JPS58222409A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To minimize the crosstalk between heads and to realize a high-density recording track pitch, by short-circuiting the winding for electric current of the head which is not actuated at the time of recording or reproducing. CONSTITUTION:When one frame signal 31 of a period F is inputted into a recording amplifier 4, signals of odd fields fa are recorded on a magnetic sheet 2 by a head 3a ad another head 3b is under a short-circuited condition by a relay 23. When a head changeover pulse 32 is then inputted into a head changeover pulse input terminal 21, the relay 23 is actuated, signals of even fields fb are recorded by the head 3b, and the head 3a is set to a short-circuited condition by the relay 23. Since the winding for electric current of one head which is not actuated is short-circuited and the magnetic resistance is apparently increased in this way when each field signal is recorded, the crosstalk between cores caused by magnetic fluxes leaking from the adjoining actuated head can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording and reproducing apparatus that records and reproduces signals on a rotating magnetic recording medium by operating a plurality of recording and reproducing heads in time series.

For example, when recording and reproducing multiple frame video signals on an ultra-small rotating magnetic medium with an outer diameter of approximately 2 inches, it is necessary to obtain a linear velocity of the magnetic medium sufficient for nine magnetic heads. Since the recording limit is one field per revolution and 10 normal frames are recorded, K uses two heads to record an odd field signal on one of two adjacent recording tracks in the first revolution, and then Means is taken to record even field signals on the other recording track in time series with each head in one rotation of the head.

Figure 1 shows its configuration, in which a magnetic sheet 2 with a diameter of approximately 2 inches is fixed to a spindle motor 1.
The recording/reproducing heads 3a and 3b are arranged so as to rotate at a speed of 0.00 revolutions/minute and contact the magnetic surface side thereof. During recording, one frame of recording signal is input to the recording amplifier 4, and the output signal is passed through the recording/reproduction changeover switch 6, and the head changeover switch 7, which operates in synchronization with the rotation of the sheet, selects either the head 3a or the head 3b. It is recorded on the magnetic sheet 2. Here, the switching switch and cheer select the head 3α during odd field recording and the head 3b during even field recording, and one frame of video signal is recorded on the magnetic sheet 2. On the other hand, during playback, head 6α
The signals reproduced by the heads 3h and 3h are read out alternately by the D changeover switch 7, amplified by the reproduction amplifier 5, and outputted as one frame signal.

In order to increase the recording density with such a conventional device, it is necessary to narrow the recording track pitch and to sufficiently narrow the distance between the two heads. However, when two heads are placed adjacent to each other, magnetic flux flows from one head that is in a recording state to the other head that is not in a recording state due to leakage magnetic flux from the V.
So-called recording crosstalk occurs.

Furthermore, during playback, the head that is not in playback mode causes the magnetic flux sucked in from the recording sheet to flow into the core of the adjacent playback head that is in playback mode, resulting in crosstalk caused by playback to the head that is in playback mode. All of these problems cause deterioration of loop circulation, generation of beats, and synchronization errors, resulting in deterioration of image quality. This crosstalk between recording and playback tends to increase in inverse proportion to the square of the distance between the two heads, so it is difficult to make the distance between the two heads sufficiently close. , it is difficult to use recording media effectively at high density.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording and reproducing device that can increase the density of recording track pitches and effectively utilize recording media by reducing crosstalk between adjacent heads. .

In order to achieve the above object, in the present invention, when the windings of a coil-type magnetic head are short-circuited, a reverse magnetic field is generated that prevents changes in the magnetic flux flowing through the head core, and the magnetic resistance to the alternating magnetic field appears to increase. Focusing on this, crosstalk between adjacent heads is improved by short-circuiting the windings of heads that are not in recording or reproducing operation in a plurality of magnetic heads that operate in time series.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

FIG. 2 shows the configuration of the recording/reproducing system of the present invention, and the same parts as in FIG. 1 are given the same numbers, so the explanation will be omitted. In Figure 2, 23 is a reed relay for head switching, 2
2 is a relay driving transistor, and 21 is a head switching pulse input terminal. To explain the operation during recording,
First, one frame signal 61 of period F shown in FIG. 3(α)
When inputted into the recording amplifier 4, the signal of the odd field fα is recorded on the magnetic sheet 2 by the head 6α.

During this period, the head 3h is short-circuited by the relay 23. Next, the head switching pulse 32 shown in FIG. 5<b> is input to the head switching pulse input terminal 21, thereby operating the head switching relay 23 and recording the signal of the even field fh from the head 3hVc. During this period, the head 6a is short-circuited by the relay 23.

The frame signal is recorded on the magnetic sheet by the above operation, but the current winding of the head that is not in operation at the time of recording each field signal is short-circuited, and the apparent magnetic resistance becomes large, so that the head that is not in operation at the time of recording each field signal has a large apparent magnetic resistance. Core-to-core crosstalk due to stray magnetic flux is reduced, and recording crosstalk can be significantly improved. In addition, when there is no playback operating pressure during playback, the windings are short-circuited, reducing the efficiency of sucking magnetic flux from the magnetic sheet.Therefore, leakage of magnetic flux to the rad core to the adjacent playback operation is reduced, and playback Time crosstalk is also improved.

As described above, according to this embodiment, crosstalk between adjacent heads can be improved, so the track pitch of the heads 3α and 5b can be narrowed, and the magnetic recording sheet can be used effectively.

FIG. 4 shows another embodiment of the present invention, in which the insertion position of the relay 23 for head switching is different.

The other operations are the same as those of the first embodiment, and the operation is substantially the same.

Although all of the embodiments described above use mechanical relays for head switching, it is clear that the same function can be achieved even if an electronic switch using a semiconductor or the like is used as the head switching element. .

As described above, according to the present invention, crosstalk between adjacent heads can be reduced, so the distance between the heads can be arranged narrower than in the past, and high-density recording is possible.

This enables effective use of magnetic sheets by　　.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a recording/reproducing system of a conventional magnetic recording/reproducing device, FIGS. 2 and 3 are block diagrams showing the configuration of an embodiment of the present invention, and FIG. 4 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 3 is a block diagram showing the configuration of another embodiment. 1... Spindle motor 2...
......Magnetic sheet 6...Recording/playback head 4...Recording amplifier 5.
・・・・・・・・・Reproduction amplifier 6・・・・・・・・・・・・
・Record/playback selector switch 7・・・・・・・・・・・・
Head switching switch □ 21...- Head switching pulse input terminal 22
......Drive transistor 23...
...Head switching rele agent patent attorney Usui 1) Toshiyuki 1st Σ et al. 2nd item ↑Vc

Claims (1)

[Claims] A magnetic recording and reproducing device that has a plurality of adjacently arranged wire-wound magnetic recording and reproducing heads, and records and reproduces a plurality of different signals on a rotating disc-shaped magnetic recording medium by operating each head in time series. means for short-circuiting the current windings of the other recording heads except for the recording head in the recording operation state during recording, and short-circuiting the reproducing windings of the other reproducing heads other than the reproduction head in the reproducing operation state during reproduction. 1. A magnetic recording and reproducing device comprising: means for