JPH11298242A - Oscillator and high-frequency module using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a miniaturized oscillator. SOLUTION: This oscillator is provided with an oscillation circuit 11 formed from a collector ground transistor 18 and a resonance circuit 20 and an oscillation circuit 12 formed from a collector ground transistor 40 and a resonance circuit 42, and the oscillation circuits 11 and 12 are selectively activated by a control voltage applied to a transistor 13. Thus, the miniaturized oscillator can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oscillator for selectively outputting two kinds of oscillation frequencies and a high-frequency module using the same.

[0002]

2. Description of the Related Art A conventional oscillator will be described below.
As shown in FIG. 5, a conventional oscillator includes an oscillation circuit 1 that outputs a first frequency and an oscillation circuit 2 that outputs a second frequency.
An NPN switch transistor 3 for turning on / off the oscillation circuit 1 and a PNP for turning on / off the oscillation circuit 2
And the type transistor 4. Then, according to the input from the control voltage input terminal 5, the oscillation circuit 1 and the oscillation circuit 2 are selectively selected and output from the output terminal 6.

[0003]

However, in such a conventional configuration, two transistors, an NPN transistor 3 and a PNP transistor 4, are required to select either the oscillation circuit 1 or the oscillation circuit 2. Therefore, there is a problem that the oscillator becomes large.

Accordingly, an object of the present invention is to provide a downsized oscillator for solving this problem.

[0005]

In order to achieve this object, an oscillator according to the present invention comprises a first oscillating circuit formed by a first common-collector transistor and a first resonant circuit,
And a second oscillation circuit formed by a second resonance circuit. The first oscillation circuit and the second oscillation circuit are controlled by a control voltage applied to a third transistor.
And the oscillation circuit of the above is selectively activated.

Thus, a downsized oscillator can be provided.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a first oscillation circuit formed by a first common-collector transistor and a first resonance circuit, a second common-collector transistor and a second common-collector transistor. A second oscillation circuit formed of two resonance circuits, wherein the oscillator selectively activates the first oscillation circuit and the second oscillation circuit by a control voltage applied to a third transistor. Since the first oscillation circuit and the second oscillation circuit can be switched by using only one third transistor, the size of the oscillator can be reduced. Further, since the switching of the oscillation circuit can be performed by one third transistor, a low-cost oscillator can be obtained. Further, the switching of the oscillation circuit is performed by the third transistor 1
Since the first oscillation circuit and the second oscillation circuit are not simultaneously turned on or off at the same time and one of the oscillation circuits is always turned on, load current averaging is performed. Can be achieved. This reduces noise to the outside. Also, since there is no change in the transient current, the design of the power supply to be supplied is easy.

The third transistor according to the second aspect of the present invention is connected to the emitter of the first transistor via the first resistor and to the base of the second transistor via the second resistor. The oscillator according to claim 1, wherein a control voltage is applied to the base of the third transistor, and a switch circuit can be realized with a simple configuration.

According to a third aspect of the present invention, there is provided the oscillator according to the second aspect, wherein a third transistor is disposed between the first transistor and the second transistor. The distance can be shortened, which can contribute to miniaturization. Also, by shortening the wiring distance, the oscillation frequency does not directly affect other circuits.

According to a fourth aspect of the present invention, there is provided the oscillator according to the second aspect, wherein the first transistor, the second transistor, and the third transistor are all NPN transistors. Since it can be configured, the types of purchased parts can be reduced, and parts management is easy.

According to a fifth aspect of the present invention, a printed circuit board on which an oscillator is mounted uses a four-layer board, electronic components are mounted on the first layer, and the second and fourth layers are entirely grounded. A part of the inductance forming the resonance circuit on the third layer is formed by the pattern, and the remaining part of the inductance is led out to the first layer by a through hole and the remaining part of the inductance is formed on the first layer. 3. The oscillator according to claim 2, wherein the inductance is formed in a pattern, and the oscillator is separated from the outside at a high frequency by these ground patterns. Further, by using a multilayer substrate, the size of the oscillator can be reduced. Further, since the inductance is formed in a pattern, it is resistant to vibration and is advantageously used for a mobile phone or the like. Furthermore, since the remaining part of the inductance is provided in the first layer, the oscillation frequency can be easily adjusted.

According to a sixth aspect of the present invention, a common emitter amplifier formed of a transistor is connected to the output of the oscillator according to the first aspect of the present invention, and a resonance circuit is provided at a collector of the transistor of the amplifier. Is a high-frequency module for switching a resonance frequency according to a control voltage input from a control voltage input terminal. Since an amplifier is also provided with a resonance circuit, an oscillator having good selection characteristics can be obtained. Further, since this control voltage input terminal is connected to the control voltage input terminal of the oscillator, the passing characteristic of the amplifier is changed in accordance with the switching of the oscillation frequency of the oscillator, so that the control is simple.

According to a seventh aspect of the present invention, there is provided a printed circuit board on which electronic components are mounted and which has a substantially rectangular shape, a control voltage input terminal, a tuning voltage input terminal, and an output terminal near corners of the printed circuit board, respectively. And a power supply terminal, and a ground terminal is provided between these terminals.
Wherein the degree of high-frequency insulation between the control voltage input terminal, the tuning voltage input terminal, the output terminal, and the power supply terminal is improved. Therefore, they do not interfere with each other.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram of the oscillator according to the present invention. In FIG. 1, an oscillator according to the present invention includes an oscillation circuit 11, an oscillation circuit 12, and an NPN switch transistor 13 for selectively switching between the oscillation circuit 11 and the oscillation circuit 12.
It is composed of The base of the transistor 13 is connected to the control voltage input terminal 15 via the resistor 14. The collector is connected to the power terminal 1 via the resistor 16.
7 is connected.

The oscillation circuit 11 includes an NPN-type oscillation transistor 18 and a coupling capacitor 1 connected to the transistor 18.
9 is connected to the resonance circuit 20. The collector of the transistor 18 is grounded to the ground via the capacitor 21 and is connected to the power supply terminal 17. The base is supplied with a bias voltage by resistors 22 and 23 and is connected to the emitter via a capacitor 24. This emitter is connected to the collector of the switch transistor 13 via a resistor 25 and to the output terminal 27 via a coupling capacitor 26. A capacitor 28 is provided between the emitter of the transistor 18 and the ground.

The resonance circuit 20 includes an inductance 30 formed in a pattern, and a series connection of a fixed capacitor 31 and a variable capacitor 32 connected in parallel with the inductance 30. The cathode side of the variable capacitor 32 is connected to a control voltage input terminal 35 via a high resistance 33. Here, the inductance 30 is divided into a fixed inductance 30a and a frequency adjustment inductance 30b.

Similarly, the oscillation circuit 12 is connected to an NPN oscillation transistor 40 and a resonance circuit 42 via a coupling capacitor 41 connected to the transistor 40. The collector of the transistor 40 is grounded to the ground via the capacitor 43 and is connected to the power supply terminal 17. The base is connected to the collector of the transistor 13 by a resistor 44 and is connected to the ground by a resistor 45 to apply a bias voltage. The base is connected to the emitter via a capacitor 46. This emitter is connected to ground via a resistor 47 and to the output terminal 27 via a coupling capacitor 48. A capacitor 49 is provided between the emitter of the transistor 40 and the ground.

Similarly, the resonance circuit 42 includes an inductance 50 formed in a pattern and a series connection of a fixed capacitor 51 and a variable capacitor 52 connected in parallel with the inductance 50. The cathode side of the variable capacitor 52 is connected to the control voltage input terminal 35 via the high resistance 53. Here, the inductance 50 is divided into a fixed inductance 50a and a frequency adjustment inductance 50b.

With respect to the oscillator configured as described above,
The operation will be described below. The oscillation circuit 11 outputs a frequency of about 1.7 GHz to the output terminal 27 by the transistor 18 for oscillation and its peripheral circuit and the resonance circuit 20. Also, the oscillation frequency changes the capacitance of the capacitor 32 depending on the magnitude of the voltage input to the tuning voltage input terminal 35, so that the output frequency can be controlled. The upper and lower limits of the oscillation frequency are determined by trimming the inductance 30b.

The same applies to the oscillation circuit 12. That is, the oscillation circuit 12 outputs a frequency of about 1.0 GHz to the output terminal 27 by the transistor 40 for oscillation and its peripheral circuit and the resonance circuit 42. In addition, the oscillation frequency changes the capacitance of the variable capacitor 52 according to the signal input to the tuning voltage input terminal 35, so that the output frequency can be controlled. The upper limit and lower limit of the oscillation frequency are determined by trimming the inductance 50b.

Here, switching between the oscillation circuit 11 and the oscillation circuit 12 is performed by the transistor 13. That is, when the control voltage input terminal 15 is set to high, the transistor 13 is turned on. Since the emitter of the transistor 13 is connected to the ground, the collector becomes zero potential. That is, a current flows through the transistor 18 and the transistor 40 is turned on and the transistor 40 is turned off. That is, a frequency of 1.7 GHz is output from the oscillation circuit 11 to the output terminal 27.

Similarly, when the control voltage input terminal 15 is set low, the transistor 13 is turned off and the collector is set high. Then, the transistor 18 is turned off and the transistor 40 is turned on. That is, output terminal 2
A frequency of 1.0 GHz is output from the oscillation circuit 12 to 7.

FIG. 2 shows an amplifier connected to the output terminal 27 of the oscillator and composed of NPN transistors. This amplifier comprises an amplifying circuit 62 connected to an input terminal 61 and a capacitor 63 from the output of the amplifying circuit 62.
Amplifying circuit 64 connected via the
Output terminal 6 connected to the output of
6, a first resonance circuit 68 connected between the collector of the transistor 67 and the power supply terminal 17 of the amplification circuit 62 and capable of switching the frequency, and between the transistor 69 of the amplification circuit 64 and the power supply terminal 17. Connected to the control voltage input terminal 71 (connected to the control voltage input terminal 35 in FIG. 1) and the resonance frequency of the resonance circuits 68 and 70. And a switch circuit 72 for changing over.

Here, the first resonance circuit 68 includes a series connection of the inductances 74a and 74b and a capacitor (this capacitor is formed by a stray capacitance of a pattern) 75
Formed in parallel. The capacitor 75 and the inductance 74b are designed to resonate at a higher frequency of 1.7 GHz, and the capacitor 75, the inductance 74a and the inductance 74b are resonated at a lower frequency of 1.0 GHz.

Similarly, the second resonance circuit 70 includes a series connection of the inductances 75a and 75b and a capacitor (this capacitor is formed by a stray capacitance of a pattern).
77 are connected in parallel. The higher frequency of the capacitor 77 and the inductance 75b resonates at 1.7 GHz, and the lower frequency of the sum of the capacitor 77, the inductance 75a and the inductance 75b, 1.0 GHz.
It is designed to resonate. Here, the capacitor 7
8 and the capacitor 79 are both DC cut capacitors.

With respect to the amplifier configured as described above,
The operation will be described below. The signal input to the input terminal 61 (connected to the output terminal 27 of the oscillator) is amplified by the amplifier circuits 62 and 64 and output from the output terminal 66. Here, when the control voltage input terminal 71 is high, both the transistors 80 and 81 of the switch transistor circuit 72 are turned on. Since the emitters of these transistors 80 and 81 are connected to the ground, the collectors are at the ground level. Since the capacitors 78 and 79 are capacitors for cutting DC current, the inductances 74a and 74b
And the connection point of the inductances 75a and 75b are grounded in an alternating current. That is, the resonance circuit 6
Reference numeral 8 denotes a parallel resonance circuit of a capacitor 75 and an inductance 74b, and a resonance circuit 70 serves as a parallel resonance circuit of a capacitor 77 and an inductance 75b. Becomes

Next, when the control voltage input terminal 71 is low, the transistor 80 of the switch transistor circuit 72,
81 are both turned off. That is, these transistors 8
Since the collectors of 0 and 81 have high impedance, the connection point between the inductances 74a and 74b and the connection point between the inductances 75a and 75b are open in AC.
That is, the resonance circuit 68 is a parallel resonance circuit in which the inductances 74a and 74b are connected in series with the capacitor 75, and the resonance circuit 70 is a parallel resonance circuit in which the capacitor 77 and the inductances 75a and 75b are connected in series. An amplifier that resonates at a frequency (1.0 GHz) and efficiently passes this frequency.

FIG. 3 is a plan view of a high-frequency module to which the oscillator shown in FIG. 1 and the amplifier shown in FIG. 2 are connected. In FIG. 3, reference numeral 90 denotes a substantially square four-layer printed circuit board. The four corners of the printed circuit board 90 have a control voltage input terminal 15, a tuning voltage input terminal 35,
An output terminal 66 and a power supply terminal 17 are provided, and a total of four ground terminals 91 are provided on each side between them. The size of this high-frequency module is 10 mm in length, 12 mm in width, and 2 mm in thickness.

By thus providing the signal terminals apart and providing the ground terminal 91 between them, the influence between the terminals is reduced. That is, measures are taken against noise. Further, since terminals are provided at four corners, the mounting balance at the time of mounting is good. Also, the oscillation circuit 11
Since the switch transistor 13 is disposed between the first and second transistors, the wiring can be shortened, which contributes to downsizing.
Further, a control voltage input terminal 15 is provided on the transistor 13 side, and a tuning voltage input terminal 35 is provided on the oscillation circuits 11 and 12 side. After the oscillator, amplifier circuits 62 and 64 are arranged in this order, and an output terminal 66 is provided near the output of the amplifier circuit 64. With such an arrangement, downsizing can be achieved.

FIG. 4 is a sectional view of the high-frequency module. In FIG. 4, 90 is a four-layer printed circuit board,
On a first layer 90a of the printed circuit board 90, an electronic component 92 constituting an oscillator or an amplifier is mounted. Reference numeral 93 denotes a metal shield case, which is provided on the printed circuit board 90 so as to cover the electronic component 92. The second layer 90b and the fourth layer 90d of the printed circuit board 90 are all ground patterns. The third layer 90c includes a resonance circuit 2
0 and the resonance circuit 4
2 and an inductance 50a constituting a part thereof are formed in a pattern and mounted. Then, the inductances 30b and 50b are formed from these inductances through the through holes to the first layer 90a, respectively.
The frequency is adjusted by trimming these inductances 30b and 50b.

[0031]

As described above, according to the present invention, a first oscillation circuit formed by a first common-collector transistor and a first resonance circuit, a second common-collector transistor, and a second resonance circuit A second oscillation circuit formed by
The first oscillation circuit and the second oscillation circuit are selectively activated by a control voltage applied to a third transistor, whereby the first oscillation circuit is constituted by only one third transistor. And the second oscillation circuit, the size of the oscillator can be reduced.

Since the switching of the oscillation circuit can be performed by one third transistor, a low-cost oscillator can be obtained.

Further, since the switching of the oscillation circuit is performed by one third transistor, the first oscillation circuit and the second oscillation circuit are not simultaneously turned on or off at the same time, and are not necessarily turned off at the same time. Since only the oscillating circuit is turned on, load current can be averaged. This reduces noise to the outside. Also, since there is no change in the transient current, the design of the power supply to be supplied is easy.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an oscillator according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of an amplifier connected to the oscillator.

FIG. 3 is a plan view of the high-frequency module according to one embodiment of the present invention.

FIG. 4 is a sectional view of the same.

FIG. 5 is a circuit diagram of a conventional oscillator.

[Explanation of symbols]

 Reference Signs List 11 oscillation circuit 12 oscillation circuit 13 transistor 15 control voltage input terminal 18 transistor 20 resonance circuit 27 output terminal 40 transistor 42 resonance circuit

Claims (7)

[Claims] A first common-collector transistor and a first common-collector transistor;
A first oscillating circuit formed by a resonant circuit of the above, and a second oscillating circuit formed by a second grounded-collector transistor and a second resonant circuit, wherein a control voltage applied to a third transistor causes An oscillator for selectively activating a first oscillation circuit and the second oscillation circuit. A third transistor connected to the emitter of the first transistor via a first resistor and connected to a base of the second transistor via a second resistor; The oscillator according to claim 1, wherein a control voltage is applied to a base of the oscillator. 3. The oscillator according to claim 2, wherein a third transistor is arranged between the first transistor and the second transistor. 4. The oscillator according to claim 2, wherein each of the first transistor, the second transistor, and the third transistor is an NPN transistor. 5. The printed circuit board on which the oscillator is mounted has four
The electronic component is mounted on the first layer using a layer substrate, and the second and fourth layers are formed as ground patterns on the entire surface and the third layer is mounted on the third layer.
A part of the inductance forming the resonance circuit in the layer is formed in a pattern, and the remaining part of the inductance is led out to the first layer by a through hole, and the remaining inductance is formed in the first layer in a pattern. The oscillator according to claim 2. 6. An oscillator according to claim 1, wherein a common emitter amplifier formed of a transistor is connected to the output of the oscillator, a resonance circuit is provided at a collector of the transistor of the amplifier, and the resonance circuit is inputted from a control voltage input terminal. A high frequency module that switches the resonance frequency according to the control voltage to be applied. 7. A substantially rectangular printed circuit board on which electronic components are mounted, and a control voltage input terminal, a tuning voltage input terminal, an output terminal, and a power supply terminal are provided near corners of the printed circuit board, respectively. 7. The high-frequency module according to claim 6, wherein a ground terminal is provided between these terminals.