DE2315277A1 - MULTI-TRACK MAGNETIC HEAD ARRANGEMENT - Google Patents

Description

7499-73 / Kö / S. _ooin n "

RCA Docket No. : 64.690 Δ O IOZ / /

Convention Date:
March 27, 1972

RCA Corporation, New York, N.Y., V.St.A,

Multi-track magnetic head arrangement

The invention relates to a multi-track magnetic head assembly for Recording and playing back several information tracks on one magnetic recording media.

With multi-channel magnetic recording (multi-track magneto graphie) it is desirable to keep the distance between the individual tracks or channels as small as possible so for a given amount of information as little space as possible on the magnetic recording medium or storage medium required will. For this purpose, a multitrack transducer or magnetic head arrangement is required that is as compact or compact as possible. In known arrangements of this type, however, the compact leads Build-up to crosstalk between the various channels. This is of course undesirable and, depending on the intended difficulties observed in operation of the magnetic head assembly have as a consequence.

For example, consider the multi-track magnetic head arrangement shown in FIG. which is typical of the state of the art. There are a number of magnetic cores 2, each with a magnetic gap 4 arranged along a conductor 6. By means of a switch arrangement 8 are certain of the magnetic cores 2 on the

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Conductor 6 on both sides of the individual magnetic cores coupled wires 10 controlled one after the other with signals. Such an arrangement
is usable as long as only one channel or one at a time
Track is to be recorded or played back or the same information is recorded on several different tracks,
since in these cases any crosstalk is not particularly disadvantageous.

If, on the other hand, different information is to be recorded or played back separately in adjacent channels or tracks at the same time, the required compactness of the transducer arrangement brings difficulties with it, as in this case a problem
significant crosstalk effect cannot be allowed. In
however, the arrangement according to FIG. 1 is unsuitable in this regard. In order to control neighboring magnetic cores with different signals at the same time, two different signals have to be sent simultaneously through the common connecting wires 10 between the cores. Since such wires have a finite resistance (impedance), the result is a mixture of the two signals and
consequently crosstalk between the adjacent channels. One can
It is true that crosstalk can be avoided by using wires with a large diameter and consequently correspondingly lower impedance; however, in this case one runs into difficulties with regard to the required compact structure. On the other hand, if the wires are made so thin that compactness is achieved, so
their impedance increases and, accordingly, the undesirable crosstalk ef ect.

The invention is based on the object with a very compact Structure of the multi-track magnetic head arrangement the crosstalk between to minimize neighboring transducer elements,

According to the invention this object is achieved in a multi-track magnetic head arrangement of the type mentioned in that
by a number of closely spaced magnetic circuit core elements made of magnetic material with, ie a transmission gap, at one end of which the signal transmission "to or from the recording medium takes place., at a distance from this .3paljb

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end of a common conductor element is passed and that an isolating signal coupler is provided for each core element is, through its own conductors, on both sides of the core element in question by means of electrical connections to the common Conductor element are connected, is coupled to the core element, such that the common conductor element, the conductor of the Signal coupler and the electrical connections each have their own electrical loop through only the relevant signal coupler and form the associated core element.

This ensures that common with extremely compact structure Ohmic connections for exciting or driving neighboring ones Converter elements are avoided.

The invention is explained in detail below with reference to the drawing. Show it:

FIG. 1 shows the multitrack magnetic head arrangement according to FIG. 1 discussed above the state of the art;

2a and 2b perspective representations of magnetic core arrangements according to Ausführungsbexspxelen of the invention

Figure 3 is a plan view of an inventive More track-Magnet head arrangement! and.

Figure 4 is a perspective view of a for the Magnejb head arrangement suitable signal coupler arrangement ".

Figure 2a shows an embodiment of a magnetic core arrangement for a multi-track magnetic head assembly 3 · The magnetic head assembly 3 consists of a number of individual core elements 5 in the form of two magnet cores arranged close together, the individual core elements 5 being arranged next to one another are that a series of separate signal transmission columns 7 is formed, as shown in Figure 2a. Each of the core elements is penetrated by an opening 9 through which a conductor element can be passed, as will be explained below. The core elements 5 are formed as elevations of a common piece 11 made of magnetic material. For the core elements 5 of the Piece 11 can be any suitable magnetic material such as

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Ferrite, Alfecon, Sendust can be used.

Figure 2b shows another embodiment of a suitable one Core arrangement. The core elements 12 with the signal transmission gaps 14 are spatially arranged in the same way as in Figure 2a, but separately attached to a common base 16 made of non-magnetic material, for example glued. The core elements 12 are preferably in an essentially parallel alignment next to one another in that shown in FIG. 2b Way arranged so that they detect with their surface 18 the magnetic recording medium (not shown). Again can any suitable magnetic material such as ferrite, alfecon, sendust can be used for the core elements 12;

Each of the core elements 12 in FIG. 2b is penetrated close to the transmission gap 14 by an opening 20 in communication therewith. A preferably continuous conductor element 22 ^s , for example a wire, is passed through all openings 20 of the core elements 12.

The construction and manufacture of magnetic core elements from of the type shown in Figures 2a and 2b are detailed in U.S. Patent Specification 3,544,982.

Figure 3 shows an embodiment of an inventive Multi-track magnetic head assembly with several core elements. In figure 3, a plurality of magnetic head core members 30 are substantially parallel to each other along an imaginary axis 32 through the corresponding Signal transmission column 34 arranged. The individual core elements 30 each belong to their own channels N to N + 5 for the recording and playback of separate signal tracks of a magnetic Recording medium (not shown). ,

For each core element 30 of the channels N to N + 5 there is a separate one isolating signal coupler 36 is provided. The signal coupler 36 serves to feed separate signals to the associated core element 30 and derive from it. The isolating signal coupler 36 may be any suitable known transformer or push-pull

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Be a driver arrangement that provides a two-stroke control for the the core element 30 provides passing signal.

A separate, separate signal path is provided between each of the core elements 30 and the associated signal coupler 36. In fact, in the manner shown in FIG. 2b, a common conductor element in the form of wire 38, for example, is passed through all core elements 30. The signal path for the individual core elements 30 is in each case formed by a pair of further conductors in the form of, for example, wires 40, which are connected to the common on both sides of the core elements 30 at points 42-48. Conductor element or wire 38 are connected. This results in a separate conduction path between each of the core elements 30 and the relevant signal coupler 36. The individual signal paths for the individual core elements 30 for recording and playback are indicated by the arrows 49 to 54, the individual channels N to N + 5 correspond. For example, when recording in channel Ii + 2, the current flows through the loop in question, including the part of the common conductor element 38 between points 44 and AS, and the recording on the recording medium takes place by normal magnetic transformation, the magnetic field generated being the current in the loop for N + 2 and the number of turns in the loop for N + 2 coupling the core element 30 of the loop N + 2. As shown in FIG. 3, the loops N to N + 5 form a single turn, consisting of the conductor elements 38 and 40. However, the individual loops N to N + 5 can also each comprise several turns, which the core element 30 in question with the associated η Couple the signal coupler.

There is essentially no between the individual loops Crosstalk or no mixing of signal currents because the each adjacent loops have only a single point of contact. For example, loop N + 2 has only one Point 44 together with loop N + 1 and only point 45 together with the loop .V. + 3.

As mentioned earlier, this is important as the connective

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Conductors like 38 and 40 have significant impedance. Used for recording adjacent channels with separate information an extremely compact multi-track head arrangement is required, so the conductors must be extremely small in cross-sectional area so that their self-impedance is quite large. Since the invention according to the arrangement in a given conductor no signals of different Channels can meet and mingle is An extremely compact structure is possible with minimal crosstalk between the channels.

Figure 4 shows a multi-track magnetic head assembly 56 of the on the basis of FIGS. 2a, 2b and 3 explained type. In FIG. 4, only two channels N and N + 1 are shown for explanatory purposes; However In practice, a hundred or more such channels can be provided in the same way. In Figure 4 is the signal coupler a transformer 60 for the individual core elements 58. Each Transformer 60 has a core 62 made of magnetic material. As As shown, the cores 62 of the transformers are in the form of Toroidal cores. Each toroidal core 62 is wound with a first winding 64. The winding 64 preferably consists of several turns and has connections 66 for signal transmission between the core element concerned and the recording / reproducing circuit (Not shown). The second winding 68 for each channel consists of a single turn which passes through the toroidal core 62 and with the corresponding head core 58 coupled. The windings are each on both sides of the corresponding head core 58 to the common conductor 70, which penetrates all head cores 5.8, such as shown connected. The turns ratio for the windings 64 and 68 can be selected as desired so that the desired Upward or downward transformation of the transmitted Signals.

Using the principles of the invention, Multi-track magnetic transducer arrangements with IOC channels with one color made of 80 tracks per 2.54 cm, although also 100 to 200 tracks per 2.54 cm are possible. The transducer assemblies were to linear packing densities of 12,000 to 40-QOO 3its per 2.54 cm at 1 to. 3 megabits per second and tape speeds in

3 0 98 42 / 0-8 61

-ff. -

Range of 102 - 305 cm / see (40 - 120 in / sec) tested. Testing on crosstalk (under static and recording / playback conditions) between adjacent and next but one lanes when using toroidal transformers for signal coupling Fourth of, for example, 7 db below the noise threshold. The tests showed that. crosstalk, if at all, almost exclusively between the toroidal coupling transformers and occurs only at the highest levels and frequencies used. Further improvements to crosstalk can be achieved by optimizing the recording currents and through transformer shielding.

Extremely compact transducer arrangements were made in accordance with the invention. For example, for the dimension A (Figure 4) of the individual head cores 58 with gap a track width of 0.170 mm (0.007 inches) with a track pitch of B. of 0.127 mm (0.005 inches). For the conductor elements 68 and 70 was for example, wire as small as 0.09 mm (0.0035 inch) is used.

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Claims (3)

Claims \ lX Multi-track magnetic head arrangement for recording and playing back several information tracks on a magnetic recording medium, characterized in that a number of closely spaced magnetic circuit core elements (30) made of magnetic material each have a transmission gap, at one end of which the Signal transmission to or from the recording medium takes place, at a distance from this end of the gap, a common conductor element (38) is passed and that an isolating signal coupler (-36) is provided for each core element (30), which is connected by its own conductor (40) on both sides of the relevant core element are connected to the common conductor element (38) by means of electrical connections (42-48), is coupled to the core element (30) in such a way that 'the common conductor element (38), the conductors (40) of the signal coupler (36 ) and the electrical connections (42-48) each have their own electrical loop through only the relevant one n form the signal coupler and the associated core element. 2. Magnetic head arrangement according to claim 1, characterized in that characterized in that the signal coupler has a trans A formator having a first winding (64) with multiple bonds and a second winding (68) passing through the closed loop with the common conductor element and its own conductors is formed, contains (Figure 4). 3. Magnetic head assembly according to claim 1 or 2, d a d u r ch marked,. that the core elements (30) in arranged substantially symmetrically along a given axis (32) are and that the signal couplers (36) for the successive core elements alternately on one and on the other side of this axis are arranged. 4 Magnetic head arrangement according to one of Claims 1 to 3 / characterized, . that the individual 309842/086 1 Core elements in the immediate vicinity of the transfer gap are penetrated by an opening through which the common conductor element is performed in such a way that there are separate closed single winding signal loops with their own conductors of the signal coupler for the individual core elements. 309842/0861