WO1999050835A1 - Procede de detection de bord de rangee de bande dans une structure de positionneur a bande magnetique - Google Patents

Procede de detection de bord de rangee de bande dans une structure de positionneur a bande magnetique Download PDF

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Publication number
WO1999050835A1
WO1999050835A1 PCT/US1998/006260 US9806260W WO9950835A1 WO 1999050835 A1 WO1999050835 A1 WO 1999050835A1 US 9806260 W US9806260 W US 9806260W WO 9950835 A1 WO9950835 A1 WO 9950835A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
time period
clock pulses
frequency
frequency signal
Prior art date
Application number
PCT/US1998/006260
Other languages
English (en)
Inventor
Ronald Dean Gillingham
Steven Gregory Trabert
John Paul Mantey
Original Assignee
Storage Technology Corporation
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 Storage Technology Corporation filed Critical Storage Technology Corporation
Priority to EP98913304A priority Critical patent/EP1075689A1/fr
Priority to JP2000541672A priority patent/JP2002510110A/ja
Priority to PCT/US1998/006260 priority patent/WO1999050835A1/fr
Publication of WO1999050835A1 publication Critical patent/WO1999050835A1/fr

Links

Classifications

    • 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
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B5/584—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following on tapes
    • 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
    • G11B27/30—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 on the same track as the main recording
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B2220/00—Record carriers by type
    • G11B2220/90—Tape-like record carriers

Definitions

  • the invention relates to the field of dynamic magnetic information storage or retrieval.
  • the tape - tape head positioning may be affected by variations in the tape or tape head, tape movement caused by air flow, temperature, humidity, tape shrinkage, and other factors, especially at the outside edges of the tape.
  • servo stripes have been employed to provide a reference point to maintain correct positioning of the tape with respect to the tape head.
  • One or more servo stripes may be used depending upon the number of data tracks which are placed upon the tape.
  • the sensed signal from the servo stripe is fed to a control system which moves the head and keeps the servo signal at nominal magnitude.
  • the nominal signal occurs when the servo read gap is located in a certain position relative to the servo stripe.
  • a one-half inch wide length of magnetic tape 11 may contain up to 288 or more data tracks on multiple data bands 12. With such a large number of data tracks it may be desirable to include up to five or more servo bands 13 to improve data read and write function performance.
  • Servo bands 13 may utilize various patterns or frequency regions to allow precise tape to tape head positioning thus allowing a data read head to more accurately read data from data bands 12.
  • the invention is a novel method for detecting a frame edge in a servo stripe pattern by generating a digital signal in response to a change in - 6-
  • Fig. 2 is an illustration of a servo pattern including multiple erase bands
  • Fig. 3 is a graph of the analog signal generated from the servo pattern of Fig. 2;
  • a third frequency signal which may be, for example, an erase frequency signal, is written in a predetermined band pattern in each frame over second area 28.
  • the erase frequency pattern is written in the form of parallelograms 17 which may take the form of a square or rectangle.
  • the analog signal from Fig. 5 is converted into a digital signal 31 by a data qualifier 32.
  • Data qualifier 32 may also be referred to as a zero crossing detector as used in data read channels as is known in the art.
  • the half period defined by each high and low pulse of digital signal 31 is proportional to the frequency period of the analog signal.
  • the frequency of digital signal 31 in fields 29 of Fig. 5 is different than the frequency of digital signal in fields 25, 26, 25 of Fig. 5.
  • the frequency of the signals in fields 25 and 26 is substantially identical. Because it is a digital signal, the amplitude differences between fields 25 and 26 of Fig. 5 are no longer significant.
  • a clock signal 33 from a crystal oscillator 34 is supplied to a counter 35 along with digital signal 31.
  • Clock signal 33 is a very accurate high frequency signal.
  • Counter 35 counts the number 36 of clock pulses 33 during a given half period of digital signal 31. Because the period of the signal in field 29 is about half of the period of the signals in fields 25 and 26, the counter will count half as many clock pulses 33 during a given half period of signal 31 in field 29 as compared to the number of clock pulses 33 during a given half period of signal 31 in fields 25 and 26. For example, referring to Fig.
  • Counter comparator logic 35 will generate a detection signal 37 in response to a change in count of clock pulses in 33 in successive half periods of digital signal 31. That is, compare logic circuitry in counter 35 is used to compare the number 36 of clock pulses 33 which are counted during each half period defined by a high or low pulse in digital signal 31. For example, upon detecting the decrease in the number 36 of clock pulses 33 during each half - 10 -
  • the transition in the number 36 of clock pulses 33 may not change from, for example, precisely 8 to 4 and back to 8 again. Uncertainty in these transition counts may be accounted for by delaying the detection signal one or more half periods of signal 31.
  • detection signal 37 changes state (high to low or vice versa) after two half periods of predetermined change in clock pulse counts 36 are detected.
  • the predetermined change in count may be, for example, from two successive half cycles with 6 or more counts to two half cycles with 5 or less counts (at 38) .
  • a change in count from two successive half cycles to a count of 5 or less to two half cycles with counts of 6 or more results in an output signal at 39.
  • the count frequency and the required number of counts to define a transition may be varied according to engineering design considerations as is known to one skilled in the art. While two half periods of frequency change are used in the preferred embodiment for redundancy/ accuracy purposes, any number of half periods of change may be used in accordance with the invention.

Abstract

L'invention concerne un procédé de détection d'un bord de rangée de bande dans une piste de positionneur sur la longueur d'une bande magnétique. Le procédé consiste à convertir un signal analogique en un signal numérique et à détecter une variation de fréquence du signal numérique au niveau d'un bord de rangée de bande. Un signal de détection est généré en réaction à une variation de fréquence détectée.
PCT/US1998/006260 1998-03-30 1998-03-30 Procede de detection de bord de rangee de bande dans une structure de positionneur a bande magnetique WO1999050835A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP98913304A EP1075689A1 (fr) 1998-03-30 1998-03-30 Procede de detection de bord de rangee de bande dans une structure de positionneur a bande magnetique
JP2000541672A JP2002510110A (ja) 1998-03-30 1998-03-30 テープ・サーボ・パターンにおけるフレーム端検出法
PCT/US1998/006260 WO1999050835A1 (fr) 1998-03-30 1998-03-30 Procede de detection de bord de rangee de bande dans une structure de positionneur a bande magnetique

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1998/006260 WO1999050835A1 (fr) 1998-03-30 1998-03-30 Procede de detection de bord de rangee de bande dans une structure de positionneur a bande magnetique

Publications (1)

Publication Number Publication Date
WO1999050835A1 true WO1999050835A1 (fr) 1999-10-07

Family

ID=22266716

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1998/006260 WO1999050835A1 (fr) 1998-03-30 1998-03-30 Procede de detection de bord de rangee de bande dans une structure de positionneur a bande magnetique

Country Status (3)

Country Link
EP (1) EP1075689A1 (fr)
JP (1) JP2002510110A (fr)
WO (1) WO1999050835A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8947821B1 (en) 2014-07-17 2015-02-03 International Business Machines Corporation Detecting a servo pattern using a data channel in a magnetic tape drive

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5477103A (en) * 1993-06-04 1995-12-19 Cirrus Logic, Inc. Sequence, timing and synchronization technique for servo system controller of a computer disk mass storage device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5477103A (en) * 1993-06-04 1995-12-19 Cirrus Logic, Inc. Sequence, timing and synchronization technique for servo system controller of a computer disk mass storage device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8947821B1 (en) 2014-07-17 2015-02-03 International Business Machines Corporation Detecting a servo pattern using a data channel in a magnetic tape drive
US9324348B2 (en) 2014-07-17 2016-04-26 International Business Machines Corporation Detecting a servo pattern using a data channel in a magnetic tape drive

Also Published As

Publication number Publication date
EP1075689A1 (fr) 2001-02-14
JP2002510110A (ja) 2002-04-02

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