Patent US3559181A successfully refreshed from Google Patents.
US3946315A
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Single frequency signalling in a radiotelephone communication system with idle condition signal generator at one terminal activated by another terminal
Assignee: Raytheon Co
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Filing: 1975-06-27
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Granted: 1976-03-23
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Expires: 1995-06-27
Abstract
Abstract Single frequency signaling system which simulates the low level tone during the idle circuit condition even though the radio frequency carriers in the transmission link through a repeater have been turned off. Said system utilizes 2600 Hz detectors having long time constants to turn the transmitters on and off and to connect 2600 Hz oscillators to the receive lines to simulate the idle circuit condition.
Inventors
- 👤 Galen F. Tustison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:57
CPC Classifications
H; H04; H04W; H04W84/00; H04W84/02; H04W84/10; H04W84/14
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
151 words
A communication system comprising at least two radio frequency terminals and a radio frequency repeater wherein at least one of the terminals comprises, in combination: a land based telephone system; a first radio frequency transmitter coupled to said land based telephone system; a first radio frequency receiver coupled to said land based telephone system; means for turning said first transmitter off whenever and so long as said telephone system generates an idle circuit condition signal to said first transmitter; means for generating an idle circuit condition signal; means for coupling said means for generating an idle circuit condition signal to said telephone system whenever an idle circuit condition signal is received by said first receiver for longer than a first time interval; and means for uncoupling said means for generating idle circuit condition signal from said telephone system upon the occurrence of a received radio frequency signal by said first receiver.
Claim 2
Dependent Claim
151 words
A communication system comprising at least two radio frequency terminals and a radio frequency repeater wherein at least one of the terminals comprises, in combination: a land based telephone system; a first radio frequency transmitter coupled to said land based telephone system; a first radio frequency receiver coupled to said land based telephone system; means for turning said first transmitter off whenever and so long as said telephone system generates an idle circuit condition signal to said first transmitter; means for generating an idle circuit condition signal; means for coupling said means for generating an idle circuit condition signal to said telephone system whenever an idle circuit condition signal is received by said first receiver for longer than a first time interval; and means for uncoupling said means for generating idle circuit condition signal from said telephone system upon the occurrence of a received radio frequency signal by said first receiver.
Claim 3
Dependent Claim
53 words
The communications system according to claim 1 wherein said means for turning said first transmitter off comprises: an ON/OFF control port in said first transmitter, said ON/OFF control port being responsive to digital signals; and a means for detecting the presence of an idle circuit condition signal coupled to said ON/OFF control port.
Claim 4
Dependent Claim
25 words
The communications system according to claim 2 wherein said means for detecting the presence of said idle circuit condition signal comprises a 2600 Hz detector.
Claim 5
Dependent Claim
22 words
The communications system according to claim 1 wherein said means for generating an idle circuit condition signal comprises a 2600 Hz oscillator.
Claim 6
Dependent Claim
147 words
The communications system according to claim 1 wherein said means for coupling the idle circuit condition signal generator comprises: a means for detecting the presence of the idle circuit condition signal; a flip-flop, said flip-flop having its set input coupled to the output of said means for detecting the presence of the idle circuit condition signal; a relay, said relay having a set of normally closed contacts and a set of normally open contacts, said normally closed contacts interposed between said first receiver and said telephone system and said normally open contacts interposed between said means for generating an idle circuit condition signal and said telephone system, said relay responsive to an output of said flip-flop to close said normally open contacts and open said normally closed contacts to couple said generating means to said telephone system and to uncouple said first receiver from said telephone system.
Claim 7
Dependent Claim
84 words
The communications system according to claim 5 wherein said means for uncoupling said idle circuit condition signal generator comprises: an automatic gain control output port in said first receiver providing a signal related to said received radio frequency signal; and a differentiator, said differentiator having its input and output coupled respectively to said AGC output port and the reset input of said flip-flop wherein a signal on said reset input allows said sets of relay contacts to assume said normally closed and open states.
Claim 8
Dependent Claim
65 words
The communications system according to claim 1 wherein at least one of the other terminals comprises, in combination: telephone terminal equipment device; a second radio frequency transmitter coupled to said equipment; a second radio frequency receiver coupled to said equipment; and means for turning said second transmitter off whenever and so long as said equipment generates an idle circuit condition signal to said second transmitter.
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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) | 1979-03-23 | 1979-09-22 | 1980-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-23 | 1983-09-22 | 1984-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-23 | 1987-09-22 | 1988-03-23 | $7700.00 | Window Closed / Lapsed |