GB1363574A - Data recording and replay systems - Google Patents

Data recording and replay systems

Info

Publication number
GB1363574A
GB1363574A GB982672A GB982672A GB1363574A GB 1363574 A GB1363574 A GB 1363574A GB 982672 A GB982672 A GB 982672A GB 982672 A GB982672 A GB 982672A GB 1363574 A GB1363574 A GB 1363574A
Authority
GB
United Kingdom
Prior art keywords
pulse
ones
long
circuit
recording
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
GB982672A
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.)
British Aircraft Corp Ltd
Original Assignee
British Aircraft Corp 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 British Aircraft Corp Ltd filed Critical British Aircraft Corp Ltd
Priority to GB982672A priority Critical patent/GB1363574A/en
Publication of GB1363574A publication Critical patent/GB1363574A/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
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/14—Digital recording or reproducing using self-clocking codes
    • G11B20/1403—Digital recording or reproducing using self-clocking codes characterised by the use of two levels
    • G11B20/1407—Digital recording or reproducing using self-clocking codes characterised by the use of two levels code representation depending on a single bit, i.e. where a one is always represented by a first code symbol while a zero is always represented by a second code symbol
    • G11B20/1419—Digital recording or reproducing using self-clocking codes characterised by the use of two levels code representation depending on a single bit, i.e. where a one is always represented by a first code symbol while a zero is always represented by a second code symbol to or from biphase level coding, i.e. to or from codes where a one is coded as a transition from a high to a low level during the middle of a bit cell and a zero is encoded as a transition from a low to a high level during the middle of a bit cell or vice versa, e.g. split phase code, Manchester code conversion to or from biphase space or mark coding, i.e. to or from codes where there is a transition at the beginning of every bit cell and a one has no second transition and a zero has a second transition one half of a bit period later or vice versa, e.g. double frequency code, FM code

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Recording Measured Values (AREA)

Abstract

1363574 Recording and transmitting digital data BRITISH AIRCRAFT CORP Ltd 29 March 1973 [2 March 1972] 9826/72 Heading G4C [Also in Division H4] Data words are recorded or transmitted using long and short pulses to represent binary digits, the number of ones and the number of zeros in each word being compared and the longest pulse length being selected to represent the binary value occurring least often, a signal indicating which pulse length represents the binary value " 1 " also being recorded or transmitted. As described counter 12 (Fig. 2) counts the number of ones in a word held in a shift register 10 and sets a coding selector 14 controlling a steering circuit 16 so that ones and zeros from the register are directed to either long pulse generator 18 or short pulse generator 20, the outputs of which are connected to recording or transmitting circuits 22. The first pulse fed to the circuit 22 is a long or short pulse indicative of the representation of the binary digit " 1 ". Decoding is effected by feeding the first pulse to a circuit (28, Fig. 3, not shown) controlling a decoder selector (30) which converts the received data back to its original form.
GB982672A 1973-03-29 1973-03-29 Data recording and replay systems Expired GB1363574A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB982672A GB1363574A (en) 1973-03-29 1973-03-29 Data recording and replay systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB982672A GB1363574A (en) 1973-03-29 1973-03-29 Data recording and replay systems

Publications (1)

Publication Number Publication Date
GB1363574A true GB1363574A (en) 1974-08-14

Family

ID=9879528

Family Applications (1)

Application Number Title Priority Date Filing Date
GB982672A Expired GB1363574A (en) 1973-03-29 1973-03-29 Data recording and replay systems

Country Status (1)

Country Link
GB (1) GB1363574A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2350009A1 (en) * 1976-04-26 1977-11-25 Minnesota Mining & Mfg METHOD AND DEVICE FOR CODING AND DECODING BINARY SIGNALS
DE2950132A1 (en) * 1979-12-13 1981-06-19 Brown, Boveri & Cie Ag, 6800 Mannheim Carrier PCM system - compares binary with clock and outputs signal reversal of state for similar states and defers one pulse for dissimilar
FR2635606A1 (en) * 1988-08-17 1990-02-23 France Etat Method of reading a longitudinal time code and device for implementing such a method

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2350009A1 (en) * 1976-04-26 1977-11-25 Minnesota Mining & Mfg METHOD AND DEVICE FOR CODING AND DECODING BINARY SIGNALS
DE2950132A1 (en) * 1979-12-13 1981-06-19 Brown, Boveri & Cie Ag, 6800 Mannheim Carrier PCM system - compares binary with clock and outputs signal reversal of state for similar states and defers one pulse for dissimilar
FR2635606A1 (en) * 1988-08-17 1990-02-23 France Etat Method of reading a longitudinal time code and device for implementing such a method

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee