US4896371A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Synchronous AM transmission system having reduced self interference effects
Assignee: Individual
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Filing: 1987-11-20
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Granted: 1990-01-23
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Expires: 2007-11-20
Abstract
Abstract A synchronous transmission system that improves reception in areas where the main and the satellite signal create significant self interference. At least one of the synchronous transmitters is phase modulated in accordance with a selected modulation function which varies at a sub sonic rate.
Inventors
- 👤 Leonard R. Kahn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:07
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/65; H04H20/67
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
109 words
An improved synchronous AM transmission system, comprising: first and second AM transmitters, each having program and carrier signal inputs; means for supplying a program signal to the program signal input of each of said transmitters; first means for supplying a first carrier signal of predetermined frequency to the carrier signal input of a selected one of said transmitters; and second means for supplying to the carrier signal input of the other of said transmitters a second carrier signal of substantially the same frequency as that of said first carrier signal and having a relative phase with respect thereto which is varied in accordance with a selected phase modulation function.
Claim 2
Dependent Claim
109 words
An improved synchronous AM transmission system, comprising: first and second AM transmitters, each having program and carrier signal inputs; means for supplying a program signal to the program signal input of each of said transmitters; first means for supplying a first carrier signal of predetermined frequency to the carrier signal input of a selected one of said transmitters; and second means for supplying to the carrier signal input of the other of said transmitters a second carrier signal of substantially the same frequency as that of said first carrier signal and having a relative phase with respect thereto which is varied in accordance with a selected phase modulation function.
Claim 3
Dependent Claim
31 words
A system in accordance with claim 1 wherein said modulation function is such as to vary the phase of said second carrier signal about a quiescent value by less than ±180°.
Claim 4
Dependent Claim
27 words
A system in accordance with claim 2 wherein said modulation function is such as to vary the phase of said second carrier signal by less than ±90°.
Claim 5
Dependent Claim
17 words
A system in accordance with claim 2 or 3 wherein said modulation function is a triangular waveform.
Claim 6
Dependent Claim
15 words
A system in accordance with claim 2 or 3 wherein said quiescent value is adjustable.
Claim 7
Dependent Claim
27 words
A system in accordance with claim 2 or 3 wherein said modulation function varies the phase of said second carrier signal at a predetermined sub sonic rate.
Claim 8
Dependent Claim
169 words
An improved synchronous AM transmission system having at least two system transmitters whose transmitted signals interfere to create one or more nulls in a mush zone, comprising: first and second system AM transmitters, each having program and carrier signal inputs; means for supplying a program signal to the program signal input of said first transmitter means for supplying a program signal to the program signal input of said second transmitter; first means for supplying a first carrier signal of predetermined frequency to the carrier signal input of a selected one of said transmitters; and second means for supplying to the carrier signal input of the other said transmitters a second carrier signal of substantially the same frequency as that of said first carrier signal and having a relative phase with respect thereto which varies about a quiescent value by less than ±90, where said variation is at a sub sonic rate in accordance with a triangular waveform phase modulation function, thereby causing the location of said null to vary.
Claim 9
Dependent Claim
169 words
An improved synchronous AM transmission system having at least two system transmitters whose transmitted signals interfere to create one or more nulls in a mush zone, comprising: first and second system AM transmitters, each having program and carrier signal inputs; means for supplying a program signal to the program signal input of said first transmitter means for supplying a program signal to the program signal input of said second transmitter; first means for supplying a first carrier signal of predetermined frequency to the carrier signal input of a selected one of said transmitters; and second means for supplying to the carrier signal input of the other said transmitters a second carrier signal of substantially the same frequency as that of said first carrier signal and having a relative phase with respect thereto which varies about a quiescent value by less than ±90, where said variation is at a sub sonic rate in accordance with a triangular waveform phase modulation function, thereby causing the location of said null to vary.
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) | 1993-01-22 | 1993-07-24 | 1994-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-22 | 1997-07-24 | 1998-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-22 | 2001-07-24 | 2002-01-23 | $7700.00 | Window Closed / Lapsed |