GB1308701A - Intrusion detection apparatus having protection against jamming - Google Patents

Intrusion detection apparatus having protection against jamming

Info

Publication number
GB1308701A
GB1308701A GB1152970A GB1152970A GB1308701A GB 1308701 A GB1308701 A GB 1308701A GB 1152970 A GB1152970 A GB 1152970A GB 1152970 A GB1152970 A GB 1152970A GB 1308701 A GB1308701 A GB 1308701A
Authority
GB
United Kingdom
Prior art keywords
alarm
amplifier
signals
transistor
doppler
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
GB1152970A
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.)
Johnson Service Co
Original Assignee
Johnson Service Co
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 Johnson Service Co filed Critical Johnson Service Co
Publication of GB1308701A publication Critical patent/GB1308701A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K3/00—Jamming of communication; Counter-measures
    • H04K3/80—Jamming or countermeasure characterized by its function
    • H04K3/88—Jamming or countermeasure characterized by its function related to allowing or preventing alarm transmission
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/50—Systems of measurement based on relative movement of target
    • G01S13/52—Discriminating between fixed and moving objects or between objects moving at different speeds
    • G01S13/56—Discriminating between fixed and moving objects or between objects moving at different speeds for presence detection
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K3/00—Jamming of communication; Counter-measures
    • H04K3/20—Countermeasures against jamming
    • H04K3/22—Countermeasures against jamming including jamming detection and monitoring

Landscapes

  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • Signal Processing (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Burglar Alarm Systems (AREA)

Abstract

1308701 Intruder alarms JOHNSON SERVICE CO 10 March 1970 [10 March 1969] 11629/70 Heading G4N [Also in Division H4] A detection system comprises a microwave transmitter, a receiver and amplifier, an alarm responsive to signals of predetermined amplitude in a predetermined range of Doppler frequencies and means responsive to an amplifier output greater than said predetermined amplitude. In a system for detecting an intruder in a surveillance area, a transistor oscillator 1 feeds through a coaxial cavity 18 to a transmitting aerial 2. The oscillator frequency is controlled by a regulated D.C. bias or line 21, which is modulated by a free-running transistor multivibrator 8. Signals received at aerial 6 thus have a background component of the modulating frequency, e.g. 500 Hz, as well as the Doppler signals, e.g. 1-180 Hz due to moving objects in the surveillance area. The mixer 10 output passes through a low pass amplifier having # rapid roll-off above 180 Hz. The three parallel detector channels 12-14 are responsive to different kinds of signals. The motion alarm circuit 12 has a filter passing only the expected Doppler frequencies, followed by a Schmitt trigger which on reception of a Doppler signal of large enough amplitude, turns off transistor 24 which de-energizes coil 27 thus operating the alarm relay 17. Supervisory circuit 13 is receptive only to the modulation frequency of 500 Hz and integrates the signals to prevent operation of a second alarm. If the transmitter or receiver malfunction, the supervisory signal is lost and the second alarm is triggered. A signal at a frequency inside the roll-off portion of the amplifier 11 characteristic could saturate amplifier 11 without operating the motion alarm and thereby de-sensitise the apparatus to Doppler signals. Anti-jamming circuit 14includes a high part filler 30 producing with amplifier 11 an overall constant gain-with-frequency response. The filter output is detected by diode 35 and fed to the base of transistor 29. If the signal amplitude is high enough, the transistor will turn off thereby operating the alarm 17.
GB1152970A 1969-03-10 1970-03-10 Intrusion detection apparatus having protection against jamming Expired GB1308701A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US80562269A 1969-03-10 1969-03-10

Publications (1)

Publication Number Publication Date
GB1308701A true GB1308701A (en) 1973-03-07

Family

ID=25192050

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1152970A Expired GB1308701A (en) 1969-03-10 1970-03-10 Intrusion detection apparatus having protection against jamming

Country Status (4)

Country Link
US (1) US3618083A (en)
DE (1) DE2011380A1 (en)
FR (1) FR2037882A5 (en)
GB (1) GB1308701A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2257590A (en) * 1991-06-26 1993-01-13 C & K Systems Inc Microwave operated automatic door

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3961323A (en) * 1971-02-22 1976-06-01 American Multi-Lert Corporation Cargo monitor apparatus and method
US3733602A (en) * 1971-05-20 1973-05-15 Motorola Inc Microwave intrusion detecting system and apparatus
US3760400A (en) * 1972-02-10 1973-09-18 Aerospace Res Intrusion detection system employing quadrature sampling
US3886549A (en) * 1972-03-24 1975-05-27 Omni Spectra Inc Intrusion detection system
US3877002A (en) * 1973-05-25 1975-04-08 Omni Spectra Inc Intrusion detecting system
US3947834A (en) * 1974-04-30 1976-03-30 E-Systems, Inc. Doppler perimeter intrusion alarm system using a leaky waveguide
US4622539A (en) * 1984-05-03 1986-11-11 Honeywell Inc. Alarm system with alarm message supervision
GB8627332D0 (en) * 1986-11-14 1987-03-18 Marconi Co Ltd Radar system
US5469180A (en) * 1994-05-02 1995-11-21 Motorola, Inc. Method and apparatus for tuning a loop antenna
US5950110A (en) * 1997-08-06 1999-09-07 Interactive Techanologies, Inc. Jamming detection in a wireless security system
US6114955A (en) * 1998-06-03 2000-09-05 Interactive Technologies, Inc. System and method for antenna failure detection
JP3793822B1 (en) * 2005-01-07 2006-07-05 オプテックス株式会社 Microwave sensor
JP4747652B2 (en) * 2005-04-15 2011-08-17 株式会社デンソー FMCW radar
US9905120B1 (en) 2016-08-29 2018-02-27 At&T Digital Life, Inc. Alarm initiation when sensor is intentionally jammed
CN110398781A (en) * 2019-08-05 2019-11-01 深圳迈睿智能科技有限公司 Anti-interference microwave sounding module and anti-interference method

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3111657A (en) * 1960-03-16 1963-11-19 Specialties Dev Corp Compensation for turbulence and other effects in intruder detection systems
US3242486A (en) * 1962-04-20 1966-03-22 Johnson Service Co Intrusion detection system
FR1332066A (en) * 1962-05-30 1963-12-16
US3378834A (en) * 1966-05-10 1968-04-16 Johnson Service Co Perimeter intrusion detection system
US3383678A (en) * 1966-12-23 1968-05-14 Advanced Devices Lab Inc Moving object detection system
US3465336A (en) * 1968-05-09 1969-09-02 Us Army Doppler radar with clutter controlled filter channel

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2257590A (en) * 1991-06-26 1993-01-13 C & K Systems Inc Microwave operated automatic door

Also Published As

Publication number Publication date
DE2011380A1 (en) 1970-09-24
FR2037882A5 (en) 1970-12-31
US3618083A (en) 1971-11-02

Similar Documents

Publication Publication Date Title
GB1308701A (en) Intrusion detection apparatus having protection against jamming
GB1406925A (en) Surveillance system and method utilizing both electrostatic and electromagnetic fields
US4605922A (en) Intrusion detector
GB1342552A (en) Intruder detection systems
GB1440398A (en) Reuduction of false alarms in electronic theft-detection systems
ES2113883T3 (en) PERIODIC IMPULSE DISCRIMINATION SYSTEM.
US3863240A (en) Electromagnetic intrusion detection system
GB1392767A (en) Ultrasonic alarm circuit
GB1448336A (en) Intrusion detection system
GB1161743A (en) Improvements in or relating to signalling and communication systems
GB1432514A (en) Variable frequency communicating apparatus
US3706982A (en) Intrusion detection system
GB1450236A (en) Intrusion detector
GB1424026A (en) Radar systems
GB1454626A (en) Transmitter output monitor for a dvor beacon system
GB1205153A (en) Intrusion detector radar system
ES8503874A1 (en) Motion detection systems.
GB1308702A (en) Intrusion detection apparatus having supervisory control means
ES442400A1 (en) Systems for the detection of moving objects within a survey area by microwave diffraction
GB1390913A (en) Monitoring systems
US4529972A (en) Signal transmitting and receiving arrangements
FR2351461A1 (en) Theft deterrent system with radio transmitters - has each object fitted with transmitter providing alarm signal when carried out of range
GB1520196A (en) Alarm and theft prevention apparatus
US3500401A (en) Radar detection device
GB1222871A (en) Improvements in or relating to detection systems

Legal Events

Date Code Title Description
PS Patent sealed [section 19, patents act 1949]
PCNP Patent ceased through non-payment of renewal fee