JPH11308048A - High frequency oscillation circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high frequency oscillation circuit in which characteristics such as S/N ratio are not deteriorated and wherein unnecessary impedance is not connected to the base of transistors in an oscillation frequency. SOLUTION: Two oscillation transistors 1 and 17 and a resonator 7 which is connected between the collectors of the transistors 1 and 17 via capacitors 5 and 19, are provided, whereas the bases of the two transistors 1 and 17 are connected directly without a capacitor in-between, and a differential signal output is extracted as an oscillation output between output coupling capacitors 6 and 20, which are connected to the emitters of the transistors 1 and 17 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency oscillation circuit such as a voltage controlled oscillator in a wireless communication device such as a portable telephone and a satellite communication.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to the drawings.

FIG. 5 is a circuit diagram of a conventional high-frequency oscillation circuit. In FIG. 5, 1 and 17 are oscillation transistors,
2, 3, 4, 18, 34, 35 are capacitors, 5, 19
Is a resonator coupling capacitor, 6 and 20 are output coupling capacitors, 7 is a resonator, 8 and 22 are varactor diode coupling capacitors, 9 and 23 are varactor diodes, 11, 1
2, 13, 25, 26, 27 are bias resistors, 14,
28 is a varactor diode bias choke, 15, 1
6 is a high-frequency output terminal, 10, 24, and 29 are high-frequency chokes, 30 and 32 are bypass capacitors, 31 is a tuning voltage supply terminal, and 33 is a bias voltage supply terminal.

[0004] The conventional high-frequency oscillation circuit having the above configuration operates as follows.

In FIG. 5, the base of the oscillation transistor 1 and the base of the oscillation transistor 17 are connected by a capacitor 4 having a low impedance in the oscillation frequency band. Are equivalently grounded. Capacitors 2 and 18 are connected to transistors 1 and 17, respectively, as collector-emitter capacitance elements. Capacitors 34 and 35 are connected to transistors 1 and 17 as collector-base capacitance elements, respectively. The capacitor 3 is connected to the transistor 1
Connected between the emitters of
In this circuit with the base grounded, it is equivalently connected between the emitter and the base. Further, the resonator 7 connected via the resonator coupling capacitors 5 and 19 is a half-wavelength resonator having an open end, and a middle point of the resonator is equivalent to a short-circuit point to the ground. Therefore, the resonator 7 serves as an inductive element between the collector and base of the transistor 1 via the resonator coupling capacitor 5, and the resonator 7 similarly serves as an inductive element between the collector and base of the transistor 17 via the capacitor 19. Equivalently connected.

As described above, in the circuit of FIG. 5, two grounded-base clap type oscillating circuits perform an oscillating operation while having a phase difference of 180 degrees as mutual oscillating signals by a half-wavelength resonator, and output signals thereof are output. Are output coupling capacitors 6, 2
0, a high frequency output terminal 1 as a differential output between the two.
It is taken out from between 5 and 16.

The varactor diodes 9 and 23 are connected to the resonator 7 via varactor diode coupling capacitors 8 and 22, respectively. Further, since the anodes of the varactor diodes 9 and 23 are each provided with a DC ground potential by the varactor diode bias chokes 14 and 28, the varactor diodes 9 and 23 are controlled by the voltage value applied to the tuning voltage supply terminal 31 via the high frequency choke coil 29. The capacitance values of 9 and 23 change, and the oscillation frequency can be varied.

[0008]

However, in the above configuration, since a capacitor is connected between the bases of the two oscillation transistors, the S / N and the like deteriorate due to the impedance component of the oscillation frequency of the capacitor. Had the problem of doing so.

An object of the present invention is to provide a high-frequency oscillating circuit in which characteristics such as S / N are not degraded in consideration of such conventional problems.

[0010]

According to the first aspect of the present invention, a first oscillating transistor, a second oscillating transistor,
A resonator connected between the collectors of the first oscillation transistor and the second oscillation transistor;
Are directly connected between the bases of the first and second oscillation transistors and the second oscillation transistor.
This is a high-frequency oscillation circuit that takes out a differential signal output from both emitters of the oscillation transistor as an oscillation output.

Further, according to the present invention, a first oscillation transistor, a second oscillation transistor, and a first oscillation transistor are provided.
A resonator connected between both bases of the first oscillation transistor and the second oscillation transistor, and directly connected between both collectors of the first oscillation transistor and the second oscillation transistor. This is a high-frequency oscillation circuit that takes out a differential signal output from both emitters of two oscillation transistors as an oscillation output.

With the above configuration, unnecessary impedance is not applied to the base at the oscillating frequency, and a high-frequency oscillating circuit without deterioration in characteristics such as S / N can be obtained.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a circuit diagram showing a high-frequency oscillation circuit according to a first embodiment of the present invention. In FIG.
1, 17 are oscillation transistors, 2, 3, 18, 33, 3
4 is a capacitor, 5 and 19 are resonator coupling capacitors,
6, 20 are output coupling capacitors, 7 is a resonator, 8, 22
Is a varactor diode coupling capacitor, 9, 23 are varactor diodes, 11, 12, 13, 25, 26 are bias resistors, 14, 27 are varactor diode bias chokes, 15, 16 are high frequency output terminals, 10, 24,
28 is a high frequency choke, 29 and 31 are bypass capacitors, 30 is a tuning voltage supply terminal, and 32 is a bias voltage supply terminal. Here, the capacitors 2, 18 are first and second capacitors, the resonator coupling capacitors 5, 19 are third and fourth capacitors, the capacitor 3 is a fifth capacitor, and the output coupling capacitor 6 , 20 are sixth and seventh capacitors.

The high-frequency oscillation circuit having the above-described configuration according to the first embodiment of the present invention operates as follows.

In FIG. 1, oscillation transistors 1 and 17 have their base terminals directly connected. Capacitors 2 and 18 are collector-emitter capacitance elements, and capacitors 33 and 34 are collector-emitter capacitors, respectively.
As the capacitance between the bases, their element values are selected so that the C / N characteristics and the like are optimal in the oscillation frequency band, and they are connected to the transistors 1 and 17, respectively.

The capacitor 3 is connected between the emitters of the transistors 1 and 17, and its element value is selected so that the C / N characteristics and the like are optimal in the oscillation frequency band. Further, the resonator coupling capacitors 5 and 19
Is a half-wavelength resonator having an open end, and the middle point of the resonator is equivalently a short-circuit point with the ground.
The resonator 7 is equivalently connected between the collector and the base of the transistor 1 as an inductive element, and via the capacitor 19, the resonator 7 is equivalently connected between the collector and the base of the transistor 17 as an inductive element.

The varactor diodes 9 and 23 are connected to the resonator 7 via varactor diode coupling capacitors 8 and 22, respectively. Further, since the anodes of the varactor diodes 9 and 23 are each provided with a DC ground potential by the varactor diode bias chokes 14 and 27, the varactor diodes 9 and 23 are controlled by the voltage value applied to the tuning voltage supply terminal 30 via the high-frequency choke coil 28. The capacitance values of 9 and 23 change, and the oscillation frequency can be varied.

As described above, in the circuit shown in FIG. 1, the two grounded clap type oscillating circuits perform an oscillating operation while having a phase difference of 180 degrees as mutual oscillating signals by the half-wavelength resonator, and output signals thereof are output. Are output coupling capacitors 6, 2
0, a high frequency output terminal 1 as a differential output between the two.
It is taken out from between 5 and 16.

According to the above arrangement, the base electrodes of the oscillation transistors are directly connected to each other, so that the base-grounding capacitor connected between the bases of the oscillation transistors is not connected in the prior art. By eliminating the impedance element that is a noise source in the base,
A high-frequency oscillation circuit without characteristic deterioration such as / N can be obtained. (Embodiment 2) FIG. 2 is a circuit diagram showing a high-frequency oscillation circuit according to a second embodiment of the present invention. In FIG.
1, 17 are oscillation transistors, 2, 3, 18 are capacitors, 5 and 19 are resonator coupling capacitors, 6 and 20 are output coupling capacitors, 7 is a resonator, 8, 22 are varactor diode coupling capacitors, and 9 and 23 are Varactor diodes, 11, 12, 25, 26, 43, and 44 are bias resistors, 14 and 27 are varactor diode bias chokes, 15 and 16 are high-frequency output terminals, 28 is a high-frequency choke, 29 and 31 are bypass capacitors, and 30 is a bypass capacitor. A tuning voltage supply terminal 32 is a bias voltage supply terminal. Here, the capacitors 2 and 18 are first and second capacitors, the resonator coupling capacitors 5 and 19 are third and fourth capacitors, the capacitor 3 is a fifth capacitor, and the output coupling capacitor 6 , 20 are sixth and seventh capacitors.

The high-frequency oscillation circuit according to the second embodiment of the present invention configured as described above operates as follows.

In FIG. 2, oscillating transistors 1 and 17 each have their collector terminals directly connected.
Capacitors 2 and 18 have element values selected as base-emitter capacitive elements so that C / N characteristics and the like are optimal in an oscillation frequency band, and are connected to transistors 1 and 17, respectively.

The capacitor 3 is connected between the emitters of the transistors 1 and 17, and its element value is selected so that the C / N characteristics and the like are optimal in the oscillation frequency band. Further, the resonator coupling capacitors 5 and 19
Is a half-wavelength resonator having an open end, and the middle point of the resonator is equivalently a short-circuit point with the ground.
The resonator 7 is equivalently connected between the collector and the base of the transistor 1 as an inductive element, and via the capacitor 19, the resonator 7 is equivalently connected between the collector and the base of the transistor 17 as an inductive element.

The varactor diodes 9 and 23 are connected to the resonator 7 via varactor diode coupling capacitors 8 and 22, respectively. Further, since the anodes of the varactor diodes 9 and 23 are each provided with a DC ground potential by the varactor diode bias chokes 14 and 27, the varactor diodes 9 and 23 are controlled by the voltage value applied to the tuning voltage supply terminal 30 via the high-frequency choke coil 28. The capacitance values of 9 and 23 change, and the oscillation frequency can be varied.

As described above, in the circuit shown in FIG. 2, the two grounded-collector clap type oscillating circuits perform the oscillating operation while having a phase difference of 180 degrees as an oscillating signal of each other by the half-wavelength resonator, and the output thereof is provided. Is the output coupling capacitor 6,
20 and a high-frequency output terminal 1 as a differential output between the two.
It is taken out from between 5 and 16.

According to the above configuration, by directly connecting the collector electrodes of the oscillation transistor,
Conventionally, by removing the impedance element which is a noise source in the collector at high frequency without connecting the collector grounding capacitor connected between the collectors of the oscillation transistors, a high-frequency oscillation circuit without deterioration of characteristics such as S / N is provided. Obtainable. (Embodiment 3) FIG. 3 is a circuit diagram showing a high-frequency oscillation circuit according to a third embodiment of the present invention. In FIG. 3, 3
5, 36 are buffer amplifier transistors, 11, 25,
37 and 38 are bias resistors, 31 is a bypass capacitor, 39 and 40 are high frequency choke coils, 41 and 42 are interstage coupling capacitors, 6 and 20 are output coupling capacitors,
32 is a bias voltage supply terminal, and 15 and 16 are high frequency output terminals. The other parts are made up of the same components as in FIG. Here, the interstage coupling capacitor 4
Reference numerals 1 and 42 denote sixth and seventh capacitors, and output coupling capacitors 6 and 20 denote eighth and ninth capacitors.

The high-frequency oscillating circuit according to the third embodiment of the present invention having the above configuration operates as follows.

In FIG. 3, oscillation transistors 1 and 17 constitute a grounded-base clap oscillation circuit as in the first embodiment, and each of them has a 180 ° phase difference as an oscillation signal. Oscillation is performed while holding. The output is amplified by buffer amplifier transistors 35 and 36 via inter-stage coupling capacitors 41 and 42, respectively, passes through output coupling capacitors 6 and 20, and is output as a differential output between the high-frequency output terminals 15 and 16 between the two. Taken out.

Here, the buffer amplifier transistor 3
Reference numerals 5 and 36 denote a common-emitter type differential amplifier circuit.
The configuration is such that the emitters of the two buffer amplifier transistors are directly connected.

As described above, the oscillation is achieved by directly connecting the emitter electrodes of the two buffer amplifier transistors without connecting the emitter-grounding capacitor connected between the two buffer amplifier transistors. Both the circuit section and the buffer amplifier section eliminate the grounding capacitor having an impedance component in high frequency,
A high-frequency oscillation circuit without characteristic deterioration such as / N can be obtained.

In the DC bias circuit, the collectors of the oscillating transistors 1 and 17 are the first and second oscillating transistors.
Are connected to the emitters of buffer amplifier transistors 35 and 36 by high-frequency chokes 10 and 24, which are inductors. Therefore, the buffer amplifier transistor 35 and the oscillation transistor 1 share a common collector current path, and similarly, the buffer amplifier transistor 36
And the oscillation transistor 17 have a common collector current path.

According to the above configuration, it is possible to obtain a high-frequency oscillation circuit capable of reducing current consumption as compared with a circuit in which a collector current flows through separate current paths to the oscillation transistor and the buffer amplifier transistor. . (Embodiment 4) FIG. 4 is a circuit diagram showing a high-frequency oscillation circuit according to a fourth embodiment of the present invention. In FIG. 4, 3
5, 36 are buffer amplifier transistors, 33, 34,
43 and 44 are bias resistors, 31 is a bypass capacitor, 39 and 40 are high frequency choke coils, 37 and 38 are interstage coupling capacitors, 6 and 20 are output coupling capacitors,
32 is a bias voltage supply terminal, and 15 and 16 are high frequency output terminals. The other parts are made up of the same components as in FIG. Here, the interstage coupling capacitor 3
7, 38 are sixth and seventh capacitors, and the output coupling capacitors 6, 20 are eighth and ninth capacitors.

The high-frequency oscillation circuit according to the fourth embodiment of the present invention configured as described above operates as follows.

In FIG. 4, the oscillation transistors 1 and 17 constitute a common-collector-type clap-type oscillation circuit, similarly to the above-described second embodiment, and each of them has a phase difference of 180 degrees as an oscillation signal. Oscillation is performed while holding. The output is amplified by buffer amplifier transistors 35 and 36 via inter-stage coupling capacitors 37 and 38, respectively, passes through output coupling capacitors 6 and 20, and is output as a differential output between the high-frequency output terminals 15 and 16 between the two. Taken out.

Here, the buffer amplifier transistor 3
Reference numerals 5 and 36 denote a common-emitter type differential amplifier circuit.
The configuration is such that the emitters of the two buffer amplifier transistors are directly connected.

As described above, by connecting the emitter electrodes of the two buffer amplifier transistors directly without connecting the common-emitter capacitor connected between the two buffer amplifier transistors,
Since both the oscillation circuit section and the buffer amplifier section can perform a differential circuit operation without using a grounding capacitor at a high frequency, a high-frequency oscillation circuit without deterioration in characteristics such as S / N due to the impedance of the grounding capacitor is obtained. be able to.

In the DC bias circuit, the collectors of the oscillation transistors 1 and 17 are connected to the emitters of the buffer amplifier transistors 35 and 36. Therefore, the buffer amplifier transistors 35 and 36
And the oscillating transistors 1 and 17 have a common collector current path.

According to the above configuration, it is possible to obtain a high-frequency oscillation circuit capable of lowering current consumption as compared with a circuit in which a collector current flows through the oscillation transistor and the buffer amplifier transistor through separate current paths. .

The circuit configuration of the above embodiment is an example, and the base or the collector of the two oscillation transistors is directly connected so as not to be affected by the impedance of the grounding capacitor. The configuration of the additional circuit around the transistor is not limited to this, as long as the configuration is such that the emitters of one buffer amplifier transistor are directly connected.

[0039]

As described above, according to the present invention, the base grounding capacitor connected between the two oscillation transistors is not connected, and the base between the two oscillation transistors is not connected.
Alternatively, by directly connecting the collectors, it is possible to obtain a high-frequency oscillation circuit that is not affected by the impedance of the grounding capacitor and that does not deteriorate in characteristics such as S / N.

When a buffer amplifier is connected to the oscillation circuit, the capacitor between the emitters of the two buffer amplifier transistors is not connected, and the emitters of the two buffer amplifier transistors are directly connected.
Not affected by the impedance of the grounding capacitor,
A high-frequency oscillation circuit without characteristic deterioration such as / N can be obtained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a high-frequency oscillation circuit according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a high-frequency oscillation circuit according to a second embodiment of the present invention.

FIG. 3 is a circuit diagram illustrating a high-frequency oscillation circuit according to a third embodiment of the present invention.

FIG. 4 is a circuit diagram showing a high-frequency oscillation circuit according to a fourth embodiment of the present invention.

FIG. 5 is a circuit diagram showing a conventional high-frequency oscillation circuit.

[Explanation of symbols]

1,17 oscillation transistor 2,3,18,33,34 capacitor 5,19 resonator coupling capacitor 6,20 output coupling capacitor 7 resonator 8,22 varactor diode coupling capacitor 9,23 varactor diode 11,12,13,25 , 26, 33, 34, 43, 4
4 Bias resistor 14, 27 Varactor diode bias choke 15, 16 High frequency output terminal 10, 24, 28, 39, 40 High frequency choke 29, 31 Bypass capacitor 30 Tuning voltage supply terminal 32 Bias voltage supply terminal 35, 36 Buffer amplifier transistor 41 , 42-stage coupling capacitor

Claims (8)

[Claims] A first oscillation transistor, a second oscillation transistor, and a resonator connected between the collectors of the first oscillation transistor and the second oscillation transistor; A high-frequency oscillation circuit which directly connects between the bases of the transistor and the second oscillation transistor, and takes out a differential signal output as an oscillation output from between the emitters of the first and second oscillation transistors. . A first oscillation transistor, a second oscillation transistor, and a resonator connected between the bases of the first oscillation transistor and the second oscillation transistor; A high-frequency oscillation circuit, wherein a collector of the transistor and the collector of the second oscillation transistor are directly connected, and a differential signal output is taken out as an oscillation output from between the emitters of the first oscillation transistor and the second oscillation transistor. . A first capacitor connected between a collector and an emitter of the first oscillation transistor; a second capacitor connected between a collector and an emitter of the second oscillation transistor; A third capacitor connected between the collector of the oscillating transistor and the resonator; a fourth capacitor connected between the collector of the second oscillating transistor and the resonator; A fifth capacitor connected between the emitter of the first oscillation transistor and the emitter of the second oscillation transistor, a sixth capacitor having one end connected to the emitter of the first oscillation transistor, And a seventh capacitor having one end connected to the emitter of the oscillating transistor, wherein the oscillating output is provided by the sixth capacitor and the seventh capacitor. The high-frequency oscillation circuit according to claim 1, wherein the high-frequency oscillation circuit is taken out through a filter. 4. The base of the first oscillation transistor.
A first capacitor connected between the emitters;
A second capacitor connected between the base and the emitter of the oscillation transistor, a third capacitor connected between the base of the first oscillation transistor and the resonator, and a second capacitor connected between the base and the resonator of the first oscillation transistor. A fourth capacitor connected between a base and the resonator, a fifth capacitor connected between an emitter of the first oscillation transistor and an emitter of the second oscillation transistor,
A sixth capacitor having one end connected to the emitter of the first oscillation transistor; and a seventh capacitor having one end connected to the emitter of the second oscillation transistor, wherein the oscillation output is the sixth capacitor. The capacitor and the seventh
3. The high-frequency oscillation circuit according to claim 2, wherein the high-frequency oscillation circuit is taken out through the capacitor. 5. A first buffer amplifier transistor having a base connected to the sixth capacitor, a second buffer amplifier transistor having a base connected to the seventh capacitor, and the first buffer amplifier transistor. An eighth capacitor having one end connected to the collector of
A ninth capacitor having one end connected to a collector of the second buffer amplifier transistor, wherein an emitter of the first buffer amplifier transistor and an emitter of the second buffer amplifier transistor are directly connected; 4. The high-frequency oscillation circuit according to claim 3, wherein the oscillation output is taken out from between the other end of the eighth capacitor and the other end of the ninth capacitor. 6. A first buffer amplifier transistor having a base connected to the sixth capacitor, a second buffer amplifier transistor having a base connected to the seventh capacitor, and the first buffer amplifier transistor An eighth capacitor having one end connected to the collector of
A ninth capacitor having one end connected to a collector of the second buffer amplifier transistor, wherein an emitter of the first buffer amplifier transistor and an emitter of the second buffer amplifier transistor are directly connected; The high-frequency oscillation circuit according to claim 4, wherein the oscillation output is taken out from between the other end of the eighth capacitor and the other end of the ninth capacitor. 7. A first inductor connected between a collector of said first oscillation transistor and an emitter of said first buffer amplifier transistor, a collector of said second oscillation transistor and said second buffer. A second inductor connected between the emitter of the amplifier transistor and a collector current of the first buffer amplifier transistor and a collector current of the first oscillation transistor; 6. The high-frequency oscillation circuit according to claim 5, wherein a current path of the collector current of the buffer amplifier transistor and the current path of the collector current of the second oscillation transistor are shared. 8. A collector of the first oscillation transistor is connected to an emitter of the first buffer amplifier transistor, and a collector of the second oscillation transistor is connected to an emitter of the second buffer amplifier transistor. The current path of the collector current of the first buffer amplifier transistor and the collector current of the first oscillation transistor are shared, and the collector current of the second buffer amplifier transistor and the collector current of the second oscillation transistor are shared. 7. The high-frequency oscillation circuit according to claim 6, wherein a current path with a collector current is shared.