GB2016762A - MFM data encoder with write precompensation - Google Patents

MFM data encoder with write precompensation

Info

Publication number
GB2016762A
GB2016762A GB7907381A GB7907381A GB2016762A GB 2016762 A GB2016762 A GB 2016762A GB 7907381 A GB7907381 A GB 7907381A GB 7907381 A GB7907381 A GB 7907381A GB 2016762 A GB2016762 A GB 2016762A
Authority
GB
United Kingdom
Prior art keywords
precompensation
mfm
write precompensation
write
rom
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.)
Granted
Application number
GB7907381A
Other versions
GB2016762B (en
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.)
Tektronix Inc
Original Assignee
Tektronix Inc
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 Tektronix Inc filed Critical Tektronix Inc
Publication of GB2016762A publication Critical patent/GB2016762A/en
Application granted granted Critical
Publication of GB2016762B publication Critical patent/GB2016762B/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
    • G11B20/10009—Improvement or modification of read or write signals
    • G11B20/10046—Improvement or modification of read or write signals filtering or equalising, e.g. setting the tap weights of an FIR filter
    • G11B20/10194—Improvement or modification of read or write signals filtering or equalising, e.g. setting the tap weights of an FIR filter using predistortion during writing

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Signal Processing For Digital Recording And Reproducing (AREA)
  • Digital Magnetic Recording (AREA)
  • Compression, Expansion, Code Conversion, And Decoders (AREA)
  • Dc Digital Transmission (AREA)

Abstract

An encoding circuit for converting an input stream of serial data bits at (12) to an MFM encoded output stream of serial data bits with write precompensation comprises a ROM (4) acting as a look-up table and providing an MFM coding for a current bit at QB the coding depending upon the previous two bits at QC, Q1, as well as the next, at Qa, the encoded signal being provided in serial format 22. With write precompensation, a transition which would be expected at either of the positions "NORMAL" Fig. 2 is shifted to +/-250 nS in dependence on the ROM algorithm. The precompensation corrects for bit shifting which otherwise occurs when MFM data is recorded on the inner tracks of a magnetic disc recorder. The presence or absence of precompensation is controlled by a signal at A4. Use of delay lines for precompensation is thus avoided. <IMAGE>
GB7907381A 1978-03-16 1979-03-02 Data encoder with write precompensation Expired GB2016762B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US88740378A 1978-03-16 1978-03-16

Publications (2)

Publication Number Publication Date
GB2016762A true GB2016762A (en) 1979-09-26
GB2016762B GB2016762B (en) 1982-08-25

Family

ID=25391063

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7907381A Expired GB2016762B (en) 1978-03-16 1979-03-02 Data encoder with write precompensation

Country Status (6)

Country Link
JP (1) JPS59888B2 (en)
CA (1) CA1172766A (en)
DE (1) DE2909822C2 (en)
FR (1) FR2420250A1 (en)
GB (1) GB2016762B (en)
NL (1) NL7902070A (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4245263A (en) * 1979-05-14 1981-01-13 Honeywell Information Systems Inc. Write precompensation and write encoding for FM and MFM recording
DE3326912A1 (en) * 1983-07-26 1985-02-07 Siemens AG, 1000 Berlin und 8000 München Device for code conversion
US4756008A (en) * 1986-03-03 1988-07-05 Hitachi, Ltd. Digitized quadrature phase shift keying modulator

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3067422A (en) * 1958-12-24 1962-12-04 Ibm Phase distortion correction for high density magnetic recording
US3482228A (en) * 1965-10-21 1969-12-02 Sperry Rand Corp Write circuit for a phase modulation system
US3685033A (en) * 1970-08-24 1972-08-15 Honeywell Inc Block encoding for magnetic recording systems
US3879342A (en) * 1973-12-28 1975-04-22 Honeywell Inf Systems Pre-recorded digital data compensation system
US4000513A (en) * 1975-07-28 1976-12-28 Computer Peripherals, Inc. Apparatus and method for data recording with peak shift compensation

Also Published As

Publication number Publication date
NL7902070A (en) 1979-09-18
GB2016762B (en) 1982-08-25
JPS59888B2 (en) 1984-01-09
FR2420250A1 (en) 1979-10-12
DE2909822C2 (en) 1982-06-03
FR2420250B1 (en) 1983-08-12
DE2909822A1 (en) 1979-09-20
CA1172766A (en) 1984-08-14
JPS54133019A (en) 1979-10-16

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Legal Events

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