US3968438A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Off channel gain control circuit
Assignee: Philips North America LLC
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Filing: 1975-02-27
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Granted: 1976-07-06
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Expires: 1995-02-27
Abstract
Abstract A circuit controls the gain of a first active stage in a radio receiver. The control voltage is derived from a point ahead of a filter, and thus controls the gain when a strong off channel signal is present. A normal AGC can also be used for on channel signals.
Inventors
- 👤 Harry Thanos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:43
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3052
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
132 words
A circuit comprising a signal path including a tuned circuit input means for receiving an input signal, a first active stage coupled to said input means and a filter means coupled to said active stage for defining on channel signals within the passband of the filter and off channel signals outside of said passband, off channel gain control means having an input coupled to said tuned circuit input means for receiving strong signals across said tuned circuit and an output means coupled to said active stage for controlling the gain thereof in accordance with the strength of an off channel signal, and an on channel gain control means having an input coupled to said path after said filter and an output coupled to said active stage through said tuned circuit input means.
Claim 2
Dependent Claim
132 words
A circuit comprising a signal path including a tuned circuit input means for receiving an input signal, a first active stage coupled to said input means and a filter means coupled to said active stage for defining on channel signals within the passband of the filter and off channel signals outside of said passband, off channel gain control means having an input coupled to said tuned circuit input means for receiving strong signals across said tuned circuit and an output means coupled to said active stage for controlling the gain thereof in accordance with the strength of an off channel signal, and an on channel gain control means having an input coupled to said path after said filter and an output coupled to said active stage through said tuned circuit input means.
Claim 3
Dependent Claim
16 words
A circuit as claimed in claim 1 wherein said active stage comprises a radio frequency amplifier.
Claim 4
Dependent Claim
14 words
A circuit as claimed in claim 1 wherein said active stage comprises a mixer.
Claim 5
Dependent Claim
21 words
A circuit as claimed in claim 1 said off channel gain control means further comprises adjustable means for setting a threshold.
Claim 6
Dependent Claim
32 words
A circuit as claimed in claim 1 further comprising means coupled between both of said control means for preventing operation of said off channel means when said on channel means is operating.
Claim 7
Dependent Claim
31 words
A circuit as claimed in claim 1 wherein said off channel gain control comprises a transistor having a base coupled to said path, and a collector coupled to said active stage.
Claim 8
Dependent Claim
18 words
A circuit as claimed in claim 6 further comprising a threshold adjusting variable resistor coupled to said base.
Claim 9
Dependent Claim
57 words
A circuit as claimed in claim 6 wherein said transistor further comprises an emitter, and further comprising an on channel gain control means having an input coupled to said path after said filter and an output means coupled to said emitter for cutting off said off channel gain control means when said on channel means is operating.
References Cited (Backward Citations)
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US3478271A
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Cited
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Cited
US3622887A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-07-06 | 1980-01-05 | 1980-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-06 | 1984-01-05 | 1984-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-06 | 1988-01-05 | 1988-07-06 | $7700.00 | Window Closed / Lapsed |