GB1529566A - Magnetic recording - Google Patents

Magnetic recording

Info

Publication number
GB1529566A
GB1529566A GB4474774A GB4474774A GB1529566A GB 1529566 A GB1529566 A GB 1529566A GB 4474774 A GB4474774 A GB 4474774A GB 4474774 A GB4474774 A GB 4474774A GB 1529566 A GB1529566 A GB 1529566A
Authority
GB
United Kingdom
Prior art keywords
tape
watermarked
magnetic
oct
detected
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
GB4474774A
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.)
EMI Ltd
Original Assignee
EMI 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 EMI Ltd filed Critical EMI Ltd
Priority to GB4474774A priority Critical patent/GB1529566A/en
Priority to DE19752545580 priority patent/DE2545580A1/en
Priority to FR7531358A priority patent/FR2288369A1/en
Priority to NL7512181A priority patent/NL7512181A/en
Priority to JP50124866A priority patent/JPS5165605A/ja
Publication of GB1529566A publication Critical patent/GB1529566A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B23/00—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
    • G11B23/28—Indicating or preventing prior or unauthorised use, e.g. cassettes with sealing or locking means, write-protect devices for discs
    • G11B23/281—Indicating or preventing prior or unauthorised use, e.g. cassettes with sealing or locking means, write-protect devices for discs by changing the physical properties of the record carrier
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K1/00—Methods or arrangements for marking the record carrier in digital fashion
    • G06K1/12—Methods or arrangements for marking the record carrier in digital fashion otherwise than by punching
    • G06K1/125—Methods or arrangements for marking the record carrier in digital fashion otherwise than by punching by magnetic means
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/02—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the selection of materials, e.g. to avoid wear during transport through the machine
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
    • G11B20/00094—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving measures which result in a restriction to authorised record carriers
    • G11B20/00123—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving measures which result in a restriction to authorised record carriers the record carrier being identified by recognising some of its unique characteristics, e.g. a unique defect pattern serving as a physical signature of the record carrier
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B23/00—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
    • G11B23/30—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture with provision for auxiliary signals
    • G11B23/36—Signals on record carriers or on containers and recorded by the same method as the main recording
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
    • G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
    • G11B27/19—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier
    • G11B27/28—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
    • G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
    • G11B5/842—Coating a support with a liquid magnetic dispersion
    • G11B5/845—Coating a support with a liquid magnetic dispersion in a magnetic field

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Signal Processing (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Magnetic Record Carriers (AREA)
  • Paints Or Removers (AREA)
  • Manufacturing Of Magnetic Record Carriers (AREA)

Abstract

1529566 "Watermarked" magnetic tape EMI Ltd 2 Oct 1975 [16 Oct 1974 21 Jan 1975] 44747/74 and 2546/75 Heading G5R Magnetic tape in which the preferred axes of magnetization of the particles forming the magnetic layer are normally aligned in the direction of tape length, is "watermarked" during manufacture by altering the orientation of the preferred axes at positions along the length of the tape. The magnetic axis of the particles is changed through an angle of about 25 degrees only whereby the resultant change in remanence at these positions is sufficiently low not to interfere with the playback of a signal recorded on the tape yet is of sufficient level to be detected. Where the "watermarked" tape has a number of tracks one of these can be used for detection purposes only or where the tape is single track an information free part of the track can be magnetized with a unidirectional field so that the watermark signal can be detected.
GB4474774A 1974-10-16 1974-10-16 Magnetic recording Expired GB1529566A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
GB4474774A GB1529566A (en) 1974-10-16 1974-10-16 Magnetic recording
DE19752545580 DE2545580A1 (en) 1974-10-16 1975-10-11 MAGNETIC RECORDING CARRIER, METHOD OF MANUFACTURING THEREOF, AND INFORMATION RECORDING SYSTEM
FR7531358A FR2288369A1 (en) 1974-10-16 1975-10-14 MAGNETIC RECORDING
NL7512181A NL7512181A (en) 1974-10-16 1975-10-16 MAGNETIC RECORDING MEDIUM AND METHOD FOR ITS MANUFACTURE.
JP50124866A JPS5165605A (en) 1974-10-16 1975-10-16

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB4474774A GB1529566A (en) 1974-10-16 1974-10-16 Magnetic recording
GB254675 1975-01-21

Publications (1)

Publication Number Publication Date
GB1529566A true GB1529566A (en) 1978-10-25

Family

ID=26237585

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4474774A Expired GB1529566A (en) 1974-10-16 1974-10-16 Magnetic recording

Country Status (5)

Country Link
JP (1) JPS5165605A (en)
DE (1) DE2545580A1 (en)
FR (1) FR2288369A1 (en)
GB (1) GB1529566A (en)
NL (1) NL7512181A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0067178A1 (en) * 1980-12-16 1982-12-22 Minnesota Mining Mfg Australia Method and apparatus for verification of recorded messages.

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4242400A (en) * 1977-10-15 1980-12-30 E M I Limited Magnetically structured materials
JPS5552564A (en) * 1978-10-13 1980-04-17 Sony Corp Check unit for suitability of stuck label of tape cassette
DE2922882A1 (en) * 1979-06-06 1980-12-11 Stockburger H METHOD FOR SECURING CARTRIDGES AND THEIR LABELS AND / OR PACKAGING AGAINST IMITATION
FR2515403A1 (en) * 1981-10-28 1983-04-29 Quadrivium Inf METHOD FOR IDENTIFYING A SOUND RECORDING AND DUPLICATION INSTALLATION IMPLEMENTING THE METHOD
FR2534433B1 (en) * 1982-10-08 1986-04-11 Thomson Csf METHOD FOR PROTECTING A SEQUENCE OF VIDEO IMAGES AGAINST FRAUDULENT USE AND DEVICES FOR CARRYING OUT SAID METHOD
DE3319343A1 (en) * 1982-11-08 1984-05-10 Vault Corp METHOD AND DEVICE FOR THE IMPOSSIBILITY OF UNAUTHORIZED COPIES OF RECORDED DATA
DE3375854D1 (en) * 1982-11-22 1988-04-07 Dysan Corp Method and apparatus for authenticating memory disk
AT378620B (en) * 1983-08-11 1985-09-10 Heinz Seidl MAGNETOGRAM CARRIER WHOSE ORIGIN IS NON-REMARKABLY MARKED
JPH0512068Y2 (en) * 1985-02-27 1993-03-26
JPH0512067Y2 (en) * 1985-02-27 1993-03-26
JPS62502297A (en) * 1985-03-18 1987-09-03 ミネソタ　マイニング　アンド　マニユフアクチユアリング　コンパニ− Magnetic tape cassette with prerecorded infrasound
JP2569294Y2 (en) * 1991-01-25 1998-04-22 日産自動車株式会社 Striatum protector

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0067178A1 (en) * 1980-12-16 1982-12-22 Minnesota Mining Mfg Australia Method and apparatus for verification of recorded messages.
EP0067178A4 (en) * 1980-12-16 1983-02-09 Minnesota Mining Mfg Australia Method and apparatus for verification of recorded messages.

Also Published As

Publication number Publication date
NL7512181A (en) 1976-04-21
JPS5165605A (en) 1976-06-07
DE2545580A1 (en) 1976-05-06
FR2288369A1 (en) 1976-05-14

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Legal Events

Date Code Title Description
PS Patent sealed
746 Register noted 'licences of right' (sect. 46/1977)
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PE20 Patent expired after termination of 20 years

Effective date: 19951001