US3898593A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switchable resistive attenuators
Assignee: Gemalto Terminals Ltd
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Filing: 1973-09-26
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Granted: 1975-08-05
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Expires: 1993-09-26
Abstract
Abstract An adjustable attenuator comprises first and second inputs, first and second resistors connected in series from the first input, and a switch for selectively connecting the end of the second resistor remote from the first resistor either to the first input or to the second input, the output of the attenuator being taken between the junction between the resistors and the second input. Thus when the switch is in its first state, the two resistors are connected in parallel with each other and in series with the first input, providing an attenuation factor substantially equal to one, while when the switch is in its second state, the two resistors are series connected between the first and second inputs as a potential divider chain. This arrangement insures that any stray capacitance introduced by the switch is not connected across the output of the attenuator.
Inventors
- 👤 Umar Qureshi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:31
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/24
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
157 words
A switchable resistive attenuator comprising first and second input terminals between which an A.C. voltage to be attenuated may be applied, a capacitance, a first resistance having one end connected to said first input terminal via said capacitance, a second resistance having one end connected to the other end of the first resistance, an output terminal connected to the junction between the first and second resistances, and switching means having first and second settings for coupling the other end of said second resistance to said one end of said first resistance in the first of said settings and for coupling said other end of said second resistance to said second input terminal in the second of said settings, the output voltage from the attenuator appearing between said output terminal and the second input terminal, whereby the effect of insulation resistance and stray capacitance of the switching means on the magnitude of the output voltage is substantially eliminated.
Claim 2
Dependent Claim
157 words
A switchable resistive attenuator comprising first and second input terminals between which an A.C. voltage to be attenuated may be applied, a capacitance, a first resistance having one end connected to said first input terminal via said capacitance, a second resistance having one end connected to the other end of the first resistance, an output terminal connected to the junction between the first and second resistances, and switching means having first and second settings for coupling the other end of said second resistance to said one end of said first resistance in the first of said settings and for coupling said other end of said second resistance to said second input terminal in the second of said settings, the output voltage from the attenuator appearing between said output terminal and the second input terminal, whereby the effect of insulation resistance and stray capacitance of the switching means on the magnitude of the output voltage is substantially eliminated.
Claim 3
Dependent Claim
204 words
A switchable resistive attenuator comprising first and second input terminals between which an A.C. or D.C. voltage to be attenuated may be applied, a first resistance having one end coupled to the first input terminal, a second resistance having one end connected to the other end of the first resistance, an output terminal connected to the junction between the first and second resistances, and switching means having first and second settings for coupling the other end of said second resistance to said one end of said first resistance in the first of said settings and for coupling said other end of said second resistance to said second input terminal in the second of said settings, the output voltage from the attenuator appearing between said output terminal and the second input, whereby the effect of insulation resistance and stray capacitance of the switching means on the magnitude of the output voltage is substantially eliminated, said attenuator further comprising a third resistance connected between said second input terminal and said other end of the second resistance, the value of the third resistance being chosen to maintain the input impedance of the attenuator substantially the same when the switching means is in the first and second settings.
Claim 4
Dependent Claim
204 words
A switchable resistive attenuator comprising first and second input terminals between which an A.C. or D.C. voltage to be attenuated may be applied, a first resistance having one end coupled to the first input terminal, a second resistance having one end connected to the other end of the first resistance, an output terminal connected to the junction between the first and second resistances, and switching means having first and second settings for coupling the other end of said second resistance to said one end of said first resistance in the first of said settings and for coupling said other end of said second resistance to said second input terminal in the second of said settings, the output voltage from the attenuator appearing between said output terminal and the second input, whereby the effect of insulation resistance and stray capacitance of the switching means on the magnitude of the output voltage is substantially eliminated, said attenuator further comprising a third resistance connected between said second input terminal and said other end of the second resistance, the value of the third resistance being chosen to maintain the input impedance of the attenuator substantially the same when the switching means is in the first and second settings.
Claim 5
Dependent Claim
46 words
An attenuator as claimed in claim 2 and further comprising a fourth resistance, and second switching means having first and second settings in which said fourth resistance is respectively short-circuited and connected between said other end of said second resistance and said first mentioned switching means.
Claim 6
Dependent Claim
87 words
An attenuator as claimed in claim 3 and further comprising a fifth resistance connected between said one end of said first resistance and said second switching means, the value and connection of said fifth resistance being such that the input impedance of the attenuator is substantially the same when the first mentioned switching means and the further switching means are simultaneously in their second and first settings respectively and when the first mentioned switching means and the further switching means are both simultaneously in their second settings.
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) | 1978-08-04 | 1979-02-03 | 1979-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-04 | 1983-02-03 | 1983-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-04 | 1987-02-03 | 1987-08-05 | $7700.00 | Window Closed / Lapsed |