JPH0196807A - Magnetic recording device - Google Patents

Abstract

PURPOSE:To reduce the error ratio at the time of overwriting and to increase the interchangeability with other machine by correcting a recording current at the time of writing to a magnetic recording medium. CONSTITUTION:Input digital data, after they are MFM-modulated by modulation circuits 1-1-1-N, are supplied to recording current correcting circuits 2-1-2-N and writing circuits 3-1-3-N. Respective correcting circuits 2i convert a modulation signal to a recording correcting current and sends it to recording heads 4-1-4-N. On the other hand, a writing circuit 3i converts the modulation signal to a recording current and sends it to a corresponding head 4i. Consequently, the data as per the prescribed ones are recorded at a magnetic recording medium.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic recording medium configured to record digital data on a magnetic recording medium in accordance with the recording current by supplying a recording current to a magnetic recording head. This relates to a recording device.

[Prior Art] Conventionally, when writing digital data onto a magnetic recording medium, a magnetic recording head was driven with a recording current having the same waveform as the digital data. However, according to this, there are many types of magnetic flux reversal intervals, from short to long, depending on the modulation method such as MFM, so the peak position of the reproduced signal for determining information "l II" or "0" is the magnetic flux This produces a peak shift that is pushed from areas of high inversion density to areas of low density.

In order to suppress such a peak shift, a method of correcting the recording current waveform that drives the recording head has conventionally been adopted.

FIG. 4 is a waveform diagram for explaining the peak shift correction method that has been actually adopted in the past, where (A) shown in the figure (a) is digital data, and (B) shown in the figure (b).
is a modulation signal waveform obtained by MFM modulating the digital data (A). The peak shift is from the higher density of magnetic flux reversal to the lower density, that is, the above MFM modulation signal waveform (B)
occurs from the shortest to the longest level reversal interval, and the fourth
Broken diagram (d)! The waveform is shown as IN(DI). Therefore, if the current at the time of reversal of the recording current is increased as shown in (C) of FIG. 4(C), the solid line (D2) of FIG. 4(d)
As shown in , the peak position is corrected compared to the above (DI), and the peak shift is considerably suppressed.

FIG. 5 is a block diagram showing the configuration of a conventional magnetic recording device for performing the above peak shift correction, and in the same figure, (1-1), (1-2), ... (1-N)
The modulation circuit performs MFM modulation on input digital data. (2-1), (2-2), ... (2-N) are recording current correction circuits, and each of the above-mentioned modulation circuits (1-1), (1
-2) Perform the recording correction described above on the modulated signal generated by (1-N) to generate a recording signal. (:1-1), (3-2), . . . (3-N) are m writing circuits that apply a recording current according to the recording signal to the recording heads (4-1), (4-2). , .-(4-N). Each of the above recording heads (4-1), (4-2),
--(4-N) writes the recording signal on the magnetic recording medium.

Next, the operation of the above configuration will be explained.

The input digital data is sent to the modulation circuit (1-1).

MFM modulation is performed by (1-2), . . . (1-N).

The MFM modulated signal is sent to the recording current correction circuit (2-)
), (2-2), ... (2-N) to correct the above-mentioned recording current, and each write circuit (:l-]),
(:]-2), ... (:1-N) is replaced with a recording current consisting of a pulse current of a predetermined width, and each recording head (4-1), (4-2), ... (4 -N), and each recording head (4-1), (4-2
), . . . (4-N) Record data is recorded on the magnetic recording medium according to the above-mentioned recording current.

FIG. 6 is a specific circuit diagram of a conventional magnetic recording device disclosed in, for example, Japanese Unexamined Patent Publication No. 59-207009. In the figure, (31) and (32) are flip-flops,
(33) is an exclusive OR gate, (34) to (41) are N
AND gate, (42), (43), (46)~
(49), (54).

(55) is the resistance, (44), (45), (50), (5
1), (56), and (57) are transistors, (52) is a buffer, and (53) is an inverter.

Next, the operation of the circuit shown in FIG. 6 will be explained.

For the digital data shown in FIG. 7(a), the MFM
The modulated signal becomes as shown in FIG. 7(b).

Also, as a pulse signal input to the write circuit (c
) gives the waveform of

First, the modulation signal (b) is input to the flip-flop circuit (31) in synchronization with the clock, and its output is input to the flip-flop circuit (32), and the exclusive OR gate (33) is Then, the modulation signal (b
) detects the level reversal position. The signal is NAND
The signal is input to gates (34) and (38), and the waveforms shown in FIGS. 7(d) and (e) are obtained as output signals. The waveform signals shown in (d) and (e) are signals indicating the position at which the current peak value of the write current is changed.

The output of the NAND gate (34) is the NAND gate (
35) and (35), and furthermore, the output of the NAND gate (35) is input to the NAND gate (37). The pulse signal shown in FIG. 7(c) is input to the other input terminals of the NAND gates (36) and (37),
As a result, the waveform shown in FIG. 7Cf) is obtained as the output signal of the NAND gate (36), and the waveform shown in FIG.
) The waveform shown in FIG. 7(g) is obtained as the output signal. Similarly, the waveforms shown in FIG. 7(h) and (i) are obtained as the output signals of the NAND gates (40) and (41).

The outputs of the NAND gates (36) and (37) are input to the bases of transistors (50) and (44), respectively, and when the base voltage is at "L" level, the transistors (
50) and (44). Similarly, NAND gate (
The outputs of transistors (40) and (41) are also connected to transistors (5
1).

(45) is input to the base.

The above transistors (44), (45), (50) and (51) limit the write current and perform the conduction/non-conduction switching function of the resistors (46) and (47) that change the peak value of the pulse. do. For example, in the waveform of FIG. 7(f), the transistor (50) is conductive in the 'L'' section, and no current flows through the resistor (46).When current flows through this resistor (46), As the write current decreases over that period, the peak value of the write current can be controlled by switching the transistor (50).

The output of the flip-flop (31) is input to a buffer circuit (52) and an inverter circuit (53), and the output signal is a transistor ('56) for the period of "H".

(57) can be made conductive to obtain a write current. As a result of the above, a write current having the waveform shown in FIG. 7(j) is obtained.

FIG. 8 is a diagram showing a schematic configuration example of a magnetic head of a PCM recorder. In the figure, (58) is a magnetic tape which is a recording medium, (59) is a pre-reading head, (60) is an erasing head, ( 61) is a write head, (62) is a rear read head, (63) is a playback amplifier, (64) is an erase amplifier,
(65) is a write amplifier, and (66) is a signal processing circuit.

When performing follow-up recording, that is, dubbing, using a PCM recorder equipped with the magnetic head configured as described above, the data is read using the pre-reading head (59) and then recording starts from a certain section, so the erasing head (60) and the writing head are used. Overwriting (hereinafter referred to as override) occurs due to the distance from the head (61) and the turn-on timing of the erase amplifier (64) and write amplifier (65).

When such an override occurs, it is difficult to erase previously recorded data, so it is necessary to correct the recording current. However, if you perform recording with recording current correction and then perform override by correcting the recording current, the result will be lower than if you record without correcting the recording current and then correct the recording current and override. The error rate will be higher. Furthermore, when the recording current is corrected, the range of appropriate values of the reproduction system constants is narrower than when the recording current is not corrected, making it difficult to maintain compatibility with other devices.

[Problems to be Solved by the Invention] Since the conventional fjA1% recording device is configured as described above, it is not possible to arbitrarily turn on and off correction of the recording current. Therefore, there were problems such as not being able to sufficiently reduce the error rate when overriding, and also making it difficult to maintain compatibility with other devices.

This invention was made to solve the above-mentioned problems, and its purpose is to provide a magnetic recording device that can sufficiently reduce the error rate at the time of overwriting, and that can be easily compatible with other devices. shall be.

[Means for Solving the Problems] The Fj1 recording device according to the present invention is provided with a recording current correction circuit that corrects the recording current when writing to a magnetic recording medium separately from the plurality of write circuits. The present invention is characterized in that the recording current correction circuit is configured to be arbitrarily controllable.

[Function] According to the present invention, at the time of overriding, the recording current correction circuit provided separately from the writing circuit is turned on,
By correcting the recording current when writing to a magnetic recording medium, the error rate is reduced.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the configuration of a magnetic recording device according to an embodiment of the present invention, in which (1-1)
, (1-2), ... (]-N) is a modulation circuit for MFM modulating input digital data, (2-1).

(2-2), ... (2-N) are each of the above modulation circuits (1
A recording current correction circuit (3-1) that generates a recording current correction signal using the modulation signal created by -1), (1-2), . . . (1-N).

(3-2), ... (:1-N) convert the above modulation signal into a recording current, and apply the converted recording current to the recording heads (4-1), (4-2), ... (4-N). Each of the above recording heads (4-1)
, (4-2), . . . -(4-N) write the recording signal on the magnetic recording medium.

Next, the operation of the above configuration will be explained.

The input digital data is sent to the modulation circuit (1-1).

After being subjected to MFM modulation by (1-2), -... (+-N), each recording current correction circuit (2-1), (2-2)
,...(2-N) and write circuit (3-1) ,(
3-2), ... (3-N).

Recording current correction circuit (2-1), (2-2), ... (2
The modulation signal input to the recording head (4-N) is converted into a recording correction current by the recording current correction circuits (2-1), (2-2), ... (2-N).
1), (4-2), .-(4-N). On the other hand, the write circuit (:1-1), (3-2),...
・The modulation signal input to (:1-N) is sent to these write circuits (3-1), C3-2), ... (3-N)
is converted into a recording current by the recording head (4-1
), (4-2), ... (4-N),
Predetermined data is recorded on the magnetic recording medium.

FIG. 2 is a diagram showing the specific circuit configuration of only one track in the magnetic recording apparatus of the present invention, in which (5) is a flip-flop, (6), (7),
(8) and (9) are open collector buffers, (10
), (11), (13), (14) are transistors, (
12) and (15) are the transistors (10
).

(11), (13), (14) are the base current limiting resistors; (18) is the recording head; (16) and (17) are the recording current limiting resistors flowing through the recording head (18);
9) is a monostable multivibrator, (20), (21)
, (23), (24) are AND gates, (22) are recording current correction on/off switches, (25), (26) are buffers, (27), (28) are transistors, (29)
, (30) is a variable resistance.

Next, the operation of the circuit shown in FIG. 2 will be explained.

Modulation data from the modulation circuit is sent to the flip-flop (5)
The frequency is divided by two to generate two data with opposite phases. In addition, the recording on/off signal becomes "H'' during recording and becomes °°L'° at other times.The above-mentioned flip-flop (
5) The signal at point (E) on the output side is H'', and recording is on/
When the signal at point (G) on the input side of the OFF signal is "H", point (11) on the output side of buffers (5) and (8) becomes high impedance.

At this time, since the signal at point (F) on the output side of the flip-flop (5) is "L", the signal at point (1) on the output side of the buffers (7) and (9) becomes "L". Therefore, in this case, transistors (10) and (14) are turned on, and (J)
A current flows through the point in the direction of (y).

Conversely, the signal at point (E) above is "L" and the signal at point (G) is "
In the case of "H", transistors (11) and (1:l) are turned on, and current flows to the above point (J) in the direction of (x).In addition, if the point (G) is "L", all transistors (11) and (1:l) are turned on. Transistor (10
), (11), (13), and (14) are turned off, and (J
) No current flows through the point. The above timing charts are shown in FIGS. 3(E) to (J). In this Figure 3, (J
) and (0) are current waveforms with the (X) direction as 10, and the others are voltage waveforms.

On the other hand, the modulation data input to the monostable multivibrator (19) becomes a narrow pulse signal, and the AN
D circuits (20) and (21) respectively output signals (F) and
(E), and then an AND circuit (2:l
) and (24), the recording current correction on/off signal (l
, ) and buffers (25), (26)
and become signals (M) and (N). This signal (M),
(N) is converted into a current by variable resistors (29) and (:10) and added to the signal (J) to become a recording current (0),
The voltage is applied to the recording head (18).

In the above embodiment, the recording current correction on/off switch (22) is shown as being manual, but the recording current correction on/off switch (22) may be linked to an erase signal or the like.

Further, in the above embodiment, the monostable multivibrator (19) is used to determine the recording current correction time, but instead of this, a flip-flop or the like may be used to set the time interval. .

[Effects of the Invention] As described above, according to the present invention, the recording current correction circuit is provided separately from the writing circuit, and this recording current correction circuit can be controlled arbitrarily, so that the recording current is adjusted only during override. By performing the correction, the error rate during override can be sufficiently reduced. Also,
It is possible to turn off the recording current correction operation except when overriding, and it is possible to ensure a wide range of appropriate values for the constants of the reproduction system and facilitate compatibility with other devices.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a magnetic recording device according to an embodiment of the present invention, FIG. 2 is a specific circuit diagram of the magnetic recording device according to an embodiment of the present invention, and FIG. 3 is shown in wS2. Figure 4 is a waveform diagram for explaining the conventional peak shift correction method, Figure 5 is a block diagram showing the configuration of a conventional magnetic recording bag, and Figure 6 is a time chart showing the waveforms of each part of the circuit. Specific circuit diagram of conventional magnetic recording device, No. 7
The figure is a time chart showing the waveforms of various parts of the circuit shown in FIG. 6, and FIG. 8 is a schematic diagram of the magnetic head of the PCM recorder. (+-t), (1-2),...(1-N)...
Modulation circuit, (2-1). (2-2),...(2-N)...recording current correction circuit, (:1-1). (3-2),...(3-N)...writing circuit,
(4-1), (4-2), ... (4-N)... Recording head. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Masu Oiwa 1st 3rd figure
-ノ Nノ \-I ~１ノ -一ノ \１ノ
~-/ ``+/%+ノFigure 8+alri, E@(+'4a, Nail

Claims (1)

[Claims] (1) A plurality of modulation circuits that modulate digital data, a plurality of write circuits that convert each modulation signal from each modulation circuit into a write signal consisting of a pulse current of a predetermined width, and a plurality of write circuits that perform writing to a magnetic recording medium. What is claimed is: 1. A magnetic recording device comprising: a recording current correction circuit for controlling the recording current; the recording current correction circuit is configured to be arbitrarily controllable.