JP2003243935A - High frequency oscillation circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high frequency oscillation circuit from which a harmonic component of a fundamental oscillation wave is extracted without the need for using a frequency multiplier circuit so as to reduce the current consumption and the chip area of an integrated circuit. <P>SOLUTION: In a Colpitts oscillation circuit employing first and second transistors 1, 2 for oscillation, capacitors C8, C9 acting like impedance elements are connected between base terminals of the first and second transistors, and the even-multiple harmonics with respect to the fundamental oscillation wave are extracted from an output terminal 14 placed to a connection midpoint 16 between the capacitors C8, C9. Further, collector terminals of the first and second transistors 1, 2 are connected together, a bias impedance element is connected between a power supply and a connection point of the collector terminals, and the output terminal may be placed to the connecting point of the collector terminals. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency oscillating circuit, and more particularly to a high frequency oscillating circuit for use in various communication devices and for extracting a harmonic component of a fundamental oscillating wave.

[0002]

2. Description of the Related Art High-frequency oscillator circuits are widely used in communication devices such as mobile phones and TV tuners.
Since a signal in a frequency band of several megahertz [MHz] to several gigahertz [GHz] is oscillated and output, a device for efficiently extracting the harmonic component of the fundamental oscillation wave has been made.

FIG. 3 shows an example of the configuration of a conventional high-frequency oscillator circuit. This circuit comprises a balanced voltage-controlled Colpitts oscillator circuit 10 and a frequency multiplier circuit 20. In the figure, the Colpitts oscillator circuit 10 is provided with an inductive element 3 forming a resonance circuit and split capacitors C1, C2, C3. As the inductive element 3, for example, a coil or a crystal oscillator is used. Further, a first transistor 1 and a second transistor 2 for oscillation are arranged to feed back and oscillate the resonance frequency of the resonance circuit.

That is, in the first transistor 1, the base terminal thereof is connected to the DC blocking capacitor C4 and the dividing capacitor C1, the emitter terminal is connected to the dividing capacitor Cl and the dividing capacitor C2, and the collector terminal thereof is connected to the power source Vcc.
Connect to. In the second transistor 2, the base terminal is connected to the connection point of the DC blocking capacitor C5 and the dividing capacitor C3, the emitter terminal is connected to the connecting point of the dividing capacitor C3 and the dividing capacitor C2, and the collector terminal is connected to the power supply Vcc.

Further, voltage controlled variable capacitance diodes 4 and 5 for controlling the oscillation frequency by the control voltage Vc, bias resistors R1 to R6, and high frequency blocking resistors R7 to R10 are arranged. That is, the input terminal of the control voltage Vc is connected between the resistors R9 and R10, and the voltage controlled variable capacitance diode 4 is connected between the resistor R9 and the DC blocking capacitor C4 at one end of the inductive element 3. The voltage controlled variable capacitance diode 5
Is connected to the other end of the inductive element 3 between the resistor R10 and the DC blocking capacitor C5. As a result, the circuit becomes a voltage control type, and the oscillation frequency is controlled by applying the control voltage Vc which is a reverse voltage to the voltage control type variable capacitance diodes 4 and 5.

Next, the frequency multiplication circuit 20 is provided to take out a harmonic component of the fundamental oscillation wave of the Colpitts oscillation circuit 10, and this circuit 20 has a third transistor 11 and a fourth transistor 12. . That is, the third
The base terminal of the transistor 11 is connected to the base terminal of the first transistor 1 for oscillation through the DC blocking capacitor C6 and the signal extracting resistor R17, and the fourth transistor 12 has a base terminal of the DC blocking capacitor. It is connected to the base terminal of the second transistor 2 for oscillation through C7 and the resistor R18 for extracting a signal. Then, the emitter terminals of both the third transistor 11 and the fourth transistor 12 are connected, and the output terminal 14 is connected to the midpoint 13 between the emitter terminals. The resistors R11 to R16 in the figure are arranged as bias resistors.

According to the above configuration, the fundamental frequency wave oscillated from the Colpitts oscillator circuit 10 is multiplied by the frequency multiplier circuit 20.
Is supplied to the frequency multiplying circuit 20, a harmonic of an integral multiple of the fundamental frequency is formed based on the amplifying action of the third transistor 11 and the fourth transistor 12, and this harmonic is output from the output terminal 14. Taken out.

[0008]

However, in the above-mentioned conventional high frequency oscillation circuit, the frequency multiplication circuit 20 is provided in order to extract the harmonic component of an integral multiple of the fundamental oscillation frequency, and the existence of this frequency multiplication circuit 20. As a result, there is a problem that the current consumption increases and the area of the integrated circuit chip increases when integrated into a circuit.

The present invention has been made in view of the above problems, and an object thereof is to extract a harmonic component of a fundamental oscillation wave without using a frequency multiplication circuit, thereby reducing current consumption and reducing an integrated circuit chip area. Another object of the present invention is to provide a high-frequency oscillator circuit capable of achieving the above.

[0010]

In order to achieve the above object, a high frequency oscillation circuit according to a first aspect of the present invention is a Colpitts oscillation circuit which performs balanced operation using a first transistor and a second transistor for oscillation. This Colpitts oscillator circuit is provided with a harmonic extraction circuit for extracting a harmonic of an even multiple of the fundamental frequency by using an impedance element. In the invention according to claim 2, as the harmonic extraction circuit, an impedance element for extracting a harmonic of an even multiple of a fundamental frequency is connected between the base and the base of the first transistor and the second transistor,
It is characterized in that the harmonic output terminal is provided at the midpoint of the impedance element. According to a third aspect of the present invention, as the harmonic extraction circuit, the first transistor and the second transistor are provided.
Connect the collectors of the transistors to each other, and connect an impedance element between the collectors to the power source to extract even higher harmonics of the fundamental frequency. The output terminal of is provided.

According to the second aspect of the present invention, the conventional idea of forming a harmonic by using a frequency multiplier is amended, and an impedance element is provided between the base terminal of the oscillating first transistor and the base terminal of the second transistor. , The fundamental frequency waves oscillated by these first and second transistors cancel each other at the midpoint,
It was confirmed that even harmonics of this fundamental frequency appeared. Therefore, if the output terminal is connected to the midpoint of the impedance element, the even harmonic components of the fundamental frequency can be efficiently extracted.

Similarly, when the collectors of the oscillating first transistor and the second transistor are connected to each other, the connection point of the collectors, which is the middle point of the resistors existing in the two collectors themselves, is also provided. In addition, it was confirmed that although the fundamental frequency waves oscillated by the first and second transistors cancel each other out, harmonics of an even multiple of this fundamental frequency appear. Further, by arranging an impedance element for bias between the connection point between the collectors and the power supply Vcc, even harmonic components of even multiples are satisfactorily taken out from the output terminal arranged at the connection point between the collectors.

[0013]

FIG. 1 shows the configuration of a high-frequency oscillator circuit according to a first embodiment of the present invention, which is a balanced voltage-controlled high-frequency Colpitts oscillator. An impedance element is arranged between the base terminals of two oscillation transistors. As shown in FIG. 1, this circuit is provided with an inductive element 3 and split capacitors C1, C2, C3 forming a resonance circuit as in the conventional case. As the inductive element 3, for example, a coil,
A crystal oscillator is used. Further, a first transistor 1 and a second transistor 2 for oscillation are arranged to feed back and oscillate the resonance frequency of the resonance circuit.

That is, in the first transistor 1, the base terminal is connected to the DC blocking capacitor C4 and the dividing capacitor C1, the emitter terminal is connected to the dividing capacitor Cl and the dividing capacitor C2, and the collector terminal is the power source Vcc.
Connect to. In the second transistor 2, the base terminal is connected to the connection point of the DC blocking capacitor C5 and the dividing capacitor C3, the emitter terminal is connected to the connecting point of the dividing capacitor C3 and the dividing capacitor C2, and the collector terminal is connected to the power supply Vcc.

Further, voltage controlled variable capacitance diodes 4 and 5 for controlling the oscillation frequency by the control voltage Vc, bias resistors R1 to R6, and high frequency blocking resistors R7 to R10 are arranged. That is, the input terminal of the control voltage Vc is connected between the resistors R9 and R10, and the voltage controlled variable capacitance diode 4 is connected between the resistor R9 and the DC blocking capacitor C4 at one end of the inductive element 3. The voltage controlled variable capacitance diode 5
Is connected to the other end of the inductive element 3 between the resistor R10 and the DC blocking capacitor C5.

Then, capacitors C8 and C9 having the same capacitance as impedance elements are connected in series between the base terminal of the first transistor 1 and the base terminal of the second transistor, and the midpoint 16 of these capacitors C8 and C9 is connected. The output terminal 14 is connected to and the signal is taken out from the output terminal 14. The above-mentioned capacitors C8 and C9 have a role of taking out even harmonics without attenuating the fundamental oscillation wave, and when viewed from the midpoint 16, the impedance is high with respect to the fundamental oscillation wave, A low impedance is used for even harmonics. Instead of the capacitors C8 and C9, other impedance elements such as resistors may be arranged.

The first embodiment has the above-mentioned structure. In this high frequency oscillator circuit, the inductive element 3 and the dividing capacitor C are used.
A predetermined fundamental frequency wave is oscillated by performing an oscillating operation by the first transistor 1 and the second transistor 2 with respect to the resonance circuit composed of 1, C2 and C3.
The circuit is of a voltage control type, and the fundamental frequency of oscillation can be variably controlled by changing the control voltage Vc of the reverse voltage supplied to the voltage control type variable capacitance diodes 4 and 5. You can do it.

The midpoint of the capacitors C8 and C9 arranged between the base terminals of the transistors 1 and 2 is the midpoint of the resonance circuit. Here, the oscillated fundamental frequency waves cancel each other out. , Even harmonics of this fundamental frequency appear at a higher level than the fundamental frequency wave. Therefore, it is possible to extract even harmonics from the output terminal 14.

FIG. 2 shows the structure of the high frequency oscillator circuit of the second embodiment. In this second embodiment, an impedance element is provided between the collector connection point of two oscillation transistors and the power supply. It is arranged. As shown in FIG. 2, the basic configuration of this circuit is the same as that of the first embodiment, and the inductive element 3 and the dividing capacitors C1, C2, C3 are used.
And a first and second oscillating transistor 1 for feeding back and amplifying the resonance frequency of the resonance circuit.
2 is placed. Further, voltage control type variable capacitance diodes 4 and 5 for controlling the oscillation frequency by the voltage Vc are provided, and this circuit is a balanced type voltage control Colpitts oscillation circuit.

The collector terminal of the first transistor 1 and the collector terminal of the second transistor are connected, and a resistor R19 as an impedance element is inserted between the connection point 17 and the power supply Vcc. The output terminal 14 is connected to. Further, capacitors C8 and C9 are connected in series between the base terminals of the first and second transistors 1 and 2 as in the first embodiment.

Here, a resistance exists in the collectors of the first and second transistors 1 and 2, and the collector resistance and the resistance R19 serve to take out even harmonics. Are doing The resistor R19 functions as a bias resistor (impedance element).
Other impedance elements may be arranged instead of the resistor R19.

According to the configuration of the second embodiment, the first transistor 1 and the second transistor 2 are the same as in the first embodiment.
A predetermined fundamental frequency wave is oscillated by the, and the fundamental frequency is variably controlled by the control voltage Vc. Here, the connection point 17 between the collector terminals of both the transistors 1 and 2 becomes the middle point of the resonance circuit, and the existence of the resistor R19 with the power supply Vcc causes the oscillated fundamental frequency at this connection point 17. While the waves cancel each other out, even harmonics appear at higher levels than the fundamental frequency wave. As a result, it is possible to take out even harmonics from the output terminal 14.

[0023]

As described above, according to the present invention,
An impedance element for extracting a harmonic of an even multiple of the fundamental frequency is connected between the base and base of the first and second transistors for oscillation of the Colpitts oscillator circuit, and the output terminal is connected to the midpoint of this impedance element. Impedance for extracting the higher harmonic wave of an even multiple of the fundamental frequency between the power supply and the connection point between the collectors of the first transistor and the second transistor of the Colpitts oscillator circuit. The elements are connected and the output terminals are provided at the connection points between the collectors so that even harmonics of the fundamental frequency can be taken out from these output terminals. Wave components can be extracted efficiently, and current consumption and integrated circuit chip area can be reduced. Theft is possible.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a high-frequency oscillator circuit (voltage control type) according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a high frequency oscillation circuit (voltage control type) according to a second embodiment.

FIG. 3 is a circuit diagram showing a configuration of a conventional high-frequency oscillator circuit.

[Explanation of symbols]

1 ... 1st transistor, 2 ... 2nd transistor, 3 ...
Inductive element, 4, 5 ... Voltage controlled variable capacitance diode,
10 ... Colpitts oscillator circuit, 20 ... Frequency multiplier circuit, C
1 to C3 ... Dividing capacitors forming a resonance circuit, C4 and C5
... DC blocking capacitors, C8, C9 ... Capacitors as impedance elements, R7, R10 ... High frequency blocking resistors, R1
9 ... Bias resistor as an impedance element.

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[Procedure amendment]

[Submission date] March 26, 2002 (2002.3.2)
6)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

The collector terminal of the first transistor 1 and the collector terminal of the second transistor are connected, and a resistor R19 as an impedance element is inserted between the connection point 17 and the power supply Vcc. to connect the output terminal 14.

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

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Claims (3)

[Claims] 1. A Colpitts oscillating circuit that performs balanced operation using an oscillating first transistor and a second transistor, wherein an impedance element is used in this Colpitts oscillating circuit to extract even harmonics of a fundamental wave frequency. High-frequency oscillator circuit with a harmonic extraction circuit. 2. As the harmonic extraction circuit, between the base and base of the first transistor and the second transistor,
2. The high frequency oscillation circuit according to claim 1, wherein an impedance element for extracting a harmonic of an even multiple of the fundamental frequency is connected, and the output terminal for the harmonic is provided at the midpoint of the impedance element. 3. The harmonic extraction circuit, wherein collectors of the first transistor and the second transistor are connected to each other, and a harmonic of an even multiple of the fundamental frequency is provided between a connection point of the collectors and a power supply. The high-frequency oscillator circuit according to claim 1, wherein an impedance element for taking out is connected, and an output terminal for the higher harmonic wave is provided at a connection point between the collectors.