Patent US3613093A successfully refreshed from Google Patents.
US3613093A
Expired / Lapsed
US
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Surveillance system with improved detecting network
Assignee: POSTMASTER GENERAL USA
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Filing: 1969-09-29
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Granted: 1971-10-12
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Expires: 1989-09-29
Abstract
Abstract This invention relates to a surveillance system utilizing a telephone line not only for transmitting an alarm signal between an area under surveillance and a central monitoring station but also for supplying the power necessary for the operation of the system. In the operation of one embodiment of this system, electrical signals are generated by a pickup transducer in response to the detection of an intrusion into the area under surveillance, are amplified, and are supplied to a detecting network. After insuring that the signals received are the result of an actual intrusion and not the result of some extraneous noise, the detecting network is operative to trigger an alarm circuit whereby an alarm signal is transmitted via a telephone line to a central monitoring station.
Inventors
- 👤 David Woodward Reynolds
- 👤 Donald George Hang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:11
CPC Classifications
H; H04; H04M; H04M11/00; H04M11/04; G; G08; G08B; G08B13/00; G08B13/16; G08B13/1654; G08B13/1672
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
178 words
An electronic surveillance means comprising: a. Acoustical transducer means for converting sound energy into electrical signals; b. Transistor means for amplifying said electrical signals; c. Alarm means responsive to said amplified signals for indicating at a monitoring station an intrusion, said alarm means including; 1. a unijunction oscillator circuit, 2. a resistor connected in electrical shunt with said unijunction oscillator circuit, and 3. means for connecting said unijunction oscillator circuit and said resistor to a telePhone line; d. Means for preventing said alarm means from responding to said amplified signals until a predetermined time interval has passed sufficient to insure that said electrical signals from said transducer means is in response to an actual intrusion, said preventing means including; 1. solid state switching means for selectively connecting said alarm means to the telephone line, 2. integration means for controlling the operation of said solid state switching means, and 3. limiting means for limiting the current to said integration means thereby insuring that a sufficient number of sounds are present from an intrusion before said alarm means is activated.
Claim 2
Dependent Claim
178 words
An electronic surveillance means comprising: a. Acoustical transducer means for converting sound energy into electrical signals; b. Transistor means for amplifying said electrical signals; c. Alarm means responsive to said amplified signals for indicating at a monitoring station an intrusion, said alarm means including; 1. a unijunction oscillator circuit, 2. a resistor connected in electrical shunt with said unijunction oscillator circuit, and 3. means for connecting said unijunction oscillator circuit and said resistor to a telePhone line; d. Means for preventing said alarm means from responding to said amplified signals until a predetermined time interval has passed sufficient to insure that said electrical signals from said transducer means is in response to an actual intrusion, said preventing means including; 1. solid state switching means for selectively connecting said alarm means to the telephone line, 2. integration means for controlling the operation of said solid state switching means, and 3. limiting means for limiting the current to said integration means thereby insuring that a sufficient number of sounds are present from an intrusion before said alarm means is activated.
Claim 3
Dependent Claim
12 words
a resistor connected in electrical shunt with said unijunction oscillator circuit, and
Claim 4
Dependent Claim
12 words
a resistor connected in electrical shunt with said unijunction oscillator circuit, and
Claim 5
Dependent Claim
13 words
integration means for controlling the operation of said solid state switching means, and
Claim 6
Dependent Claim
13 words
integration means for controlling the operation of said solid state switching means, and
Claim 7
Dependent Claim
80 words
An electronic surveillance means as described in claim 1 wherein: a. Said solid state switching means comprises a silicon controlled rectifier having a trigger electrode; and b. Said integration means comprises a capacitive network connected to the output of said amplifying means, a said capacitive network being coupled to said trigger electrode and controlling the conducting state of said silicon controlled rectifier, said silicon controlled rectifier operable to connect said unijunction oscillator circuit and said resistor to a telephone line.
Claim 8
Dependent Claim
49 words
An electronic surveillance means as described in claim 2, further including: a. Resistor means for dissipating any charge on said capacitive means to restore it to an uncharged condition, and b. Switch means operable to connect said resistor means directly across said capacitive means for dissipating any charge thereon.
Claim 9
Dependent Claim
29 words
limiting means for limiting the current to said integration means thereby insuring that a sufficient number of sounds are present from an intrusion before said alarm means is activated.
Claim 10
Dependent Claim
29 words
limiting means for limiting the current to said integration means thereby insuring that a sufficient number of sounds are present from an intrusion before said alarm means is activated.
Claim 11
Dependent Claim
56 words
means for connecting said unijunction oscillator circuit and said resistor to a telePhone line; d. Means for preventing said alarm means from responding to said amplified signals until a predetermined time interval has passed sufficient to insure that said electrical signals from said transducer means is in response to an actual intrusion, said preventing means including;
Claim 12
Dependent Claim
56 words
means for connecting said unijunction oscillator circuit and said resistor to a telePhone line; d. Means for preventing said alarm means from responding to said amplified signals until a predetermined time interval has passed sufficient to insure that said electrical signals from said transducer means is in response to an actual intrusion, said preventing means including;
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-11 | 1975-04-12 | 1975-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-11 | 1979-04-12 | 1979-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-11 | 1983-04-12 | 1983-10-12 | $7700.00 | Window Closed / Lapsed |