WO2019208675A1 - Oscillation device, and oscillation frequency adjusting method - Google Patents

Abstract

Provided are an oscillation device with which it is possible to easily lower the level of difficulty of an oscillation frequency adjusting operation, and an oscillation frequency adjusting method. The oscillation device (1) is provided with an amplifier circuit (3) and a feedback circuit (4). The amplifier circuit (3) amplifies a signal that has been input to the input terminal (31) and outputs an amplified signal from an output terminal (32). The feedback circuit (4) is electrically connected between the output terminal (32) and the input terminal (31). The feedback circuit (4) includes a resonator (2), a first transmission line (41), and a second transmission line (42). The first transmission line (41) is electrically connected between the output terminal (32) and the resonator (2). The second transmission line (42) is electrically connected between the input terminal (31) and the resonator (2). The oscillation device (1) is further provided with an adjusting unit (5). The adjusting unit (5) adjusts at least one of length and characteristic impedance with respect to a target line comprising at least one of the first transmission line (41) and the second transmission line (42).

Description

Oscillator and method for adjusting oscillation frequency

The present disclosure relates generally to an oscillation device and an adjustment method of an oscillation frequency, and more particularly to an oscillation device including a resonator and an adjustment method of an oscillation frequency.

Patent Document 1 describes an oscillation device (microwave oscillation circuit) including a first stub, a resonator (dielectric resonator), a second stub, and a transistor.

In this oscillation device, the second stub and the resonator constitute a basic oscillation circuit. The first stub forms a feedback circuit and improves the oscillation output. In this oscillation device, a DC voltage is applied to a transistor that connects a basic oscillation circuit (second stub and resonator) and a feedback circuit (first stub), and the transistor is operated as an oscillator.

JP 2001-251139 A

In the oscillation device configured as described above, the oscillation frequency can be adjusted by adjusting the resonance frequency of the resonator. However, when the resonance frequency of the resonator changes, the phase of the signal fed back by the feedback circuit is likely to change. Therefore, in order to realize positive feedback by the feedback circuit, the phase needs to be adjusted, and as a result, the difficulty of adjusting the oscillation frequency becomes relatively high.

The present disclosure has been made in view of the above-described reasons, and an object thereof is to provide an oscillation device and an oscillation frequency adjustment method that can easily reduce the difficulty of adjustment of the oscillation frequency.

The oscillation device according to one embodiment of the present disclosure includes an amplifier circuit and a feedback circuit. The amplifier circuit amplifies the signal input to the input terminal and outputs the amplified signal from the output terminal. The feedback circuit is electrically connected between the output terminal and the input terminal. The feedback circuit includes a resonator, a first transmission line, and a second transmission line. The first transmission line is electrically connected between the output terminal and the resonator. The second transmission line is electrically connected between the input terminal and the resonator. The oscillation device further includes an adjustment unit. The adjustment unit adjusts at least one of a length and a characteristic impedance for a target line including at least one of the first transmission line and the second transmission line.

The method for adjusting the oscillation frequency according to one aspect of the present disclosure is a method for adjusting the oscillation frequency of an oscillation device including an amplifier circuit and a feedback circuit. The amplifier circuit amplifies the signal input to the input terminal and outputs the amplified signal from the output terminal. The feedback circuit is electrically connected between the output terminal and the input terminal. The feedback circuit includes a resonator, a first transmission line, and a second transmission line. The first transmission line is electrically connected between the output terminal and the resonator. The second transmission line is electrically connected between the input terminal and the resonator. In the adjustment method of the oscillation frequency, the oscillation frequency is adjusted by adjusting at least one of a length and a characteristic impedance of a target line including at least one of the first transmission line and the second transmission line.

FIG. 1 is an explanatory diagram conceptually showing the configuration of the oscillation device according to the first embodiment. FIG. 2 is a block diagram schematically showing the flow of an electric signal in the oscillation device same as above. 3A is a schematic plan view showing a state before adjustment by the adjustment unit of the oscillation device same as above, and FIG. 3B is a schematic plan view showing a state after adjustment by the adjustment unit of the oscillation device same as the above. FIG. 4A is an explanatory diagram illustrating characteristics of the feedback circuit of the above-described oscillation device, and FIG. 4B is an explanatory diagram illustrating characteristics of the feedback circuit of the comparative example. FIG. 5 is a flowchart showing a specific example of a method for adjusting the oscillation frequency. 6A to 6E are explanatory views schematically showing the main part of the oscillation device according to the second embodiment.

(Embodiment 1)
(1) Overview As shown in FIG. 1, the oscillation device 1 according to the present embodiment includes a resonator 2 and generates a device that oscillates at an oscillation frequency, that is, a continuous electrical vibration having periodicity. Device. The “oscillation frequency” in the present disclosure is the frequency of the output signal (electric signal) of the oscillation device 1.

The oscillation device 1 according to the present embodiment includes an amplifier circuit 3 and a feedback circuit 4. The amplifier circuit 3 amplifies the signal input to the input terminal 31 and outputs it from the output terminal 32. The feedback circuit 4 is electrically connected between the output terminal 32 and the input terminal 31. Here, the feedback circuit 4 includes the resonator 2, the first transmission line 41, and the second transmission line 42. The first transmission line 41 is electrically connected between the output terminal 32 and the resonator 2. The second transmission line 42 is electrically connected between the input terminal 31 and the resonator 2.

In other words, the output terminal 32 of the amplifier circuit 3 and the resonator 2 are electrically connected by a transmission line including the first transmission line 41, and between the input terminal 31 of the amplifier circuit 3 and the resonator 2. Are electrically connected by a transmission line including the second transmission line 42. Therefore, a part of the output signal output from the output terminal 32 of the amplifier circuit 3 passes through the first transmission line 41, the resonator 2, and the second transmission line 42 included in the feedback circuit 4 in this order, and the amplifier circuit 3 The input terminal 31 is fed back.

The oscillation device 1 configured in this manner outputs an output signal from the output terminal 32 of the amplifier circuit 3. Here, the frequency of the output signal output from the output terminal 32, that is, the oscillation frequency of the oscillation device 1 is determined by the feedback circuit 4. The oscillation device 1 further includes an adjustment unit 5 as a configuration for adjusting the oscillation frequency. The adjustment unit 5 adjusts at least one of the length and the characteristic impedance of the target line including at least one of the first transmission line 41 and the second transmission line 42.

That is, in the oscillation device 1 according to the present embodiment, at the adjustment unit 5, at least one of the length of the target line (at least one of the first transmission line 41 and the second transmission line 42) and the characteristic impedance of the feedback circuit 4 is set. It can be adjusted. Since the characteristic of the feedback circuit 4 is changed by adjusting the length or characteristic impedance of the target line, as a result, the oscillation frequency can be adjusted. Details will be described in the section “(2.2) Adjustment Unit”. However, in order to adjust the oscillation frequency, the length or characteristic impedance of the target line is adjusted as compared with the case where the resonance frequency of the resonator 2 is adjusted. In this case, the phase of the signal fed back by the feedback circuit 4 hardly changes. Therefore, according to the oscillation device 1 according to the present embodiment, it is difficult to adjust the phase when adjusting the oscillation frequency, and as a result, it is easy to reduce the difficulty of the adjustment operation of the oscillation frequency.

(2) Details Hereinafter, the oscillation device 1 according to the present embodiment will be described in more detail. In the present embodiment, as an example, a case where the oscillation device 1 generates an output signal composed of a microwave will be described. That is, the oscillation device 1 outputs a microwave that is a radio wave (electromagnetic wave) having a frequency of 300 MHz to 3 THz. The oscillation device 1 according to the present embodiment is used, for example, as a microwave power source for heating a microwave absorber, a microwave oven, a microwave therapy device, a lighting device for a microwave excitation type electrodeless lamp, or the like.

In particular, the oscillation device 1 according to the present embodiment uses an amplifier circuit 3 made of a solid element (semiconductor element). The oscillation device 1 using such a solid element can stabilize the oscillation frequency and can be downsized as compared with an oscillation device using a magnetron.

Furthermore, the oscillation device 1 according to the present embodiment employs a configuration in which a part of the output signal output from the output terminal 32 of the amplifier circuit 3 is positively fed back to the input terminal 31 by the feedback circuit 4. This makes it possible to reduce the circuit scale as compared with an oscillation device configured to use a negative resistance. As an example of an oscillation device that uses negative resistance, a small signal is generated by a phase locked loop (PLL: Phase Locked Loop), and the small signal is passed through a phase shifter and then amplified by an amplifier. There is an oscillation device configured to generate a signal.

(2.1) Overall Configuration First, the overall configuration of the oscillation device 1 according to the present embodiment will be described with reference to FIG. 1 and FIG. FIG. 1 is an explanatory diagram conceptually showing the configuration of the oscillation device 1, and FIG. 2 is a block diagram schematically showing the flow of electrical signals in the oscillation device 1. However, the configuration illustrated in FIGS. 1 and 2 is merely an example of the oscillation device 1 according to the present embodiment, and is not intended to limit the specific connection relationship, the number of elements (capacitors and the like), and the like.

As described above, the oscillation device 1 includes the amplifier circuit 3, the feedback circuit 4, and the adjustment unit 5. In the present embodiment, the oscillation device 1 further includes an output unit 6 for taking out an output signal, and a circuit board 7 (see FIG. 3A) on which various electronic components such as the amplifier circuit 3 are mounted. Here, not all the components of the oscillation device 1 will be described strictly. For example, description of power supply means to the active element (amplifier circuit 3 and the like) will be omitted as appropriate.

The amplifier circuit 3 has an input terminal 31 and an output terminal 32. The amplifier circuit 3 amplifies the signal (voltage signal) input to the input terminal 31 and outputs it from the output terminal 32. The “terminal” in the present disclosure may not be a component for connecting an electric wire or the like, and may be, for example, a lead of an electronic component or a part of a conductor included in the circuit board 7.

That is, the amplifier circuit 3 has a predetermined gain (amplification factor), and when a sinusoidal signal having a certain amplitude is input to the input terminal 31 of the amplifier circuit 3, the output terminal 32 of the amplifier circuit 3. In this case, a sinusoidal signal whose amplitude is amplified by the gain (voltage gain) appears. In the present embodiment, the amplifier circuit 3 is configured using a solid element (semiconductor element). Specifically, the amplifier circuit 3 is realized by a single packaged electronic component, and is realized by, for example, a semiconductor element including a transistor, an operational amplifier (op amp), or the like.

The output terminal 32 of the amplifier circuit 3 is electrically connected to the output unit 6. The output unit 6 is realized by, for example, a terminal to which an electric wire can be connected, an electrode to which a lead wire can be connected, a connector to which a cable can be connected, a wireless communication module, or the like. As a result, the output unit 6 can extract the signal amplified by the amplifier circuit 3 as an output signal.

The feedback circuit 4 is electrically connected between the output terminal 32 and the input terminal 31. The feedback circuit 4 has a function of feeding back a part of the output signal output from the output terminal 32 of the amplifier circuit 3 to the input terminal 31 of the amplifier circuit 3. In particular, the feedback circuit 4 includes at least the resonator 2 and feeds back a signal component having a specific frequency corresponding to the resonance frequency of the resonator 2 in the output signal. That is, the feedback circuit 4 has a certain frequency characteristic.

Here, the feedback circuit 4 is a positive feedback circuit that positively feeds back a part of the output signal output from the output terminal 32 to the input terminal 31. In the present embodiment, the feedback circuit 4 is directly connected between the output terminal 32 and the input terminal 31 of the amplifier circuit 3 without any other circuit, and a part of the output signal of the amplifier circuit 3 is directly connected. Positive feedback. In other words, the basic circuit for oscillation of the oscillation device 1 is configured by the amplifier circuit 3 and the feedback circuit 4. As described above, the oscillation device 1 using positive feedback can reduce the circuit scale as compared with the oscillation device configured to use negative resistance.

The feedback circuit 4 includes a first transmission line 41 and a second transmission line 42 in addition to the resonator 2. The resonator 2 generates electrical vibration at a specific resonance frequency. The resonator 2 is, for example, a TEM (Transverse Electromagnetic) mode dielectric resonator, a so-called coaxial resonator.

The first transmission line 41 is electrically connected between the output terminal 32 and the resonator 2. The second transmission line 42 is electrically connected between the input terminal 31 and the resonator 2. Thereby, the output terminal 32 of the amplifier circuit 3 and the resonator 2 are electrically connected by the transmission line including the first transmission line 41, and the input terminal 31 of the amplifier circuit 3 and the resonator 2 are connected. Are electrically connected by a transmission line including the second transmission line 42. Therefore, a part of the output signal output from the output terminal 32 of the amplifier circuit 3 passes through the first transmission line 41, the resonator 2, and the second transmission line 42 included in the feedback circuit 4 in this order, and the amplifier circuit 3 The input terminal 31 is fed back.

The feedback circuit 4 further includes a first coupling capacitor C1, a second coupling capacitor C2, a third transmission line 43, and a fourth transmission line 44. The first coupling capacitor C <b> 1 is electrically connected between the output terminal 32 and the first transmission line 41. The second coupling capacitor C <b> 2 is electrically connected between the input terminal 31 and the second transmission line 42. Each of the first coupling capacitor C1 and the second coupling capacitor C2 has a capacitance set individually. The first coupling capacitor C <b> 1 is a capacitor that capacitively couples between the output terminal 32 and the resonator 2. The second coupling capacitor C <b> 2 is a capacitor that capacitively couples between the input terminal 31 and the resonator 2. In the present embodiment, each of the first coupling capacitor C1 and the second coupling capacitor C2 is realized by a chip capacitor such as a multilayer ceramic capacitor as an example.

The third transmission line 43 is electrically connected between the second coupling capacitor C2 and the input terminal 31. The fourth transmission line 44 is electrically connected between the first coupling capacitor C <b> 1 and the output terminal 32. More specifically, the fourth transmission line 44 electrically connects the branch point 40 set between the output terminal 32 and the output unit 6 and the first coupling capacitor C1. In FIG. 1, each of the first transmission line 41, the second transmission line 42, the third transmission line 43, and the fourth transmission line 44 is represented by a rectangular symbol such as a resistor for convenience. It does not represent the resistance component of the transmission line.

Thereby, the output terminal 32 of the amplifier circuit 3 is electrically connected to the resonator 2 through the fourth transmission line 44, the first coupling capacitor C1, and the first transmission line 41. The resonator 2 is electrically connected to the input terminal 31 of the amplifier circuit 3 through the second transmission line 42, the second coupling capacitor C2, and the third transmission line 43. Therefore, a part of the output signal output from the output terminal 32 includes the fourth transmission line 44, the first coupling capacitor C1, the first transmission line 41, the resonator 2, the second transmission line 42, the second coupling capacitor C2, It passes through the third transmission line 43 in this order and is fed back to the input terminal 31. Here, the fourth transmission line 44 connecting the first coupling capacitor C1 and the branch point 40 is preferably as short as possible. Thereby, the loss in the feedback circuit 4 can be reduced.

In the present embodiment, each of the first transmission line 41 and the second transmission line 42 is realized by a conductor (wiring) of a circuit board 7 (see FIG. 3A) made of a printed wiring board. Each of the third transmission line 43 and the fourth transmission line 44 is similarly realized by a conductor of the circuit board 7. That is, the conductor formed on one surface of the circuit board 7 constitutes each of the first transmission line 41, the second transmission line 42, the third transmission line 43, and the fourth transmission line 44. More specifically, in this embodiment, since the resonator 2 is a coaxial resonator, the first transmission line 41 and the second transmission line 42 are electrically connected to the internal conductor 21 of the resonator 2. The outer conductor 22 of the resonator 2 is electrically connected to the ground.

Each of the first coupling capacitor C1 and the second coupling capacitor C2 is mounted on the circuit board 7. That is, the first end C1a (see FIG. 3A) and the second end C1b (see FIG. 3A) of the first coupling capacitor C1 are the fourth transmission line 44 and the first transmission line formed on one surface of the circuit board 7, respectively. 41 is joined with solder. The first end C2a (see FIG. 3A) and the second end C2b (see FIG. 3A) of the second coupling capacitor C2 are connected to the second transmission line 42 and the third transmission line 43 formed on one surface of the circuit board 7, respectively. On the other hand, it is joined with solder.

The adjustment unit 5 adjusts at least one of the length and the characteristic impedance of the target line including at least one of the first transmission line 41 and the second transmission line 42. The “length” of the target line in the present disclosure means the physical length of a path (line) through which the electric signal actually passes when the electric signal propagates through the target line. In addition, the “characteristic impedance” of the target line in the present disclosure is the target for the frequency of the electric signal when the electric signal propagates through the target line when the target line is regarded as a distributed constant line (distributed constant circuit). This means the impedance inherent to the line.

In the present embodiment, the target lines are both the first transmission line 41 and the second transmission line 42. Furthermore, in this embodiment, the adjustment unit 5 adjusts the “length” of the length and the characteristic impedance for the target line. That is, in the present embodiment, at least the “length” of both the first transmission line 41 and the second transmission line 42 can be adjusted by the adjustment unit 5. Since the characteristic of the feedback circuit 4 is changed by adjusting the length of the target line, as a result, the oscillation frequency can be adjusted. Details of the adjustment unit 5 will be described in the section “(2.2) Adjustment unit”.

Here, in this embodiment, the capacity of the first coupling capacitor C1 is smaller than the capacity of the second coupling capacitor C2. That is, the first coupling capacitor C1 and the second coupling capacitor C2 use capacitors having different capacitance values. Thereby, the coupling degree of the capacitive coupling between the resonator 2 and the output terminal 32 by the first coupling capacitor C1 is more than the coupling degree of the capacitive coupling between the resonator 2 and the input terminal 31 by the second coupling capacitor C2. Becomes smaller. In other words, the coupling state between the resonator 2 and the output terminal 32 is relatively loosely coupled, and the coupling state between the resonator 2 and the input terminal 31 is relatively tightly coupled.

Thereby, compared with the case where the resonator 2 and the output terminal 32 are tightly coupled, the change in the output impedance of the amplifier circuit 3 due to the feedback circuit 4 being connected to the output terminal 32 of the amplifier circuit 3. Becomes smaller. On the other hand, since the second coupling capacitor C2 has a relatively large capacitance value, impedance matching between the feedback circuit 4 and the input terminal 31 can be achieved. However, if the capacitance value of the first coupling capacitor C1 is too small, a part of the output signal output from the output terminal 32 of the amplifier circuit 3 is not fed back to the input terminal 31 of the amplifier circuit 3 through the feedback circuit 4. . Therefore, the capacitance value of the first coupling capacitor C1 is ensured so that at least a part of the output signal is fed back.

In the present embodiment, the first transmission line 41 and the second transmission line 42 differ in the amount of change in the oscillation frequency for the same amount of adjustment by the adjustment unit 5. That is, the first transmission line 41 and the second transmission line 42 are both target lines, but the first transmission line 41 and the second transmission line 42 have a length (or characteristic impedance) at the adjustment unit 5. The amount of change in the oscillation frequency differs when is adjusted by the same amount.

“Adjustment of the same amount” in the present disclosure means that the same amount, that is, a value, is changed in the same manner with respect to an adjustment target (at least one of length and characteristic impedance). For example, if the object of adjustment is “length”, extending both the first transmission line 41 and the second transmission line 42 by the same length (for example, 1 mm) means that the first transmission line 41 is extended. And the same amount of adjustment for the second transmission line 42.

Here, as an example, in the first transmission line 41 and the second transmission line 42, the first transmission line 41 has a larger amount of change in oscillation frequency for the same amount of adjustment by the adjustment unit 5. For example, when the lengths of the first transmission line 41 and the second transmission line 42 are extended by the same amount, the amount of change in the oscillation frequency is greater in the first transmission line 41. In other words, the first transmission line 41 is for coarse adjustment of the oscillation frequency, and the second transmission line 42 is fine adjustment of the oscillation frequency.

“Coarse adjustment” and “fine adjustment” as used in this disclosure mean adjustments with relatively different roughness. A relatively coarse adjustment is a “coarse adjustment” and a relatively fine adjustment is a “fine adjustment”. It is. That is, “coarse adjustment” is performed when the oscillation frequency is changed with a relatively large step size, and “fine adjustment” is performed when the oscillation frequency is changed with a relatively small step size. For example, when adjusting the oscillation frequency to a target value, it is possible to first adjust the oscillation frequency to the vicinity of the target value by coarse adjustment, and then adjust the oscillation frequency to be closer to the target value by fine adjustment. It is.

In the present embodiment, as described above, the functions for the coarse adjustment and the fine adjustment in the first transmission line 41 and the second transmission line 42 are the capacitance values of the first coupling capacitor C1 and the second coupling capacitor C2, respectively. It is realized by the difference. That is, in this embodiment, the coupling state between the first transmission line 41 and the amplifier circuit 3 by the first coupling capacitor C1 is relatively loosely coupled, and the second transmission line 42 and the amplification by the second coupling capacitor C2 are amplified. The coupling state with the circuit 3 is relatively tight coupling. That is, in the first transmission line 41 and the second transmission line 42, the coupling state with respect to the amplifier circuit 3 is not uniform but non-uniform. As the coupling becomes looser, the influence on the change in the oscillation frequency becomes larger. Therefore, the change in the length (or characteristic impedance) of the first transmission line 41 coupled to the amplifier circuit 3 by the first coupling capacitor C1. Thus, the oscillation frequency changes sensitively.

(2.2) Adjustment Unit Next, the adjustment unit 5 will be described in detail with reference to FIGS. 3A and 3B.

In the present embodiment, the adjustment unit 5 adjusts the “length” of the length and the characteristic impedance for the target line (both the first transmission line 41 and the second transmission line 42). FIG. 3A is a schematic plan view showing a state before adjustment by the adjustment unit 5, and FIG. 3B is a schematic plan view showing a state after adjustment by the adjustment unit 5.

That is, as shown in FIG. 3A, each of the first transmission line 41 and the second transmission line 42 that are target lines is realized by a conductor (wiring) of the circuit board 7. In the state shown in FIG. 3A, it is assumed that the length L1 of the first transmission line 41 is equal to the length L2 of the second transmission line 42 (L1 = L2).

In the present embodiment, as an example, the adjustment unit 5 is realized by trimming units 51 and 52 formed on the first transmission line 41 and the second transmission line 42, which are target lines, as shown in FIG. 3B. The trimming portions 51 and 52 are formed by partially removing a part of the first transmission line 41 and the second transmission line 42 made of the conductor of the circuit board 7 by, for example, laser trimming or sandblasting.

The trimming portion 51 is a cut formed along the short direction of the first transmission line 41. In the example of FIG. 3B, one trimming part 51 is formed at each edge of the first transmission line 41 in the short direction. Has been. Thereby, when the electric signal propagates through the first transmission line 41, the path (line) through which the electric signal actually passes meanders in the short direction of the first transmission line 41 so as to avoid the trimming portion 51. It will be. Therefore, due to the adjustment unit 5 (trimming unit 51), the length L1 of the first transmission line 41 is longer in the state of FIG. 3B than in the state of FIG. 3A.

Similarly, the trimming portion 52 is a cut formed along the short direction of the second transmission line 42. In the example of FIG. 3B, the trimming part 52 is 2 at each edge of the second transmission line 42 in the short direction. It is formed one by one. Thereby, when the electric signal propagates through the second transmission line 42, the path (line) through which the electric signal actually passes meanders in the short direction of the second transmission line 42 so as to avoid the trimming portion 52. It will be. Therefore, due to the adjustment unit 5 (trimming unit 52), the length L2 of the second transmission line 42 is longer in the state of FIG. 3B than in the state of FIG. 3A.

That is, the length L1 of the first transmission line 41 is the number of trimming parts 51 (including zero), the position of the trimming part 51, the length dimension of the trimming part 51 in the short direction of the first transmission line 41, and the trimming. The width can be adjusted by the width dimension of the portion 51, the shape of the trimming portion 51, and the like. Similarly, the length L2 of the second transmission line 42 is the number of trimming parts 52 (including zero), the position of the trimming part 52, the length dimension of the trimming part 52 in the short direction of the second transmission line 42, Adjustment is possible depending on the width dimension of the trimming portion 52, the shape of the trimming portion 52, and the like.

According to such an adjustment unit 5, the characteristic impedance actually changes with the adjustment of the length of the target line (both the first transmission line 41 and the second transmission line 42). However, in this embodiment, in order to simplify the description, only the “length” of the length of the target line and the characteristic impedance is adjusted by the adjustment unit 5.

As described above, the characteristic of the feedback circuit 4 changes as shown in FIG. 4A by adjusting the length (or characteristic impedance) of the target line. FIG. 4B is a diagram illustrating a change in characteristics of the feedback circuit 4 when the resonance frequency of the resonator 2 is adjusted as a comparative example. In the comparative example shown in FIG. 4B, an example in which the resonance frequency of the resonator 2 is adjusted by adjusting the length of the resonator 2 composed of a coaxial resonator (specifically, by cutting the outer conductor of the resonator 2). Show. 4A and 4B, “X1” is the oscillation frequency (Freq.), “X2” is the phase of the signal fed back by the feedback circuit 4, and “X3” is fed back by the feedback circuit 4. Indicates the signal strength (MAG). 4A and 4B exemplify a case where the oscillation frequency is adjusted in the vicinity of 2.450 [GHz]. The horizontal axes of FIGS. 4A and 4B are the line length and the resonator length (the length of the resonator 2), respectively, and the values increase as they approach the right end of the graph, that is, become “long”. ing.

That is, in the oscillation device 1 according to the present embodiment, as shown in FIG. 4A, the longer the length of the target line (both the first transmission line 41 and the second transmission line 42) becomes (the closer to the right end of the graph). ), And the oscillation frequency (X1) decreases substantially linearly. At this time, the intensity (X3) of the signal fed back by the feedback circuit 4 hardly changes, and the phase (X2) of the signal fed back by the feedback circuit 4 is suppressed to a relatively small change. Specifically, when the change of the phase of the signal fed back by the feedback circuit 4 is allowed to be less than ± 5 [degree], the oscillation frequency is about 2.438 [GHz] to 2.452 [GHz]. The range can be adjusted.

On the other hand, in the comparative example, as shown in FIG. 4B, the oscillation frequency (X1) decreases substantially linearly as the length of the resonator 2 becomes longer (closer to the right end of the graph). At this time, the strength (X3) of the signal fed back by the feedback circuit 4 hardly changes, but the phase (X2) of the signal fed back by the feedback circuit 4 changes relatively greatly. Specifically, when the change of the phase of the signal fed back by the feedback circuit 4 is allowed to be less than ± 5 [degree], the oscillation frequency is about 2.439 [GHz] to 2.447 [GHz]. It can be adjusted only within the range.

In short, in order to adjust the oscillation frequency, as compared with the comparative example in which the resonance frequency of the resonator 2 is adjusted, the length (or characteristic impedance) of the target line is adjusted as in the oscillation device 1 according to the present embodiment. In this case, the phase of the signal fed back by the feedback circuit 4 hardly changes. Therefore, according to the oscillation device 1 according to the present embodiment, it is difficult to adjust the phase when adjusting the oscillation frequency, and as a result, it is easy to reduce the difficulty of the adjustment operation of the oscillation frequency.

(2.3) Adjustment Method Next, a method for adjusting the oscillation frequency in the oscillation device 1 according to the present embodiment will be described.

That is, the method for adjusting the oscillation frequency according to the present embodiment is a method for adjusting the oscillation frequency of the oscillation device 1 including the amplifier circuit 3 and the feedback circuit 4. The amplifier circuit 3 amplifies the signal input to the input terminal 31 and outputs it from the output terminal 32. The feedback circuit 4 is electrically connected between the output terminal 32 and the input terminal 31. Here, the feedback circuit 4 includes the resonator 2, the first transmission line 41, and the second transmission line 42. The first transmission line 41 is electrically connected between the output terminal 32 and the resonator 2. The second transmission line 42 is electrically connected between the input terminal 31 and the resonator 2. In this method for adjusting the oscillation frequency, the oscillation frequency is adjusted by adjusting at least one of the length and the characteristic impedance of the target line including at least one of the first transmission line 41 and the second transmission line 42.

This method of adjusting the oscillation frequency is executed, for example, when the oscillation device 1 is manufactured and before shipment from the factory. Thereby, it is possible to ship the oscillation device 1 in which the oscillation frequency is adjusted to the predetermined target frequency from the factory. However, the method for adjusting the oscillation frequency is not limited to when the oscillation device 1 is manufactured (before shipment from the factory), and may be executed by the user of the oscillation device 1 after shipment from the factory, for example.

By the way, in the present embodiment, the target lines are both the first transmission line 41 and the second transmission line 42 as described above. In the method for adjusting the oscillation frequency according to the present embodiment, the oscillation frequency is coarsely adjusted by adjusting one of the first transmission line 41 and the second transmission line 42, and the oscillation frequency is finely adjusted by adjusting the other. That is, as described above, in the present embodiment, the first transmission line 41 and the second transmission line 42 differ in the amount of change in oscillation frequency for the same amount of adjustment by the adjustment unit 5. Here, as an example, the first transmission line 41 is for coarse adjustment of the oscillation frequency, and the second transmission line 42 is fine adjustment of the oscillation frequency.

Hereinafter, a specific example of the method for adjusting the oscillation frequency according to the present embodiment will be described with reference to the flowchart shown in FIG. FIG. 5 illustrates an adjustment method for adjusting the oscillation frequency f1 of the oscillation device 1 so as to approach the target frequency f0.

In the method for adjusting the oscillation frequency, first, the oscillation frequency f1 of the current oscillation device 1 is measured (S1). Thereafter, the absolute value (| f1-f0 |) of the difference between the measured oscillation frequency f1 and the target frequency f0 is compared with the first threshold value Vth1 (S2). At this time, if the absolute value of the difference is less than the first threshold value Vth1 (S2: Yes), the absolute value of the difference is compared with the second threshold value Vth2 (S3). The second threshold value Vth2 is smaller than the first threshold value Vth1 (Vth2 <Vth1). At this time, if the absolute value of the difference is less than the second threshold value Vth2 (S3: Yes), a series of steps of the method for adjusting the oscillation frequency ends.

In step S2, if the absolute value of the difference is greater than or equal to the first threshold value Vth1 (S2: No), the oscillation frequency f1 is compared with the target frequency f0 (S4). If the oscillation frequency f1 is higher than the target frequency f0 (S4: Yes), the length L1 of the first transmission line 41 is extended (S6), and the process returns to step S1. If the length L1 of the first transmission line 41 is increased, the oscillation frequency f1 is roughly adjusted in a direction to decrease. On the other hand, if the oscillation frequency f1 is equal to or lower than the target frequency f0 (S4: No), the length L1 of the first transmission line 41 is shortened (S7), and the process returns to step S1. If the length L1 of the first transmission line 41 is shortened, the oscillation frequency f1 is coarsely adjusted to increase.

In step S3, if the absolute value of the difference is equal to or greater than the second threshold value Vth2 (S3: No), the oscillation frequency f1 is compared with the target frequency f0 (S8). If the oscillation frequency f1 is higher than the target frequency f0 (S8: Yes), the length L2 of the second transmission line 42 is extended (S10), and the process returns to step S1. If the length L2 of the second transmission line 42 is increased, the oscillation frequency f1 is finely adjusted to decrease. On the other hand, if the oscillation frequency f1 is equal to or lower than the target frequency f0 (S8: No), the length L2 of the second transmission line 42 is shortened (S9), and the process returns to step S1. If the length L2 of the second transmission line 42 is shortened, the oscillation frequency f1 is finely adjusted to increase.

In step S3, the above-described processing is repeated until the absolute value (| f1-f0 |) of the difference between the oscillation frequency f1 and the target frequency f0 is less than the second threshold value Vth2 (S3: Yes). Thus, the oscillation frequency f1 is adjusted until the error from the target frequency f0 is less than the second threshold value Vth2.

(3) Modification Example 1 is only one of various embodiments of the present disclosure. The first embodiment can be variously modified according to the design or the like as long as the object of the present disclosure can be achieved. The modifications described below can be applied in appropriate combinations.

The resonator 2 is not limited to a coaxial resonator but may be, for example, a TE (Transverse-Electric) mode dielectric resonator. When the resonator 2 is a TE mode dielectric resonator, the resonance frequency of the resonator 2 can be adjusted by changing the distance between the resonator 2 and the shield plate (a metal plate connected to the ground). Even in this case, if the resonance frequency of the resonator 2 is adjusted, the phase of the signal fed back by the feedback circuit 4 is likely to change, so adjustment of the oscillation frequency by the adjustment unit 5 is useful. Furthermore, the resonator 2 is not limited to a dielectric resonator, and may be, for example, an RC resonance circuit or an RLC resonance circuit.

The target line to be adjusted by the adjusting unit 5 is not limited to both the first transmission line 41 and the second transmission line 42, and may be at least one of the first transmission line 41 and the second transmission line 42. That's fine. That is, only the first transmission line 41 (or only the second transmission line 42) of the first transmission line 41 and the second transmission line 42 may be an adjustment target (target line) by the adjustment unit 5. Furthermore, the adjustment part 5 should just adjust at least one of length and characteristic impedance about an object track | line, and may adjust both length and characteristic impedance, or only characteristic impedance.

Further, in the first transmission line 41 and the second transmission line 42, the first transmission line 41 may have a smaller amount of change in the oscillation frequency for the same amount of adjustment by the adjustment unit 5. Alternatively, the first transmission line 41 and the second transmission line 42 may have the same amount of change in oscillation frequency for the same amount of adjustment by the adjustment unit 5.

In addition, each of the first transmission line 41 and the second transmission line 42 is not limited to a conductor formed on one surface of the circuit board 7, and is realized by, for example, a lead wire, an electric wire (insulation coated wire), a conductive plate, or the like. May be. Similarly, each of the third transmission line 43 and the fourth transmission line 44 may be realized by, for example, a lead wire, an electric wire, or a conductive plate.

Further, the amplifier circuit 3 may be realized by a plurality of electronic components.

In the present disclosure, in the comparison of two values such as the absolute value of the difference (| f1−f0 |) and the first threshold value Vth1, “greater than or equal to” means that the two values are equal and one of the two values is the other. Including both of cases exceeding However, the present invention is not limited to this, and “more than” here may be synonymous with “greater than” including only when one of the binary values exceeds the other. That is, whether or not the case where the two values are equal can be arbitrarily changed depending on the setting of the reference value or the like, so there is no technical difference between “greater than” or “greater than”. Similarly, “less than” may be synonymous with “below”.

(Embodiment 2)
As shown in FIGS. 6A to 6E, the oscillation device 1 according to the present embodiment is different from the oscillation device 1 according to the first embodiment in the configuration of the adjustment unit 5. Hereinafter, the same configurations as those of the first embodiment are denoted by common reference numerals, and the description thereof is omitted as appropriate.

6A to 6E schematically illustrate a configuration for adjusting at least one of the length and the characteristic impedance of the first transmission line 41 as the target line. Therefore, in FIGS. 6A to 6E, the illustration of the configuration (resonator 2 and the like) not directly related to the adjustment unit 5 is omitted as appropriate.

First, in the first configuration example shown in FIG. 6A, the adjustment unit 5 is realized by a notch 53 formed in the first transmission line 41. The notch 53 is formed by partially removing a part of the first transmission line 41 made of a conductor of the circuit board 7 by, for example, laser trimming or sandblasting. As a result, the line width of at least a part of the first transmission line 41 is reduced by the notch 53, and at least the characteristic impedance of the first transmission line 41 changes.

In the second configuration example shown in FIG. 6B, the adjustment unit 5 is realized by the protruding portion 54 formed in the first transmission line 41. The protruding portion 54 is a portion protruding in the short direction of the first transmission line 41 from the edge in the short direction of the first transmission line 41 made of the conductor of the circuit board 7. As a result, the line width of at least a part of the first transmission line 41 is increased by the protrusion 54, and at least the characteristic impedance of the first transmission line 41 changes.

In the third configuration example shown in FIG. 6C, the adjustment unit 5 is realized by the bypass unit 55 and the bypass unit 56 formed in the first transmission line 41. The detour portion 55 is a portion bent in a substantially U shape in plan view in a part of the first transmission line 41 made of the conductor of the circuit board 7. The bypass unit 56 is made of solder, copper foil, a lead plate, or the like, and linearly shorts both ends of the bypass unit 55. In this configuration, at least the length of the first transmission line 41 changes depending on the presence or absence of the bypass unit 56.

In the fourth configuration example shown in FIG. 6D, the adjustment unit 5 is realized by a plurality of electrode units 57 formed on the first transmission line 41. The plurality of electrode portions 57 are arranged along the longitudinal direction of the first transmission line 41, and each of the plurality of electrode portions 57 constitutes an electrode for connecting the first coupling capacitor C <b> 1 in the first transmission line 41. . In this configuration, the connection position of the first coupling capacitor C1 in the first transmission line 41 is set in the longitudinal direction of the first transmission line 41 by connecting the first coupling capacitor C1 to any of the plurality of electrode portions 57. Can be adjusted along (see arrow A1). As a result, at least the length of the first transmission line 41 changes.

In the fifth configuration example shown in FIG. 6E, the adjustment unit 5 is realized by the shield plate 58 disposed so as to face the first transmission line 41. The shield plate 58 is electrically connected to the ground. In this configuration, by changing the distance between the first transmission line 41 and the shield plate 58 (see arrow A2), at least the characteristic impedance of the first transmission line 41 changes.

6A to 6E described above is merely an example, and for example, the first to fifth configuration examples may be appropriately combined. Further, the oscillation device 1 may further employ the adjusting unit 5 having another configuration.

The configuration (including modifications) described in the second embodiment can be used in appropriate combination with the various configurations (including modifications) described in the first embodiment.

(Summary)
As described above, the oscillation device (1) according to the first aspect includes the amplifier circuit (3) and the feedback circuit (4). The amplifier circuit (3) amplifies the signal input to the input terminal (31) and outputs it from the output terminal (32). The feedback circuit (4) is electrically connected between the output terminal (32) and the input terminal (31). The feedback circuit (4) includes a resonator (2), a first transmission line (41), and a second transmission line (42). The first transmission line (41) is electrically connected between the output terminal (32) and the resonator (2). The second transmission line (42) is electrically connected between the input terminal (31) and the resonator (2). The oscillation device (1) further includes an adjustment unit (5). The adjustment unit (5) adjusts at least one of the length and the characteristic impedance of the target line including at least one of the first transmission line (41) and the second transmission line (42).

According to this aspect, at least one of the length of the target line and the characteristic impedance of the feedback circuit (4) can be adjusted by the adjustment unit (5). Since the characteristic of the feedback circuit (4) is changed by adjusting the length or characteristic impedance of the target line, as a result, the oscillation frequency can be adjusted. Moreover, compared with the case where the resonance frequency of the resonator (2) is adjusted in order to adjust the oscillation frequency, when the length or characteristic impedance of the target line is adjusted, feedback is performed by the feedback circuit (4). Changes in signal phase are unlikely to occur. Therefore, according to the oscillation device (1), it is difficult to adjust the phase when adjusting the oscillation frequency, and as a result, it is easy to reduce the difficulty of the adjustment operation of the oscillation frequency.

In the oscillation device (1) according to the second aspect, in the first aspect, the feedback circuit (4) positively feeds back a part of the output signal output from the output terminal (32) to the input terminal (31). It is a positive feedback circuit.

According to this aspect, it is possible to reduce the circuit scale as compared with the configuration using negative resistance.

In the oscillation device (1) according to the third aspect, in the first or second aspect, the target lines are both the first transmission line (41) and the second transmission line (42). The first transmission line (41) and the second transmission line (42) differ in the amount of change in oscillation frequency for the same amount of adjustment by the adjustment unit (5).

According to this aspect, it is possible to coarsely adjust the oscillation frequency on one side of the first transmission line (41) and the second transmission line (42) and finely adjust the oscillation frequency on the other side, and the adjustment work of the oscillation frequency It becomes easy.

In the oscillation device (1) according to the fourth aspect, in any one of the first to third aspects, the feedback circuit (4) includes a first coupling capacitor (C1) and a second coupling capacitor (C2). Also have. The first coupling capacitor (C1) is electrically connected between the output terminal (32) and the first transmission line (41). The second coupling capacitor (C2) is electrically connected between the input terminal (31) and the second transmission line (42). The capacity of the first coupling capacitor (C1) is smaller than the capacity of the second coupling capacitor (C2).

According to this aspect, the change in the output impedance of the amplifier circuit (3) due to the connection of the feedback circuit (4) to the output terminal (32) of the amplifier circuit (3) can be suppressed relatively small. Further, impedance matching between the feedback circuit (4) and the input terminal (31) can be achieved.

The method for adjusting the oscillation frequency according to the fifth aspect is a method for adjusting the oscillation frequency of the oscillation device (1) including the amplifier circuit (3) and the feedback circuit (4). The amplifier circuit (3) amplifies the signal input to the input terminal (31) and outputs it from the output terminal (32). The feedback circuit (4) is electrically connected between the output terminal (32) and the input terminal (31). Here, the feedback circuit (4) includes a resonator (2), a first transmission line (41), and a second transmission line (42). The first transmission line (41) is electrically connected between the output terminal (32) and the resonator (2). The second transmission line (42) is electrically connected between the input terminal (31) and the resonator (2). In this method of adjusting the oscillation frequency, the oscillation frequency is adjusted by adjusting at least one of the length and the characteristic impedance of the target line including at least one of the first transmission line (41) and the second transmission line (41). .

According to this aspect, at least one of the length of the target line and the characteristic impedance of the feedback circuit (4) can be adjusted. Since the characteristic of the feedback circuit (4) is changed by adjusting the length or characteristic impedance of the target line, as a result, the oscillation frequency can be adjusted. Moreover, compared with the case where the resonance frequency of the resonator (2) is adjusted in order to adjust the oscillation frequency, when the length or characteristic impedance of the target line is adjusted, feedback is performed by the feedback circuit (4). Changes in signal phase are unlikely to occur. Therefore, according to the adjustment method of the oscillation frequency described above, it is difficult to adjust the phase when adjusting the oscillation frequency, and as a result, the difficulty of adjusting the oscillation frequency can be easily reduced.

In the oscillation frequency adjustment method according to the sixth aspect, in the fifth aspect, the target lines are both the first transmission line (41) and the second transmission line (42). In this method of adjusting the oscillation frequency, the oscillation frequency is coarsely adjusted by adjusting one of the first transmission line (41) and the second transmission line (42), and the oscillation frequency is finely adjusted by adjusting the other.

According to this aspect, it is possible to coarsely adjust the oscillation frequency on one side of the first transmission line (41) and the second transmission line (42) and finely adjust the oscillation frequency on the other side, and the adjustment work of the oscillation frequency can be performed. It becomes easy.

Not limited to the above-described aspects, various aspects (including modifications) of the oscillation device (1) according to the first and second embodiments can be embodied by a method for adjusting the oscillation frequency.

The configurations according to the second to fourth aspects are not essential to the oscillation device (1) and can be omitted as appropriate. The configuration according to the sixth aspect is not a configuration essential to the method for adjusting the oscillation frequency, and can be omitted as appropriate.

DESCRIPTION OF SYMBOLS 1 Oscillator 2 Resonator 3 Amplification circuit 4 Feedback circuit 5 Adjustment part 31 Input terminal 32 Output terminal 41 1st transmission line 42 2nd transmission line C1 1st coupling capacitor C2 2nd coupling capacitor

Claims (6)

An amplifier circuit that amplifies the signal input to the input terminal and outputs the amplified signal from the output terminal;
A feedback circuit electrically connected between the output terminal and the input terminal,
The feedback circuit is
A resonator,
A first transmission line electrically connected between the output terminal and the resonator;
A second transmission line electrically connected between the input terminal and the resonator,
An adjustment unit that adjusts at least one of a length and a characteristic impedance of a target line including at least one of the first transmission line and the second transmission line;
Oscillator. The feedback circuit is a positive feedback circuit that positively feeds back a part of an output signal output from the output terminal to the input terminal.
The oscillation device according to claim 1. The target line is both the first transmission line and the second transmission line,
In the first transmission line and the second transmission line, the amount of change in oscillation frequency for the same amount of adjustment by the adjustment unit is different.
The oscillation device according to claim 1 or 2. The feedback circuit is
A first coupling capacitor electrically connected between the output terminal and the first transmission line;
A second coupling capacitor electrically connected between the input terminal and the second transmission line;
A capacity of the first coupling capacitor is smaller than a capacity of the second coupling capacitor;
The oscillation device according to any one of claims 1 to 3. An amplifier circuit that amplifies the signal input to the input terminal and outputs it from the output terminal;
A feedback circuit electrically connected between the output terminal and the input terminal,
The feedback circuit is
A resonator,
A first transmission line electrically connected between the output terminal and the resonator;
A second transmission line electrically connected between the input terminal and the resonator, and a method for adjusting an oscillation frequency of an oscillation device comprising:
Adjusting the oscillation frequency by adjusting at least one of length and characteristic impedance for a target line consisting of at least one of the first transmission line and the second transmission line;
How to adjust the oscillation frequency. The target line is both the first transmission line and the second transmission line,
The method for adjusting an oscillation frequency according to claim 5, wherein the oscillation frequency is coarsely adjusted by adjusting one of the first transmission line and the second transmission line, and the oscillation frequency is finely adjusted by adjusting the other.

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