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US3649847A
Expired / Lapsed
US
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Electrically controlled attenuation and phase shift circuitry
Assignee: RCA Licensing Corp
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Filing: 1970-10-30
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Granted: 1972-03-14
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Expires: 1990-10-30
Abstract
Abstract Input signal current combined with a substantially constant direct current bias is coupled to the junction of the emitter electrode of a transistor biased in common base configuration and one electrode of a diode poled similarly to the base-emitter junction of the transistor. A variable direct current supply is coupled to the other electrode of the diode. The collector of the transistor provides an output signal current, the average value of which is complementary to the average current flow through the diode. An electrically controlled attenuator is thus provided. This attenuator mechanism can be used to regulate a reactive current flow in phase shift circuitry to afford electrically controlled phase shift networks. Such electrically controlled attenuation and phase shift circuitry is well suited for use in remotely controlled television receivers and lends itself to monolithic integrated circuit construction.
Inventors
- 👤 Allen Leroy Limberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:40
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64; H04N9/643; H03; H03G; H03G1/00; H03G1/0005; H03G1/0035; H03G1/0052; H03H; H03H11/00; H03H11/02; H03H11/16; H03H11/20
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
208 words
A variable attenuator for electrical signal currents comprising: first and second semiconductor devices, said first device having at least first and second electrodes and said second device having at least first, second and third electrodes, the second electrodes of said devices being coupled to a common circuit junction; bias current means coupled to said junction for providing forward bias direct current components to each of said devices, said bias current means comprising a transistor including a collector electrode direct current coupled to said junction, a base electrode and an emitter electrode and means coupled between said base and emitter electrodes for establishing a substantially constant quiescent current between said emitter and collector electrodes; means coupled to said junction for supplying signal currents to said devices; means coupled to said first electrode of said first device for bypassing signal currents to a point of reference potential; means coupled to said first electrode of said first device for supplying a variable control current to said first device so as to vary proportioning of signal currents between said first and second devices; and output signal utilization means coupled between said first and third electrodes of said second device for deriving output signals determined by said input signals and said control current.
Claim 2
Dependent Claim
208 words
A variable attenuator for electrical signal currents comprising: first and second semiconductor devices, said first device having at least first and second electrodes and said second device having at least first, second and third electrodes, the second electrodes of said devices being coupled to a common circuit junction; bias current means coupled to said junction for providing forward bias direct current components to each of said devices, said bias current means comprising a transistor including a collector electrode direct current coupled to said junction, a base electrode and an emitter electrode and means coupled between said base and emitter electrodes for establishing a substantially constant quiescent current between said emitter and collector electrodes; means coupled to said junction for supplying signal currents to said devices; means coupled to said first electrode of said first device for bypassing signal currents to a point of reference potential; means coupled to said first electrode of said first device for supplying a variable control current to said first device so as to vary proportioning of signal currents between said first and second devices; and output signal utilization means coupled between said first and third electrodes of said second device for deriving output signals determined by said input signals and said control current.
Claim 3
Dependent Claim
86 words
A variable attenuator for electric signal currents in accordance with claim 1 wherein: said means for supplying a variable control current comprises a variable resistance element and a source of operating potential in series combination with said variable resistance element, said series combination being coupled to said first electrode of said first device, said source of operating potential being so poled in said series combination to caUse said control current to flow in a forward direction between said first and second electrodes of said first device.
Claim 4
Dependent Claim
97 words
A variable attenuator in accordance with claim 1 wherein: said means for supplying variable control current comprises first and second resistive elements, at least one of which has a variable resistance; a source of operating potential coupled in a first series combination with said first resistive element, said first series combination being coupled between said point of reference potential and said first electrode of said second device; said second resistive element being coupled in series combination with said source and also being connected between said point of reference potential and said first electrode of said second device.
Claim 5
Dependent Claim
66 words
A variable attenuator in accordance with claim 1 wherein: each of said first and second devices comprises a like semiconductor junction between said first and second electrodes, said second device further comprising an additional semiconductor junction between said first and third electrodes, each of said bias and control currents being in a forward current direction through junctions between respective second and first electrodes of said devices.
Claim 6
Dependent Claim
34 words
A variable attenuator in accordance with claim 4 wherein: said first device further comprises a third electrode and means for direct current coupling said third electrode to said first electrode of said first device.
Claim 7
Dependent Claim
26 words
A variable attenuator in accordance with claim 5 wherein: said direct current coupling means couples said control current to said first electrode of said first device.
Claim 8
Dependent Claim
40 words
A variable attenuator in accordance with claim 6 wherein: said first device comprises a second transistor and said second device comprises a third transistor, each having base, emitter and collector electrodes corresponding, respectively, to said first, second and third electrodes.
Claim 9
Dependent Claim
43 words
A variable attenuator in accordance with claim 7 wherein: said third transistor is arranged in a common base configuration, and said signal utilization means comprises a load impedance coupled between said collector electrode of said third transistor and a source of energizing potential.
Claim 10
Dependent Claim
29 words
A variable attenuator in accordance with claim 8 wherein: said bias current means comprises an emitter resistor coupled between said emitter electrode and a source of direct bias potential.
Claim 11
Dependent Claim
49 words
A variable attenuator in accordance with claim 9 wherein: said source of direct bias potential comprises means coupled to said base electrode of said transistor of said bias current means for supplying a temperature-compensated bias voltage so as to produce a temperature-independent, constant bias current in said emitter resistor.
Claim 12
Dependent Claim
29 words
A variable attenuator in accordance with claim 9 wherein: said means for supplying input signals is coupled to said base electrode of said transistor of said bias current means.
Claim 13
Dependent Claim
135 words
A variable attenuator in accordance with claim 8 wherein: at least said load impedance and said bias current means are disposed within the confines of a single monolithic semiconductor body and comprise: first and second similarly diffused resistor structures, said collector electrode of said transistor in said bias current means being direct coupled to the joined emitters of said second and third transistors; means connecting said second resistor between said emitter electrode of said bias current means transistor and a bias reference potential; means for applying biasing potential between said base and emitter electrodes of said last-named transistor to cause constant current flow essentially independent of variation of the temperature of said monolithic semiconductor body, in said second resistor structure; and means for applying input signal currents to said base electrode of said last-named transistor.
Claim 14
Dependent Claim
29 words
A variable attenuator in accordance with claim 1 wherein: said bias current means cOmprises an emitter resistor coupled between said emitter electrode and a source of direct bias potential.
Claim 15
Dependent Claim
49 words
A variable attenuator in accordance with claim 13 wherein: said source of direct bias potential comprises means coupled to said bias electrode of said transistor of said bias current means for supplying a temperature-compensated bias voltage so as to produce a temperature-independent, constant bias current in said emitter resistor.
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) | 1975-03-14 | 1975-09-13 | 1976-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-14 | 1979-09-13 | 1980-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-14 | 1983-09-13 | 1984-03-14 | $7700.00 | Window Closed / Lapsed |