US3839709A - Discriminative intruder-detecting system - Google Patents

Discriminative intruder-detecting system Download PDF

Info

Publication number
US3839709A
US3839709A US00289877A US28987772A US3839709A US 3839709 A US3839709 A US 3839709A US 00289877 A US00289877 A US 00289877A US 28987772 A US28987772 A US 28987772A US 3839709 A US3839709 A US 3839709A
Authority
US
United States
Prior art keywords
antenna
frequency
low
transceiver unit
space
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 - Lifetime
Application number
US00289877A
Other languages
English (en)
Inventor
K Sugiura
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.)
Hitachi Unisia Automotive Ltd
Original Assignee
Japan Electronic Control Systems Co Ltd
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 Japan Electronic Control Systems Co Ltd filed Critical Japan Electronic Control Systems Co Ltd
Application granted granted Critical
Publication of US3839709A publication Critical patent/US3839709A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • G08B13/2491—Intrusion detection systems, i.e. where the body of an intruder causes the interference with the electromagnetic field

Definitions

  • a discriminative intruder-detecting system includes a transceiver unit and a modulator unit both of which [22] Flled: Sept 1972 are completely separate from and unconnected to [21] App], N 289,877 each other.
  • the transceiver unit has an oscillator and antenna which cooperate to transmit waves of radio fre uenc throu h the s ace which is to be uarded.
  • the mod ulator unit has a dipole antenna grovided Sept. 28, 1971 Japan 4675 103 a pair of feed points to a low frequency OS- cillator is connected for introducing low-frequency [52] 340/258 340/276, 343/65 R components to the dipole antenna, this latter antenna Int. Cl.
  • 340/258 B carrying the modulator unit on his person and entering 3,400,393 9/1968 Ash 343/6.5 R the guarded space will not set off the warning device 3.471.845 10/1969 Soko1off..; 340/258 B while an unauthorized individual will reflect waves 3,478,344 l1/l969 Sewitegebel Ct 8i 343/65 SS ithout low frequency omponents back to the an- 3665'448 5/1972 McGlmchey 340/280 tenna of the transceiver unit so as to cause the warning device to operate.
  • the present invention relates to systems for detecting the presence of intruders in a space to which the intruders have gained unauthorized entry.
  • a discriminative intruder-detecting system which includes a radio transceiver unit adapted to be placed within a space which is to be guarded so as to remain stationary in this space.
  • the transceiver unit includes a radio-frequency oscillator means for generating an oscillation output of radio frequency and an antenna means which is operatively connected with the oscillator means for transmitting through the space which is to be guarded radio waves at the frequency. determined by the oscillator means.
  • a warning means is provided for giving a warning signal which indicates the presence of an intruder in the guarded space.
  • An electrical circuit means forms part of the transceiver unit and electrically connects the warning means to the transceiver unit for actuating the warning means in response to radio waves reflected from an intruder in the space and received by the antenna means.
  • a modulator unit is separate from and has no connection with the transceiver unit, this modulator unit being adapted to be carried on the person of an individual who is authorized to enter the guarded space.
  • the modulator unit includes a modulating antenna means which resonates at the radio frequency of the wave transmitted by the antenna means of the transceiver unit.
  • This modulator unit includes a means which is operatively connected to the modulator antenna means for introducing a lowfrequency component into the wave reflected by the modulator antenna means back to the antenna means of the transceiver unit.
  • waves received by the antenna means of the transceiver unit from an authorized individual in the guarded space who carries the modulator unit will include a low-frequency component.
  • the circuit means which electrically connects the warning means to the transceiver unit includes a detecting circuit means for detecting the presence of the waves receivedfrom the modulator antenna means with the low-frequency component and for preventing actuation of the warning means when the waves with the lowfrequency component are received by the antenna means of the transceiver unit.
  • FIG. 1 is a schematic diagram illustrating a transceiver unit and warning device used in the system of the invention.
  • FIG. 2 is a wiring diagram of a modulator unit of the invention.
  • the discriminative intruder-detecting system of the invention includes a transceiver unit which is illustrated in FIG. 1.
  • the transceiver unit which is illustrated in FIG. 1.
  • transceiver unit A shown in FIG. 1 is adapted to cooperate in the manner described below with a modulator unit B shown in FIG. 2, this latter unit B being separate from and having no connection with the transceiver unit A.
  • modulator unit B shown in FIG. 2 this latter unit B being separate from and having no connection with the transceiver unit A.
  • These units A and B cooperate with each other in such a way that a warning signal is not given by the warning means C shown at the right end of FIG. 1 when a person carrying the modulator B enters the space which is guarded by the transceiver unit A.
  • This transceiver unit A illustrated in FIG. 1 is of a type which is adapted to actuate the warning means C which is electrically connected to the remainder of the transceiver unit A through the illustrated circuitry.
  • This circuitry includes a radio-frequency oscillator means 1 of conventional construction which is capable of oscillating at radio frequency (for example, at several G Hz).
  • the oscillation output of the radio-frequency oscillator means 1 is transmitted from a fixed antenna means 2 carried by the transceiver unit A, this antenna means 2 being electrically connected with the oscillator means 1 and transmitting the waves of radio frequency throughout the space which is to be guarded when the unit A is installed in and remains stationary in the latter space.
  • the warning means C is located also in this space and is electrically connected to the transceiver unit A in the manner shown schematically in FIG. 1.
  • the modulator unit B which is illustrated in FIG. 2 is a portable unit of relatively small size which can conveniently be carried on the person of an authorized individual in a pocket, for example.
  • This unit B is completely separate from and has no connection with the unit A, as pointed out above.
  • this unit B also has no connection with the warning means C.
  • the construction of the modulator unit B is such that it will cooperate with the transceiver unit A.
  • This modulator unit B has a modulator antenna means 11 which resonates at the specific radio frequency of the waves transmitted by the stationary antenna means 2.
  • the modulator antenna means 11 is in the form of a half-wave dipole antenna.
  • the modulator unit B further includes an astable circuit (astable multivibrator) 12 in the form of a lowfrequency oscillator means 12 (this low-frequency oscillator means 13 including an amplifying circuit, etc.).
  • This low-frequency oscillator means generates a lowfrequency signal which is applied across the feed points 14 and 15 of the dipole antenna 11.
  • a directional means 16 is connected between these feed points 14 and 15 to which the low-frequency oscillator means is electrically connected.
  • this directional means takes the form of a semi-conductor diode.
  • the wave transmitted from the antenna means 2 of the transceiver unit A is reflected from the dipole antenna 11 while being modulated with a frequency at which the dipole antenna 11 is intermittently disconnected, this being the low-frequency oscillation generated by the low-frequency oscillator means 13, and the result is that the modulator means B reflects back to the antenna means 2 a radio wave which has low-frequency components.
  • the antenna means 11 resonates at the specific radio frequency of the wave transmitted from the antenna means 2 and reflects back to the latter antenna means a wave which has low-frequency components and which is received by the antenna means 2 and introduced into the transceiver unit A.
  • the transceiver unit A shown in FIG. 1 will receive the radio wave reflected back to the antenna means 2 from the antenna means 11 which contains the low-frequency components.
  • the electrical circuit means which connects the warning means C to the transceiver unit A includes not only the oscillator means 1 and the antenna 2 but also the detecting circuit means 3.
  • This detecting circuit means 3 is capable of responding to the presence of the low-frequency component in the waves received from the modulator antenna means 11, and with this circuitry the response of the detecting circuit means 3 to the presence of the low-frequency components will prevent the warning means C from being actuated.
  • the detecting circuit means 3 will operate to prevent the warning means C from being actuated, and thus no warning signal will be given in connection with the presence of an intruder in the guarded space.
  • the output signal resulting from the received waves which are received by the transceiver unit A of FIG. 1 is forced to pass through a filter circuit 4 and is then amplified by way of the amplifying circuit 5 so as to actuate a relay 6 which is connected with the amplifying circuit 5 in order to control the warning device C by opening and closing contacts of the delay 6.
  • the waves reflected from the intruder back to the antenna means 2 will not have the lowfrequency components, and under these circumstances the detecting circuit means 3 will not prevent operation of the warning means C, so that the warning signal will be given.
  • the portable modulator unit B of the invention Since the portable modulator unit B of the invention is carried about on a person who moves about in the guarded space, for example by walking around therein, this modulator unit B will necessarily move and there will thus be created the so-called Doppler-frequency signals at the transceiver unit A. It is also desirable to prevent the warning means C from being actuated by such Doppler-frequency signals. With the transceiver unit A which is shown in FIG. 1, the Doppler-frequency signals are eliminated by means of the filter circuit means 4 which forms part of the electrical circuit means connecting the warning means C to the transceiver unit A.
  • the oscillation frequency of the lowfrequency oscillator means 13 which forms part of the modulator unit B is selected so as to have a value which differs substantially from the Doppler-frequency, this difference being sufficient to enable the filter circuit means 4 to eliminate these signals and thus prevent undesirable actuation of the warning means C.
  • the discriminative intruder-detecting system of the invention may be conveniently installed in a reception room or in a warehouse into which persons will enter only for a limited time.
  • the intruder-detecting system of the invention there will be no warning signal as, for example, when a guard enters the guarded space in order to inspect this space which is guarded by the system of the invention, as long as the guard carries on his person the modulator unit B of FIG. 2.
  • a radio transceiver unit adapted to be placed within a space which is to be guarded and to remain stationary in said space, said transceiver unit including a radiofrequency oscillator means for generating an oscillation output of radio frequency and antenna means operatively connected with said oscillator means for transmitting through the space which is to be guarded radio waves at the frequency determined by said oscillator means, warning means for providing a warning signal which indicates the presence of an intruder in said space, electrical circuit means forming part of said transceiver unit and electrically connecting said warning means to said transceiver unit for preventing acutuation of said warning means in response to radio waves reflected from an authorized individual in said space and received by said antenna means, and a modulator unit separate from and having no connection with said transceiver unit, said modulator unit being adapted to be carried on the person of an indiviual who is authorized to enter the guarded space, said modulator unit including a modulating antenna means which resonates at
  • said modulating antennameans is a half-wave dipole antenna having a pair of feeding points, said means which is operatively connected to said dipole antenna for providing said low-frequency component including a lowfrequency oscillator means connected to said points for generating a low-frequency signal across said points, and a directional means connected between said points for electrically disconnecting said dipole antenna intermittently in response to the low-frequency signals from said low-frequency oscillator means, so that a wave transmitted from said antenna of said transceiver unit and reflected by said dipole antenna is modulated with the frequency at which said dipole antenna is intermittently disconnected, to provide the reflected radio wave which contains said low-frequency components.
  • said means for eliminating said Doppler-frequency signals includes a filter circuit means, and said means for introducing a low-frequency component including a lowfrequency oscillator means which is electrically connected with said modulating antenna means and which has an oscillation frequency sufficiently different from the Doppler frequency to permit said filter circuit means to filter one frequency from the other.
  • said lowfrequency oscillator means of said modulator unit forms said means operatively connected to said modulating antenna means for introducing a low-frequency component into the wave reflected thereby back to said antenna means of said transceiver unit
  • said modulating antenna means includes a half wave dipole antenna having a pair of feed points to which said lowfrequency oscillator means is electrically connected.
  • said modulator unit includes a directional means connected between said feed points for electrically disconnecting said dipole antenna intermittently in response to the low-frequency signals from said low-frequency oscillator means.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Burglar Alarm Systems (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
  • Transceivers (AREA)
  • Transmitters (AREA)
US00289877A 1971-09-28 1972-09-18 Discriminative intruder-detecting system Expired - Lifetime US3839709A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP46075103A JPS5143760B2 (enrdf_load_stackoverflow) 1971-09-28 1971-09-28

Publications (1)

Publication Number Publication Date
US3839709A true US3839709A (en) 1974-10-01

Family

ID=13566486

Family Applications (1)

Application Number Title Priority Date Filing Date
US00289877A Expired - Lifetime US3839709A (en) 1971-09-28 1972-09-18 Discriminative intruder-detecting system

Country Status (2)

Country Link
US (1) US3839709A (enrdf_load_stackoverflow)
JP (1) JPS5143760B2 (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4353064A (en) * 1981-01-14 1982-10-05 Honeywell Inc. Battery operated access control card
US4484182A (en) * 1981-07-01 1984-11-20 Shorrock Developments Limited Intruder detection apparatus for functioning free of disturbance while in close proximity to high-power pulse-moldulated radars
US4593273A (en) * 1984-03-16 1986-06-03 Narcisse Bernadine O Out-of-range personnel monitor and alarm
US5523739A (en) * 1994-05-31 1996-06-04 Manneschi; Alessandro Metal detector for control of access combined in an integrated form with a transponder detector
GB2347540A (en) * 1999-03-01 2000-09-06 Lea Ziff An alarm system
GB2350221A (en) * 1999-05-19 2000-11-22 Jeffrey Moss Woolf Intruder alarm system
FR2812433A1 (fr) * 2000-07-28 2002-02-01 Turquoise Com Internat Lda Procede et dispositif pour la protection en continu contre les intrusions dans des locaux eventuellement habites

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE791039A (fr) * 1971-11-08 1973-05-07 Lewis Security Syst Ltd Systemes de securite
JPS50122199A (enrdf_load_stackoverflow) * 1974-03-12 1975-09-25
JPS50122197A (enrdf_load_stackoverflow) * 1974-03-12 1975-09-25
JPS53121037A (en) * 1978-03-31 1978-10-23 Toyoda Gosei Co Ltd Primer composition
JP4489539B2 (ja) * 2004-09-03 2010-06-23 株式会社マキタ レーダ装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2400309A (en) * 1941-10-31 1946-05-14 Baldwin Co Oscillation generator
US3376507A (en) * 1962-01-08 1968-04-02 Varian Associates Balanced microwave hybrid function mixer assembly
US3400393A (en) * 1966-12-19 1968-09-03 Saul H. Ash Weapon safety mechanism
US3471845A (en) * 1966-05-27 1969-10-07 Sylvania Electric Prod Security system
US3478344A (en) * 1965-06-21 1969-11-11 Ralph K Schwitzgebel Behavioral supervision system with wrist carried transceiver
US3665448A (en) * 1970-08-03 1972-05-23 Hugh A Mcglinchey Electronic shoplifting prevention system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2400309A (en) * 1941-10-31 1946-05-14 Baldwin Co Oscillation generator
US3376507A (en) * 1962-01-08 1968-04-02 Varian Associates Balanced microwave hybrid function mixer assembly
US3478344A (en) * 1965-06-21 1969-11-11 Ralph K Schwitzgebel Behavioral supervision system with wrist carried transceiver
US3471845A (en) * 1966-05-27 1969-10-07 Sylvania Electric Prod Security system
US3400393A (en) * 1966-12-19 1968-09-03 Saul H. Ash Weapon safety mechanism
US3665448A (en) * 1970-08-03 1972-05-23 Hugh A Mcglinchey Electronic shoplifting prevention system

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4353064A (en) * 1981-01-14 1982-10-05 Honeywell Inc. Battery operated access control card
US4484182A (en) * 1981-07-01 1984-11-20 Shorrock Developments Limited Intruder detection apparatus for functioning free of disturbance while in close proximity to high-power pulse-moldulated radars
US4593273A (en) * 1984-03-16 1986-06-03 Narcisse Bernadine O Out-of-range personnel monitor and alarm
US5523739A (en) * 1994-05-31 1996-06-04 Manneschi; Alessandro Metal detector for control of access combined in an integrated form with a transponder detector
GB2347540A (en) * 1999-03-01 2000-09-06 Lea Ziff An alarm system
GB2347540B (en) * 1999-03-01 2002-10-02 Lea Ziff An alarm system
GB2350221A (en) * 1999-05-19 2000-11-22 Jeffrey Moss Woolf Intruder alarm system
FR2812433A1 (fr) * 2000-07-28 2002-02-01 Turquoise Com Internat Lda Procede et dispositif pour la protection en continu contre les intrusions dans des locaux eventuellement habites
WO2002011096A1 (fr) * 2000-07-28 2002-02-07 Turquoise Comercio Internacional Lda Procede et dispositif pour la protection en continu contre les intrusions dans des locaux eventuellement habites

Also Published As

Publication number Publication date
JPS5143760B2 (enrdf_load_stackoverflow) 1976-11-24
JPS4841697A (enrdf_load_stackoverflow) 1973-06-18

Similar Documents

Publication Publication Date Title
US5309144A (en) Proximity sensing security system
US3839709A (en) Discriminative intruder-detecting system
US3691558A (en) Moving object microwave detection system
US3732555A (en) Selective intrusion alarm system
US4139844A (en) Surveillance method and system with electromagnetic carrier and plural range limiting signals
US4275390A (en) Burglar alarm device
JPS6245504B2 (enrdf_load_stackoverflow)
US6633254B1 (en) Self-modulating remote moving target detector
US4092636A (en) Protective alarm system for window using reflected microwave energy
GB1440398A (en) Reuduction of false alarms in electronic theft-detection systems
US4161729A (en) Beacon add-on subsystem for collision avoidance system
US3863240A (en) Electromagnetic intrusion detection system
US3056951A (en) Safe alarm system
KR830004992A (ko) 차량용 침입 경보장치
US4284985A (en) Stolen equipment recovery device
US3579221A (en) Alarm system
US4243979A (en) Burglar alarm security circuit arrangement
US4134108A (en) Emergency alarm device
US20060255914A1 (en) System and transmitter
US3970940A (en) Overall equipment condition checking
US4224607A (en) Intruder detector system having improved uniformity of detection sensitivity
US4087802A (en) Method and apparatus for electronic surveillance of precisely defined control zone
US4843244A (en) Security sensors
GB2218553A (en) Security system
WO2000019236A1 (en) Object identification apparatus