Patent US3740676A successfully refreshed from Google Patents.
US3740676A
Expired / Lapsed
US
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Continuously variable resistance attenuator using lossy transmission line and having constant signal transit time
Assignee: Tektronix Inc
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Filing: 1972-03-29
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Granted: 1973-06-19
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Expires: 1992-03-29
Abstract
Abstract A continuously variable resistance attenuator is described in which the signal conductor of a distortionless lossy transmission line is employed as an attenuation resistance uniformly distributed along such line, and the connection of an output contact is moved along such signal conductor to change the attenuator setting. The transmission line has a plurality of separate shunt resistors of equal value extending between the signal conductor and the ground conductor of the line and uniformly distributed along the line to provide a lossy line of uniform characteristic impedance. The input end of such lossy line is connected to a non-lossy line of the same characteristic impedance, and its other end is terminated in a termination resistor equal to such characteristic impedance. In one embodiment, the lossy transmission line is moved relative to a fixed input contact and a fixed output contact to provide a constant transit time for the signal to pass through the attenuator, due to the fixed distance between such contacts and to reduce the size of the contacts for improved high frequency response. The input contact is provided by a fixed portion of the non-lossy line which engages its movable portion attached to the lossy line to provide a transmission line stretcher of variable length.
Inventors
- 👤 V Garuts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:25
CPC Classifications
H; H01; H01C; H01C10/00; H01C10/26; H01P; H01P1/00; H01P1/22; H01P1/227; H03; H03H; H03H7/00; H03H7/24
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
168 words
A variable resistance attenuator of wide frequency bandwidth comprising: first transmission line means of substantially uniform characteristic impedance including a signal conductor and a ground conductor forming a lossy transmission line, said signal conductor being of resistance material to proviDe an attenuation resistance distributed substantially uniformly along the length of said signal conductor, and a plurality of separate shunt resistors of substantially the same resistance connected between said signal conductor and said ground conductor and spaced substantially uniformly along the length of said signal conductor; first signal coupling means connected to one end of said signal conductor through a first connection; second signal coupling means connected to said signal conductor through a second connection; control means for moving said second connection along the attenuation resistance of said signal conductor to vary the attenuation setting; said control means moving the first transmission line means to change the attenuator setting of said second connection while maintaining the same electrical signal path length between said first connection and said second connection.
Claim 2
Dependent Claim
168 words
A variable resistance attenuator of wide frequency bandwidth comprising: first transmission line means of substantially uniform characteristic impedance including a signal conductor and a ground conductor forming a lossy transmission line, said signal conductor being of resistance material to proviDe an attenuation resistance distributed substantially uniformly along the length of said signal conductor, and a plurality of separate shunt resistors of substantially the same resistance connected between said signal conductor and said ground conductor and spaced substantially uniformly along the length of said signal conductor; first signal coupling means connected to one end of said signal conductor through a first connection; second signal coupling means connected to said signal conductor through a second connection; control means for moving said second connection along the attenuation resistance of said signal conductor to vary the attenuation setting; said control means moving the first transmission line means to change the attenuator setting of said second connection while maintaining the same electrical signal path length between said first connection and said second connection.
Claim 3
Dependent Claim
69 words
An attenuator in accordance with claim 1 in which the second connection includes a fixed contact engaging the attenuation resistance and the first connection includes another fixed contact coupled to said one end of said first line, said first transmission line means being moved relative to said fixed contacts to change the attenuator setting so that the distance between said fixed contacts remains the same for different attenuator settings.
Claim 4
Dependent Claim
68 words
An attenuator in accordance with claim 2 in which the first signal coupling means includes a second transmission line of substantially uniform characteristic impedance equal to that of said first transmission line means, and including a signal conductor and a ground conductor insulated from each other to provide a non-lossy second line and connected, respectively, to the signal conductor and the ground conductor of the first transmission line.
Claim 5
Dependent Claim
56 words
An attenuator in accordance with claim 3 in which the second transmission line is formed in two separate sections joined by said first connection, one of said sections being fixed in position and the other of said sections being attached to the first transmission line for movement therewith to change the length of said second line.
Claim 6
Dependent Claim
44 words
An attenuator in accordance with claim 4 in which said one section of said second line has its signal conductor forming the fixed contact of said first connection which is in engagement with the signal conductor of said other section of said second line.
Claim 7
Dependent Claim
92 words
An attenuator in accordance with claim 2 in which the first transmission line means is formed by a rotor member of insulating material with the signal conductor forming said attenuation resistance, the ground conductor, and said shunt resistors provided as layers on said rotor member, and in which the fixed contacts are provided on a stator member of insulating material and connected to separate conductive regions on said stator member so that rotation of said rotor member causes the second connection to move along the attenuation resistance of the signal conductor layer.
Claim 8
Dependent Claim
83 words
An attenuator in accordance with claim 6 in which the first signal coupling means includes a second transmission line of non-lossy type having a substantially uniform characteristic impedance equal to that of the first transmission line means and formed of two separate sections including one section provided on the stator member and another section provided on the rotor member, said one section having a signal conductor forming the fixed contact of said first connection which engages the signal conductor of the other section.
Claim 9
Dependent Claim
43 words
An attenuator in accordance with claim 7 in which the signal conductor of said other section is provided by a conductive layer of said rotor connected to said one end of the first transmission line means for movement therewith on the rotor member.
Claim 10
Dependent Claim
56 words
An attenuator in accordance with claim 6 in which the rotor member is an annular plate mounted in a hole in another plate forming the stator member, and the shunt resistor layers extend radially outward from the ground conductor layer to the signal cOnductor layer which are coated on the same side of said rotor plate.
Claim 11
Dependent Claim
38 words
An attenuator in accordance with claim 7 which also includes a termination resistor equal to said characteristic impedance provided as a layer on the stator plate between the other end of the signal conductor and the ground conductor.
Claim 12
Dependent Claim
174 words
A variable resistance attenuator of wide frequency bandwidth comprising: first transmission line means of substantially uniform characteristic impedance including signal conductor means and ground conductor means forming a lossy transmission line, said signal conductor means being of resistance material to provide an attenuation resistance distributed along a length of said signal conductor means and separate shunt conductance means connected between said signal conductor means and said ground conductor means and distributed along the length of said signal conductor means in proportion to said attenuation resistance; first signal coupling means connected to one end of said signal conductor means through first connection means; second signal coupling means connected to said signal conductor means through second connection means; control means for moving said second connection means along said attenuation resistance of said signal conductor means to vary the attenuation setting, said control means moving said first transmission line means to change the attenuator setting of said second connection means while maintaining the same electrical signal path between said first connection means and said second connection means.
Claim 13
Dependent Claim
174 words
A variable resistance attenuator of wide frequency bandwidth comprising: first transmission line means of substantially uniform characteristic impedance including signal conductor means and ground conductor means forming a lossy transmission line, said signal conductor means being of resistance material to provide an attenuation resistance distributed along a length of said signal conductor means and separate shunt conductance means connected between said signal conductor means and said ground conductor means and distributed along the length of said signal conductor means in proportion to said attenuation resistance; first signal coupling means connected to one end of said signal conductor means through first connection means; second signal coupling means connected to said signal conductor means through second connection means; control means for moving said second connection means along said attenuation resistance of said signal conductor means to vary the attenuation setting, said control means moving said first transmission line means to change the attenuator setting of said second connection means while maintaining the same electrical signal path between said first connection means and said second connection means.
Claim 14
Dependent Claim
22 words
A variable resistance attenuator according to claim 11 wherein said separate shunt conductance means comprises a plurality of separate shunt resistance means.
Claim 15
Dependent Claim
202 words
A variable resistance attenuator of wide frequency bandwidth comprising: first transmission line means of substantially uniform characteristic impedance including first signal conductor means and first ground conductor means defining a lossy transmission line, said signal conductor means being of resistance material to provide an attenuation resistance distributed along a length of said signal conductor means and separate shunt conductance means connected between said signal conductor means and said ground conductor means and distributed along the length of said signal conductor means in proportion to said attenuation resistance; second transmission line means of substantially uniform characteristic impedance equal to that of said first transmission line means and including second signal conductor means and second ground conductor means defining a non-lossy transmission line; first signal coupling means including first connection means connecting said first signal coupling means to said first signal conductor means; second signal coupling means including second connection means connecting said second signal coupling means to said second signal conductor means; and control means for moving said first and second transmission line means relative to one another to change the attenuator setting of said first connection means while maintaining the same electrical signal path length between said first and second connection means.
Claim 16
Dependent Claim
202 words
A variable resistance attenuator of wide frequency bandwidth comprising: first transmission line means of substantially uniform characteristic impedance including first signal conductor means and first ground conductor means defining a lossy transmission line, said signal conductor means being of resistance material to provide an attenuation resistance distributed along a length of said signal conductor means and separate shunt conductance means connected between said signal conductor means and said ground conductor means and distributed along the length of said signal conductor means in proportion to said attenuation resistance; second transmission line means of substantially uniform characteristic impedance equal to that of said first transmission line means and including second signal conductor means and second ground conductor means defining a non-lossy transmission line; first signal coupling means including first connection means connecting said first signal coupling means to said first signal conductor means; second signal coupling means including second connection means connecting said second signal coupling means to said second signal conductor means; and control means for moving said first and second transmission line means relative to one another to change the attenuator setting of said first connection means while maintaining the same electrical signal path length between said first and second connection means.
Claim 17
Dependent Claim
48 words
A variable resistance attenuator according to claim 13 wherein said second signal coupling means defines third transmission line means including third signal conductor means connected to said first signal conductor means and third ground conductor means connected to said first ground conductor means defining another non-lossy transmission line.
Claim 18
Dependent Claim
22 words
A variable resistance attenuator according to claim 14 wherein said separate shunt conductance means comprises a plurality of separate shunt resistance means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |