the oscillation circuit, and ω represents oscillation angular frequency, and
(Exp. 5) represents negative resistance and load capacitance for oscillating a series arm consisting of L 1 /C 1 /R 0 of the oscillator.
6. A high-frequency piezoelectric oscillator according to any one of claims 1 , 2 , and 3 , wherein
the resistance within a range according to claim 5 is organized within an inductor, and the inductor having the inductor and the resistor integrated together is connected in parallel to the interelectrode capacitance C 0 of the vibrator.
7. A high-frequency piezoelectric oscillator according to claim 4 , wherein
the resistance within a range according to claim 5 is organized within an inductor, and the inductor having the inductor and the resistor integrated together is connected in parallel to the interelectrode capacitance C 0 of the vibrator.