US4075566A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Co-channel interference suppression apparatus
Assignee: CATV COMPONENTS Co
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Filing: 1974-04-15
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Granted: 1978-02-21
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Expires: 1994-04-15
Abstract
Abstract The present invention refers to apparatus intended to suppress multiple co-channel interference and reflections from desired stations. The outputs of a two antenna array, which has been directed at the desired station, are fed to a sum-and-difference hybrid. The outputs of the hybrid are adjusted in amplitude and phase and combined to null the interference signal. The phase shift required for nulling is either ±90°. The sign is determined by the side of the array on which the interference source is located. The phase relation is true regardless of the exact location of the interference, requiring only a single adjustment in amplitude to null the source of interference. By adding a third antenna to the array and a phase detector to the system, a signal representing the direction of the source of interference is produced and is used to introduce either a ±90° phase shift and to set the required attenuation automatically cancelling the interference signal even if the interference signal source moves as effectively occurs with the resultant of multiple sources of interference.
Inventors
- 👤 Timothy D'Arcangelis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:54
CPC Classifications
H; H01; H01Q; H01Q3/00; H01Q3/26; H01Q3/2605; H01Q3/2611; H01Q3/2617; H01Q3/2623; H04; H04B; H04B1/00; H04B1/06; H04B1/10; H04B1/12; H04B1/123; H04B1/126
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
296 words
Apparatus to suppress an interference signal on the same frequency as a desired signal, comprising: a) a sum and difference hybrid having a first and second input port and two output ports, one a sum port and the other a difference port, the first and second input ports receving signals from a first and second antenna respectively of a two antenna array directed at the desired signal source, b) a combiner having a first and second input port and one output port the first input port of the combiner being connected to the hybrid sum port and the second input port of the combiner being connected to the hybrid difference port, c) means for introducing a change in amplitude in the signal from one of the output ports of the hybrid to permit the interference signal component of said signal from the hybrid to be made equal in magnitude to the interference signal component of the signal from the other output port of the hybrid, and d) means for introducing a change in phase of substantially 90° in one of the output signals from the hybrid to permit the interference component of that signal to be placed in phase opposition with the interference component of the other output signal from the hybrid to produce cancellation of the interference signal components when the hybrid output signals are added in the combiner, said means for introducing a change in phase includes a variable phase shifter, a fixed 90° phase shifter, a switchable 180° phase shifter in series with the 90° phase shifter to produce in combination a plus 90° total phase shift when the 180° phase shifter is switched out of the circuit and a -90° phase shift when the 180° phase shifter is switched into the circuit.
Claim 2
Dependent Claim
296 words
Apparatus to suppress an interference signal on the same frequency as a desired signal, comprising: a) a sum and difference hybrid having a first and second input port and two output ports, one a sum port and the other a difference port, the first and second input ports receving signals from a first and second antenna respectively of a two antenna array directed at the desired signal source, b) a combiner having a first and second input port and one output port the first input port of the combiner being connected to the hybrid sum port and the second input port of the combiner being connected to the hybrid difference port, c) means for introducing a change in amplitude in the signal from one of the output ports of the hybrid to permit the interference signal component of said signal from the hybrid to be made equal in magnitude to the interference signal component of the signal from the other output port of the hybrid, and d) means for introducing a change in phase of substantially 90° in one of the output signals from the hybrid to permit the interference component of that signal to be placed in phase opposition with the interference component of the other output signal from the hybrid to produce cancellation of the interference signal components when the hybrid output signals are added in the combiner, said means for introducing a change in phase includes a variable phase shifter, a fixed 90° phase shifter, a switchable 180° phase shifter in series with the 90° phase shifter to produce in combination a plus 90° total phase shift when the 180° phase shifter is switched out of the circuit and a -90° phase shift when the 180° phase shifter is switched into the circuit.
Claim 3
Dependent Claim
20 words
Apparatus as claimed in claim 1, wherein said means for introducing a change in amplitude is an electronically controlled attenuator.
Claim 4
Dependent Claim
259 words
Apparatus as claimed in claim 2 further comprising a) a second sum and difference hybrid having a first and second input ports and two output ports, one output port being a sum port and the other a difference port, said second hybrid receiving at its first input port a signal from said second antenna and at its second input port a signal from a third antenna that is directed at the desired signal source and separated from the first two antennas in the horizontal plane, b) a phase detector having a first and second input ports and an output port, said phase detector receiving at its first and second input ports signals from the difference outputs of the first and second hybrid respectively to produce at the output port of the phase detector a signal corresponding to the phase difference between the interference signal components from the hybrid difference ports and thus a signal corresponding to the direction of the source of interference signal with respect to the direction of the antenna array. c) a shaping network having an input port and three output ports, said output ports, being connected to the electronic control input ports of the electronically controlled attenuator, switchable 180° phase shifter and variable phase shifter respectively, said shaping network adjusted to convert the output signal produced in accordance with the transfer function of the phase detected signal to the output control signals determined by the transfer function of the electronic phase shifter and attenuator to cancel the interference component in the output of the combiner.
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) | 1981-02-20 | 1981-08-22 | 1982-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-20 | 1985-08-22 | 1986-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-20 | 1989-08-22 | 1990-02-21 | $7700.00 | Window Closed / Lapsed |