GB1237109A - Discriminating amplifier for high frequency detection devices - Google Patents

Discriminating amplifier for high frequency detection devices

Info

Publication number
GB1237109A
GB1237109A GB5991068A GB5991068A GB1237109A GB 1237109 A GB1237109 A GB 1237109A GB 5991068 A GB5991068 A GB 5991068A GB 5991068 A GB5991068 A GB 5991068A GB 1237109 A GB1237109 A GB 1237109A
Authority
GB
United Kingdom
Prior art keywords
counter
pulses
circuit
alarm
trigger
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
GB5991068A
Inventor
Norman Ian Buckley
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.)
Shorrock Developments Ltd
Original Assignee
Shorrock Developments 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 Shorrock Developments Ltd filed Critical Shorrock Developments Ltd
Priority to GB5991068A priority Critical patent/GB1237109A/en
Publication of GB1237109A publication Critical patent/GB1237109A/en
Expired legal-status Critical Current

Links

Classifications

    • 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

Landscapes

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

Abstract

1,237,109. Burglar alarms. SHORROCK DEVELOPMENTS Ltd. 4 Dec., 1969 [17 Dec., 1968], No. 59910/68. Heading G4N. A discriminating device for use with a Doppler alarm system comprises a band-pass amplifier 1 feeding a trigger circuit 2 arranged to produce pulses in the event of movement of an intruder within the field of surveillance, a first counter 3 responsive to said pulses and a change-over circuit 4 actuated by the first counter 3 on receipt of a first number of pulses within a first predetermined time to connect said pulses to a second counter 5 and an alarm circuit 6 actuated on receipt of a second number of pulses by said second counter 5 within a second time. The circuit is applicable to operation with an X-band Gunn diode transmitter-receiver (not shown). Amplifier 1 should pass frequencies in the range 1-300 Hz. which are squared in a Schmitt trigger 2 and passed by a zener diode D1 to an emitter follower T6 feeding the first and second counters 3, 5. In the first counter 3, capacitor C1 is charged step-wise by T7, D2. If five pulses are received in two seconds, capacitor C1 will be charged sufficiently to trigger monostable circuit T10, T11 which turns on T8 so as to inhibit the first counter 3. The monostable circuit 4 also turns off T12 so that the second counter 5 is rendered operative. If 40 pulses are received during the two minute period of timer 4, a transistor circuit T14 . . . T17 is triggered which releases relay R and operates an alarm. The various time periods are selected so that the alarm is not operated by movements of small objects.
GB5991068A 1968-12-17 1968-12-17 Discriminating amplifier for high frequency detection devices Expired GB1237109A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB5991068A GB1237109A (en) 1968-12-17 1968-12-17 Discriminating amplifier for high frequency detection devices

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5991068A GB1237109A (en) 1968-12-17 1968-12-17 Discriminating amplifier for high frequency detection devices

Publications (1)

Publication Number Publication Date
GB1237109A true GB1237109A (en) 1971-06-30

Family

ID=10484632

Family Applications (1)

Application Number Title Priority Date Filing Date
GB5991068A Expired GB1237109A (en) 1968-12-17 1968-12-17 Discriminating amplifier for high frequency detection devices

Country Status (1)

Country Link
GB (1) GB1237109A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2475742A1 (en) * 1980-02-07 1981-08-14 Dreuilhe Jacqueline Movement detecting radar head - includes anti-masking circuit initiating alarm if large object causes high level of reflected radiation to be received
GB2271873A (en) * 1992-09-03 1994-04-27 Josef Petr Prokopius Electronic burglar alarm system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2475742A1 (en) * 1980-02-07 1981-08-14 Dreuilhe Jacqueline Movement detecting radar head - includes anti-masking circuit initiating alarm if large object causes high level of reflected radiation to be received
GB2271873A (en) * 1992-09-03 1994-04-27 Josef Petr Prokopius Electronic burglar alarm system
GB2271873B (en) * 1992-09-03 1997-02-26 Josef Petr Prokopius Electronic burglar alarm system

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