FR2345773A1 - Burglar alarm surveillance system - uses detector applying impedance to signal circuit with output amplitude continuously compared with input signal amplitude - Google Patents

Burglar alarm surveillance system - uses detector applying impedance to signal circuit with output amplitude continuously compared with input signal amplitude

Info

Publication number
FR2345773A1
FR2345773A1 FR7608405A FR7608405A FR2345773A1 FR 2345773 A1 FR2345773 A1 FR 2345773A1 FR 7608405 A FR7608405 A FR 7608405A FR 7608405 A FR7608405 A FR 7608405A FR 2345773 A1 FR2345773 A1 FR 2345773A1
Authority
FR
France
Prior art keywords
signal
amplitude
surveillance system
burglar alarm
input signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
FR7608405A
Other languages
French (fr)
Inventor
Albert Ducornait
Jacques Topart
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Smith & Cie Ets
Original Assignee
Smith & Cie Ets
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Smith & Cie Ets filed Critical Smith & Cie Ets
Priority to FR7608405A priority Critical patent/FR2345773A1/en
Publication of FR2345773A1 publication Critical patent/FR2345773A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
    • G08B29/02—Monitoring continuously signalling or alarm systems
    • G08B29/06—Monitoring of the line circuits, e.g. signalling of line faults
    • G08B29/08—Signalling of tampering with the line circuit
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation

Abstract

The alarm and surveillance system continuously transmits a first signal. This first signal has a determined amplitude and frequency. The signal is sent along a line to which are connected a certain number of identical detectors. Each detector has in series the contact of a detector sensing variation in state and an impedance circuit. This impedance circuit is turned to the frequency of the first signal. A second signal is continuously transmitted along the line. This signal also having determined amplitude and frequency and is different to that of the first. The variation in amplitudes of the two signals on the line are detected and compared. In the case of detection of a difference greater than a predetermined step an alarm signal is triggered.
FR7608405A 1976-03-23 1976-03-23 Burglar alarm surveillance system - uses detector applying impedance to signal circuit with output amplitude continuously compared with input signal amplitude Withdrawn FR2345773A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR7608405A FR2345773A1 (en) 1976-03-23 1976-03-23 Burglar alarm surveillance system - uses detector applying impedance to signal circuit with output amplitude continuously compared with input signal amplitude

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7608405A FR2345773A1 (en) 1976-03-23 1976-03-23 Burglar alarm surveillance system - uses detector applying impedance to signal circuit with output amplitude continuously compared with input signal amplitude

Publications (1)

Publication Number Publication Date
FR2345773A1 true FR2345773A1 (en) 1977-10-21

Family

ID=9170814

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7608405A Withdrawn FR2345773A1 (en) 1976-03-23 1976-03-23 Burglar alarm surveillance system - uses detector applying impedance to signal circuit with output amplitude continuously compared with input signal amplitude

Country Status (1)

Country Link
FR (1) FR2345773A1 (en)

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Legal Events

Date Code Title Description
ST Notification of lapse