GB1527454A - Safety alarm system - Google Patents

Safety alarm system

Info

Publication number
GB1527454A
GB1527454A GB14809/77A GB1480977A GB1527454A GB 1527454 A GB1527454 A GB 1527454A GB 14809/77 A GB14809/77 A GB 14809/77A GB 1480977 A GB1480977 A GB 1480977A GB 1527454 A GB1527454 A GB 1527454A
Authority
GB
United Kingdom
Prior art keywords
audio frequency
frequency signal
modulated
radio
alarm
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.)
Expired
Application number
GB14809/77A
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.)
Securiton AG
Original Assignee
Securiton AG
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 Securiton AG filed Critical Securiton AG
Publication of GB1527454A publication Critical patent/GB1527454A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
    • H04B1/40—Circuits
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
    • G08B21/02—Alarms for ensuring the safety of persons
    • G08B21/0297—Robbery alarms, e.g. hold-up alarms, bag snatching alarms
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B25/00—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems
    • G08B25/01—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium
    • G08B25/016—Personal emergency signalling and security systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/02—Transmitters
    • H04B1/04—Circuits

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Security & Cryptography (AREA)
  • Alarm Systems (AREA)
  • Transmitters (AREA)

Abstract

Each transmitter of the security alarm system can be accommodated in a housing of a wristwatch and exhibits a crystal oscillator, the radio-frequency signal of which is modulated by an audio frequency supplied by an oscillator with piezo-electric resonator. This audio frequency forms a code signal. In the case of a threat, the person carrying the transmitter triggers the alarm and the modulated radio-frequency signal is radiated via an antenna. A receiver which is installed, for example, in a building, responds only to particular code signals. For this purpose, it exhibits an antenna, a receiving section for reception, amplification, mixing and demodulation of the modulated radio-frequency signal. The audio frequency at the output of the receiving section is supplied to a number of decoders each provided with a piezoelectric resonator as receiving filter and with an evaluating circuit so that the threatened person from which the alarm originates can be accurately determined.
GB14809/77A 1976-04-10 1977-04-07 Safety alarm system Expired GB1527454A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19762615769 DE2615769A1 (en) 1976-04-10 1976-04-10 SECURITY ALARM SYSTEM FOR TRANSMISSION OF CODED SIGNALS, WITH A TRANSMITTER DISCOVERED BY A PERSONAL PORTABLE TRANSMITTER

Publications (1)

Publication Number Publication Date
GB1527454A true GB1527454A (en) 1978-10-04

Family

ID=5975049

Family Applications (1)

Application Number Title Priority Date Filing Date
GB14809/77A Expired GB1527454A (en) 1976-04-10 1977-04-07 Safety alarm system

Country Status (5)

Country Link
CH (1) CH610128A5 (en)
DE (1) DE2615769A1 (en)
FR (1) FR2347831A1 (en)
GB (1) GB1527454A (en)
IT (1) IT1081342B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2120048A (en) * 1982-02-26 1983-11-23 Mitsubishi Electric Corp Rescue transmitter apparatus
US5625674A (en) * 1992-01-08 1997-04-29 Thomson Consumer Electronics, Inc. Use of a VCXO in the base unit of a two-handset cordless telephone system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2120048A (en) * 1982-02-26 1983-11-23 Mitsubishi Electric Corp Rescue transmitter apparatus
US5625674A (en) * 1992-01-08 1997-04-29 Thomson Consumer Electronics, Inc. Use of a VCXO in the base unit of a two-handset cordless telephone system
SG84476A1 (en) * 1992-01-08 2001-11-20 Thomson Consumer Electronics Use of vcxo in the base unit of a two-handset cordless telephone system

Also Published As

Publication number Publication date
IT1081342B (en) 1985-05-21
DE2615769A1 (en) 1977-10-27
CH610128A5 (en) 1979-03-30
FR2347831A1 (en) 1977-11-04

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee