JPH06243412A - Magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To provide a magnetic recording/reproducing device capable of correting charactristics caused by the shift of the track arrangement of a head switching a waveform equalizer circuit for each side, improving a error rate and obtaining a good reproducing characteristic. CONSTITUTION:An amplifier 1, a filter circuit 13 and a differentiation circuit 14 are connected to a magnetic head 11 in sequence. A storage capacity switching control circuit 15, a track switching control circuit 16 and a side switching control circuit 17 are connected to the filter circuit 13 and the differentiation circuit 14, and filter characteristics for reproducing waveforms are switched by a disk capacity, a track to be read and a side to be read. A side switching function is added to the reproducing filter circuit 13 and thus, the error rate of the device is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus, such as a floppy disk apparatus, in which two magnetic heads are arranged offset in the track direction.

[0002]

2. Description of the Related Art In a conventional floppy disk device, in a magnetic recording / reproducing system, the recording density on the inner circumference side is higher than that on the outer circumference side, so that the resolution of the reproduced signal is lowered and the peak shift is increased. . Therefore, the filter characteristic of the waveform equalizer circuit is switched depending on the track position to be read, so that the resolution is improved and the read margin characteristic is improved.

FIG. 5 is a schematic block diagram showing the structure of a magnetic recording / reproducing apparatus in a conventional floppy disk apparatus. In FIG. 5, the reproduction signal read by the magnetic head 51 is amplified by the amplifier 52, then passes through the low-pass filter 53 and the differentiating circuit 54, and then the comparator circuit 5
A point which is input to 7 and crosses zero is detected, and the pulse is passed through the pulse shaping circuit 58 to be output as a pulse signal.

The track position in the floppy disk device is, for example, as shown in FIG. 7, in the case of a disk 1 having a 3.5 inch size and a track density of 135 TPI, the side 1 side is the inner side with respect to the side 0 side. They are arranged on the side offset by 8 tracks.

In the conventional floppy disk device, in order to correct the recording format capacity and the reproduction characteristic due to the difference in recording density between the outer circumference side and the inner circumference side, as shown in FIG. 5, the waveform equalization circuit is switched depending on the recording capacity. By using the storage capacity switching control circuit 55 for performing the above and the track switching control circuit 56 for switching the waveform equalizing circuit according to the track position, the cutoff frequency of the low pass filter, the boost amount of the pulse slimming circuit, etc. are switched. The read signal was improved by improving the resolution of the playback signal.

[0006]

However, in order to maintain the backward compatibility, the recording density is set to be higher than the linear recording density of the unformat capacity 1 MB, 2 MB, etc., and the heads 2 and 3 as shown in FIG. In order to realize a high recording density having a dislocation, the magnetic heads 2 or 3 to be selected are selected by the conventional means for only track switching of the waveform equalization circuit.
This causes a difference in reproduction characteristics on the inner circumference side. For example, in a waveform equalization circuit adapted to the side 0 side, when side 0 and side 1 are reproduced on the same track, side 1 side is 3.5 inches larger than side 0 side, 135T
In PI recording, since it is located on the inner circumference side for 8 tracks,
The resolution of the reproduced signal is deteriorated, the read margin is reduced, and the error rate is deteriorated. On the contrary, when the waveform equalization circuit is adapted to the side 1 side, the side 0 side is the side 1 side.
Since it is located on the outer periphery from the side, the error rate of the floppy disk device decreases due to an increase in the noise jitter component on the side 0 side and the zero cross of the saddle of the differentiating circuit. Thus, in the conventional floppy disk device,
In order to correct the reproduction characteristic caused by the high density recording on the inner circumference side, although the means for switching the characteristic of the waveform equalizing circuit according to the track position reproduced by the magnetic head is used, the side 0 and the side Since the correction of the track layout deviation of No. 1 is not performed, the waveform equalization setting is not set on each side, and the error rate of the floppy disk device decreases as the recording density increases. There is.

In order to adapt the magnetic head to such a circuit, it is necessary to adjust the gap length for each of the magnetic heads mounted on side 0 and side 1 when manufacturing the magnetic head. There is a problem that the manufacturing process and the assembly process of the floppy disk drive device become complicated.

The present invention is intended to solve the above-mentioned problems of the prior art, and the reproduction waveform of the magnetic head is set by optimally setting the waveform equalization circuit for each reproduction waveform of the plurality of heads. And the error rate can be improved, and it is not necessary to change the gap length on the side 0 side and the side 1 side when manufacturing the magnetic head, and the manufacturing process of the magnetic head can be simplified. Moreover, it is an object of the present invention to provide a magnetic recording / reproducing apparatus which can be used even in a magnetic head having a poor resolution and which can improve the yield of the magnetic head.

[0009]

To achieve the above object, the present invention provides a plurality of magnetic heads for reading signals recorded on a magnetic medium, and a voltage signal read by the magnetic heads. And a waveform equalizing circuit and a comparator circuit, each of which includes a differentiating circuit, and a waveform shaping circuit including a pulse shaping circuit,
The waveform equalization circuit is configured to be able to correct the difference in recording density caused by the deviation of the track arrangement of the magnetic heads.

[0010]

According to the present invention configured as described above, the reproduction waveform read by the side 0 and side 1 magnetic heads can be set to optimum waveform equalization on each side. The characteristic can be corrected by the deviation of Further, when manufacturing the magnetic head, it is not necessary to change the gap length on the side 0 side and the side 1 side.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram showing the structure of a magnetic recording / reproducing apparatus according to an embodiment of the present invention. In FIG. 1, the magnetic head 11 includes an amplifier 12 and a filter circuit 1.
3, the differential circuit 14 is sequentially connected. Filter circuit 1
3 and the differentiation circuit 14 include a storage capacity switching control circuit 1
5, a track switching control circuit 16 and a side switching control circuit 17 are connected. Differentiator circuit 1
4 is sequentially connected to the comparator circuit 18 and the pulse shaping circuit 19.

FIG. 2 is a circuit diagram showing an example of the configuration of the side switching control circuit 17 in FIG.

The filter circuit 13 is built in the LSI, and the LSI is provided with a terminal for determining the filter characteristic. As shown in FIG. 2, one ends of a resistor 21 and a resistor 22 are connected in parallel to the filter characteristic setting terminal 20,
The other end of the resistor 21 is connected to the collector terminal of the transistor 23, the other end of the resistor 22 is connected to the emitter terminal of the transistor 23, and the emitter terminal of the transistor 23 is grounded. The base terminal of the transistor 23 is connected to one end of a resistor 24, and the other end of the resistor 24 is connected to a side select signal of the floppy disk device interface and a power supply line via the resistor 25.

The operation of the above configuration will be described below. The filter circuit 13 of FIG. 1 has a pulse slimming function, and a dedicated terminal for setting a cutoff frequency of the filter circuit 13 and a boost amount of pulse slimming is provided in the LSI, and a built-in ROM of the LSI (not shown) is provided. Depending on the format capacity used and the track position, the floppy disk device is switched. The boost amount of the filter circuit 13 is set by the resistors 21 and 2 connected between the dedicated terminal 20 for setting and the ground.
It changes according to the resistance value of 2. When the side 0 of the floppy disk device is selected, the side select signal of the interface is at high level, so the filter circuit 1
The boost amount of 3 is set by the resistors 21 and 22 by the switching function of the transistor 23 shown in FIG. When the side 1 is selected, the side select signal is at the low level, so the boost amount of the filter circuit 13 is set by the resistor 22 by the switching function of the transistor 23 shown in FIG.

FIG. 3 is a diagram showing the characteristics of the filter circuit 13 with respect to the innermost side 0 and side 1. As shown in FIG. 3, even when the recording signal on the magnetic medium is read at the same track position on the side 0 and side 1, the boost amount can be set larger on the side 1 side than on the side 0. It is possible to improve the reduction in resolution due to the amount of track deviation due to the arrangement.

FIG. 4 is a diagram showing reproduction characteristics when the embodiment of the present invention is applied to the unformatted capacity 4 MB mode. The reproduction characteristic of FIG. 4 is that the slimming function is not used from 0 track to 31 track,
An example is shown in which the boosting amount of the slimming function is switched in two steps between 7 tracks and 48 tracks to 79 tracks. FIG. 6 shows the reproduction characteristics in the unformatted capacity 4 MB mode in the conventional circuit configuration. As is apparent from this, according to the embodiment of the present invention, the reproduction characteristic of the side 1 shown in FIG. 6 can be improved to the reproduction characteristic of the side 1 shown in FIG. 4, and the error rate of the floppy disk device can be improved. Can be improved.

The present invention is not limited to a circuit for switching the filter characteristic for each side by a switching element such as a transistor 23 having a slimming function externally attached to an LSI. For example, a cutoff frequency of a low pass filter or Even if the boost amount of the pulse slimming function and the damping of the differentiating circuit are switched by the control circuit inside the LSI, or switched by a switching means using an external transistor, a resistor or the like, the same effect as the above embodiment can be obtained.

[0019]

As described above, according to the present invention, the reproduction waveforms read by the side 0 and side 1 magnetic heads can be set to optimum waveform equalization on each side. It is possible to correct the characteristics due to the deviation, and it is possible to obtain good reproduction characteristics and improve the error rate of the floppy disk device. Further, since it is not necessary to change the gap length on the side 0 side and the side 1 side when manufacturing the magnetic head, the manufacturing process of the magnetic head can be simplified, and the resolution which could not be conventionally adopted on the side 1 side is poor. Since the head can also be used, the yield of the magnetic head can be improved. Furthermore, when realizing high-density recording while ensuring backward compatibility, the optimum waveform equalization can be set for each side even with a conventional head layout that has a misalignment. Is obtained.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing the configuration of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a side switching control circuit in the magnetic recording / reproducing apparatus.

FIG. 3 is a diagram showing characteristics of a filter circuit in the magnetic recording / reproducing apparatus.

FIG. 4 is a diagram showing reproduction characteristics in the magnetic recording / reproducing apparatus.

FIG. 5 is a schematic block diagram showing the configuration of a magnetic recording / reproducing device in a conventional floppy disk device.

FIG. 6 is a diagram showing reproduction characteristics in the magnetic recording / reproducing apparatus.

[Fig. 7] 3.5-inch size and track density of 135T
Diagram showing the arrangement of the head and track of the PI floppy disk device

[Explanation of symbols]

 11 magnetic head 12 amplifier 13 filter circuit 14 differentiating circuit 15 storage capacity switching control circuit 16 track switching control circuit 17 side switching control circuit 18 comparator circuit 19 pulse shaping circuit 21 resistor 22 resistor 23 transistor 24 resistor 25 resistor

Claims (1)

[Claims] 1. A plurality of magnetic heads for reading a signal recorded on a magnetic medium, and a waveform equalizing circuit and a waveform shaping circuit for reproducing a voltage signal read by the magnetic head. A magnetic recording / reproducing apparatus characterized in that, in the waveform equalizing circuit, a difference in recording density caused by a deviation in track arrangement of the magnetic heads can be corrected.