JPS6233367Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a switched variable resistance attenuator in which a desired amount of attenuation is obtained by switching and connecting a plurality of unbalanced attenuation circuits.

A conventional variable attenuator of this type has attenuation circuits 11, 12, 13, and 14 connected in cascade, each including resistance elements R ₁ , R ₂ , and R ₃ connected in a T-shape, as shown in FIG.
Both ends of the cascade connection are terminals 15 and 16, and the common terminal of each attenuation circuit 11, 12, 13, and 14 is connected to an external common terminal 17 through switches S ₁ , S ₂ , S ₃ , and S ₄ respectively. and each attenuation circuit 11,
Switches S ₅ , S ₆ , S ₇ and S ₈ are connected between both ends of each series element 12, 13 and 14, respectively. Switches S ₁ to _{S 4} are mutually opposite to switches S ₅ to _{S 8} , respectively.
ON/OFF controlled.

In Figure 1, switches S ₁ , S ₃ , S ₆ , and S ₈ are OFF,
S ₂ , S ₄ , S ₅ , and S ₇ are turned on, and the attenuation circuits 12 and 1
4 is inserted between terminals 15 and 16. By controlling switches S ₁ to S ₈ in this way, terminal 1
The amount of attenuation between terminals 15 and 16 is set to a desired value by controlling an attenuation circuit inserted between terminals 5 and 16. For example, when the attenuation amounts of the attenuation circuits 11, 12, 13, and 14 are 1, 2, 4, and 8 dB, the attenuation amounts can be set to any of 16 different attenuation amounts from 0 to 15 dB by selecting and controlling the switch.

In order to obtain the desired amount of attenuation in this way, the switches S ₁ S ₅ , S ₂ S ₆ , S ₃ S ₇ , S ₄ , S ₈ are each controlled by one actuator, that is, the actuators are connected to the attenuation circuit. The number of controls required is the same as the number of controls, and it is necessary to set and control four controls. Having such a large number of controls makes operation cumbersome and time-consuming, and the structure is complicated and large due to the large number of parts. It takes shape.

This invention provides a switched variable resistance attenuator that can be constructed with a small number of operators, and therefore is easy to operate, has a small number of parts, is simple in structure, and can be constructed in a small size.

FIG. 2 shows an embodiment of this invention, in which unbalanced attenuation circuits 11 to 14 are connected in cascade, and both ends thereof are connected to terminals 15 and 16. The unbalanced attenuation circuits 11 to 14 are, for example, resistive elements as shown in the figure.
R ₁ , R ₂ , and R ₃ are connected in a T-shape, and others are connected in a π-shape, each with two input/output terminals and an internal common terminal, that is, 1a.
1b1c, 2a2b2c, 3a3b3c, 4a4
They each have b4c. At least two adjacent attenuation circuits 11, 12, 13, 14 are formed as a set on a common insulating substrate 18, 19, respectively.

The input/output terminals 1a and 1b of the attenuation circuit 11 are connected to the fixed contact pair 21a and 21b, and the internal common terminal 1
c, the external common terminal 17 is a fixed contact pair 22a, 22
b, respectively. Similarly, each attenuation circuit 1
2, 13, 14, two fixed contact pairs 23 each
a, 23b, 24a24b, 25a25b, 26
a26b, 27a27b, and 28a28b are respectively provided, and each input/output terminal and common terminal are connected to the corresponding one.

Fixed contact pair 21 of attenuation circuits 11 and 12 forming a pair
a21b, 22a22b, 23a23b, 24a
Contactors 5a, 5b, 5c, and 5d are provided for short-circuiting 24b and releasing the short-circuit, respectively. In this embodiment, these contacts 5a to 5
d are held by a common rotor (not shown), and the short-circuiting of the fixed contact pair by these contacts is not limited to a specific one, but is changed according to the setting of the attenuation amount. Four contacts 6a to 6d are provided for short-circuit control of the fixed contact pair of the attenuation circuits 13 and 14.

In order to perform switching contact between the contactor and the fixed contact pair, the resistive elements R ₁ to R ₃ and the fixed contact pair are arranged in a pattern, as shown in FIG. 3, for example. That is, an attenuation circuit 11,
12, 13, and 14 are formed in an array. circuit 11,
The fixed contact pair 21a, 21 is centered around the center 31 of 12.
b and fixed contact pairs 22a, 22b are arranged 90 degrees apart from each other, fixed contact pairs 23a, 23b and fixed contact pairs 24a, 24b are arranged 180 degrees apart, and these four fixed contact pairs are the same. is located on the double circle of Similarly, the fixed contact pair 25a is connected to the center 32.
25b and 26a, 26b are shifted by 90 degrees, and fixed contact pairs 27a, 27b and 28a, 28b are shifted by 180 degrees.
It is shifted by ゜. Resistance elements R ₁ , R ₂ , and R ₃ of each attenuation circuit are patterned to form the circuit shown in FIG. 2 for the fixed contact pairs arranged in this way.

As shown in FIG. 4, the contacts 5a to 5d are semicircular arc-shaped contacts 5a and 5b with both ends of the conductor piece 33 separated by 180 degrees, and both ends of the conductor piece 33 are separated along the arc. It is divided into two parts. In addition, contacts 5c and 5d are provided at each part of the conductor piece 34, which is connected by shifting the quarter arc by 90 degrees, and the ends thereof are arranged by shifting the quarter arc by 90 degrees.
divided. These contacts 5a to 5d are located on the same circle, the outer part of each division matches the circle passing through the fixed contacts 21a, 22b, 23a, 24a, and the inner part matches the circle passing through the fixed contacts 21b, 22a, 2
It matches the circle passing through 3b and 24b.

Therefore, each attenuation amount of attenuation circuits 11 and 12 is set to 1 dB,
2dB, and the contacts 5a, 5 as shown in Figure 5A.
b are fixed contact pairs 21a21b and 24a2, respectively.
4b and short-circuit them, the fixed contact pairs 22a22b and 23a23b are respectively opened, and the attenuation amount of both the attenuation circuits 11 and 12 is set to zero. When the contacts 5a to 5d are rotated counterclockwise by 90 degrees from this position in the counterclockwise direction in FIG.
2a, 22b, 24a, and 24b are short-circuited, and the other fixed contact pairs are opened, and the attenuation circuit 11
is 1 dB, and the attenuation circuit 12 is zero. Thereafter, in the same way, contactors 5a to 5d are further rotated by 90 degrees and 180 degrees.
When it is rotated counterclockwise by a degree, the states shown in FIG. 5C and D are obtained, and the attenuation circuits 11 and 12 become zero, 2 dB, 1 dB, and 2 dB, respectively. Attenuation circuit 11,1
Attenuation 0, 1, 2, 3 dB between both ends of 2 cascade connections
FIG. 6 shows a relationship showing which fixed contact pair is short-circuited by which contact when obtaining each of the above. In FIG. 6, the blank fixed contact pairs are open.

Next, the contacts 5a to 5 for the substrate 18 having the pattern shown in FIG. 3 are used to make the attenuation variable using the contacts shown in FIG.
A specific example for rotatably holding d, 6a to 6d will be described with reference to FIGS. 7 to 11. FIG. 8 shows a sectional view of the variable attenuator, and FIG. 9 is an exploded perspective view thereof. On the insulating substrate 18, patterns of attenuation circuits 11 to 14 and fixed contact pairs are provided as shown in FIG. Rotating bodies 35, 3 made of an insulating material made of synthetic resin are formed on the insulating substrate 18 facing them.
6 is rotatably arranged. The rotating bodies 35 and 36 each have a substantially disk shape, and the insulating substrate 18
conductor pieces 33, 34, 3 on the opposite surface, respectively.
7 and 38 are attached. The conductor pieces 37 and 38 have the same shape as the conductor pieces 33 and 34, and contacts 6a to 6d are formed thereon in the same relationship as the contacts 5a to 5d. The conductor pieces can be attached to the rotating body by inserting a pin 39 integrally formed in the rotating body into a small hole 41 formed in the conductive piece and then thermally tightening the pin 39. rotating body 35,
A boss 35a is provided at the center of the surface of 36 facing the substrate 18,
The bosses 35b are integrally formed, and the end faces of the bosses 35a and 35b are close to the substrate 18.

A case 42 made of synthetic resin or the like is disposed on the substrate 18 to cover the rotating bodies 35 and 36. The insulating substrate 18 side of the case 42 is an open surface, and a stepped portion 43 is formed on the inner peripheral surface of the open surface side, and the insulating substrate 1
8 is fitted into the case 42 so as to close its open surface, and its peripheral edge is brought into contact with the stepped portion 43. A case 42 is formed by filling the bottom surface of the insulating substrate 18 with adhesive 44,
The substrates 18 are hermetically bonded.

The recesses 45 and 46 in which the rotating bodies 35 and 36 are housed are formed on the surface of the case 42 facing the insulating substrate 18.
It is formed as shown in FIGS. 10 and 11,
Circular holes 47, 48 are located in the center of the recesses 45, 46.
is opened. Substrate 18 of rotating bodies 35 and 36
Short rotating shafts 51 and 52 are integrally formed on the opposite surface, respectively, and these rotating shafts 51 and 52 are fitted into circular holes 47 and 48 and are supported by bearings. Rotating shaft 5
1 and 52 are provided with driver grooves 53 for inserting and engaging drivers for rotating the rotating bodies 35 and 36,
54 is formed. The driver grooves 53 and 54 are formed in the shape of an arrow so that they can also indicate the attenuation amount setting positions of the rotating bodies 35 and 36. An O-ring 5 is placed on the opposing surface of the rotating bodies 35, 36 and the case 42.
5 and 56 are interposed to keep the inside of the case 42 airtight.

Each contact 5a of the conductor pieces 33, 34, 36, 37
5d and 6a to 6d are bent toward the substrate 18 and come into elastic contact with the substrate 18. rotating body 35,
36 and fixed contact pairs 21a21b to 24a24b, 25 with contacts 5a to 5d, 6a to 6d.
A desired amount of attenuation is obtained by short-circuiting desired ones of a25b to 28a28b. As shown in FIG. 9, the corresponding attenuation amount is indicated by markings 57 and 58 on the surface of the case 42 for the set angular position at which the attenuation amount is obtained. Also, the user can feel that the rotating bodies 35 and 36 are correctly set at the set angle positions, and the set positions are maintained. For this purpose, for example, as shown in FIGS. 9 and 12, the rotating body 35,
Arms extending in opposite directions along the circumferential direction are integrally formed on the circumferential surface of the rotating body 3.
Click protrusions 61 and 62 are provided on the outer circumferential surface of the free ends of both arms of the rotating body 36, and click protrusions 63 and 64 are formed integrally with the free ends of both arms of the rotating body 36 at an angular interval of 180 degrees. It is formed with On the other hand, on the inner peripheral surface of the recesses 45 and 46 of the case 42, four click recesses 65 and 66 are formed at angular intervals of 90 degrees to engage with the click protrusions 61, 62, 63 and 64, respectively. and the click protrusion 61,
62 has two recesses 65, a click protrusion 63,
64 are respectively engaged with the two recesses 66, the arrows of the driver grooves 53, 54 are made to point to each one of the indicia 57, 58 on the case surface. When the rotating bodies 35 and 36 are driven to rotate from this state, the arms of the respective click protrusions are elastically deformed and come close to the circumferential surfaces of the rotating bodies 35 and 36, and are moved away from the engagement recesses 65 and 66. It comes off.

Note that a pin 67 is integrally projected from the inner surface of the case 42, and is inserted into a small hole 68 of the base plate 18, and its protruding end is dipped and swaged. In this embodiment, two pins 67 are provided, each having a different thickness, and are used to align the substrate 18 and the case 42. Furthermore, notches 69 are formed at the four corners of the insulating substrate 18, and banks 71 that fit into the notches 69 are integrally formed at the four corners of the case 42, and the banks 71 are crushed to fix the case 42 and the substrate 18. It is used for. Small holes 15', 16' and 17' are penetrated through the four corners of the insulating substrate 18, respectively, and terminal pins 15, 16 and 17 are inserted and fixed into these. An insulating film is formed on the pattern other than the fixed contact pairs on the substrate 18, and the contacts 5a to 5d, 6a to 6
d is prevented from having an adverse effect. This insulating film also helps prevent deterioration of the resistance elements R ₁ to R ₈ .

As for the contacts 5a to 5d, for example, as shown in FIG. 13, the contacts 5a and 5d may be formed integrally with the conductor piece 33, and the contacts 5b and 5c may be formed integrally with the conductor piece 34. Furthermore, the contacts 5a to 5d do not have to be provided on the same circle. For example, as shown in FIG. 14, contacts 5a and 5b separated by 180 degrees are arranged on an outer circle, and contacts 5c and 5d separated by 90 degrees are arranged on an inner circle. This is a case where the contacts 5a and 5b are integrated with the same conductor piece 33, and the contacts 5c and 5d are integrated with the conductor piece 34. For such contacts 5a to 5d, a fixed contact pair 21a2
1b to 24a and 24b may be formed as shown in FIG. 15, for example. In this case, the first
As shown in Figure 6, connect the contacts 5a and 5b to the conductor piece 33.
The contacts 5b and 5c may be formed integrally with the conductor piece 34. In addition, in the above, the contactor 5a
~5d are formed into one conductor piece in two pieces, but each may be formed into one conductor piece. If two contacts are formed on one conductor piece, the number of parts will be reduced and assembly will be easier. .

As described above, according to this invention, settings of, for example, 0, 1, 2, and 3 dB can be selected and set by rotating one rotating body 35, and the operation is easy and the number of parts is reduced. It has a simple structure and is easy to assemble. unbalanced attenuation circuit 13,
If the attenuation amounts of 14 are set to 4 dB and 8 dB, respectively, 16 settings from 0 to 15 dB can be made using the two rotating bodies 35 and 36.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a conventional switching type variable resistance attenuator, Fig. 2 is a circuit diagram showing an example of a switching type variable resistance attenuator according to this invention, and Fig. 3 is a circuit diagram showing an example of a switching type variable resistance attenuator according to this invention. A diagram showing an example of a pattern on a substrate, FIG. 4 is a plan view showing an example of contacts 5a to 5d, and FIG. 5 is an attenuation amount setting state using the contacts in FIG. 4 and the board in FIG. 3. FIG. 6 is a diagram showing the relationship between the contacts that short-circuit the fixed contact pair in the setting state of FIG. 5, FIG. 7 is a perspective view showing an embodiment of this invention, and FIG. 9 is an exploded perspective view of FIG. 7, FIG. 10 is a bottom view of the case 42, FIG. 11 is a longitudinal sectional view of the case 42, and FIG.
The figure is a bottom view of the rotating body 35, and FIG. 13 is a contact 5a.
14 is a plan view showing still another example of the contacts 5a to 5d, and FIG. 15 is a plan view showing another example of the contacts 5a to 5d, and FIG. FIG. 16 is a plan view showing another example of the contact shown in FIG. 14. 1a~4a, 1b~4b: input/output terminal, 1c~
4c: Internal common terminal, 5a to 5d, 6a to 6d:
Contactor, 11-14: Unbalanced damping circuit, 15,
16: External input/output terminal, 17: External common terminal, 1
8: Insulating substrate, 21a21b to 28a28b: Fixed contact pair, 35, 36: Rotating body, 42: Case.

Claims (1)

[Scope of utility model registration request] Three-terminal first and second unbalanced attenuation circuits each having first and second input/output terminals and one internal common terminal are provided on the insulating substrate, and the second unbalanced attenuation circuit of the first unbalanced attenuation circuit The input/output terminal and the first input/output terminal of the second unbalanced attenuation circuit are connected to each other, and first, second, third, and fourth fixed contact pairs and an external common terminal are provided on the insulating substrate, The first fixed contact pair is connected to the first and second input/output terminals of the first unbalanced attenuation circuit, and the second fixed contact pair is connected to the internal common terminal and the second input/output terminal of the first unbalanced attenuation circuit. The external common terminals are connected to each other, the internal common terminal and the external common terminal of the second unbalanced attenuation circuit are connected to the third fixed contact pair, and the fourth fixed contact pair is connected to the second unbalanced common terminal. The first and second input/output terminals of the attenuation circuit are connected to each other, and a rotating body is rotatably disposed opposite to the first, second, third, and fourth fixed contact pairs, and the rotating body is first, second, third, and fourth shorting contacts are mounted facing the insulating substrate, and the first contact contacts the first fixed contact pair at the first rotation angle position of the rotating body. , the fourth contactor contacts the fourth fixed contact pair, and the first contactor contacts the second fixed contact pair at the second rotation angle position.
the third contact contacts the fourth fixed contact pair, the second contact contacts the first fixed contact pair at a third rotation angle position, and the fourth contact contacts the first fixed contact pair; The contactor contacts the third fixed contact pair, and the fourth
The arrangement of the fixed contact pair is such that the second contact contacts the second fixed contact pair at the rotation angle position, and the third contact contacts the third fixed contact pair. Switched variable resistance attenuator with selected arrangement.