JP2014200068A - Resonant circuit and oscillator circuit - Google Patents

Resonant circuit and oscillator circuit Download PDF

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JP2014200068A
JP2014200068A JP2014027159A JP2014027159A JP2014200068A JP 2014200068 A JP2014200068 A JP 2014200068A JP 2014027159 A JP2014027159 A JP 2014027159A JP 2014027159 A JP2014027159 A JP 2014027159A JP 2014200068 A JP2014200068 A JP 2014200068A
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vibrator
circuit
resonance
frequency
capacitance
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JP6305094B2 (en
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武仁 石井
Takehito Ishii
武仁 石井
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Nihon Dempa Kogyo Co Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide a resonant circuit that allows being resonated at a frequency different from the resonant frequency of an oscillator and to provide an oscillator circuit.SOLUTION: A resonant circuit 1 includes: a first oscillator 11; a second oscillator 12 connected in series to the first oscillator 11; an inverting amplifier 13 and a capacitive element 14 serially connected to each other in parallel with the first oscillator 11; and a negative capacitance circuit 15 provided between a node between the first oscillator 11 and the second oscillator 12 and ground. The capacitance of the capacitive element 14 is equal to, for example, the equivalent parallel capacitance of the first oscillator 11.

Description

本発明は、共振回路及び発振回路に関するものである。   The present invention relates to a resonance circuit and an oscillation circuit.

従来、共振周波数が異なる複数の水晶振動子を用いることにより、単一の水晶振動子で調整可能な周波数範囲よりも広い周波数範囲で発振周波数を調整できる反共振回路が知られている（例えば、特許文献１を参照）。   Conventionally, by using a plurality of crystal resonators having different resonance frequencies, an anti-resonance circuit that can adjust an oscillation frequency in a frequency range wider than a frequency range that can be adjusted by a single crystal resonator is known (for example, (See Patent Document 1).

図８は、従来の反共振回路４００の構成例を示す。図８において、反共振回路４００は、交流信号源４３０の出力抵抗４４０と負荷抵抗４５０とに接続されている。   FIG. 8 shows a configuration example of a conventional anti-resonance circuit 400. In FIG. 8, the anti-resonance circuit 400 is connected to the output resistor 440 and the load resistor 450 of the AC signal source 430.

反共振回路４００は、出力抵抗４４０と負荷抵抗４５０との間における異なる経路に接続された水晶振動子４１１及び水晶振動子４２１を備える。水晶振動子４１１が接続された第１の経路には、減衰器４１２、インダクタ４１３及びキャパシタ４１４が直列に設けられている。水晶振動子４１１は、インダクタ４１３とキャパシタ４１４との接続点とグランドとに接続されている。同様に、水晶振動子４２１が接続された第２の経路には、減衰器４２２、インダクタ４２３及びキャパシタ４２４が直列に設けられている。水晶振動子４２１は、インダクタ４２３とキャパシタ４２４との接続点とグランドとに接続されている。   The anti-resonance circuit 400 includes a crystal resonator 411 and a crystal resonator 421 connected to different paths between the output resistor 440 and the load resistor 450. In the first path to which the crystal resonator 411 is connected, an attenuator 412, an inductor 413, and a capacitor 414 are provided in series. The crystal resonator 411 is connected to a connection point between the inductor 413 and the capacitor 414 and the ground. Similarly, an attenuator 422, an inductor 423, and a capacitor 424 are provided in series on the second path to which the crystal resonator 421 is connected. The crystal resonator 421 is connected to a connection point between the inductor 423 and the capacitor 424 and the ground.

水晶振動子４１１及び水晶振動子４２１は、それぞれ異なる共振周波数を有しており、キャパシタ４１４及びキャパシタ４２４を介して互いに接続されている。これにより、反共振回路４００は、水晶振動子４１１の共振周波数と水晶振動子４２１の共振周波数との間の周波数において共振する。減衰器４１２及び減衰器４２２の減衰率を変化させることにより、反共振回路４００の反共振周波数が変化する。   The crystal resonator 411 and the crystal resonator 421 have different resonance frequencies, and are connected to each other via a capacitor 414 and a capacitor 424. As a result, the anti-resonance circuit 400 resonates at a frequency between the resonance frequency of the crystal resonator 411 and the resonance frequency of the crystal resonator 421. By changing the attenuation rates of the attenuator 412 and the attenuator 422, the anti-resonance frequency of the anti-resonance circuit 400 changes.

特開２００７−２９５２５６号公報JP 2007-295256 A

ところで、水晶振動子、ＭＥＭＳ（Micro-Electro-Mechanical Systems）振動子等の高いＱを有する共振子の共振周波数は、ｆＬ＝（１／２π）√｛（Ｃ１＋ＣＬ）／Ｌ１Ｃ１ＣＬ｝で表される。ここで、Ｃ１は振動子の等価回路のモーショナルキャパシタンス、ＣＬは負荷容量、Ｌ１は振動子の直列インダクタンスである。 By the way, the resonance frequency of a resonator having a high Q such as a crystal resonator or a MEMS (Micro-Electro-Mechanical Systems) resonator is f L = (1 / 2π) √ {(C 1 + C L ) / L 1 C. 1 C L }. Here, C 1 is the motional capacitance of the equivalent circuit of the resonator, the C L load capacitor, L 1 is a series inductance of the transducer.

Ｃ１が比較的小さいＭＥＭＳ振動子を用いた発振回路においては、振動子に印加するバイアス電圧を調整することによって周波数の調整が行われる。しかし、集積回路や個別部品において実現できる数ｐＦオーダーの容量値に対してＣ１が非常に小さい振動子を発振回路に用いた場合は、ＣＬ＞＞Ｃ１の関係に基づいてｆＬ＝（１／２π）√（１／Ｌ１Ｃ１）と近似できるので、共振周波数は、振動子が有するＬ１及びＣ１に基づいて定められる。したがって、上記の振動子を発振回路に用いる場合には、振動子の共振周波数の温度特性が、そのまま発振周波数の温度特性に反映されてしまう。 In the oscillation circuit C 1 is used a relatively small MEMS resonator, the frequency adjustment is performed by adjusting the bias voltage applied to the vibrator. However, if the C 1 with respect to the capacitance value of a few pF orders can be realized in integrated circuits and discrete components are used very small vibrator oscillator, f based on the relationship between C L >> C 1 L = Since it can be approximated as (1 / 2π) √ (1 / L 1 C 1 ), the resonance frequency is determined based on L 1 and C 1 of the vibrator. Therefore, when the above vibrator is used in an oscillation circuit, the temperature characteristic of the resonance frequency of the vibrator is directly reflected in the temperature characteristic of the oscillation frequency.

特に、ＭＥＭＳ振動子の共振周波数の温度特性は−３０ｐｐｍ／℃程度であり、温度変化に対する周波数変化範囲が比較的大きい。したがって、ＭＥＭＳ振動子を用いた発振回路においては、バイアス電圧を調整するだけでは、温度変化を相殺して安定した発振周波数を得ることが困難である。   Particularly, the temperature characteristic of the resonance frequency of the MEMS vibrator is about −30 ppm / ° C., and the frequency change range with respect to the temperature change is relatively large. Therefore, in an oscillation circuit using a MEMS vibrator, it is difficult to obtain a stable oscillation frequency by canceling the temperature change only by adjusting the bias voltage.

図８に示した反共振回路４００においては、単一のＭＥＭＳ振動子のバイアス電圧を調整する場合よりも広い周波数範囲で反共振周波数を変化させることができる。しかし、反共振回路４００において、反共振周波数におけるＱの値を発振回路に用いることができる程度に大きな値にするために、インダクタ４１３及びインダクタ４２３のインダクタンス値を十分に大きな値にしなければならなかった。具体的には、特許文献１においては、インダクタ４１３及びインダクタ４２３のインダクタンス値として２７μＨが例示されている。   In the anti-resonance circuit 400 shown in FIG. 8, the anti-resonance frequency can be changed in a wider frequency range than when the bias voltage of a single MEMS vibrator is adjusted. However, in the anti-resonance circuit 400, in order to make the Q value at the anti-resonance frequency large enough to be used in the oscillation circuit, the inductance values of the inductor 413 and the inductor 423 must be sufficiently large. It was. Specifically, in Patent Document 1, 27 μH is exemplified as the inductance values of the inductor 413 and the inductor 423.

しかし、インダクタは、温度変化に応じてインダクタンス値が大きく変化する。また、振動子のばらつきに応じてインダクタンス値を調整することも困難である。したがって、インダクタを用いた共振回路においては、安定した発振周波数の発振信号を得ることができなかった。さらに、μＨオーダーのインダクタンス値を有するインダクタは、集積回路に内蔵することが困難であった。したがって、従来の反共振回路４００を用いて、安定した発振周波数の発振信号を得られる発振回路を、低コストで量産することができなかった。   However, the inductance value of the inductor changes greatly according to the temperature change. It is also difficult to adjust the inductance value according to the variation of the vibrator. Therefore, an oscillation signal having a stable oscillation frequency cannot be obtained in a resonance circuit using an inductor. Furthermore, it has been difficult to incorporate an inductor having an inductance value on the order of μH in an integrated circuit. Therefore, an oscillation circuit that can obtain an oscillation signal having a stable oscillation frequency using the conventional anti-resonance circuit 400 cannot be mass-produced at a low cost.

そこで、本発明はこれらの点に鑑みてなされたものであり、集積回路に内蔵することが可能であり、かつ、振動子の共振周波数と異なる周波数で共振させることができる共振回路及び発振回路を提供することを目的とする。   Accordingly, the present invention has been made in view of these points, and a resonance circuit and an oscillation circuit that can be incorporated in an integrated circuit and can resonate at a frequency different from the resonance frequency of the vibrator are provided. The purpose is to provide.

本発明の第１の実施態様においては、第１振動子と、第１振動子と直列に接続された第２振動子と、第１振動子と並列に、互いに直列に接続された反転増幅器及び容量素子と、第１振動子と第２振動子との間のノードとグランドとの間に設けられた負性容量回路と、を備える共振回路を提供する。容量素子の容量は、例えば、第１振動子の等価並列容量と等しい。また、負性容量回路は、容量値を変化させることができてもよい。   In the first embodiment of the present invention, a first vibrator, a second vibrator connected in series with the first vibrator, an inverting amplifier connected in series with each other in parallel with the first vibrator, and Provided is a resonance circuit including a capacitive element and a negative capacitance circuit provided between a node between a first vibrator and a second vibrator and a ground. The capacitance of the capacitive element is, for example, equal to the equivalent parallel capacitance of the first vibrator. Further, the negative capacitance circuit may be able to change the capacitance value.

上記の共振回路は、第１振動子と並列に設けられた第１可変抵抗と、第２振動子と並列に設けられた第２可変抵抗と、をさらに備えてもよい。また、上記の発振回路は、第１振動子と第２振動子との間に可変容量素子をさらに備えてもよい。   The resonance circuit may further include a first variable resistor provided in parallel with the first vibrator and a second variable resistor provided in parallel with the second vibrator. The oscillation circuit may further include a variable capacitance element between the first vibrator and the second vibrator.

本発明の第２の実施態様においては、第１振動子と、第１振動子と直列に接続された第２振動子と、第１振動子と並列に、互いに直列に接続された反転増幅器及び容量素子と、第１振動子と第２振動子との間のノードとグランドとの間に設けられた負性容量回路と、第２振動子が出力する信号を第１振動子に帰還する帰還部と、を備える発振回路を提供する。   In a second embodiment of the present invention, a first vibrator, a second vibrator connected in series with the first vibrator, an inverting amplifier connected in series with each other in parallel with the first vibrator, and A capacitive element, a negative capacitance circuit provided between a node between the first vibrator and the second vibrator, and the ground, and a feedback that feeds back a signal output from the second vibrator to the first vibrator. And an oscillation circuit including the unit.

本発明に係る発振回路によれば、集積回路に内蔵することが可能であり、かつ、振動子の共振周波数と異なる周波数で共振させることができるという効果を奏する。   According to the oscillation circuit of the present invention, there is an effect that it can be built in an integrated circuit and can be resonated at a frequency different from the resonance frequency of the vibrator.

第１の実施形態に係る発振器の構成例を示す。1 shows a configuration example of an oscillator according to a first embodiment. 第１の実施形態に係る共振回路の等価回路を用いたシミュレーション回路を示す。1 shows a simulation circuit using an equivalent circuit of a resonance circuit according to a first embodiment. 第１の実施形態に係る共振回路の利得の周波数特性の一例を示す。An example of the frequency characteristic of the gain of the resonance circuit which concerns on 1st Embodiment is shown. 第１の実施形態に係る共振回路の位相の周波数特性の一例を示す。An example of the frequency characteristic of the phase of the resonance circuit which concerns on 1st Embodiment is shown. 比較例に係る共振回路の利得の周波数特性を示す。The frequency characteristic of the gain of the resonance circuit which concerns on a comparative example is shown. 第２の実施形態に係る共振回路の構成例を示す。The structural example of the resonance circuit which concerns on 2nd Embodiment is shown. 第３の実施形態に係る共振回路の構成例を示す。The structural example of the resonance circuit which concerns on 3rd Embodiment is shown. 第３の実施形態に係る共振回路の利得の周波数特性の一例を示す。An example of the frequency characteristic of the gain of the resonance circuit which concerns on 3rd Embodiment is shown. 第３の実施形態に係る共振回路の位相の周波数特性の一例を示す。An example of the frequency characteristic of the phase of the resonance circuit which concerns on 3rd Embodiment is shown. 第４の実施形態に係る発振器の構成例を示す。The structural example of the oscillator which concerns on 4th Embodiment is shown. 従来の発振回路の構成例を示す。The structural example of the conventional oscillation circuit is shown.

＜第１の実施形態＞
［発振器１００の構成］
図１は、第１の実施形態に係る発振器１００の構成例を示す。発振器１００は、共振回路１と増幅回路２とを備える。増幅回路２は、第２振動子１２が出力する信号を第１振動子１１に帰還する帰還部として機能する。共振回路１と増幅回路２とがループを形成することにより、発振器１００は、共振回路１の共振周波数の発振信号を発生させることができる。 <First Embodiment>
[Configuration of Oscillator 100]
FIG. 1 shows a configuration example of an oscillator 100 according to the first embodiment. The oscillator 100 includes a resonance circuit 1 and an amplifier circuit 2. The amplifier circuit 2 functions as a feedback unit that feeds back the signal output from the second vibrator 12 to the first vibrator 11. When the resonance circuit 1 and the amplifier circuit 2 form a loop, the oscillator 100 can generate an oscillation signal having a resonance frequency of the resonance circuit 1.

［共振回路１の構成］
共振回路１は、第１振動子回路１０と、第２振動子１２と、負性容量回路１５とを備える。第１振動子回路１０は、第１振動子１１と、反転増幅器１３と、容量素子１４とを備える。
第１振動子１１及び第２振動子１２は、例えばＡＴカット水晶振動子、ＳＣカット水晶振動子及びＭＥＭＳ振動子である。第１振動子１１と第２振動子１２とは、直列に接続されている。 [Configuration of Resonant Circuit 1]
The resonance circuit 1 includes a first vibrator circuit 10, a second vibrator 12, and a negative capacitance circuit 15. The first oscillator circuit 10 includes a first oscillator 11, an inverting amplifier 13, and a capacitive element 14.
The first vibrator 11 and the second vibrator 12 are, for example, an AT cut crystal vibrator, an SC cut crystal vibrator, and a MEMS vibrator. The first vibrator 11 and the second vibrator 12 are connected in series.

本実施形態における第１振動子１１の共振周波数ｆｒ１は、約５１．９ＭＨｚであり、反共振周波数ｆａ１は、約５２．０ＭＨｚである。第２振動子１２の共振周波数ｆｒ２は、約５２．１ＭＨｚであり、反共振周波数ｆａ２は、約５２．２ＭＨｚである。すなわち、第１振動子１１及び第２振動子１２の共振周波数と反共振周波数との関係は、ｆｒ１＜ｆａ１＜ｆｒ２＜ｆａ２である。 The resonance frequency fr 1 of the first vibrator 11 in the present embodiment is about 51.9 MHz, and the anti-resonance frequency fa 1 is about 52.0 MHz. The resonance frequency fr 2 of the second vibrator 12 is about 52.1 MHz, and the anti-resonance frequency fa 2 is about 52.2 MHz. That is, the relationship between the resonance frequency and the anti-resonance frequency of the first vibrator 11 and the second vibrator 12 is fr 1 <fa 1 <fr 2 <fa 2 .

反転増幅器１３及び容量素子１４は、第１振動子１１と並列に、互いに直列に接続されている。すなわち、反転増幅器１３の入力端子は、第１振動子１１の一端に接続されており、反転増幅器１３の出力端子は、容量素子１４の一端に接続されている。容量素子１４の他端は、第１振動子１１と第２振動子１２との間のノードに接続されている。反転増幅器１３の利得は１であることが好ましい。   The inverting amplifier 13 and the capacitive element 14 are connected in series with each other in parallel with the first vibrator 11. That is, the input terminal of the inverting amplifier 13 is connected to one end of the first vibrator 11, and the output terminal of the inverting amplifier 13 is connected to one end of the capacitive element 14. The other end of the capacitive element 14 is connected to a node between the first vibrator 11 and the second vibrator 12. The gain of the inverting amplifier 13 is preferably unity.

負性容量回路１５は、第１振動子１１と第２振動子１２との間のノードとグランドとの間に設けられている。負性容量回路１５は、正の電圧を印加すると電荷を放出する性質を持つ回路である。例えば、負性容量回路１５は、オペアンプ又は複数のトランジスタのような能動素子と、キャパシタ及び抵抗のような受動素子とを組み合わせて構成される公知の回路により構成される。   The negative capacitance circuit 15 is provided between a node between the first vibrator 11 and the second vibrator 12 and the ground. The negative capacitance circuit 15 is a circuit having a property of discharging charges when a positive voltage is applied. For example, the negative capacitance circuit 15 includes a known circuit configured by combining an active element such as an operational amplifier or a plurality of transistors and a passive element such as a capacitor and a resistor.

図２は、第１の実施形態に係る共振回路１の等価回路を用いたシミュレーション回路を示す。図２において、共振回路１は、交流信号源１６と負荷抵抗１７とに接続されている。交流信号源１６及び負荷抵抗１７は、共振回路１を図１に示した発振器１００に用いた場合の動作をシミュレーションするために設けられている。   FIG. 2 shows a simulation circuit using an equivalent circuit of the resonance circuit 1 according to the first embodiment. In FIG. 2, the resonance circuit 1 is connected to an AC signal source 16 and a load resistor 17. The AC signal source 16 and the load resistor 17 are provided for simulating the operation when the resonance circuit 1 is used in the oscillator 100 shown in FIG.

第１振動子１１においては、等価並列容量１１１と、互いに直列に接続された等価直列容量１１２、等価直列インダクタ１１３及び等価直列抵抗１１４とが並列に接続されている。第２振動子１２においては、等価並列容量１２１と、互いに直列に接続された等価直列容量１２２、等価直列インダクタ１２３及び等価直列抵抗１２４とが並列に接続されている。   In the first vibrator 11, an equivalent parallel capacitor 111, an equivalent series capacitor 112, an equivalent series inductor 113, and an equivalent series resistor 114 connected in series with each other are connected in parallel. In the second vibrator 12, an equivalent parallel capacitor 121, an equivalent series capacitor 122, an equivalent series inductor 123, and an equivalent series resistor 124 connected in series with each other are connected in parallel.

容量素子１４の容量は、第１振動子１１の等価並列容量１１１の容量と等しい。交流信号源１６が出力する信号は、等価並列容量１１１に入力されるとともに反転増幅器１３に入力される。反転増幅器１３を介して容量素子１４に入力される信号は、等価並列容量１１１に入力される信号と逆相である。したがって、等価並列容量１１１を通過した信号は、等価並列容量１１１と容量値が等しい容量素子１４を通過した信号により打ち消される。   The capacitance of the capacitive element 14 is equal to the capacitance of the equivalent parallel capacitance 111 of the first vibrator 11. A signal output from the AC signal source 16 is input to the equivalent parallel capacitor 111 and input to the inverting amplifier 13. The signal input to the capacitive element 14 via the inverting amplifier 13 is in reverse phase to the signal input to the equivalent parallel capacitor 111. Therefore, the signal that has passed through the equivalent parallel capacitor 111 is canceled by the signal that has passed through the capacitive element 14 having the same capacitance value as the equivalent parallel capacitor 111.

負性容量回路１５の容量値は、例えば、容量素子１４、等価並列容量１１１及び等価並列容量１２１の容量値と符号が反対で、容量素子１４、等価並列容量１１１及び等価並列容量１２１の容量値を合計した値に等しい。第１振動子１１と第２振動子１２との間に負性容量回路１５があることで、等価並列容量１１１、容量素子１４及び等価並列容量１２１の影響が打ち消されるので、共振回路１は、第１振動子１１の反共振周波数の影響を受けにくくなり、第１振動子１１の共振周波数と第２振動子１２の共振周波数との間で発振しやすくなる。このように、負性容量回路１５が接続されるノード、すなわち、第１振動子回路１０と第２振動子１２との接続点から、第１振動子回路１０を見ても、第２振動子１２を見ても、第１振動子回路１０の容量素子１４、等価並列容量１１１、及び第２振動子１２の等価並列容量１２１を見えないようにすることで、第１振動子１１の共振周波数と第２振動子１２の共振周波数の中間に共振周波数を成立させることができる。   The capacitance values of the negative capacitance circuit 15 are, for example, opposite in sign to the capacitance values of the capacitive element 14, equivalent parallel capacitance 111, and equivalent parallel capacitance 121, and the capacitance values of the capacitive element 14, equivalent parallel capacitance 111, and equivalent parallel capacitance 121 Is equal to the sum of Since the negative capacitance circuit 15 is provided between the first vibrator 11 and the second vibrator 12, the effects of the equivalent parallel capacitor 111, the capacitor element 14, and the equivalent parallel capacitor 121 are canceled out. It becomes difficult to be influenced by the anti-resonance frequency of the first vibrator 11, and it becomes easy to oscillate between the resonance frequency of the first vibrator 11 and the resonance frequency of the second vibrator 12. As described above, even if the first vibrator circuit 10 is viewed from the node to which the negative capacitance circuit 15 is connected, that is, the connection point between the first vibrator circuit 10 and the second vibrator 12, the second vibrator 12, the resonance frequency of the first vibrator 11 can be reduced by making the capacitive element 14 of the first vibrator circuit 10, the equivalent parallel capacity 111, and the equivalent parallel capacity 121 of the second vibrator 12 invisible. And the resonance frequency of the second vibrator 12 can be established in the middle.

なお、負性容量回路１５の容量値が容量素子１４、等価並列容量１１１及び等価並列容量１２１の容量値を合計した値よりも小さくなると、共振回路１の共振周波数が第１振動子１１の共振周波数に近づく。また、負性容量回路１５の容量値が容量素子１４、等価並列容量１１１及び等価並列容量１２１の容量値を合計した値よりも大きくなると、共振回路１の共振周波数が第２振動子１２の共振周波数に近づく。したがって、負性容量回路１５の容量値を変化させることにより、共振回路１の共振周波数を変化させることができる。例えば、負性容量回路１５にバリキャップダイオードのような可変容量素子を用いれば、当該可変容量素子に印加する電圧を変化させることによって共振回路１の共振周波数を変化させることができる。   Note that when the capacitance value of the negative capacitance circuit 15 becomes smaller than the sum of the capacitance values of the capacitive element 14, the equivalent parallel capacitance 111, and the equivalent parallel capacitance 121, the resonance frequency of the resonance circuit 1 becomes the resonance of the first vibrator 11. Approaching the frequency. Further, when the capacitance value of the negative capacitance circuit 15 becomes larger than the sum of the capacitance values of the capacitive element 14, the equivalent parallel capacitance 111, and the equivalent parallel capacitance 121, the resonance frequency of the resonance circuit 1 becomes the resonance of the second vibrator 12. Approaching the frequency. Therefore, the resonance frequency of the resonance circuit 1 can be changed by changing the capacitance value of the negative capacitance circuit 15. For example, if a variable capacitance element such as a varicap diode is used for the negative capacitance circuit 15, the resonance frequency of the resonance circuit 1 can be changed by changing the voltage applied to the variable capacitance element.

図３Ａは、第１の実施形態に係る共振回路１の利得の周波数特性の一例を示す。図３Ａにおける破線は、第１振動子回路１０の利得の周波数特性である。また、図３Ａにおける１点鎖線は、第２振動子１２の利得の周波数特性である。また、図３Ａにおける実線は、共振回路１の利得の周波数特性である。図３Ｂは、第１の実施形態に係る共振回路１の位相の周波数特性の一例を示す。図３Ｂにおける破線は、第１振動子回路１０の位相である。また、図３Ｂにおける１点鎖線は、第２振動子１２の位相である。図３Ｂにおける実線は、共振回路１の位相である。   FIG. 3A shows an example of the frequency characteristic of the gain of the resonance circuit 1 according to the first embodiment. The broken line in FIG. 3A is the frequency characteristic of the gain of the first vibrator circuit 10. 3A is a frequency characteristic of the gain of the second vibrator 12. Further, the solid line in FIG. 3A is the frequency characteristic of the gain of the resonance circuit 1. FIG. 3B shows an example of the frequency characteristic of the phase of the resonance circuit 1 according to the first embodiment. The broken line in FIG. 3B is the phase of the first vibrator circuit 10. Also, the one-dot chain line in FIG. 3B is the phase of the second vibrator 12. The solid line in FIG. 3B is the phase of the resonance circuit 1.

図３Ａに示されているように、第１振動子回路１０の利得の周波数特性においては、第１振動子１１の共振周波数である５１．９ＭＨｚ付近に、利得が大きいピークがある。第２振動子１２の利得の周波数特性においては、第２振動子１２の共振周波数である５２．１ＭＨｚ付近に利得が大きいピークがある。また、共振回路１の利得の周波数特性においては、第１振動子１１の共振周波数と第２振動子１２の共振周波数との間の５２．０ＭＨｚ付近に利得が大きいピークがある。このように、共振回路１においては、第１振動子１１の共振周波数と第２振動子１２の共振周波数との間の周波数が共振周波数になることがわかる。また、図３Ｂに示されるように、第１振動子１１、第２振動子１２及び共振回路１は、それぞれの利得のピークに対応する周波数において位相が１８０度変化している。   As shown in FIG. 3A, in the frequency characteristic of the gain of the first vibrator circuit 10, there is a peak with a large gain in the vicinity of 51.9 MHz which is the resonance frequency of the first vibrator 11. In the frequency characteristics of the gain of the second vibrator 12, there is a peak with a large gain in the vicinity of 52.1 MHz which is the resonance frequency of the second vibrator 12. In the frequency characteristic of the gain of the resonance circuit 1, there is a peak with a large gain in the vicinity of 52.0 MHz between the resonance frequency of the first vibrator 11 and the resonance frequency of the second vibrator 12. Thus, in the resonance circuit 1, it can be seen that the frequency between the resonance frequency of the first vibrator 11 and the resonance frequency of the second vibrator 12 is the resonance frequency. Further, as shown in FIG. 3B, the phases of the first vibrator 11, the second vibrator 12, and the resonance circuit 1 are changed by 180 degrees at frequencies corresponding to the respective gain peaks.

第２振動子１２及び共振回路１の利得の周波数特性においては、第２振動子１２の反共振周波数である５２．２ＭＨｚ付近に、利得が小さいピークが生じている。これに対して、図３Ａの破線が示すように、第１振動子回路１０の利得の周波数特性においては反共振周波数が見られない。これは、以下の理由により、第１振動子１１と並列に反転増幅器１３及び容量素子１４が設けられていることで、第１振動子回路１０の反共振周波数が第２振動子１２の共振周波数ｆｒ２よりも高くなったためである。 In the frequency characteristics of the gains of the second vibrator 12 and the resonance circuit 1, a peak with a small gain occurs in the vicinity of 52.2 MHz which is the anti-resonance frequency of the second vibrator 12. On the other hand, as indicated by the broken line in FIG. 3A, no anti-resonance frequency is observed in the frequency characteristics of the gain of the first vibrator circuit 10. This is because the inverting amplifier 13 and the capacitive element 14 are provided in parallel with the first vibrator 11 for the following reason, so that the anti-resonance frequency of the first vibrator circuit 10 becomes the resonance frequency of the second vibrator 12. This is because it is higher than fr 2 .

第１振動子１１の反共振周波数ｆａ１は、ｆａ１＝ｆｒ１・（１／２π）√｛１＋Ｃ１／Ｃ０｝で表される。ここで、Ｃ０は第１振動子１１の等価並列容量１１１の容量値、Ｃ１は第１振動子１１の等価直列容量１１２の容量値である。上記の式からわかるように、第１振動子１１の等価並列容量１１１の容量値が小さければ小さいほど、反共振周波数ｆａ１が高くなる傾向にある。 The anti-resonance frequency fa 1 of the first vibrator 11 is represented by fa 1 = fr 1 · (1 / 2π) √ {1 + C 1 / C 0 }. Here, C 0 is the capacitance value of the equivalent parallel capacitance 111 of the first vibrator 11, and C 1 is the capacitance value of the equivalent series capacitance 112 of the first vibrator 11. As can be seen from the above equation, the smaller the capacitance value of the equivalent parallel capacitance 111 of the first vibrator 11 is, the higher the anti-resonance frequency fa 1 tends to be.

本実施形態における第１振動子回路１０では、反転増幅器１３及び容量素子１４が設けられていることによってＣ０が打ち消されるので、第１振動子回路１０の反共振周波数ｆａ１が第２振動子１２の共振周波数ｆｒ２に比べて大きくなる。その結果、共振回路１においては、第１振動子１１の共振周波数ｆｒ１と第２振動子１２の共振周波数ｆｒ２との間の全ての周波数範囲において発振条件が満たされるので、共振回路１は、広い周波数範囲で共振周波数を変化させることができる。 In the first oscillator circuit 10 according to the present embodiment, since the inverting amplifier 13 and the capacitive element 14 are provided, C 0 is canceled out, so that the anti-resonance frequency fa 1 of the first oscillator circuit 10 is the second oscillator. 12 becomes larger than the resonance frequency fr 2 of. As a result, in the resonant circuit 1, the oscillation conditions are satisfied in all frequency range between the resonance frequency fr 2 of the resonance frequency fr 1 and the second vibrator 12 of the first vibrator 11, the resonant circuit 1 The resonance frequency can be changed in a wide frequency range.

［比較例］
図３Ｃに、比較例として、共振回路１から反転増幅器１３、容量素子１４及び負性容量回路１５を削除した回路における利得の周波数特性を示す。図３Ｃにおける破線は、第１振動子１１の利得の周波数特性である。また、図３Ｃにおける１点鎖線は、第２振動子１２の利得の周波数特性である。また、図３Ｃにおける実線は、第１振動子１１及び第２振動子１２を直列に接続した比較例の回路における利得の周波数特性を示す。 [Comparative example]
FIG. 3C shows gain frequency characteristics in a circuit in which the inverting amplifier 13, the capacitive element 14, and the negative capacitance circuit 15 are removed from the resonance circuit 1 as a comparative example. The broken line in FIG. 3C is the frequency characteristic of the gain of the first vibrator 11. Also, the one-dot chain line in FIG. Also, the solid line in FIG. 3C shows the frequency characteristics of the gain in the circuit of the comparative example in which the first vibrator 11 and the second vibrator 12 are connected in series.

図３Ｃに示すように、共振回路１から反転増幅器１３、容量素子１４及び負性容量回路１５を削除した回路においては、第１振動子１１の共振周波数ｆｒ１と第２振動子１２の共振周波数ｆｒ２との間に第１振動子１１の反共振周波数ｆａ１があるので、第１振動子１１の共振周波数ｆｒ１と第２振動子１２の共振周波数ｆｒ２との間で周波数を変化させようとすると、第１振動子１１の共振周波数ｆｒ１と第２振動子１２の共振周波数ｆｒ２との間の全ての周波数範囲では発振条件が満たされず、狭い周波数範囲でしか発振条件が満たされない。 As shown in FIG. 3C, in the circuit to remove the inverting amplifier 13, the capacitor 14 and the negative capacitance circuit 15 resonant circuit 1, the resonance frequency of the resonance frequency fr 1 and the second vibrator 12 of the first oscillator 11 since there is the antiresonant frequency fa 1 of the first vibrator 11 between fr 2, the frequency is changed between the resonance frequency fr 2 of the resonance frequency fr 1 and the second vibrator 12 of the first oscillator 11 intoxicated to, the resonance frequency fr 1 of the first oscillator 11 at every frequency range between the resonance frequency fr 2 of the second vibrator 12 is not satisfied oscillation condition is not only satisfied the oscillation condition in a narrow frequency range .

［第１の実施形態における効果］
以上のとおり、第１の実施形態に係る共振回路１によれば、第１振動子１１と、第１振動子１１と直列に接続された第２振動子１２と、第１振動子１１と並列に、互いに直列に接続された反転増幅器及び容量素子と、第１振動子１１と第２振動子１２との間のノードとグランドとの間に設けられた負性容量回路１５とを備えることで、第１振動子１１の共振周波数ｆｒ１と第２振動子１２の共振周波数ｆｒ２との間の周波数に共振周波数を設定することができる。 [Effect in the first embodiment]
As described above, according to the resonance circuit 1 according to the first embodiment, the first vibrator 11, the second vibrator 12 connected in series with the first vibrator 11, and the first vibrator 11 in parallel. And an inverting amplifier and a capacitive element connected in series with each other, and a negative capacitance circuit 15 provided between the node between the first vibrator 11 and the second vibrator 12 and the ground. , it is possible to set the resonance frequency to a frequency between the resonance frequency fr 2 of the resonance frequency fr 1 and the second vibrator 12 of the first oscillator 11.

＜第２の実施形態＞
［振動子と並列に可変抵抗を備える］
図４は、第２の実施形態に係る共振回路１の構成例を示す。共振回路１は、第１可変抵抗１８及び第２可変抵抗１９をさらに備える点で図２に示した共振回路１と異なり、他の点で同じである。 <Second Embodiment>
[Equipped with a variable resistor in parallel with the vibrator]
FIG. 4 shows a configuration example of the resonance circuit 1 according to the second embodiment. The resonant circuit 1 is different from the resonant circuit 1 shown in FIG. 2 in that it further includes a first variable resistor 18 and a second variable resistor 19, and is the same in other points.

第１可変抵抗１８は、第１振動子１１と並列に設けられている。第２可変抵抗１９は、第２振動子１２と並列に設けられている。第１振動子１１を流れる電流は、第１可変抵抗１８の抵抗値を調整することによって調整される。また、第２振動子１２を流れる電流は、第２可変抵抗１９の抵抗値を調整することによって調整される。   The first variable resistor 18 is provided in parallel with the first vibrator 11. The second variable resistor 19 is provided in parallel with the second vibrator 12. The current flowing through the first vibrator 11 is adjusted by adjusting the resistance value of the first variable resistor 18. Further, the current flowing through the second vibrator 12 is adjusted by adjusting the resistance value of the second variable resistor 19.

例えば、第１可変抵抗１８の抵抗値が等価直列抵抗１１４に対して比較的大きく、第２可変抵抗１９の抵抗値が等価直列抵抗１２４に対して比較的小さい場合、交流信号源１６から出力された電流は第１振動子回路１０を通過する。そして、第１振動子回路１０を通過した電流のうち比較的多くの割合の電流が第２可変抵抗１９を通過する。したがって、この場合の共振回路１においては第２振動子１２の影響をほとんど受けず、第１振動子回路１０を通過した信号のうち、第２振動子１２の共振周波数から離れた周波数の信号も減衰されない。その結果、共振回路１の共振周波数は、第２振動子１２の共振周波数に比べて第１振動子回路１０の共振周波数に近い周波数となる。   For example, when the resistance value of the first variable resistor 18 is relatively large with respect to the equivalent series resistor 114 and the resistance value of the second variable resistor 19 is relatively small with respect to the equivalent series resistor 124, it is output from the AC signal source 16. The passed current passes through the first vibrator circuit 10. A relatively large proportion of the current that has passed through the first vibrator circuit 10 passes through the second variable resistor 19. Accordingly, in this case, the resonance circuit 1 is hardly affected by the second vibrator 12, and among the signals that have passed through the first vibrator circuit 10, signals having a frequency that is away from the resonance frequency of the second vibrator 12 are also included. Not attenuated. As a result, the resonance frequency of the resonance circuit 1 is closer to the resonance frequency of the first vibrator circuit 10 than the resonance frequency of the second vibrator 12.

他方、第１可変抵抗１８の抵抗値が等価直列抵抗１１４に対して比較的小さく、第２可変抵抗１９の抵抗値が等価直列抵抗１２４に対して比較的大きい場合、交流信号源１６から出力された電流は第１振動子回路１０の影響をほとんど受けることなく第１可変抵抗１８を通過する。そして、第１可変抵抗１８を通過した電流のうち比較的多くの割合の電流が第２振動子１２を通過する。したがって、この場合の共振回路１においては第１振動子回路１０の影響をほとんど受けず、第１振動子回路１０の共振周波数から離れた周波数の信号が減衰されることなく第２振動子１２に入力される。その結果、共振回路１の共振周波数は、第１振動子回路１０の共振周波数に比べて第２振動子１２の共振周波数に近い周波数となる。   On the other hand, when the resistance value of the first variable resistor 18 is relatively small with respect to the equivalent series resistor 114 and the resistance value of the second variable resistor 19 is relatively large with respect to the equivalent series resistor 124, it is output from the AC signal source 16. The current passes through the first variable resistor 18 with almost no influence of the first vibrator circuit 10. A relatively large proportion of the current that has passed through the first variable resistor 18 passes through the second vibrator 12. Therefore, in this case, the resonance circuit 1 is hardly affected by the first vibrator circuit 10, and a signal having a frequency away from the resonance frequency of the first vibrator circuit 10 is not attenuated to the second vibrator 12. Entered. As a result, the resonance frequency of the resonance circuit 1 is closer to the resonance frequency of the second vibrator 12 than the resonance frequency of the first vibrator circuit 10.

第１可変抵抗１８及び第２可変抵抗１９の抵抗値を変化させることにより、共振回路１に入力された信号のそれぞれの周波数成分が、第１振動子回路１０及び第２振動子１２を通過する間に減衰される量が変化する。そして、第１振動子回路１０及び第２振動子１２を通過する間に減衰する量が最も小さい周波数において、共振回路１が共振する。   By changing the resistance values of the first variable resistor 18 and the second variable resistor 19, the respective frequency components of the signal input to the resonance circuit 1 pass through the first vibrator circuit 10 and the second vibrator 12. The amount of attenuation in between changes. The resonance circuit 1 resonates at a frequency at which the amount of attenuation while passing through the first vibrator circuit 10 and the second vibrator 12 is the smallest.

［第２の実施形態における効果］
以上のとおり、第２の実施形態に係る共振回路１によれば、第１可変抵抗１８及び第２可変抵抗１９をさらに備えることにより、共振回路１の共振周波数を、第１振動子１１の共振周波数と第２振動子１２の共振周波数との間で調整することができる。すなわち、第２の実施形態に係る共振回路１においては、第１可変抵抗１８及び第２可変抵抗１９の値に応じて、図３Ａの実線で示される共振回路１の周波数特性におけるピークの周波数を、第１振動子１１の共振周波数ｆｒ１と第２振動子１２の共振周波数ｆｒ２との間で変化させることができる。 [Effects of Second Embodiment]
As described above, according to the resonance circuit 1 according to the second embodiment, by further including the first variable resistor 18 and the second variable resistor 19, the resonance frequency of the resonance circuit 1 is set to the resonance of the first vibrator 11. It is possible to adjust between the frequency and the resonance frequency of the second vibrator 12. That is, in the resonance circuit 1 according to the second embodiment, the peak frequency in the frequency characteristic of the resonance circuit 1 indicated by the solid line in FIG. 3A is set according to the values of the first variable resistor 18 and the second variable resistor 19. it can be varied between the resonant frequency fr 2 of the resonance frequency fr 1 and the second vibrator 12 of the first oscillator 11.

＜第３の実施形態＞
［第１振動子１１と第２振動子１２との間に可変容量素子を備える］
図５は、第３の実施形態に係る共振回路１の構成例を示す。第３の実施形態に係る共振回路１は、可変容量素子２０をさらに備える点で図４に示した共振回路１と異なり、他の点で同じである。図６Ａは、第３の実施形態に係る共振回路１の利得の周波数特性の一例を示す。図６Ｂは、第３の実施形態に係る共振回路１の位相の周波数特性の一例を示す。 <Third Embodiment>
[A variable capacitance element is provided between the first vibrator 11 and the second vibrator 12]
FIG. 5 shows a configuration example of the resonance circuit 1 according to the third embodiment. The resonance circuit 1 according to the third embodiment is different from the resonance circuit 1 shown in FIG. 4 in that the variable capacitance element 20 is further provided, and is the same in other points. FIG. 6A shows an example of the frequency characteristic of the gain of the resonance circuit 1 according to the third embodiment. FIG. 6B shows an example of the frequency characteristic of the phase of the resonance circuit 1 according to the third embodiment.

可変容量素子２０は、第１振動子１１と第２振動子１２との間に設けられている。可変容量素子２０は、例えば、バリキャップダイオード、又はＦＥＴと抵抗との直列接続によって構成される素子群である。可変容量素子２０の容量値を変化させることにより、共振回路１の共振周波数を変化させることができる。   The variable capacitance element 20 is provided between the first vibrator 11 and the second vibrator 12. The variable capacitance element 20 is, for example, a varicap diode or an element group configured by series connection of an FET and a resistor. By changing the capacitance value of the variable capacitance element 20, the resonance frequency of the resonance circuit 1 can be changed.

図６Ａにおける破線は、可変容量素子２０の容量値を十分に大きくした状態で第２可変抵抗１９を短絡した共振回路１における利得の周波数特性である。この状態では、第１振動子１１の周波数特性が共振回路１の周波数特性に対して強く影響するため、共振回路１の共振周波数は、第１振動子１１の共振周波数に近い。第２可変抵抗１９を短絡した状態で、可変容量素子２０の容量値を減少させることにより、共振回路１の共振周波数が高くなり、実線で示す周波数特性に変化する。   A broken line in FIG. 6A represents a frequency characteristic of gain in the resonance circuit 1 in which the second variable resistor 19 is short-circuited in a state where the capacitance value of the variable capacitance element 20 is sufficiently large. In this state, the frequency characteristic of the first vibrator 11 strongly influences the frequency characteristic of the resonance circuit 1, so that the resonance frequency of the resonance circuit 1 is close to the resonance frequency of the first vibrator 11. By reducing the capacitance value of the variable capacitance element 20 in a state where the second variable resistor 19 is short-circuited, the resonance frequency of the resonance circuit 1 increases and changes to the frequency characteristic indicated by the solid line.

また、第２可変抵抗１９の抵抗値と可変容量素子２０の容量値とを十分に大きくして、第１振動子１１の共振周波数と第２振動子１２の共振周波数との中央付近の周波数に共振回路１の共振周波数をした後に、可変容量素子２０の容量値を減少させると、第２振動子１２の周波数特性が共振回路１の周波数特性に対して強く影響するようになる。その結果、図６Ａにおける１点鎖線が示すように、共振回路１の周波数特性は第２振動子１２の周波数特性に近づく。   Further, the resistance value of the second variable resistor 19 and the capacitance value of the variable capacitance element 20 are sufficiently increased so that the resonance frequency of the first vibrator 11 and the resonance frequency of the second vibrator 12 are in the vicinity of the center. When the capacitance value of the variable capacitor 20 is decreased after the resonance frequency of the resonance circuit 1 is set, the frequency characteristic of the second vibrator 12 has a strong influence on the frequency characteristic of the resonance circuit 1. As a result, the frequency characteristic of the resonance circuit 1 approaches the frequency characteristic of the second vibrator 12 as indicated by a one-dot chain line in FIG. 6A.

［第３の実施形態における効果］
以上のとおり、第３の実施形態に係る共振回路１によれば、可変容量素子２０をさらに備えることにより、共振回路１の共振周波数をさらに自由に変化させることができる。 [Effect in the third embodiment]
As described above, according to the resonance circuit 1 according to the third embodiment, the resonance frequency of the resonance circuit 1 can be further freely changed by further including the variable capacitance element 20.

＜第４の実施形態＞
図７は、第４の実施形態に係る発振器２００の構成例を示す。図７に示した発振器２００における共振回路１は、第３振動子２１と、負性容量回路２２と、反転増幅器２３と、容量素子２４とをさらに備える点で図１に示した発振器１００における共振回路１と異なり、他の点で同じである。 <Fourth Embodiment>
FIG. 7 shows a configuration example of an oscillator 200 according to the fourth embodiment. The resonance circuit 1 in the oscillator 200 shown in FIG. 7 includes a third vibrator 21, a negative capacitance circuit 22, an inverting amplifier 23, and a capacitive element 24, so that the resonance circuit in the oscillator 100 shown in FIG. Unlike the circuit 1, it is the same in other points.

第３振動子２１の共振周波数は、第２振動子１２の共振周波数よりも高い。負性容量回路２２の容量値は、第２振動子１２の端子間容量、第３振動子２１の端子間容量及び容量素子２４と符号が反対で、これらの容量値を合計した値に等しい。反転増幅器２３及び容量素子２４は、第２振動子１２の端子間容量を相殺する。   The resonance frequency of the third vibrator 21 is higher than the resonance frequency of the second vibrator 12. The capacitance value of the negative capacitance circuit 22 is opposite in sign to the inter-terminal capacitance of the second vibrator 12, the inter-terminal capacitance of the third vibrator 21, and the capacitive element 24, and is equal to the sum of these capacitance values. The inverting amplifier 23 and the capacitive element 24 cancel the inter-terminal capacitance of the second vibrator 12.

図７に示した共振回路１が負性容量回路２２と、反転増幅器２３と、容量素子２４とを備えることにより、第１振動子１１の反共振周波数と第２振動子１２の反共振周波数が第３振動子２１の共振周波数よりも高くなるので、発振器２００は、第１振動子１１の共振周波数と第３振動子２１の共振周波数との間の周波数で発振する。負性容量回路２２の容量値を変化させることにより、第１振動子１１の共振周波数と第３振動子２１の共振周波数との間で、発振器２００の発振周波数を変化させることができる。なお、第２の実施形態と同様に、第３振動子２１と並列に可変抵抗を設けて、可変抵抗の抵抗値を変化させたり、第３の実施形態と同様に、第２振動子１２と第３振動子２１との間に可変容量素子を設けて、可変容量素子の容量値を変化させたりすることによっても、発振器２００の発振周波数を変化させることができる。   7 includes the negative capacitance circuit 22, the inverting amplifier 23, and the capacitive element 24, the anti-resonance frequency of the first vibrator 11 and the anti-resonance frequency of the second vibrator 12 can be reduced. Since it becomes higher than the resonance frequency of the third vibrator 21, the oscillator 200 oscillates at a frequency between the resonance frequency of the first vibrator 11 and the resonance frequency of the third vibrator 21. By changing the capacitance value of the negative capacitance circuit 22, the oscillation frequency of the oscillator 200 can be changed between the resonance frequency of the first vibrator 11 and the resonance frequency of the third vibrator 21. As in the second embodiment, a variable resistor is provided in parallel with the third vibrator 21 to change the resistance value of the variable resistor, or in the same manner as in the third embodiment, The oscillation frequency of the oscillator 200 can also be changed by providing a variable capacitance element between the third vibrator 21 and changing the capacitance value of the variable capacitance element.

［第４の実施形態における効果］
以上のとおり、第４の実施形態に係る発振器２００によれば、第３振動子２１と、負性容量回路２２と、反転増幅器２３と、容量素子２４とをさらに備えることで、上記の実施形態よりもさらに広い周波数範囲で、発振周波数を変化させることができる。 [Effects of the fourth embodiment]
As described above, according to the oscillator 200 according to the fourth embodiment, the third embodiment 21, the negative capacitance circuit 22, the inverting amplifier 23, and the capacitive element 24 are further provided, and thus the above-described embodiment. The oscillation frequency can be changed in a wider frequency range than that.

以上、本発明を実施の形態を用いて説明したが、本発明の技術的範囲は上記実施の形態に記載の範囲には限定されない。上記実施の形態に、多様な変更又は改良を加えることが可能であることが当業者に明らかである。そのような変更又は改良を加えた形態も本発明の技術的範囲に含まれ得ることが、特許請求の範囲の記載から明らかである。   As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

例えば、第１の実施形態においては、第１振動子１１に並列に反転増幅器１３と容量素子１４とが直列に接続されていたが、第２振動子１２に並列に反転増幅器１３及び容量素子１４と同等の回路が接続されていてもよい。
また、第４の実施形態においては、発振器２００が３個の振動子を備える構成について説明したが、発振器２００は、さらに多くの振動子を備えてもよい。 For example, in the first embodiment, the inverting amplifier 13 and the capacitive element 14 are connected in series to the first vibrator 11 in parallel. However, the inverting amplifier 13 and the capacitive element 14 are connected to the second vibrator 12 in parallel. An equivalent circuit may be connected.
In the fourth embodiment, the configuration in which the oscillator 200 includes three vibrators has been described. However, the oscillator 200 may include more vibrators.

１・・・共振回路、２・・・増幅回路、１１・・・第１振動子、１２・・・第２振動子、１３・・・反転増幅器、１４・・・容量素子、１５・・・負性容量回路、１６・・・交流信号源、１７・・・負荷抵抗、１８・・・第１可変抵抗、１９・・・第２可変抵抗、２０・・・可変容量素子、２１・・・第３振動子、２２・・・負性容量回路、２３・・・反転増幅器、２４・・・容量素子、２００・・・発振器 DESCRIPTION OF SYMBOLS 1 ... Resonance circuit, 2 ... Amplifier circuit, 11 ... 1st vibrator, 12 ... 2nd vibrator, 13 ... Inverting amplifier, 14 ... Capacitance element, 15 ... Negative capacitance circuit, 16 ... AC signal source, 17 ... load resistance, 18 ... first variable resistor, 19 ... second variable resistor, 20 ... variable capacitance element, 21 ... 3rd vibrator, 22 ... Negative capacitance circuit, 23 ... Inverting amplifier, 24 ... Capacitance element, 200 ... Oscillator

Claims (6)

第１振動子と、
前記第１振動子と直列に接続された第２振動子と、
前記第１振動子と並列に、互いに直列に接続された反転増幅器及び容量素子と、
前記第１振動子と前記第２振動子との間のノードとグランドとの間に設けられた負性容量回路と、
を備える共振回路。 A first vibrator;
A second vibrator connected in series with the first vibrator;
An inverting amplifier and a capacitive element connected in series with each other in parallel with the first vibrator;
A negative capacitance circuit provided between a node between the first vibrator and the second vibrator and the ground;
A resonant circuit comprising: 前記容量素子の容量は、前記第１振動子の等価並列容量と等しい、
請求項１に記載の共振回路。 The capacitance of the capacitive element is equal to the equivalent parallel capacitance of the first vibrator,
The resonant circuit according to claim 1. 前記負性容量回路は、容量値を変化させることができる、
請求項１又は２に記載の共振回路。 The negative capacitance circuit can change a capacitance value.
The resonance circuit according to claim 1 or 2. 前記第１振動子と並列に設けられた第１可変抵抗と、
前記第２振動子と並列に設けられた第２可変抵抗と、
をさらに備える請求項１から３のいずれか一項に記載の共振回路。 A first variable resistor provided in parallel with the first vibrator;
A second variable resistor provided in parallel with the second vibrator;
The resonance circuit according to any one of claims 1 to 3, further comprising: 前記第１振動子と前記第２振動子との間に可変容量素子をさらに備える請求項１から４のいずれか一項に記載の共振回路。   5. The resonant circuit according to claim 1, further comprising a variable capacitance element between the first vibrator and the second vibrator. 第１振動子と、
前記第１振動子と直列に接続された第２振動子と、
前記第１振動子と並列に、互いに直列に接続された反転増幅器及び容量素子と、
前記第１振動子と前記第２振動子との間のノードとグランドとの間に設けられた負性容量回路と、
前記第２振動子が出力する信号を前記第１振動子に帰還する帰還部と、
を備える発振回路。 A first vibrator;
A second vibrator connected in series with the first vibrator;
An inverting amplifier and a capacitive element connected in series with each other in parallel with the first vibrator;
A negative capacitance circuit provided between a node between the first vibrator and the second vibrator and the ground;
A feedback unit that feeds back a signal output from the second vibrator to the first vibrator;
An oscillation circuit comprising:
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05280996A (en) * 1991-10-21 1993-10-29 Nippon Denshi Kogyo Kk Processing circuit for output signal of sensor
JP2001217649A (en) * 2000-02-04 2001-08-10 Nippon Dempa Kogyo Co Ltd Piezoelectric oscillation circuit

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05280996A (en) * 1991-10-21 1993-10-29 Nippon Denshi Kogyo Kk Processing circuit for output signal of sensor
JP2001217649A (en) * 2000-02-04 2001-08-10 Nippon Dempa Kogyo Co Ltd Piezoelectric oscillation circuit

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