US3789156A - High density isolated multi-channel magnetic circuit transducer - Google Patents

High density isolated multi-channel magnetic circuit transducer Download PDF

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Publication number
US3789156A
US3789156A US00238485A US3789156DA US3789156A US 3789156 A US3789156 A US 3789156A US 00238485 A US00238485 A US 00238485A US 3789156D A US3789156D A US 3789156DA US 3789156 A US3789156 A US 3789156A
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Prior art keywords
signal
core members
core
coupling means
conducting means
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Expired - Lifetime
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US00238485A
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English (en)
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O Bessette
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RCA Corp
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RCA Corp
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    • 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
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/29—Structure or manufacture of unitary devices formed of plural heads for more than one track

Definitions

  • multi-channel magnetic transducing it is desirable to minimize spacing between tracks or channels, in order to conserve the amount of storage medium required to handle a particular amount of information. Therefore, consistent with this end, a multi-channel transducing arrangement must possess a degree of compactness. Such compactness however, in prior art arrangements, introduces cross talk between channels. This cross talk is undesirable and may be a problem depending upon the end result desired for the transducer.
  • FIG. 1 shows a plurality of magnetic cores 2, having magnetic gaps 4 therein, mounted along a conductor 6.
  • a switching means 8 is utilized to sequentially provide a drive signal to given ones of the cores 2, through the wires 10 coupled to the conductor 6 at opposite sides of each core.
  • Such an arrangement is suitable where it is desired to transduce information with only one channel or tract at a time, or where the same information is transduced with several tracks. For such arrangement, cross talk if existant may not be a significant problem.
  • the present invention is directed to a novel arrangement for minimizing cross talk between adjacent transducer elements in a multi-element transducer assembly, even where the assembly is very compact. Briefly this is accomplished by provision of a multi-element transducer assembly structure, that may be extremely compact, while avoiding common impedance connections for energizing adjacent transducer elements.
  • FIG. 1 illustrates the typical prior art multiple transducer assembly, discussed above.
  • FIGS. 2(a) and 2(b) are perspective views of examples of magnetic core structures useful in practicing the invention. I
  • FIG. 3 is a plane view showing an embodiment of a multi-element transducer assembly according to the invention.
  • FIG. 4 is a perspective view of a particular signal coupling means for the multi-element transducer.
  • FIG. 2(a) shows one example of a core structure for a multi-element magnetic transducer assembly 3.
  • the assembly 3 comprises a plurality of individual core member pairs 5 arranged in juxtaposed confronting relation to form a series of separate signal transducing gaps 7.
  • Each of the core members 5 have an aperture 9 therethrough for accommodating a conductive member which is hereinafter discussed.
  • the core members 5 are formed as projections of a common piece 11 of magnetic material. Any suitable magnetic material such as Ferrite, Alfecon, Sendust may be utilized for the core members 5 of the piece 11.
  • FIG. 2(b) shows a further example of a multielement core structure suitable for practicing the invention.
  • a plurality of core member pairs 12 are provided in juxtaposed confronting relation, to form a series of separate signal transducing gaps 14.
  • the core members 12 are sepa' rately affixed by means such as bonding, to a common support member 16 formed of a non-magnetic material.
  • the core members 12 are preferably aligned in substantially parallel longitudinal fashion and include surfaces 18 adapted to cooperate with a magnetic storage medium, not shown. Any suitable magnetic material, such as Ferrite, Alfecon, Sendust, may be utilized for the core members 12.
  • Each of the core members 12 of FIG. 2(b) have an aperture 20 therethrough in proximate and communicating relation with the transducing gaps 14.
  • a conductive element or wire 22, which is preferably continuous, passes through each of .the apertures 20 in the core members 12. The purpose and function of the element will become clear in the discussion which follows.
  • FIG. 3 there is shown an embodiment of a multi-element, multi-channel magnetic transducer assembly according to the invention.
  • a plurality of magnetic head cores members 30 are preferably arranged in substantially parallel fashion along an imaginary axis, denoted by dashed line 32, through the respective signal transducing gaps 34.
  • Each of the core members 30 form a portion of separate individual channels denoted Nthrough N 5, which provide signal transducing with separate signal tracks of a magnetic storage medium, not shown.
  • the isolating signal coupling element 36 serves as a means of providing separate signals to its associated core member 30 and recovering signals from that core member 30.
  • the isolating signal coupling means 36 may be a suitable well-known type of transformer or push-pull drive circuitry, which provide a double ended drive for the signal passed through the core member 30.
  • a common conductor means such as the wire 38 is disposed through each of core member 30, in the manner shown and described with respect to FIG. 3(b).
  • the signal path for each core member 30 is completed by a plurality of pairs of further conductive means such as the wires 40, which are electrically connected, denoted by reference numbers 42-48 of FIG. 3, to the common conductor means 38 at either side of the core members 30. This provides a 7 unique path between each of the core members 30, and
  • the individual record and playback signal paths for each of the head core members 30 are indicated by the arrows 49 through 54, which correspond with channels N through N respectively.
  • the current passed through the loop for channel N 2 including the portion between points 44 and 45 of the common conductor 38, transduced by normal magnetic transform action, where a magnetic field is established proportional to the current in loop N 2 and the number of turns in the loop N 2 which link the core member 30 for loop N 2.
  • the loop N through N 5 constitute a single turn comprised of the conductive members 38 and 40.
  • the loops N through N 5 may also be arranged to comprise a plurality of turns linking the particular core member 30 with its corresponding signal coupling means.
  • loop N 2 has only one point 44 common to loop N 2 and loop N 1 and only one point 45 common to loop N 2 and loop N 3.
  • the connecting conductors such as 38 and 40 have significant impedance.
  • the conductors must be made of extremely small cross sectional area, thereby increasing their natural impedance. Therefore avoiding comingling of different channel signals in a given conductor, by the arrangement of the present invention, permits an extremely compact structure while minimizing cross talk between channels.
  • FIG. 4 shows a multi-element magnetic transducer assembly 56 of the type shown and described with respect to FIGS. 2(a) and (b) and FIG. 3.
  • the isolating signal coupling means for each of the core members 58 is a transformer 60.
  • Each of the transformers 60 comprises, a further core member 62 of magnetic material.
  • the transformer core members 62 are in the shape of torroids.
  • Each torroidal core 62 has wound thereon a first. winding 64.
  • the winding 64 is preferably a multiple turn winding and includes terminal means 66, for interfacing transduced signals with appropriate record and playback circuity, not shown.
  • a further winding 68 for each channel is provided in the form of a single turn, which passes through the torroidal core 62 and links the transformer core 62 with its corresponding head core 58.
  • Each of the further windings 68 are connected, at either side of the corresponding head core 58, to the common conductor 70 which passes through the head cores 58 as shown.
  • the turns ratio for the windings 64 and 68 may be any desired number to provide the desired step-up or step-down of the transduced signal.
  • compact multi-element transducer assemblies have been fabricated having 160 channels providing tracks per inch, although -200 tracks per inch are possible.
  • the transducers have been tested for linear packing densities of from 12,000 to 40,000 bits per inch, at 1-3 megabits per second and at tape speeds in the range of 40-l20 inches per second.
  • the dimension A of the individual gapped head cores 58 provides a track width of 0.007 inches with a track separation B of 0.005 inches.
  • the conductive elements 68 and 70 have been, for example, provided by No. 39 wire which has a diameter of only 0.0035 inches.
  • a compact magnetic multi-element signal transducer assembly for transducing with minimal crosstalk a number of independent information signals with corresponding signal tracks on a magnetic storage medium, comprising; a plurality of individual magnetic circuit core members in proximate spaced relation, each of said core members formed ofa magnetic material and including an independent transducing gap having a first end portion adapted to cooperate with said storage medium for transducing signals therewith, common conducting means extending through each of said plurality of core members and spaced from said first end portion of said gap, a plurality of individual isolating signal coupling means each of which corresponds with a different one of said plurality of core members, each respective coupling means including its own pair of conductor segments, with adjacent pairs of said segments extending away from opposite sides of said common conducting means providing a separate conductive path between that signal coupling means and that core member corresponding thereto by respective electrical junctions joining said own conductors thereof with said common-conducting means at either side of its corresponding core means, for each pair of said conductor segments at least one member conduct
  • each of said signal coupling means includes transformer means having a first winding consisting of a plurality of electrical turns and a second winding which is formed of said closed loop path provided by said common conducting means and said conductors.
  • each of said core members includes an aperture therethrough in proximate relation with said transducing gap, said common conducting means extending through said apertures to form with said conductors a plurality of separate single turn closed loop signal paths for each of said core members.
  • a compact magnetic multielement signal transducer assembly having a plurality of individual magnetic circuit core members each including an independent gap therein having a first end portion for cooperating with a record medium for transducing independent information signals with corresponding signal tracks on a magnetic storage medium to provide a plurality of separate signal channels, wherein said transduced signals are coupled to and from said core members through conductive means exhibiting a significant impedance, means for minimizing crosstalk between said channels, comprising; a plurality of individual isolating signal coupling means each of which corresponds with a different one of said plurality of core members, a common conducting means extending through each of said plurality of core members and spaced from said first'end gap portion, further signal conducting means forming a plurality of signal conducting wire segment pairs with adjacent pairs of said wire segments extending away from opposite sides of said common conducting means and which exhibit a significant impedance to a signal passed therethrough, wherein for each of said wire segment pairs means are provided for respectively connecting a first portion of each member of said wire segment pairs

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Magnetic Heads (AREA)
  • Digital Magnetic Recording (AREA)
US00238485A 1972-03-27 1972-03-27 High density isolated multi-channel magnetic circuit transducer Expired - Lifetime US3789156A (en)

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US23848572A 1972-03-27 1972-03-27

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US (1) US3789156A (da)
JP (1) JPS535538B2 (da)
CA (1) CA1001303A (da)
DE (1) DE2315277A1 (da)
FR (1) FR2177993B1 (da)
GB (1) GB1413229A (da)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2476890A1 (fr) * 1980-02-27 1981-08-28 Ampex Structure de transducteur multicanaux a rejection amelioree de la diaphonie entre canaux
US5245494A (en) * 1991-07-15 1993-09-14 Hogan John W Write-read magnetic recording head
US5296980A (en) * 1990-05-28 1994-03-22 International Business Machines Corporation Magnetic disk apparatus having recording heads for opposite disk surfaces which are offset from each other
US20080239566A1 (en) * 2007-03-19 2008-10-02 Dimambro Bryan Electromagnetic data storage devices

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5653464Y2 (da) * 1974-09-02 1981-12-12
JPS5532198Y2 (da) * 1975-06-23 1980-07-31
JPS5639728A (en) * 1979-09-10 1981-04-15 Okadohazatsuku Kk Automatic limited feeding systematizing apparatus for breeding pig
JPS5964441A (ja) * 1982-09-30 1984-04-12 Yamato Sewing Mach Seizo Kk 重積裁断生地自動的分離抓み上げ方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2835743A (en) * 1956-02-16 1958-05-20 Ibm Magnetic transducer assembly
GB882779A (en) * 1959-07-29 1961-11-22 Nat Res Dev Improvements in or relating to multi-track magnetic heads

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2835743A (en) * 1956-02-16 1958-05-20 Ibm Magnetic transducer assembly
GB882779A (en) * 1959-07-29 1961-11-22 Nat Res Dev Improvements in or relating to multi-track magnetic heads

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2476890A1 (fr) * 1980-02-27 1981-08-28 Ampex Structure de transducteur multicanaux a rejection amelioree de la diaphonie entre canaux
US4291352A (en) * 1980-02-27 1981-09-22 Ampex Corporation Multichannel transducer structure with improved interchannel cross talk rejection
US5296980A (en) * 1990-05-28 1994-03-22 International Business Machines Corporation Magnetic disk apparatus having recording heads for opposite disk surfaces which are offset from each other
US5245494A (en) * 1991-07-15 1993-09-14 Hogan John W Write-read magnetic recording head
US20080239566A1 (en) * 2007-03-19 2008-10-02 Dimambro Bryan Electromagnetic data storage devices
US8134801B2 (en) * 2007-03-19 2012-03-13 Dimambro Bryan Electromagnetic data storage devices

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Publication number Publication date
CA1001303A (en) 1976-12-07
GB1413229A (en) 1975-11-12
JPS499223A (da) 1974-01-26
JPS535538B2 (da) 1978-02-28
FR2177993B1 (da) 1976-05-21
DE2315277A1 (de) 1973-10-18
FR2177993A1 (da) 1973-11-09

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