JPH0539020U - High frequency oscillator - Google Patents

Abstract

(57) [Summary] [Configuration] Oscillation circuit 2 that oscillates an oscillation signal of a predetermined frequency.
8 and a buffer amplifier 29 for amplifying an oscillation signal are cascade-connected, and in the high-frequency oscillation circuit in which the respective DC collector bias circuits of the oscillation circuit 28 and the buffer amplifier 29 are connected in series, the oscillation circuit 28 is a collector-grounded Colpitts. Buffer amplifier 2 composed of an oscillator circuit
9 is composed of a grounded-emitter type amplifier circuit. [Effect] The circuit can be constructed inexpensively, easily and in a small size. Further, variations in various characteristics of the entire circuit due to variations in characteristics of components can be suppressed. Further, the grounded state can be stabilized at high frequencies, and the circuit performance is improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a high-frequency oscillation circuit in which an oscillation circuit that oscillates an oscillation signal of a predetermined frequency and a buffer amplifier that amplifies the oscillation signal are connected in series, and the DC collector bias circuits of the oscillation circuit and the buffer amplifier are connected in series. .

[0002]

[Prior Art]

 FIG. 2 is a block diagram showing a configuration example of a conventional high-frequency oscillator circuit. In this figure, reference numeral 1 is an grounded-type Colpitts oscillator circuit, and 2 is an oscillator circuit that oscillates an oscillation signal of a predetermined frequency. It is a buffer amplifier that consists of a grounded-emitter amplifier circuit and amplifies the oscillation signal.

In the oscillation circuit 1, 3 is a transistor for high frequency oscillation, 4 to 7 are tuning capacitors corresponding to C (capacitor) of the LC resonant circuit, and 8 is an L (inductor) of the LC resonant circuit. A tuning microstrip line, 9 is a tuning variable capacitance diode whose junction capacitance is varied by an applied voltage, 10 is a frequency control terminal to which a control voltage V _T for controlling the oscillation frequency is applied, and 11 is a power feeding choke coil. is there. Reference numeral 12 is a bypass capacitor, 13 is a grounding capacitor, 14 and 15 are biasing resistors respectively, 16 is a coupling capacitor, and 17 is a microstrip line formed as a feeding choke coil.

In the buffer amplifier 2, 18 is a transistor for high frequency amplification, 19 is a constant voltage power supply terminal to which a constant voltage V _CC is applied, 20 and 21 are bias resistors, 22 is a grounding capacitor, and 23 is a grounding capacitor. Bypass capacitor, 24 is a microstrip line formed as a load choke coil, 25 is a microstrip line formed as a matching circuit, 26 is a coupling capacitor, and 27 is an output terminal for outputting the output signal of the buffer amplifier 2. is there.

[0005]

[Problems to be solved by the device]

 By the way, in the above-described conventional high-frequency oscillation circuit, the oscillation circuit 1 and the buffer amplifier 2 are connected in series with their respective DC collector bias circuits. Therefore, the oscillation circuit 1 and the buffer amplifier 2 need the grounding capacitors 13 and 22 separately, and the microstrip line 17 formed as a power supply choke coil to supply power to the oscillation circuit 1. Therefore, the number of components and the area occupied by the circuit increase, which has been a factor in increasing the size and cost of the circuit.

Further, the grounding capacitor 13 of the oscillating circuit 1 and the grounding capacitor 22 of the buffer amplifier 2 have different characteristics such as capacitance value and Q value. There was a drawback that the variation became large. Further, the ground point of the oscillator circuit 1 and the ground point of the buffer amplifier 2 are separated from each other on the printed circuit board, so that there is a problem that the ground state is unstable at high frequencies. The present invention has been made under such a background, and is a low-frequency, high-frequency oscillation that can be configured easily and compactly, can suppress variations in various characteristics, and can stabilize a high-frequency grounded state. The purpose is to provide a circuit.

[0007]

[Means for Solving the Problems]

 In this invention, an oscillating circuit that oscillates an oscillating signal of a predetermined frequency and a buffer amplifier that amplifies the oscillating signal are connected in series, and the oscillating circuit and the respective DC collector bias circuits of the buffer amplifier are connected in series. In the high frequency oscillating circuit, the oscillating circuit is composed of a grounded collector type Colpitts oscillating circuit, and the buffer amplifier is composed of a grounded emitter type amplifying circuit.

[0008]

According to the above configuration, the emitter of the transistor forming the buffer amplifier and the collector of the transistor forming the oscillation circuit can be directly connected.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a high-frequency oscillator circuit according to an embodiment of this idea. In this figure, parts corresponding to those in FIG. 2 are assigned the same reference numerals and explanations thereof are omitted. . In this figure, 28 is a collector-grounded Colpitts oscillator circuit, an oscillator circuit that oscillates an oscillating signal of a predetermined frequency, and 29 is a common-emitter amplifier circuit that is a buffer amplifier that amplifies the oscillating signal. .

In the oscillation circuit 28, 30 to 33 are tuning capacitors corresponding to C (capacitors) of the LC resonant circuit, 34 is a tuning microstrip line corresponding to L (inductor) of the LC resonant circuit, and 35 and 36. Are bias resistors. Further, in the buffer amplifier 29, 37 and 38 are bias resistors.

The oscillator circuit 28 and the buffer amplifier 29 are connected in series with the respective DC collector bias circuits of the oscillator circuit 28 and the buffer amplifier 29, as in the above-described conventional high-frequency oscillator circuit. By the way, in the above-mentioned conventional high-frequency oscillator circuit, the oscillator circuit 1 is composed of a base-grounded Colpitts oscillator circuit, and the emitter of the transistor 18 which constitutes the buffer amplifier 2 and the transistor which constitutes the oscillator circuit 1 are constituted. Since it cannot be directly connected to the collector of No. 3, the microstrip line 17 as a feeding choke coil was required to feed power to the oscillation circuit 1.

However, in this embodiment, since the oscillator circuit 28 is composed of a collector-grounded Colpitts oscillator circuit, the emitter of the transistor 18 and the collector of the transistor 3 can be directly connected to each other to some extent on the printed circuit board. The microstrip line 17, which requires a large area, becomes unnecessary. Further, since the emitter of the transistor 18 and the collector of the transistor 3 can be directly connected, the oscillation circuit 28 and the buffer amplifier 29 can share the grounding capacitor 22. Further, since the oscillator circuit 28 and the buffer amplifier 29 can share the grounding capacitor 22, the ground point of the oscillator circuit 28 and the ground point of the buffer amplifier 29 can be the same point.

[0013]

[Effect of the device]

 As described above, according to the present invention, the number of parts and the occupied area of the circuit can be reduced, so that there is an effect that the configuration can be inexpensive, simple and small. Further, since the grounding capacitor can be shared by the oscillation circuit and the buffer amplifier, it is possible to suppress variations in various characteristics of the entire circuit due to variations in characteristics of components. Further, since the ground point of the oscillator circuit and the ground point of the buffer amplifier can be at the same point, the ground state can be stabilized at high frequencies, which has the effect of improving the circuit performance.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a high-frequency oscillator circuit according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration example of a conventional high-frequency oscillator circuit.

[Explanation of reference symbols] 1,28 Oscillation circuit 2,29 Buffer amplifier 3,18 Transistors 4-7, 30-33 Tuning capacitor 8,34 Tuning microstrip line 9 Tuning variable capacitance diode 10 Frequency control terminal 11 Power supply Choke coil 12,23 Bypass capacitor 13,22 Grounding capacitor 14,15,20,21,35-38 Biasing resistor 16,26 Coupling capacitor 17,24,25 Microstrip line 19 Constant voltage power supply terminal 27 Output terminal

Claims (1)

[Scope of utility model registration request] 1. An oscillating circuit for oscillating an oscillating signal of a predetermined frequency and a buffer amplifier for amplifying the oscillating signal are cascade-connected, and the oscillating circuit and the respective DC collector bias circuits of the buffer amplifier are connected in series. In the high-frequency oscillation circuit, the oscillation circuit is formed of a collector-grounded Colpitts oscillation circuit, and the buffer amplifier is formed of a grounded-emitter amplification circuit.