GB1271643A - Improvements in or relating to inductive loop detector systems - Google Patents

Improvements in or relating to inductive loop detector systems

Info

Publication number
GB1271643A
GB1271643A GB3424068A GB3424068A GB1271643A GB 1271643 A GB1271643 A GB 1271643A GB 3424068 A GB3424068 A GB 3424068A GB 3424068 A GB3424068 A GB 3424068A GB 1271643 A GB1271643 A GB 1271643A
Authority
GB
United Kingdom
Prior art keywords
frequency
amplifiers
july
relating
detector
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
GB3424068A
Inventor
John Edwards
Michael Laurence Whittingham
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.)
Plessey Co Ltd
Original Assignee
Plessey 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 Plessey Co Ltd filed Critical Plessey Co Ltd
Priority to GB3424068A priority Critical patent/GB1271643A/en
Priority to IE96369A priority patent/IE33481B1/en
Publication of GB1271643A publication Critical patent/GB1271643A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/01—Detecting movement of traffic to be counted or controlled
    • G08G1/042—Detecting movement of traffic to be counted or controlled using inductive or magnetic detectors

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Traffic Control Systems (AREA)

Abstract

1,271,643. Road traffic detectors. PLESSEY CO. Ltd. 16 July, 1969 [18 July, 1968], No. 34240/68. Heading G4Q. A road traffic detection system comprises a number of detector circuits, each one being as shown in the drawing but operating at different frequencies from each other to avoid unwanted signals due to coupling between the inductive detector loops 3. Each circuit comprises an oscillator 1 coupled to a buried cable detector loop 3 tuned to the oscillator frequency. The passage of a vehicle over the loop alters its impedance to produce an output from a phase discriminator 4 which is amplified at 7 to operate a relay 8. To avoid unwanted signals at the outputs of the amplifiers 7, the difference between the operating frequencies of any two of the oscillators 1 is arranged to be outside the frequency response range of the amplifiers. As described, this frequency difference is arranged to be above the upper limit of the response range.
GB3424068A 1968-07-18 1968-07-18 Improvements in or relating to inductive loop detector systems Expired GB1271643A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB3424068A GB1271643A (en) 1968-07-18 1968-07-18 Improvements in or relating to inductive loop detector systems
IE96369A IE33481B1 (en) 1968-07-18 1969-07-14 Improvements in or relating to inductive loop detector systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3424068A GB1271643A (en) 1968-07-18 1968-07-18 Improvements in or relating to inductive loop detector systems

Publications (1)

Publication Number Publication Date
GB1271643A true GB1271643A (en) 1972-04-19

Family

ID=10363178

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3424068A Expired GB1271643A (en) 1968-07-18 1968-07-18 Improvements in or relating to inductive loop detector systems

Country Status (2)

Country Link
GB (1) GB1271643A (en)
IE (1) IE33481B1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2138613A (en) * 1983-03-16 1984-10-24 Sarasota Automation Inductive loop sensor
EP0697685A1 (en) * 1994-08-04 1996-02-21 Weiss-Electronic GmbH Elektronische Regel- und Steuergeräte, H. Weiss Method and device for determining the speed of vehicles

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2138613A (en) * 1983-03-16 1984-10-24 Sarasota Automation Inductive loop sensor
EP0697685A1 (en) * 1994-08-04 1996-02-21 Weiss-Electronic GmbH Elektronische Regel- und Steuergeräte, H. Weiss Method and device for determining the speed of vehicles
US5621314A (en) * 1994-08-04 1997-04-15 Weiss Electronic Elektronische Regel - Und Steuergerate Gmbh Method and device for determining the speed of vehicles via deriving a tripping curve

Also Published As

Publication number Publication date
IE33481L (en) 1970-01-18
IE33481B1 (en) 1974-07-10

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