US3601550A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Loop communication system
Assignee: Zenith Electronics LLC
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Filing: 1969-03-21
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Granted: 1971-08-24
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Expires: 1989-03-21
Abstract
Abstract A limited-range, induction-coupled loop communication system for the transmission of audio information to a receiver located within the loop uses a frequency-modulated carrier-wave signal to transmit audio information to one or more receivers located within the loop. Each receiver has a pair of pickup coils preferably mounted at 90* relative to each other and a phaseshifting network connected to each of their outputs to thereby create a quadrature relationship in the received signals to substantially eliminate the occurrence of null conditions with variations in receiver orientation.
Inventors
- 👤 John G Spracklen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:17
CPC Classifications
H; H04; H04B; H04B5/00; H04B10/00; H04B10/50
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
173 words
S A limited-range, induction-coupled communication system for the wireless transmission of information to a receiver located within a predetermined limited space, comprising: means for providing a carrier-wave signal having a predetermined center frequency and modulated with a signal representative of said information; transmitter means including a closed-loop antenna for transmitting said carrier-wave signal to said space and establishing therein an electromagnetic radiation field having a predetermined direction; input circuit means for receiving said carrier-wave signal, including a pair of input transducers each having a maximumsignal-coupling axis orthogonally oriented relative to each other, each said input transducer providing a separate output signal representative of said modulated carrier-wave signal; phase-shifting networks respectively coupled to said input transducers and providing phase shifts of substantially 45* and 135* respectively for establishing a quadrature phase relation between said output signals; means for combining said separate phase-shifted output signals; detector means responsive to said combined output signal for recovering said modulation signal; and output transducer means for converting said recovered modulation signal into output information corresponding to that transmitted
Claim 2
Dependent Claim
173 words
S A limited-range, induction-coupled communication system for the wireless transmission of information to a receiver located within a predetermined limited space, comprising: means for providing a carrier-wave signal having a predetermined center frequency and modulated with a signal representative of said information; transmitter means including a closed-loop antenna for transmitting said carrier-wave signal to said space and establishing therein an electromagnetic radiation field having a predetermined direction; input circuit means for receiving said carrier-wave signal, including a pair of input transducers each having a maximumsignal-coupling axis orthogonally oriented relative to each other, each said input transducer providing a separate output signal representative of said modulated carrier-wave signal; phase-shifting networks respectively coupled to said input transducers and providing phase shifts of substantially 45* and 135* respectively for establishing a quadrature phase relation between said output signals; means for combining said separate phase-shifted output signals; detector means responsive to said combined output signal for recovering said modulation signal; and output transducer means for converting said recovered modulation signal into output information corresponding to that transmitted
Claim 3
Dependent Claim
157 words
A receiver adaptable for use with a limited-range, induction-coupled communication system of the type including a transmitter employing a carrier-wave signal modulated with a signal representative of information for transmission to a predetermined limited space by establishing an electromagnetic field having a predetermined direction in said space, said receiver comprising: input circuit means for receiving said modulated carrier-wave signal, including a pair of input transducers each having a maximum-signal-coupling axis orthogonally oriented relative to each other, each said input transducer providing a separate output signal representative of said audio-modulated carrier-wave signal; phase-shifting networks respectively coupled to said input transducers and providing phase shifts of substantially 45* and 135* respectively for establishing a quadrature phase relation between said output signals; means for combining said separate phase-shifted output signals; detector means responsive to said combined output signal for recovering said modulation signal; and output transducer means for converting said recovered moduLation signal into output information corresponding to that transmitted.
Claim 4
Dependent Claim
157 words
A receiver adaptable for use with a limited-range, induction-coupled communication system of the type including a transmitter employing a carrier-wave signal modulated with a signal representative of information for transmission to a predetermined limited space by establishing an electromagnetic field having a predetermined direction in said space, said receiver comprising: input circuit means for receiving said modulated carrier-wave signal, including a pair of input transducers each having a maximum-signal-coupling axis orthogonally oriented relative to each other, each said input transducer providing a separate output signal representative of said audio-modulated carrier-wave signal; phase-shifting networks respectively coupled to said input transducers and providing phase shifts of substantially 45* and 135* respectively for establishing a quadrature phase relation between said output signals; means for combining said separate phase-shifted output signals; detector means responsive to said combined output signal for recovering said modulation signal; and output transducer means for converting said recovered moduLation signal into output information corresponding to that transmitted.
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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) | 1974-08-23 | 1975-02-22 | 1975-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-23 | 1979-02-22 | 1979-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-23 | 1983-02-22 | 1983-08-24 | $7700.00 | Window Closed / Lapsed |