Oscillator and communication apparatus

专利摘要:
The oscillator of the present invention includes an oscillator circuit to which a resonant circuit is connected, and an amplifier circuit for amplifying an output signal of the oscillator circuit. In addition to this, transmission of unnecessary waves such as higher-order harmonic components of the fundamental wave is prevented. Therefore, an oscillator in which deterioration of phase noise characteristics due to generation of unnecessary wave components such as higher harmonics is suppressed, and a communication device using such an oscillator can be obtained.
公开号:KR20010098933A
申请号:KR1020010022937
申请日:2001-04-27
公开日:2001-11-08
发明作者:후지다이마사노리；사토후미토시；하타도시오
申请人:무라타 야스타카；가부시키가이샤 무라타 세이사쿠쇼；
IPC主号:

专利说明:

Oscillator and communication apparatus
[10] The present invention relates to an oscillator used in a high frequency circuit and a communication device using the oscillator.
[11] Background Art [0002] Conventionally, oscillators used in microwave bands and the like have been constituted by colpitts type oscillation circuits or variable oscillation circuits.
[12] 9 shows a configuration example of a conventional oscillator. Referring to the oscillator circuit 2 shown in FIG. 9, Q1 represents an oscillator converter and includes a capacitor C1 connected between the base and the emitter, the collector is grounded at high frequency by the capacitor C3, C2) is provided between the emitter and the ground, and the resonant circuit 1 is provided between the base and the ground, and the call-pit oscillation circuit is constituted by constructing an induction circuit in the portion represented by the resonant circuit 1. .
[13] In addition, in the amplifying circuit 4 of FIG. 9, Q2 represents a buffer converter and transmits the oscillation signal from the emitter of the converter Q1 to the base of the converter through the condenser C5.
[14] However, if the oscillator includes an oscillating circuit and an amplifying circuit for amplifying the output signal of the oscillating circuit, the oscillating circuit generates harmonics such as second harmonic and third harmonic as well as an oscillation frequency determined by the resonance frequency. The amplification circuit also amplifies and outputs these higher harmonic components. This deteriorated the phase noise characteristics of the oscillator.
[15] Accordingly, it is an object of the present invention to provide an oscillator for suppressing deterioration of phase noise characteristics due to unnecessary waves such as the higher-order harmonics described above, and a communication device using the oscillator.
[1] 1 is a block diagram of an oscillator of the first embodiment.
[2] 2 is a circuit diagram of the oscillator.
[3] 3 is a diagram illustrating an output power spectrum of the oscillator and the conventional oscillator.
[4] 4 is a circuit diagram of an oscillator according to a second embodiment.
[5] 5 is a circuit diagram of an oscillator according to a third embodiment.
[6] 6A and 6B are circuit diagrams of an oscillator according to a fourth embodiment.
[7] 7 is a circuit diagram of an oscillator according to a fifth embodiment.
[8] 8 is a block diagram showing the structure of a communication device according to the sixth embodiment.
[9] 9 is a view showing the structure of a conventional oscillator.
[16] To this end, the present invention is an oscillator including an oscillator circuit connected with a resonant circuit and an amplifier circuit for amplifying an output signal of the oscillator circuit and outputting it from an output device, wherein an additional circuit for preventing unnecessary wave transmission is provided. It is provided between the output part and the input part of the amplification circuit. Therefore, unnecessary waves such as high-order harmonic components generated in the oscillation circuit are prevented from being transmitted to the amplifier circuit, and deterioration of the phase noise characteristic is suppressed.
[17] The additional circuit may be a filter for blocking high frequency components of unnecessary waves. In addition, the frequency to be cut off may be a higher harmonic frequency of the oscillation frequency due to the oscillation circuit. Therefore, transmission of unnecessary wave components can be effectively prevented.
[18] The additional circuit may be an isolator carrying a signal having a predetermined frequency bandwidth including the oscillation frequency of the oscillating circuit from the output of the oscillating circuit to the input of the amplifying circuit. Therefore, transmission of unnecessary waves from the oscillating circuit to the amplifying circuit can be prevented, and even if the signal is reflected on the oscillating circuit side due to mismatch occurring in the amplifying circuit, the reflected waves are blocked by the isolator and the oscillating circuit can be stabilized. Can work.
[19] In addition, according to the present invention, the communicator device is constituted by providing a PLL circuit for a local oscillation circuit using an oscillator having the above-described structure.
[20] The structure of the oscillator according to the first embodiment will be described with reference to FIGS. 1 to 3.
[21] 1 is a block diagram of an oscillator. The oscillator comprises a resonant circuit 1, an oscillator circuit 2 oscillating at a resonant frequency of the resonant circuit 1, an amplifying circuit 4 and an oscillator circuit 2 for amplifying an output signal from the oscillator circuit 2; And an additional circuit 3 for preventing unnecessary waves from being transmitted among the output signals.
[22] 2 is a circuit diagram of a specific oscillator. In Fig. 2, Q1 represents an oscillating converter, a capacitor C1 is connected between the emitter and the base of the converter, the collector is connected to ground at a high frequency through a bypass capacitor C3, and a capacitor C2. Is connected between the emitter and the ground, and the resonant circuit 1 is connected between the base and the ground, forming a call-pit oscillation circuit.
[23] In addition, a strip-line inductor L1 is connected between the collector of the Q1 and the power supply terminal Vb, the resistor R3 is connected between the emitter and the ground, and the voltage divider circuits of the resistors R1 and R2 are connected. Is connected between the power supply terminal Vb and ground, and the output is connected to the base of Q1.
[24] In the resonant circuit 1, L4 represents a stripline inductor, and VD represents a variable capacitance diode whose capacitance changes in accordance with the applied voltage. A filter circuit including a stripline inductor L5 and a capacitor C12 is provided between the variable capacitor diode VD and the control voltage terminal so that the control voltage is applied to the variable capacitor diode VD. The reactance of the resonant circuit 1 depends on the inductance of L4, the capacitance of the variable capacitance diode VD, and the capacitance of the other capacitors C9, C10, and C11. The resonance frequency is determined by these values and the capacitances of the capacitors C1 and C2 of the oscillation circuit 2, and oscillation is performed at the resonance frequency. Therefore, the oscillation frequency changes according to the control voltage Vc applied.
[25] In the amplifier circuit 4, Q2 is a buffer converter and includes a capacitor C8 and a resistor R5 connected between the emitters of Q2 and a stripline inductor L2 connected between the power supply terminal Vb and the collector. do. In addition, the output of the voltage divider circuit including the resistors R6 and R7 is transmitted to the base. In addition, the capacitor C7 is provided between the collector and the output terminal of Q2.
[26] The output of the oscillating circuit 2 is transmitted from the emitter of Q1, and is a series circuit of the capacitor C5 and the additional circuit 3 between the output of the oscillating circuit and the input of the amplifying circuit 4 (i.e., the base of Q2). Is connected. In this embodiment, the additional circuit 3 is composed of an isolator having a low insertion loss through a predetermined frequency bandwidth having an oscillation frequency as the center frequency.
[27] The isolator used above is a line circulator in which the strip center conductor is sandwiched between two ferrite plates, or a lumped constant circulator in which the central conductor is concentrated so that the static magnetic field is applied in the direction orthogonal to the ferrite plate. In other words, termination resistors for terminating the reflected wave are provided in predetermined ports of these three-port circulators to form an isolator. Alternatively, a two port isolator is used in which two center conductors are arranged to cross at a predetermined angle.
[28] In the isolator where the insertion loss decreases in the forward direction, the center frequency of the frequency bandwidth is formed to match the oscillation frequency of the oscillation circuit 2. By providing the isolator between the oscillation circuit 2 and the amplifying circuit 4, the higher-order harmonic components separated from the above-described bandwidth are suppressed, and only the fundamental wave frequency (the oscillation frequency that occurs) is caused by the amplifying circuit 4. Is amplified. Further, the reflected signal due to impedance mismatch in the connection between the additional circuit 3 and the amplification circuit 4 or the impedance mismatch in the amplification circuit 4 does not return to the oscillation circuit 2 due to the irreversibility of the isolator. . Thus, the oscillation circuit 2 is operated stably.
[29] Figure 3 shows the power spectrum of the output signal in the frequency region higher than the fundamental wave frequency of the oscillator. In Fig. 3, the thick line shows the arrangement characteristic that the additional circuit 3 is not included in the arrangement shown in Fig. 2, but the output of the oscillation circuit 2 and the input of the amplifying circuit 4 are connected only to the capacitor C5. do. The broken line shows the arrangement characteristic in which the additional circuit 3 is included. As can be seen, when the frequency moves away from the fundamental wave, frequency components higher than the output oscillation frequency decrease. Thus, the phase noise characteristic is improved.
[30] 4 shows a circuit of the oscillator according to the second embodiment. Unlike the embodiment shown in Fig. 2, the additional circuit 3 between the output of the oscillating circuit 2 and the input of the amplifying circuit 4 is composed of a frequency filter which prevents unnecessary wave transmission. In other words, the series circuit including the inductors L6 and L7 and the capacitor C13 constitutes a band pass filter, and the center frequency is set at the oscillation frequency (fundamental frequency) of the oscillation circuit 2. The passband of the filter is set such that second-order or higher harmonic components are suppressed. This arrangement, in which the additional circuit is composed of a high frequency filter, also suppresses unnecessary wave components, thus improving the phase noise characteristic.
[31] 5 is a circuit diagram of an oscillator according to a third embodiment. In the present embodiment, the additional circuit 3 is constituted by a frequency filter, but a low pass filter including capacitors C5 and C14 and an inductor L8 is used. The cutoff frequency of the filter is set at the fundamental wave frequency, which is the oscillation frequency of the oscillation circuit 2, or at a predetermined frequency between the fundamental wave frequency and the second harmonic frequency. Therefore, higher harmonic components are suppressed and the phase noise characteristic is improved.
[32] 6A and 6B are circuit diagrams of an oscillator according to a fourth embodiment. In the embodiment of FIG. 6A, a bandpass filter comprising capacitors C14, C15, C16 and inductor L9 acts as an additional circuit 3. Also, a band cancellation filter of another structure is used in the embodiment shown in Fig. 6B. In this embodiment, the parallel circuit of the inductor L10 and the capacitor C17 is connected between the output of the oscillation circuit 2 and the input of the amplifying circuit 4.
[33] With one of the arrangements shown in Figs. 6A and 6B, the center frequency of the band reject filter is set at a frequency of higher harmonics (e.g., 3 harmonics) that should be mostly suppressed. Thus, transmission of unnecessary waves is effectively suppressed.
[34] Next, Fig. 7 shows an oscillator according to the fifth embodiment. The oscillator includes an oscillation circuit 2 and an amplification circuit 4 which are cascaded. The collector of oscillation converter Q1 is connected to the emitter of buffer converter Q2, and the inductor L2 is connected between the collector of Q2 and the power supply terminal Vb. In addition, the voltage divider circuit including the resistors R0, R1, and R2 is connected between the power supply terminal Vb and the ground, and two outputs are connected to the bases of Q1 and Q2, respectively. In addition, an additional circuit 3 is connected between the emitter of Q1 and the base of Q2.
[35] Including the above circuit structure, the additional circuit 3 acts to prevent the transmission of unnecessary waves, thereby similarly improving the phase noise characteristics.
[36] Next, FIG. 8 is a block diagram showing an embodiment of a communication device according to the sixth embodiment. In Fig. 8, VCO represents a voltage controlled oscillator. The PLL-IC represents a PLL control circuit that receives an output signal of a VCO, and compares an oscillation signal of a temperature compensation crystal osillator TCXO, and outputs a control signal having a predetermined frequency and phase. The VCO receives the control voltage at the control terminal through the low pass filter LPF and oscillates at a frequency corresponding to the control voltage. These oscillation output signals are supplied to the mixed circuits MIXa and MIXb as local oscillation signals, respectively. The mixing circuit MIXa mixes the intermediate frequency signal and the local oscillation signal output from the transmitting circuit Tx, and converts the frequency into a transmission frequency signal. These signals are amplified in the amplifier circuit AMPa and emitted from the antenna ANT through the duplexer DPX. The received signal from the antenna ANT is amplified in the amplifying circuit AMPb through the duplexer DPX. The mixing circuit MIXb mixes the output signal of the amplifying circuit AMPb and the local oscillation signal and converts it into an intermediate frequency signal. The receiving circuit Rx obtains the received signal by signal processing them.
[37] The oscillators described in the first to fifth embodiments are used as VCOs in the above-described communication device.
[38] Thus, by using an oscillator having excellent phase noise characteristics, excellent communication performance without spurious interference is obtained.
[39] According to the present invention, unnecessary waves such as high-order harmonic components generated in the oscillation circuit are not input to the amplifying circuit, whereby deterioration of the phase noise characteristic is suppressed.
[40] In addition, since the filter characteristic prevents transmission of higher harmonic frequencies of the oscillation frequency due to the oscillation circuit, unnecessary wave components are effectively prevented.
[41] In addition, by using an isolator which sends a predetermined frequency bandwidth signal including the oscillation frequency of the oscillation circuit to the amplifier, unnecessary waves are transmitted from the oscillation circuit to the amplification circuit. In addition, the oscillation circuit can operate stably even when mismatch occurs in the amplification circuit and the signal is reflected to the oscillation circuit side.
[42] Further, according to the present invention, a PLL circuit for a local oscillation circuit is provided by using an oscillator having the above-described structure, and a communicator device having excellent communication performance can be obtained without spurious interference.

权利要求:
Claims (5)
[1" claim-type="Currently amended] An oscillation circuit to which a resonance circuit is connected, and
An amplifying circuit for amplifying the output signal of the oscillating circuit and outputting from an output device,
An additional circuit for preventing the transmission of unnecessary waves is provided between the output of the oscillation circuit and the input of the sound amplifier amplifier circuit.
[2" claim-type="Currently amended] 2. The oscillator according to claim 1, wherein said additional circuit is a frequency filter for blocking frequency components of said unnecessary waves.
[3" claim-type="Currently amended] 3. The oscillator according to claim 2, wherein said frequency to be cut off is a higher harmonic frequency of the oscillation frequency due to said oscillation circuit.
[4" claim-type="Currently amended] The oscillator according to claim 1, wherein said additional circuit is an isolator for transmitting a signal having a predetermined frequency bandwidth including an oscillation frequency of said oscillation circuit from an output of said oscillation circuit to an input of said amplification circuit.
[5" claim-type="Currently amended] A communication device comprising an oscillator according to any of the preceding claims.

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同族专利:

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公开号 | 公开日

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US20010035794A1|2001-11-01|

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CN1336718A|2002-02-20|

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JP2001313526A|2001-11-09|

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DE10120718A1|2001-12-20|

引用文献:

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公开号 | 申请日 | 公开日 | 申请人 | 专利标题

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法律状态:
2000-04-27|Priority to JP2000-128346

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2000-04-27|Priority to JP2000128346A

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2001-04-27|Application filed by 무라타 야스타카, 가부시키가이샤 무라타 세이사쿠쇼

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2001-11-08|Publication of KR20010098933A

优先权:

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申请号 | 申请日 | 专利标题

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JP2000-128346|2000-04-27|

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JP2000128346A|JP2001313526A|2000-04-27|2000-04-27|Oscillator and communication unit|