JP3337999B2 - Rotary attenuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary attenuator for finely adjusting a signal level.

[0002]

2. Description of the Related Art When adjusting a signal level, an attenuator comprising a resistance element is generally used. However, it is difficult to prepare an attenuator having a different attenuation amount for each adjustment. An attenuator capable of varying the amount of attenuation is used. As an attenuator capable of varying the amount of attenuation, a rotary attenuator capable of selecting an amount of attenuation according to the rotation angle of a shaft is known (Japanese Patent Laid-Open No. 57-7960).
No. 2, JP-A-7-312305). FIGS. 9 and 10 show an example of a conventional configuration of such a rotary attenuator.

FIG. 9A is a perspective view of a conventional rotary attenuator. A conventional rotary attenuator 110 includes a metal case 123 and a case 123.
And an input / output plug seat 124 having an input terminal and an output terminal, and a step mechanism 121 for rotating the rotating shaft 122 by a predetermined angle. Case 1
23, two disk-shaped substrates 12 shown in FIG.
5 and a resistor 1 provided between the two substrates 125.
27 are stored. This resistor 127 and two substrates 1
An attenuation circuit is constituted by the chip resistor 128 provided at the contact 25, and the amount of attenuation of this attenuation circuit
The attenuation amount is different for every 29. These two substrates 1
25, a plurality of contacts 129 are arranged on the circumference, and two brushes 126 are in contact with the contacts 129, respectively.

Here, when the rotating shaft 122 is rotated, the contact 129 that contacts the brush 126 is switched, and the amount of attenuation corresponding to the contact 129 selected according to the rotation angle can be obtained. The signal input from the input terminal of the input / output plug seat 124 is applied to the chip resistor 1 provided on the substrate 125 via the one brush 126 and the contact 129.
28, and the other contact 129
And the signal attenuated via the brush 126 is output from the output terminal of the input / output plug seat 124. In this case, the rotating shaft 1
Each time the 22 rotates, a signal attenuated by a different amount of attenuation is obtained from the output terminal.

[0005]

FIG. 10 shows an example of actual dimensions of such a conventional rotary attenuator.
(A). The rotary attenuator 110 shown in FIG. 10 has a configuration similar to that of the conventional rotary attenuator 110 shown in FIG. 9, and the length from the back of the case 123 to the tip of the rotary shaft 122 is about 66 mm. The height from the tip of the output plug seat 124 to the side surface of the case is about 43 mm. This is because the resistor 127 is provided between the two substrates 125, so that the internal volume of the case 123 needs to be increased, and the step mechanism 121 is provided outside the case 123. Things.

As described above, when the length is long and the height is high, a large installation volume is required, and there is a problem that the electronic device may not be able to be stored in a case of an electronic device that needs to be downsized. Further, an input / output plug seat 124 is provided on a side surface of the case 123.
Since a coaxial plug connected to the end of a coaxial cable is mounted on the H.24, there is a problem in that the height required for installation needs to be higher than that shown in FIG. Was. Therefore, an object of the present invention is to provide a small-sized rotary attenuator that can be mounted on an electronic device requiring a small size.

[0007]

In order to achieve the above object, a rotary attenuator according to the present invention comprises a plurality of resistive elements mounted on a front pattern surface and a back pattern surface, and has a mutual attenuation. Different attenuator unit circuits
A disk-shaped attenuator substrate in which a plurality of circuits are provided, and an input-side contact and an output-side contact provided for each of the attenuator unit circuits are arranged on a circumference having different diameters on one surface; A shaft for rotating the substrate, a click mechanism for rotating the substrate by a predetermined angle, the attenuator substrate, a case for housing the click mechanism, and the attenuator unit circuit selected according to the rotation angle of the shaft. An input terminal connected to the input contact and an output terminal connected to the output contact are provided on the back of the case.

According to the present invention, since a plurality of attenuation circuits having different attenuation amounts are mounted on one attenuator substrate, the volume for accommodating the attenuator substrate can be reduced. Further, since the click mechanism is also housed in the case, the overall length can be reduced. Thus, the rotary attenuator can be reduced in size. Further, since the input terminal and the output terminal are provided on the back surface of the case, the height required for mounting the electronic device on the electronic device can be reduced.

[0009]

FIG. 1 is an exploded perspective view showing the structure of a rotary attenuator according to an embodiment of the present invention.
In FIG. 1, a shaft 1 is a shaft for varying an amount of attenuation according to a rotation angle, and has a D-shaped cut at one end, the cross-section of which is cut into a D-shape. An H-cut is formed on the rear side so that the cross section of the opposite side surface is cut into an H shape, and the rear end has a small diameter. The reason why the D cut is performed is that the knob 24 attached to the tip of the shaft 1 is securely attached to the shaft 1 by the set screw 25, and the shaft 1 can be rotated without slipping. The reason is that the index plate 3 and the attenuator substrate (hereinafter referred to as “ATT substrate”) 26 described later are reliably rotated together with the shaft 1. The shaft 1 is inserted into an insertion hole formed in the center of the front panel 2,
A click mechanism is provided inside the front panel 2.

Although the details of the click mechanism will be described later, steel ball storage holes 3 formed at two opposing locations on the side surface of the protrusion formed inside the front panel 2.
The steel balls 10 are housed in the respective 1s. Then
The ball pressing spring 9 is fixed to the side surface of the protruding portion of the front panel 2 with a screw 19 so as to urge the steel ball 10. The H-cut portion of the shaft 1 is sandwiched by two leaf springs 6 and an index plate 3 having an H-shaped through hole formed therein is inserted therethrough.
It is made to rotate with. When the index plate 3 is inserted through the shaft 1, the steel plate 10 is brought into contact with the outer periphery of the index plate 3. In this case, a plurality of semi-cylindrical projections are formed on the outer peripheral edge of the index plate 3, and the steel balls 10 are urged in the direction of the shaft 1 by the ball pressing springs 9. It will be able to be located only in between. Therefore, when the shaft 1 is rotated, the steel ball 10 is engaged when the steel ball 10 has climbed over the semi-cylindrical projection formed on the index plate 3.
When rotated by an angle corresponding to the angle between the Kamaboko-shaped projections, a click feeling is obtained, and the rotation of the shaft 1 is stopped.

Following the leaf spring 6 for holding the index plate 3, the shaft 1 has a ring-shaped holder spacer 5,
Next, the earth spring 7 is inserted. Holder spacer 5
Has the effect of disposing the ATT substrate 26 at a predetermined position, and the legs of the substrate holder 4 described later are pressed into the through holes of the holder spacer 5 so that the holder spacer 5 and the A
The TT substrate 26 and the substrate holder 4 are integrated.
The corrugated earth spring 7 is connected to the front panel 2.
Is sandwiched between the rear surface of the protrusion of
The ground pattern formed on the outer periphery of the surface pattern surface of the substrate 26 is grounded via the front panel 2.

Following the earth spring 7, the ATT substrate 26 is inserted through the shaft 1, and then the substrate holder 4 is inserted through the shaft 1. Although details of the ATT substrate 26 will be described later, a plurality of chip resistors 27 are mounted on the front pattern surface and the back pattern surface, and a plurality of attenuation circuits having different attenuation amounts are formed. Further, pins 23 for positioning the ATT board 26 with respect to the shaft 1 are set at predetermined positions on the ATT board 26. The substrate holder 4 has two opposing legs as shown in the figure.
Are substantially H-shaped insertion holes. When the substrate holder 4 is inserted through the shaft 1, its feet follow the H-cut portion of the shaft 1, and
It is inserted into the through hole of the TT substrate 26. Next, the pins 23 planted on the back pattern surface of the ATT substrate 26 are engaged with the engagement grooves formed in the flange portion of the substrate holder 4. Thereby, the ATT substrate 26 can be positioned with respect to the position (rotation angle) on the circumference of the shaft 1.

After the substrate holder 4, a ring-shaped flat washer 11 is inserted into the shaft 1. This flat washer 11 is A
The TT substrate 26 functions as a spacer for separating the TT substrate 26 from the bottom surface of the storage portion of the rear case 15 by a predetermined distance. A cylindrical case is formed in a rear case 15 which is integrated with the front panel 2 to constitute a case of a rotary attenuator, and the bottom surface thereof is closed. Two brushes 8 are fixed to the bottom surface of the storage unit via brush spacers 13, and a bearing portion in which the bearing 12 is fitted is provided at the center of the bottom surface. A small-diameter portion formed at the rear end of the shaft 1 is rotatably fitted into the bearing. An output side plug and an input side plug are provided on the rear surface of the rear case 15. The plug includes an insulator 18 inserted into a shell 17, a center contact 16 disposed substantially at the center of the insulator 18, and a rear case 1.
5 comprises a hexagonal nut 20 for locking the shell 17 screwed onto the back surface.

The tips of the center contacts 16 in the output side plug and the input side plug are electrically connected to each of the two brushes 8 by soldering or the like. An insulating brush spacer 13 is provided between the two brushes 8 so that the two brushes 8 do not contact the bottom surface of the storage portion of the rear case 15. Each of the two brushes 8 is an ATT substrate 2
6 are arranged at positions where they come into contact with the input side contact and the output side contact provided on the back pattern surface, respectively. The rotary attenuator having such a configuration has a click number of, for example, 10 steps, and each time the shaft 1 rotates, for example, 1 d
The attenuation can be switched to any one of B to 10 dB. However, in the configuration shown in FIG.
Since the number of clicks can be set to two, the number of clicks can be set to ten, so that the pins 22 are implanted on the index plate 3 and the stoppers 21 engaged with the pins 22 are protruded from the front panel 2. Provided inside the part,
The rotation angle of the shaft 1 is regulated.

In the rotary attenuator of the present invention thus constructed, flat head screws 28 are inserted into mounting holes formed at four corners of the front panel 2 and screwed to the rear case 15 for assembly. Figure 2 shows the overall configuration
(A), (b) and (c) are shown. 2A is a front view of the rotary attenuator 100 of the present invention, FIG. 2B is a side view thereof, and FIG. 2C is a rear view thereof.
As shown in these figures, the rotary attenuator 100 of the present invention has a substantially rectangular parallelepiped shape.
The cut shaft 1 is projected, and an output-side plug 41 and an input-side plug 42 are projected from the back surface. The length of the rotary attenuator 100 of the present invention is approximately 45 m from the tip of the shaft 1 to the tips of the output-side plug 41 and the input-side plug 42 protruding from the rear surface of the rear case 15.
m. Also, the rotary attenuator 1 of the present invention
00 is attached by screwing a screw into which the electronic device case is inserted into two mounting screw holes 29 provided in the front panel 2, so that the length actually occupied when the electronic device case is mounted in the electronic device case is: The length from the front surface of the front panel 2 is about 27 mm. Further, the height of the rotary attenuator 100 of the present invention is about 26 mm.
It can be seen that the size is much smaller than the conventional rotary attenuator.

FIG. 3 is a sectional view showing the structure of the rotary attenuator 100 of the present invention when cut along the line AA 'shown in FIG. 2 (c). As shown in FIG. 3, the shaft 1 is inserted through the front panel 2, and a small diameter portion at the rear end is inserted into a bearing 12 inserted into an insertion hole on the bottom surface of the rear case 15 and is rotatably supported. . The leaf spring 6, index plate 3, leaf spring 6, holder spacer 5, ground spring 7, ATT board 26, board holder 4, and flat washer 11 are inserted through the shaft 1 in this order. In this case, the broken line indicates that the foot of the substrate holder 4 is located in the holder spacer 5 beyond the ATT substrate 26. Further, the outer peripheral portion of the front pattern surface of the ATT substrate 26 is electrically connected to the rear surface of the protruding portion of the front panel 2 via the corrugated earth spring 7. Further, one of the contacts 14 provided on the back pattern surface of the ATT substrate 26 is in contact with the brush 8. The same number of the contacts 14 are arranged on the circumference of two circles having different diameters on the back pattern surface of the ATT substrate 26.

Next, the click mechanism of the rotary attenuator according to the present invention will be described with reference to FIG.
However, FIG. 4A is a half sectional view showing a plan view of a configuration in which the shaft 1 is inserted through the front panel 2 in the rotary attenuator of the present invention, and FIG. FIG. 4A is a rear view taken along line AA of FIG. 4A when the index plate 3 is removed, and FIG. 4C is a rear view taken along line AA of FIG. As shown in FIG. 4A, a leaf spring 6 and an index plate 3 are inserted through the shaft 1 inserted through the front panel 2. Then, the index plate 3 is fixed to the shaft 1 by caulking a step formed in the H-cut portion of the shaft 1. At this time, the leaf spring 6
Is also fixed between the index plate 3 and the front panel 2.

The outer peripheral edge of the index plate 3 is shown in FIG.
As shown in (c), a plurality of projections are formed. Two steel balls 10 are located opposite to the valley between the kamaboko-shaped projections and the valley-shaped protrusions.
One steel ball 10 has a steel ball storage hole 3 formed to face the side surface of the protrusion of front panel 2.
1 (see FIG. 4B). Then, while being opposed on the side surface of the protruding portion of the front panel 2,
The steel ball 10 is urged in the direction of the shaft 1 by a ball pressing spring 9 fixed by screws 19 so as to cover the steel ball storage hole 31. This allows
When the shaft 1 is rotated, the index plate 3 is also rotated, but the steel ball 10 collides with the valley between the projections during the rotation while riding over the kamaboko-shaped projections, so that a click feeling can be obtained. Then, the rotation of the shaft 1 is regulated so as to stop in the valley. That is, the shaft 1 comes to a stop every time one of the kamaboko-shaped protrusions is passed, and a predetermined amount of attenuation can be selected at a position for each predetermined rotation angle.

As shown in FIG. 4B, two stoppers 21 are provided on the front surface inside the projection of the front panel 2.
a, 21b are attached. When the pin 22 planted on the index plate 3 collides with the stoppers 21a and 21b when the shaft 1 rotates, the shaft 1
Is restricted from rotating further. That is, by providing the stopper 21a and the stopper 21b, the shaft 1 can rotate by an angle therebetween. In the illustrated example, the positions of the two stoppers 21a and 21b are determined so that ten clicks can be obtained. The stopper 21b is provided at a position rotated clockwise according to the number of clicks to be obtained.

Next, FIG. 5B shows the details of the surface pattern surface formed on the surface of the ATT substrate 26. As shown in this figure, a predetermined print pattern is formed on the surface pattern surface of the disk-shaped ATT substrate 26, and two chip resistors Ra and Rb are soldered to the print pattern per unit attenuation circuit. As shown in FIG. 5A, the unit attenuation circuit is, for example, a π-type resistance attenuation circuit, and a resistance Ra connected between the input contact 14a and the ground and a resistance Ra connected between the output contact 14b and the ground. And a resistor R connected between the input side contact 14a and the output side contact 14b.
s. The amount of attenuation of the unit attenuation circuit is determined by the resistance values of the three resistors Ra, Rb, Rs of the unit attenuation circuit. In FIG. 5B, the chip resistors Ra,
The number attached to Rb indicates the attenuation when the attenuation of the rotary attenuator according to the present invention is 1 dB to 10 dB. For example, a resistor R with "6"
a and Rb are chip resistors constituting a unit attenuation circuit having an attenuation amount of 6 dB.

Then, as shown in FIG.
Are mounted on the back pattern surface, and the resistors Ra and Rb are mounted on the front pattern surface. Then, a through-hole portion A and a through-hole portion B that communicate from the front pattern surface to the back pattern surface are formed in the ATT substrate 26. ATT board 2
6, a pin 23 is implanted on the back pattern surface side at a predetermined position.
Is engaged with an engagement groove formed in the flange portion of the second member.

FIG. 6 shows the details of the back pattern surface formed on the back surface of the ATT substrate 26. As shown in this figure, a predetermined printed pattern is formed on the back pattern surface of the disk-shaped ATT substrate 26, and a resistor Rs in a unit attenuation circuit is soldered to this printed pattern. The unit attenuation circuit is the circuit shown in FIG.
The unit attenuation circuit is formed by the action of the through hole B. The number given to the chip resistor Rs indicates the attenuation when the attenuation of the rotary attenuator according to the present invention is 1 dB to 10 dB.
For example, the resistor Rs to which "5" is added is a chip resistor constituting a unit attenuation circuit having an attenuation amount of 5 dB. On the back pattern surface, an input contact 14a and an output contact 14b are provided for each unit attenuation circuit. The input contacts 14a of each unit attenuation circuit are arranged on the circumference, and the output contacts 14b of each unit attenuation circuit are similarly arranged on the circumference of a larger diameter. That is, the input side contacts 14a are arranged inside, and the output side contacts 14b are arranged outside.
Are arranged.

A configuration for guiding a signal input to the ATT board 26 configured as described above and a configuration for outputting an output signal attenuated by a predetermined amount will be described with reference to FIG. FIG.
FIG. 7A shows the relationship between the ATT board 26, the input side brush 8a and the output side brush 8b, and FIG.
Input side contact 1 provided on the back pattern surface of TT board 26
4A and 4B show the relationship between the output side contact 14b. FIG.
In the example shown in FIG. 9A, a case where the attenuation of 5 dB is selected is shown, and the signal input through the center contact 16a constituting the input plug 42 is indicated by the hatching with which the brush 8a is in contact. Is input to the inner input side contact 14a indicated by. As shown in FIG. 5A, one end of a 5 dB attenuation resistor Rs and a resistor Ra are connected to the input side contact 14a. As shown in FIG. 5A, the other end of the 5 dB attenuation resistor Rs and the resistor Rb are connected to the output contact 14b indicated by hatching with which the output brush 8b is in contact. As a result, a signal attenuated by 5 dB by the resistors Ra, Rs, and Rb is output from the brush 8b and output to the center contact 16b constituting the output-side plug 41.

The input-side contacts 14a and the output-side contacts 14b, which are respectively arranged on the circumferences having different diameters, are provided at predetermined angles, and in the example shown in FIG. ing. In this case, the kamaboko-shaped projections formed on the outer peripheral edge of the index plate 3 are also about 30 mm.
It is provided every °. Thereby, the shaft 1 is about 30 °
7 (a) when the steel ball 10 is engaged between the semi-cylindrical projections of the index plate 3.
As shown in the figure, the brushes 8a and 8b
14b. Further, when the rotary attenuator according to the present invention is attached to an electronic device, the electronic device is instructed on the currently selected attenuation. This instruction is set at the tip of the shaft 1 with a set screw 2
The position of the knob 24 attached to the ATT substrate 26 is determined by the engagement groove formed in the flange of the substrate holder 4. It is performed by combining. In other words, the pin 23 is implanted at a position where the knob 24 indicates the selected correct attenuation.

Next, a modification of the rotary attenuator of the present invention will be described with reference to FIG. In this modification, the output-side plug and the input-side plug provided on the rear surface of the rear case 15 are of a recessed type and are provided without protruding from the rear surface thereof, so that the rotary attenuator is further downsized. ing. FIG. 8A shows the rear case 15.
3 shows the configuration of an output-side plug or an input-side plug provided on the back surface of the rear case 15. A hole 15b formed with a rear case screw portion 15a is formed in the rear case 15, and this hole 15b is formed. A hole having a small diameter is formed so as to reach the inside of the rear case 15 at substantially the same center. An insulator 48 to which the center contact 46 is integrally fixed is press-fitted and fitted into the small diameter hole. A brush 8 is fixed to one end of the center contact 46 located in the rear case 15, and the brush 8 is brought into contact with the input contact 14a or the output contact 14b as described above. As described above, the output-side plug or the input-side plug includes a hole 15b in which the rear case screw portion 15a formed in the rear case 15 is formed, and a hole 15b formed in the rear case 15.
And a center contact 46 protruding inward. The center contact 46 is insulated from the rear case 15 by an insulator 48.

FIG. 8 shows an example of a coaxial connector which is screwed to such an embedded type output side plug or input side plug.
(B). The coaxial connector 50 shown in this figure includes a metal shell 51 having a substantially cylindrical shape, a tightening nut 52 fixed to the outer peripheral surface of the shell 51 so as to rotate idly,
It comprises a central contact 55 arranged substantially along the central axis of the shell 51 and an insulator 53 for holding the central contact 55 substantially along the central axis of the shell 51. The fastening nut 52 includes a hexagonal flange portion 52a and a fastening screw portion 52b having a screw formed on an outer peripheral surface. Then, the coaxial cable 56 with the core wire exposed
With the spacer 54 inserted from the front end of the shell 51
The coaxial cable 56 is fitted into the shell 51 from the rear. As a result, the core wire of the coaxial cable 56 and the center contact of the coaxial connector 50 are connected, and the shielded wire folded over the coating of the coaxial cable 56 is connected to the shell 51.

Then, the coaxial connector 50 to which the coaxial cable 56 is attached as shown in FIG. 8B is positioned at the embedded type input plug or output plug shown in FIG. The flange 52a of the attachment nut 52 is rotated to screw the fastening screw 52b to the rear case screw 15a. Thus, as shown in FIG. 8C, the center contact 46 of the input side plug or the output side plug is inserted into the center contact 55 of the coaxial connector 50 and connected. Further, the shield wire of the coaxial cable 56 is connected to the rear case 15 via the shell 51 and the fastening nut 52. As described above, if the input side plug or the output side plug is of the embedded type shown in FIG. 8A, a small coaxial connector 50 as shown in FIG. 8B can be used. Even when the coaxial connector 50 is attached as shown in c), the total length of the rotary attenuator can be shortened.

In the rotary attenuator of the present invention described above, the attenuation is 1 dB to 10 dB and the number of clicks is 10 steps. However, the present invention is not limited to this, and an arbitrary attenuation may be switched. And also
The number of clicks can also be an arbitrary number. However, in the case of the same configuration as described above, the number of clicks is up to 12 steps. The dimensions of the rotary attenuator according to the present invention described above are merely examples, and the present invention is not limited to these dimensions. A feature of the present invention is that the entire attenuator is reduced in size by incorporating an attenuation circuit on the front and back pattern surfaces of one disk-shaped ATT substrate 26. Further, the click mechanism is downsized and accommodated in the case of the attenuator, thereby achieving further downsizing. Further, by making the input-side plug and the output-side plug into the embedded type, it is possible to further reduce the size.

[0029]

As described above, in the rotary attenuator of the present invention, since a plurality of attenuation circuits having different attenuation amounts are mounted on one attenuator substrate, the volume for accommodating the attenuator substrate can be reduced. . Further, since the click mechanism is also housed in the case, the overall length can be reduced. Thus, the rotary attenuator can be reduced in size. Furthermore, since the input terminal and the output terminal are provided on the back of the case,
The height required for mounting on an electronic device can be reduced. Therefore, it is possible to provide a rotary attenuator suitable for adjusting the level of the transmission line and finely adjusting the attenuation.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing the configuration of a rotary attenuator according to an embodiment of the present invention.

FIG. 2 is a diagram showing an entire configuration of a rotary attenuator of the present invention.

FIG. 3 shows a rotary attenuator of the present invention in FIG.
It is sectional drawing which shows the structure when cut | disconnected by the AA 'line shown to (c).

FIG. 4 is a view for explaining a click mechanism of the rotary attenuator of the present invention.

FIG. 5 is a diagram showing a unit attenuation circuit in the rotary attenuator of the present invention and a diagram showing details of a surface pattern surface formed on the surface of the ATT substrate.

FIG. 6 shows A in the rotary attenuator of the present invention.
FIG. 4 is a diagram showing details of a back pattern surface formed on the back surface of the TT substrate.

FIG. 7 shows A in the rotary attenuator of the present invention.
FIG. 3 is a diagram for describing a configuration for guiding a signal input to a TT substrate and a configuration for outputting an output signal attenuated by a predetermined attenuation amount.

FIG. 8 is a diagram showing a configuration of a modification of the rotary attenuator of the present invention.

FIG. 9 is a diagram showing an example of a conventional configuration of a rotary attenuator.

FIG. 10 is a view showing an example of dimensions in a conventional configuration of a rotary attenuator.

[Explanation of symbols]

 Reference Signs List 1 shaft 2 front panel 3 index plate 4 substrate holder 5 holder spacer 6 leaf spring 7 ground spring 8, 8a, 8b brush 9 ball pressing spring 10 steel ball 11 flat washer 12 bearing 13 brush spacer 14, 14a, 14b contact 15 rear case 15a rear Case screw part 15b Hole part 16, 16a, 16b, 46, 55 Center contact 17, 51 Shell 18, 53 Insulator 19 Screw 20 Hex nut 21, 21, a, 21b Stopper 22, 23 Pin 24 Knob 25 Lock screw 26 ATT board 27 Chip resistor 28 Countersunk screw 29 Mounting screw hole 31 Steel ball storage hole 41 Output side plug 42 Input side plug 50 Coaxial connector 52 Tightening nut 52a Flange 52b Tightening screw 54 Spacer 56 Coaxial cable 1 0,110 rotary attenuator 121 step mechanism unit 122 rotates shaft 123 Case 124 output contact plug seat 125 substrate 126 brush 127 resistor 128 chip resistor 129 contacts

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-312305 (JP, A) JP-A-5-87903 (JP, A) Japanese Utility Model Showa 49-40335 (JP, U) Japanese Utility Model Showa 25- 10176 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01C 1/00-13/00

Claims (1)

(57) [Claims] 1. A plurality of attenuator unit circuits each having a different amount of attenuation and configured by mounting a plurality of resistive elements on a front pattern surface and a back pattern surface are provided. An input-side contact and an output-side contact are arranged on a circle having different diameters on one surface, and a disk-shaped attenuator substrate is rotated by a predetermined angle. A click mechanism, a case accommodating the attenuator substrate and the click mechanism, an input terminal connected to the input contact in the attenuator unit circuit selected according to a rotation angle of the shaft, and the output. A rotary attenuator, wherein an output terminal connected to a side contact is provided on a back surface of the case.