US4921465A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Varactor tuned UHF RF signal input circuit
Assignee: RCA Licensing Corp
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Filing: 1988-03-31
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Granted: 1990-05-01
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Expires: 2008-03-31
Abstract
Abstract An RF signal input circuit for a UHF tuner of a television receiver comprises a series-tuned circuit including a varactor diode and an inductance element connected in series, in the order named, between signal ground and a gate electrode of a field-effect transistor RF amplifier. The series-tuned circuit has a relatively uniform bandwidth throughout the UHF range. A capacitor connected in shunt with the gate electrode completes a "split-capacitor" configuration in which the varactor diode and the shunt capacitor form a variable impedance transformation network for making the relationship between the effective impedances of the series-tuned circuit and FET amplifier relatively uniform throughout the UHF range. The order of the varactor diode and inductance element allows a low cost adjustable capacitor comprising a grounded shield wall as one plate and a movable tab as a second plate to be connected directly across the varactor diode.
Inventors
- 👤 Alexander W. Hietala
- 👤 Max W. Muterspaugh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:36
CPC Classifications
H; H03; H03J; H03J1/00; H03J3/00; H03J3/02; H03J3/16; H03J3/18; H03J3/185
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
100 words
In a tuner, UHF tuning apparatus comprising: a UHF antenna input; a RF amplifier having an input and an output; antenna coupling means including a first inductance element for coupling said UHF antenna input to the input of said amplifier; a series-tuned circuit including a varactor diode and said first inductance element connected in series, in the order named, between a point of reference potential and the input of said amplifier; a first capacitance element connected between the input of said amplifier and said point of reference potential; and a second capacitance element connected in parallel with said varactor diode.
Claim 2
Dependent Claim
100 words
In a tuner, UHF tuning apparatus comprising: a UHF antenna input; a RF amplifier having an input and an output; antenna coupling means including a first inductance element for coupling said UHF antenna input to the input of said amplifier; a series-tuned circuit including a varactor diode and said first inductance element connected in series, in the order named, between a point of reference potential and the input of said amplifier; a first capacitance element connected between the input of said amplifier and said point of reference potential; and a second capacitance element connected in parallel with said varactor diode.
Claim 3
Dependent Claim
13 words
The apparatus recited in claim 1, wherein: said second capacitance element is adjustable.
Claim 4
Dependent Claim
51 words
The apparatus recited in claim 2, wherein: said second capacitance element includes a first plate connected to said first inductance element and a second plate comprising a portion of a shield member at least partially enclosing said UHF tuning apparatus, said first plate being movable with respect to said shield member.
Claim 5
Dependent Claim
46 words
The apparatus recited in claim 2, wherein: said antenna coupling means comprises a transformer with said first inductance element forming the secondary portion of said transformer and with a second inductance element, which is coupled to said antenna input, forming the primary portion of said transformer.
Claim 6
Dependent Claim
25 words
The apparatus recited in claim 4, wherein: said first inductance element is a strip-line inductor and said second inductance element is a coil of wire.
Claim 7
Dependent Claim
73 words
The apparatus recited in claim 5, wherein: said strip-line inductor has a first end connected to said first capacitance element and a second end connected to said varactor diode; and said second capacitance element comprises a first plate connected to said strip-line inductor and a second plate comprising a portion of a shield member at least partially enclosing said UHF tuning apparatus, said first plate being movable with respect to said shield member.
Claim 8
Dependent Claim
18 words
The apparatus recited in claim 6, wherein: said strip-line inductor and said first plate comprise a unitary structure.
Claim 9
Dependent Claim
106 words
In a tuner, UHF tuning apparatus comprising: a UHF antenna input; a RF amplifier having an input and an output; antenna coupling means including a first inductance element for coupling said UHF antenna input to the input of said amplifier; a series-tuned circuit including a varactor diode and said first inductance element connected in series, in the order named, between a point of reference potential and the input of said amplifier; a first capacitance element connected between the input of said amplifier and said point of reference potential; and a second capacitance element connected in parallel with said varactor diode; said second capacitance element being adjustable.
Claim 10
Dependent Claim
106 words
In a tuner, UHF tuning apparatus comprising: a UHF antenna input; a RF amplifier having an input and an output; antenna coupling means including a first inductance element for coupling said UHF antenna input to the input of said amplifier; a series-tuned circuit including a varactor diode and said first inductance element connected in series, in the order named, between a point of reference potential and the input of said amplifier; a first capacitance element connected between the input of said amplifier and said point of reference potential; and a second capacitance element connected in parallel with said varactor diode; said second capacitance element being adjustable.
Claim 11
Dependent Claim
147 words
In a tuner, UHF tuning apparatus comprising: a UHF antenna input; a RF amplifier having an input and an output; antenna coupling means including a first inductance element for coupling said UHF antenna input to the input of said amplifier; a series-tuned circuit including a varactor diode and said first inductance element connected in series, in the order named, between a point of reference potential and the input of said amplifier; a first capacitance element connected between the input of said amplifier and said point of reference potential; and a second capacitance element connected in parallel with said varactor diode; said second capacitance element being adjustable and including a first plate connected to said first inductance element and a second plate comprising a portion of a shield member at least partially enclosing said UHF tuning apparatus, said first plate being movable with respect to said shield member.
Claim 12
Dependent Claim
147 words
In a tuner, UHF tuning apparatus comprising: a UHF antenna input; a RF amplifier having an input and an output; antenna coupling means including a first inductance element for coupling said UHF antenna input to the input of said amplifier; a series-tuned circuit including a varactor diode and said first inductance element connected in series, in the order named, between a point of reference potential and the input of said amplifier; a first capacitance element connected between the input of said amplifier and said point of reference potential; and a second capacitance element connected in parallel with said varactor diode; said second capacitance element being adjustable and including a first plate connected to said first inductance element and a second plate comprising a portion of a shield member at least partially enclosing said UHF tuning apparatus, said first plate being movable with respect to said shield member.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-04-30 | 1993-10-30 | 1994-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-30 | 1997-10-30 | 1998-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-30 | 2001-10-30 | 2002-05-01 | $7700.00 | Window Closed / Lapsed |