JP5126333B2 - Resonator type oscillator and tuning capacitor circuit - Google Patents

Description

  The present invention relates to a resonator type oscillator configured using an inductor and a capacitor.

  Most electronic devices such as wireless communication terminal devices and AV devices use clock signals in various parts. The clock signal desirably has a small phase fluctuation called phase noise, and an oscillator using an LC resonator (resonator type oscillator) is known as an oscillator that can be realized by a semiconductor chip (substrate). Examples of conventional resonator type oscillators include those described in Patent Documents 1 and 2.

FIG. 1 is a diagram illustrating a basic configuration of a resonator type oscillator using an LC resonator.
As shown in FIG. 1, the oscillator 1 includes a resonator 2 and a gain device 11 that supplies power to the resonator 2. The resonator 2 includes an inductor 21 and a tuning capacitor circuit 3 for changing the resonance frequency of the resonator 2. In the tuning capacitor circuit 3, a plurality of capacitors 32 (32a to 32c) having different capacitances are connected in parallel, and switches 31 (31a to 31c) are connected in series to the capacitors 32 (32a to 32c). Yes. Each switch 31a-c is a switching element such as a transistor, for example, and switches the capacitance connected to the inductor 21 through its on / off control. Since the resonance (oscillation) frequency of the resonator 2 can be changed (selected) by switching the capacitance, it is easy to increase the bandwidth.

  The LC resonator has remarkably good resonance (oscillation) frequency selectivity (Q value) compared to a ring resonator and the like, and has a small phase noise. A high Q value is desirable in terms of low power consumption. This is because, when the Q value is low, power consumption by the resistance component parasitic on the resonator increases, and the necessary power increases.

  The design of the Q value of the resonator is influenced by the Q value of the inductor and the Q value of the capacitor. Both the inductor and the capacitor have a resonance frequency called a self-resonance frequency, and the characteristic value is greatly different from the characteristic value at a low frequency in the vicinity of this frequency. For this reason, it is generally difficult to design the Q value of the resonator, and in many cases, a method of finely adjusting the size after evaluating an actually manufactured inductor, capacitor, VCO circuit and the like is often used.

  As described above, in the resonator type oscillator as shown in FIG. 1, the clock signal can be obtained in a wide band by the on / off control of the switch 31 to which the capacitor 32 is connected. However, since each capacitor 32 has different characteristics, the design is more difficult. For this reason, it has been strongly desired to make it possible to easily perform a design in which characteristics such as the Q value are kept high so that the advantage of easy broadbanding can be utilized.

Japanese translation of PCT publication No. 2003-521827 Japanese National Patent Publication No. 11-507192

  An object of the present invention is to provide a technique that makes it possible to more easily perform a design in which characteristics such as a Q value of a resonator type oscillator are maintained high.

  Both of the resonator type oscillators according to the first to third aspects of the present invention utilize a resonance phenomenon formed by using an inductor and a capacitor, and each has the following configuration.

  A resonator-type oscillator according to a first aspect includes a plurality of capacitors having different capacitances for changing the resonance frequency of the resonator-type oscillator, and a switch connected in series for each of the capacitors. The length of the wiring connected to the inductor is made shorter as the capacitor has a larger capacitance.

  A resonator oscillator according to a second aspect includes a plurality of capacitors connected to a wiring extending from an inductor for changing a resonance frequency of the resonator oscillator, a switch connected in series for each capacitor, and a resonance In order to vary the frequency, the switch on / off control is performed in such a manner that the average of the length of the wiring from the inductor side relative to the capacitor located closest to the inductor side among a plurality of capacitors is suppressed. Capacity selection means to perform.

  A resonator-type oscillator according to a third aspect includes a plurality of capacitors connected to a wiring extending from an inductor for changing a resonance frequency of the resonator-type oscillator, a switch connected in series for each capacitor, and a resonance In order to vary the frequency, a capacitor selection unit that performs on / off control of the switch by preferentially selecting a capacitor having a short wiring length from the inductor among the plurality of capacitors is provided.

  Both the tuning capacitor circuits of the first and second aspects of the present invention can be used to select the frequency of the signal output from the resonator type oscillator, and each has the following configuration. ing.

  The tuning capacitor circuit according to the first aspect includes a plurality of capacitors having different capacitances and a switch connected in series for each capacitor, and the wiring of the plurality of capacitors is connected to the wiring connecting the plurality of capacitors in parallel. Among them, the plurality of capacitors are connected in such a manner that the change in electrostatic capacitance from the capacitor located at one end protrudes downward.

  The tuning capacitor circuit according to the second aspect includes a plurality of capacitors, a switch connected in series for each capacitor, and a wiring that branches into two or more in the middle, and the plurality of capacitors branch the wiring. It is arranged separately in the latter part.

  In the present invention, the influence of the resistance of the wiring accompanying the selection of the capacitor by the on / off control of the switch is reduced, and the fluctuation of the Q value accompanying the selection is suppressed. For this reason, the level (level) that causes a problem in circuit design, that is, the level of points to be improved can be further relaxed. As a result, circuit design becomes easier. In addition, the range to be considered in circuit design can be further narrowed, and there is a point that the importance is lowered. These also work to make circuit design easier.

  In the present invention, fluctuations in wiring resistance due to capacitor selection are suppressed. Therefore, it is possible to further suppress the Q value from fluctuating with the selection.

  In the present invention, the resistance of the wiring is further reduced. For this reason, it is possible to minimize the decrease in the Q value due to the resistance.

  Any of the above acts to make circuit design easier.

It is a figure explaining the basic composition of the resonator type oscillator using LC resonator. It is a figure explaining the circuit structure of the resonator type oscillator by 1st Embodiment. It is a figure explaining the realization method of a capacity selection control part. It is a figure explaining arrangement | positioning of the element which comprises a tuning capacitor circuit, and its modeling. It is a figure explaining arrangement | positioning of the element which comprises the conventional tuning capacitor circuit. It is a figure explaining arrangement | positioning of the element which comprises a tuning capacitor circuit, and its modeling (2nd Embodiment). It is a figure explaining arrangement | positioning of the element which comprises a tuning capacitor circuit, and its modeling (3rd Embodiment). It is a figure explaining arrangement | positioning of the element which comprises a tuning capacitor circuit, and its modeling (4th Embodiment). It is a figure explaining arrangement | positioning of the element which comprises a tuning capacitor circuit, and its modeling (5th Embodiment). It is a figure explaining arrangement | positioning of the element which comprises a tuning capacitor circuit, and its modeling (6th Embodiment). It is a figure explaining on / off control for capacitor selection in the modification of a 6th embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<First Embodiment>
FIG. 2 is a diagram for explaining a circuit configuration of the resonator type oscillator (hereinafter abbreviated as “oscillator”) according to the first embodiment.

  The oscillator is operated by the power supply voltage VDD. The power supply voltage VDD is applied to the sources of two p-channel MOS FETs (hereinafter “P-transistors”) T1 and T2. The gates of the P transistors T1 and T2 are connected to the other drain. Two varactors V1 and V2 connected in series and an inductor L1 are connected between the drains of the P transistors T1 and T2. The drain of the P transistor T1 is connected to the drain of an n-channel MOS FET (hereinafter referred to as “N transistor”) T3, the gate of the N transistor T4, and the tuning capacitor circuit 210 for changing the resonance frequency of the oscillator. The drain of the transistor T2 is connected to the drain of the N transistor T4, the gate of the N transistor T3, and the tuning capacitor circuit 220 for changing the resonance frequency of the oscillator. The oscillator signal is also output from this same node. A terminal a connected between the two varactors V1 and V2 is a control terminal for finely adjusting the oscillation frequency.

The tuning capacitor circuit 210 includes a plurality of capacitors 211 (211a to 211a) having different electrostatic capacities (here, a total of 6 that are 2 ⁿ times the reference electrostatic capacitance Ca (n is an integer from 0 to 5)). f) are connected in parallel, and switches 212 (212a-f) are connected in series to the capacitors 211 (211a-f), respectively. Each switch 212 is, for example, a switching element, more specifically, for example, an N transistor. The same applies to the other tuning capacitor circuit 220. The capacitance selection control unit 230 performs on / off control of each switch 31a to 31c of each tuning capacitor circuit 210, and switches the capacitance to be connected to the inductor L1. If each switch 212 is an N transistor, it is turned on by inputting an H signal to the gate. As a result, the capacitor 211 and the ground can be energized. Since each tuning capacitor circuit 210, 220 has six capacitors 211, the capacitance selection control unit 230 outputs a 6-bit signal. Since the tuning capacitor circuits 210 and 220 have the same configuration, only the tuning capacitor circuit 210 will be described below.

FIG. 3 is a diagram for explaining a method of realizing the capacity selection control unit 230.
The capacity selection control unit 230 is for outputting a signal of a requested frequency through on / off control of the switch. As a method that can be adopted for realizing the control unit 230, a direct control method shown in FIG. 3A, a logic gate control method shown in FIG. 3B, and a CPU control method shown in FIG. The three are the main ones.

  The direct control method shown in FIG. 3A outputs an N-bit input signal input from the outside for frequency designation to a corresponding switch for each bit. If the input signal can be output to the switch, an N-bit input signal may be output to the corresponding switch for each bit. Therefore, in the tuning capacitor circuits 210 and 220 as shown in FIG. 2, N = 6 or more.

  The logic gate control method shown in FIG. 3B decodes an N-bit input signal and generates an L-bit signal to be output to each switch. In the tuning capacitor circuits 210 and 220 as shown in FIG. 2, L = 6 or more. In FIG. 10, L = 10 or more. N may be any number.

  The CPU control method shown in FIG. 3C is the same as the logic gate method in signal input / output. However, various selection methods can be realized. It is also possible to flexibly deal with the situation.

  In the present embodiment, the arrangement of the capacitor 211 in the tuning capacitor circuit 210 is devised so that the design of a broadband, high-performance oscillator becomes easier. Next, with reference to FIG. 4 and FIG. 5, the arrangement | positioning and the effect acquired by the device of the arrangement | positioning are demonstrated concretely.

  Usually, the circuit configuration is shown in a circuit diagram. However, the arrangement of elements and the like constituting the circuit is determined in consideration of various viewpoints including high density and influence between elements. For example, when a circuit is mounted on a semiconductor chip (substrate), other elements such as other inductors and transistors are often arranged at the center of the circuit, so that the unevenness of the unevenness is usually severe. In that case, the surface of the chip can be used more efficiently when the small elements are arranged inside than when the large elements are arranged inside. For these reasons, there are many cases where circuit diagrams do not show the actual arrangement (layout).

  FIG. 4 is a diagram for explaining the arrangement of elements constituting the tuning capacitor circuit 210 and the modeling thereof. In FIG. 4, reference numeral 402 denotes a wiring for connecting a plurality of capacitors 211 in parallel, and 401 denotes a wiring for connecting the wiring 402 and the oscillator. Thereby, in the present embodiment, the length of the wiring connecting the inductor L1 is shorter for the capacitor 211 having a larger capacitance. Here, for convenience, only a total of four capacitors 211 with 211a to 211d are shown.

  In the wiring through which an AC signal flows, the capacitance cannot be ignored. Therefore, the capacitor 403 having the capacitance Cb existing in the wiring 401 or the wiring including the wiring 402 is considered. Since the inductor L1 is connected, it is assumed that the inductance of the wiring is included in it. It is assumed that the resistance value of the wiring 401 is Ra and the resistance value of the wiring 402 is Rb. Each capacitor 211 is connected to a different position. The change of the resistance value Rb depending on the position is simulated by the coefficient k.

The voltage generated at both ends of the capacitor 211 changes depending on the capacitance of the capacitor 211. For this reason, the switch 212 corresponds to the electrostatic capacity of the capacitor 211 connected in series thereto. Accordingly, when the resistance value of the switch 212a connected to the capacitor 211a having the capacitance Ca is Rc, for example, the resistance value of the switch 212d connected to the capacitor 211d having the capacitance of 8 (= 2 ³ ) × Ca is Rc / 8.

The Q value is obtained as follows.
Q = 1 / ωCR (1)
Here, ω is an angular frequency (rad / s) obtained by 2πf (resonance (oscillation) frequency), C is a capacitance (F), and R is a resistance value (Ω).

In the case of modeling as shown in FIG. 4, the Q value is obtained as follows using equation (1).
Q = 1 / ωCR = 1 / (ω × (M · Ca + Cb) × (Ra + k · Rb + Rc / M))
(2)
Here, M is a value (here, an integer) obtained by dividing the capacitance of all the capacitors 211 selected by turning on the switch 211 by the capacitance Ca.

  As is apparent from the equation (2), the total capacitance C (= (M · Ca + Cb)) is automatically determined by the selection of the capacitor 211. However, the value of k · Rb varies depending on the capacitor 211 to be selected. Since the value of the coefficient k increases as the distance from the inductor L1 increases, in the configuration illustrated in FIG. 4, the total resistance value R increases as the capacitor 211 having a smaller capacitance is selected. As such, since the direction of change is reversed between the total capacitance C and the total resistance value R, even if the Q value varies depending on the capacitor 211 to be selected, the variation can be further suppressed. Yes.

  Selecting a smaller capacitance capacitor 211 means generating a higher frequency signal. For this reason, the deterioration of the Q value is usually not a big problem.

  On the other hand, as shown in FIG. 5, when the capacitor 211 having a larger capacitance is arranged so that the length of the wiring connecting the inductor L1 becomes longer (FIG. 4 of Patent Document 1), it is more static. The total resistance value R increases as the capacitor 211 having a larger capacitance is selected. For this reason, compared with the structure shown in FIG. 4, Q value will fall more.

  As described above, the plurality of capacitors 211 having different capacitances are arranged such that the capacitor 211 having a larger capacitance is closer to the inductor L1, in other words, the resistance value existing between the inductors L1 is smaller. By disposing, the variation of the Q value accompanying the selection of the capacitor 211 is further suppressed and compensated. As a result of the Q value being compensated, a high-performance oscillator over a wide band can be realized more easily.

  As is well known, an equivalent capacitance rapidly increases near a self-resonant frequency. As the capacity increases, the Q value decreases according to equation (1). However, by adopting the configuration as shown in FIG. 4, it becomes possible to easily cope with such a situation. The contribution of the self-resonant frequency causes a deviation from the model and makes the design difficult. However, since the degree is relaxed, the design becomes easier. In terms of design, in addition to the fact that the degree to be improved is more relaxed, there is an effect that a range to be considered becomes narrower or a point that becomes less important occurs.

<Second Embodiment>
FIG. 6 is a diagram for explaining the arrangement and modeling of the elements constituting the tuning capacitor circuit 210 according to the second embodiment. The configuration of the capacitor circuit 210 will be described in detail with reference to FIG.

  The configuration of the oscillator is basically the same as that of the first embodiment except for the tuning capacitor circuit 210 (220). The types of elements constituting the circuit 210 are basically the same. For this reason, description will be made in the form of paying attention to the circuit 210 by using the reference numerals in the first embodiment as they are. The same applies to the following embodiments. In FIG. 6, the capacitor 211 is extracted and shown.

  In the second embodiment, as shown in FIG. 6, when considering a line passing through the capacitor 211 a located at the center, the plurality of capacitors 211 are symmetrical with respect to the capacitance with the line as the axis of symmetry. Are arranged as follows. Thereby, the change in electrostatic capacitance from the closer (or farther) from the inductor L1 has a downwardly convex shape. (Here, the convex shape of the capacitance change means that the capacitance changes from large to small toward the axis of symmetry from the side closer to (or farther from) the inductor L1.)

  In the first embodiment, only one capacitor 211 is selected. On the other hand, in the second embodiment, only one capacitor 211a located in the center is selected in the figure, but the other capacitors 211 are selected as one set. Thus, for example, two capacitors 211a located on both sides of the capacitor 211a are selected at the same time (the total capacitance is 2 × Ca, the resistance value of the two switches 212a is Rc / 2, 1 2 capacitors 211b located outside them are selected at the same time (total capacitance is 2 × Ca, 2 capacitors). The resistance value of the switch 212a is Rc / 2, which is the same as when one capacitor 211c is selected). The capacity selection control unit 230 performs on / off control of the switch 212 for performing such selection.

  When the configuration shown in FIG. 6 is employed, as described above, the closer the capacitor 211 is, the farther the capacitor 211 is selected as the total capacitance increases. For this reason, the fluctuation of the resistance value k · Rb (value of the coefficient k) for the wiring 402 accompanying the capacitor 211 to be selected is further suppressed as compared with the first embodiment. As a result, the Q value can be made more constant regardless of the capacitor 211 (total capacitance) to be selected.

<Third Embodiment>
FIG. 7 is a diagram for explaining the arrangement and modeling of the elements constituting the tuning capacitor circuit 210 according to the third embodiment. The configuration of the capacitor circuit 210 will be described in detail with reference to FIG. Also in FIG. 7, the capacitor 211 is extracted.

  In the third embodiment, as shown in FIG. 7, the plurality of capacitors 211 are divided so as to sandwich the wiring 402 and are connected to both sides of the wiring 402. Therefore, the wiring 402 can be made shorter as compared with the first and second embodiments. The reason why the resistance value of the wiring 402 is expressed as “k · Rb / 2” is that the resistance value can be reduced by half from the first embodiment. Therefore, the influence of the resistance of the wiring 402 on the Q value is further reduced.

  In the third embodiment, the other capacitors 211a to 211c except for the capacitor 211d having the largest capacitance are connected to the other side of the capacitor 211d. This is to make the length of the wiring 402 shorter. The capacitors 211a to 211c arranged on the other side are arranged such that the larger the capacitance, the closer to the inductor L1 side. Thereby, an effect similar to that of the first embodiment is also obtained. The capacitance selection control unit 230 in the third embodiment performs on / off control of the switch 212 for selecting only one capacitor 211, as in the first embodiment.

<Fourth embodiment>
FIG. 8 is a diagram for explaining the arrangement and modeling of elements constituting the tuning capacitor circuit 210 according to the fourth embodiment. The configuration of the capacitor circuit 210 will be described in detail with reference to FIG. Also in FIG. 8, the capacitor 211 is extracted and shown.

  In the fourth embodiment, as shown in FIG. 8, the wiring 401 is branched from the middle. As a result, the portion 401a is branched from the inductor L1 side, one portion 401b after branching, and the other portion 401c. Accordingly, the wiring 402 becomes two wirings 402a and 402b. The capacitance of the capacitor 403 is Cb ′.

  When the arrangement as shown in FIG. 8 is adopted, the wiring 402 can be made shorter as in the third embodiment, so that the influence of the resistance on the Q value can be further reduced. Further, the flatness of the semiconductor chip can be improved as compared with the third embodiment. However, the resistance of the wiring 401 becomes larger. The capacitance selection control unit 230 in the fourth embodiment performs on / off control of the switch 212 for selecting only one capacitor 211 as in the third embodiment.

<Fifth embodiment>
FIG. 9 is a diagram for explaining the arrangement and modeling of elements constituting the tuning capacitor circuit 210 according to the fifth embodiment. The configuration of the capacitor circuit 210 will be described in detail with reference to FIG. Also in FIG. 9, the capacitor 211 is extracted and shown.

  In the fifth embodiment, similarly to the third embodiment, as shown in FIG. 9, the plurality of capacitors 211 are arranged separately with the wiring 402 interposed therebetween. On each side, a plurality of capacitors 211 having different capacitances are arranged so that the change in capacitance from the inductor L1 side protrudes downward. The numerical values “1”, “2”, “4”, and “8” shown in FIG. 9 correspond to the value of M in equation (2), and should be selected so that the total capacitance is M × Ca. The capacitor 211 is represented by a numerical value. From this, the capacity selection control unit 230 in the fifth embodiment performs on / off control of the switch 212 for performing such selection.

  Capacitor 211a and switch 212 (hereinafter referred to as “dummy unit”) denoted as “Dummy” are provided in order to suppress an adverse effect on the manufacturing process due to a layout difference in the vicinity. Therefore, it is excluded from selection targets. In order to suppress the adverse effect, it is desirable to provide dummy units at the locations indicated by broken lines in the drawing. The same applies to other embodiments.

  In the arrangement as shown in FIG. 9, capacitors 211 having the same capacitance are arranged so as to be symmetric with respect to a point shown on the wiring 402, and the capacitors 211 having the same capacitance are selected. For this reason, similarly to the second embodiment, it is possible to suppress the fluctuation of the resistance of the wiring 402 caused by the capacitor 211 to be selected. In addition, since the length of the wiring 402 can be made shorter, the influence of the resistance can be further reduced.

  In this embodiment, a plurality of capacitors 211 having different electrostatic capacities are arranged on both sides of the wiring 402. However, by adopting the wiring 401 or 402 branched in the middle, a portion after the branching is provided. You may make it perform such arrangement | positioning, respectively.

<Sixth Embodiment>
FIG. 10 is a diagram for explaining the arrangement and modeling of elements constituting the tuning capacitor circuit 210 according to the sixth embodiment. The configuration of the capacitor circuit 210 will be described in detail with reference to FIG. Also in FIG. 10, the capacitor 211 is extracted and shown.

  In the sixth embodiment, as shown in FIG. 10, a plurality of capacitors 211 having the same capacitance are arranged on one side of the wiring 402. Dummy units are provided at both ends of the line. Each numerical value of “1”, “2”, “4”, and “8” shown in FIG. 10 corresponds to the value of M in the expression (2) as in the fourth embodiment, The arrow indicates the capacitor 211 to be selected so that the total capacitance is M × Ca. Therefore, the capacity selection control unit 230 in the sixth embodiment performs on / off control of the switch 212 for performing such selection. Even in the sixth embodiment, since the fluctuation of the resistance of the wiring 402 can be avoided or suppressed, the same effect as in the second embodiment can be obtained.

  When the arrangement shown in FIG. 10 is adopted, the capacitor 211 on the inductor L1 side may be preferentially selected. For example, when an N-bit signal is input to the capacitance selection control unit 230 and an L-bit signal is output to select the capacitor 211 excluding the dummy unit (FIG. 3), for example, according to the N-bit input signal The capacitor 211 may be selected by outputting an L-bit signal having the contents shown in FIG. In FIG. 11, L ≧ N is assumed, and symbols 1 to L represent corresponding bit digits. Thereby, the output value is represented by 0 or 1 for each bit. 1 represents an H signal for turning on the switch 212. The signal of the first bit is input to the switch 212 connected to the capacitor 211 closest to the inductor L1 (the resistance value of the wiring to be connected is minimum), and the signal of the second bit is connected to the capacitor 211 located next to the capacitor 211. Input to the switch 212. The correspondence between the digit of the bit and the capacitor 211 is like that.

  When the capacitor selection control unit 230 performs such selection, the resistance of the wiring 402 with respect to the total capacitance obtained by the selection can be minimized. Therefore, the capacitor 211 can be selected so that the Q value is always optimum.

  In the sixth embodiment (and its modifications), a plurality of capacitors 211 having the same capacitance are arranged only on one side of the wiring 402, but as in the third embodiment, It may be arranged on both sides. Alternatively, as in the fourth embodiment, a plurality of capacitors 211 may be divided and connected in parallel. In the case of adopting the CPU control method for realizing the capacity selection control unit 230, a program for enabling on / off control for selecting the capacitor 211 as described above is prepared, and a portable recording medium or You may distribute via a communication network.

(Appendix 1)
In a resonator type oscillator composed of an inductor and a capacitor,
A plurality of capacitors having different capacitances for varying the resonance frequency of the resonator-type oscillator, and a switch connected in series for each capacitor;
The length of the wiring to be connected to the inductor for each of the plurality of capacitors is shortened as the capacitor having a larger capacitance is obtained.
A resonator type oscillator characterized by the above.
(Appendix 2)
In a resonator type oscillator composed of an inductor and a capacitor,
A plurality of capacitors having different capacitances for varying the resonance frequency of the resonator-type oscillator, and a switch connected in series for each capacitor;
The arrangement of the plurality of capacitors along the wiring to be connected to the inductor has a shape in which the change in the capacitance from the inductor side is convex downward.
A resonator type oscillator characterized by the above.
(Appendix 3)
In a resonator type oscillator composed of an inductor and a capacitor,
A plurality of capacitors for varying the resonance frequency of the resonator-type oscillator, and a switch connected in series for each capacitor;
The plurality of capacitors are arranged separately with a wiring to be connected to the inductor interposed therebetween,
A resonator type oscillator characterized by the above.
(Appendix 4)
A plurality of capacitors having different capacitances arranged on at least one side of the wiring are set to have a direction in which a change in the capacitance from the inductor side becomes smaller.
4. The resonator type oscillator according to appendix 3, wherein
(Appendix 5)
A plurality of capacitors having different capacitances are arranged on both sides of the wiring,
The plurality of capacitors have a shape in which the change in capacitance from the inductor side is convex downward,
4. The resonator type oscillator according to appendix 3, wherein
(Appendix 6)
In a resonator type oscillator composed of an inductor and a capacitor,
A plurality of capacitors for varying the resonance frequency of the resonator-type oscillator, a switch connected in series for each capacitor;
A wiring branching into two or more connected to the inductor,
The plurality of capacitors are arranged separately in a portion after branching the wiring,
A resonator type oscillator characterized by the above.
(Appendix 7)
A plurality of capacitors having different capacitances arranged in at least one of the parts after the branching are in a direction in which a change in the capacitance from the inductor side is reduced.
The resonator type oscillator according to appendix 6, wherein the resonator is an oscillator.
(Appendix 8)
In a resonator type oscillator composed of an inductor and a capacitor,
A plurality of capacitors connected to a wiring extending from the inductor and configured to vary a resonance frequency of the resonator-type oscillator, and a switch connected in series for each capacitor;
In order to vary the resonance frequency, the switch is controlled in such a manner that the average length of the wiring from the inductor side with respect to the capacitor located closest to the inductor side among the plurality of capacitors is suppressed. Capacity selection means for performing on / off control;
A resonator-type oscillator comprising:
(Appendix 9)
In a resonator type oscillator composed of an inductor and a capacitor,
A plurality of capacitors connected to a wiring extending from the inductor and configured to vary a resonance frequency of the resonator-type oscillator, and a switch connected in series for each capacitor;
Capacitance selection means for performing on / off control of the switch by preferentially selecting a capacitor having a short wiring length from the inductor among the plurality of capacitors in order to vary the resonance frequency;
A resonator-type oscillator comprising:
(Appendix 10)
In a tuning capacitor circuit that can be used to select the frequency of a signal output from a resonator type oscillator,
A plurality of capacitors having different capacitances, and a switch connected in series for each capacitor,
The plurality of capacitors are connected in such a manner that the change in capacitance from the capacitor located at one end of the plurality of capacitors is convex downward with respect to the wiring connecting the plurality of capacitors in parallel. ing,
A tuning capacitor circuit characterized by that.
(Appendix 11)
In a tuning capacitor circuit that can be used to select the frequency of a signal output from a resonator type oscillator,
A plurality of capacitors, and a switch connected in series for each capacitor,
The plurality of capacitors are connected separately in a form sandwiching wires connecting the plurality of capacitors in parallel.
A tuning capacitor circuit characterized by that.
(Appendix 12)
In a tuning capacitor circuit that can be used to select the frequency of a signal output from a resonator type oscillator,
A plurality of capacitors, a switch connected in series for each capacitor;
And wiring that branches into two or more along the way,
The plurality of capacitors are arranged separately in a portion after branching the wiring,
A tuning capacitor circuit characterized by that.

210, 220 Tuning capacitor circuit 211a-f, 403 Capacitor 212a-f Switch 230 Capacitance selection controller 401, 401a-c, 402, 402a, 402b Wiring L1 Inductor T1-4 Transistors V1, V2 Varactor

Claims (4)

In a resonator type oscillator composed of an inductor and a capacitor,
A plurality of capacitors connected to a wiring extending from the inductor and configured to vary a resonance frequency of the resonator-type oscillator, and a switch connected in series for each capacitor;
In order to vary the resonance frequency, the switch is controlled in such a manner that the average length of the wiring from the inductor side with respect to the capacitor located closest to the inductor side among the plurality of capacitors is suppressed. Capacity selection means for performing on / off control;
A resonator-type oscillator comprising: In a resonator type oscillator composed of an inductor and a capacitor,
A plurality of capacitors connected to a wiring extending from the inductor and configured to vary a resonance frequency of the resonator-type oscillator, and a switch connected in series for each capacitor;
Capacitance selection means for performing on / off control of the switch by preferentially selecting a capacitor having a short wiring length from the inductor among the plurality of capacitors in order to vary the resonance frequency;
A resonator-type oscillator comprising: In a tuning capacitor circuit that can be used to select the frequency of a signal output from a resonator type oscillator,
A plurality of capacitors having different capacitances, and a switch connected in series for each capacitor,
For the wiring connecting the plurality of capacitors in parallel, the capacitance of the plurality of capacitors connected from one end to the other end of the wiring increases from the center of the wiring toward both ends of the wiring. So that the plurality of capacitors are connected,
A tuning capacitor circuit characterized by that. In a tuning capacitor circuit that can be used to select the frequency of a signal output from a resonator type oscillator,
A plurality of capacitors, a switch connected in series for each capacitor;
Wiring that is branched into a plurality of branches along the way,
A capacitor having the largest capacitance among the plurality of capacitors is singly disposed in one of the plurality of branches, and at least one of the plurality of branches includes one of the plurality of capacitors. 2 or more capacitors are placed,
A tuning capacitor circuit characterized by that.