JPS6063777A - Detection system of dislocation between record medium and head - Google Patents

Abstract

PURPOSE:To allow a normal disk to detect dislocation by recording prescribed signals at plural positions which are different in the width direction and in the relative moving direction to a head on a prescribed track of recording media and using these signals. CONSTITUTION:H1-H4 denote positions which divide a track in the width direction into five equal parts. Signals S1 to be reproduced during the period from the time, which is elapsed by t1 to the time when index signals can be obtained, to DELTAt are recorded in H0-H2 areas. Signals S2-S4 are recorded in the same manner. Signals S1- S4 can obtain a reproduction output at a constant level. In order to reproduce said recorded signals S1-S4 on said reference track, a signal GU from a control circuit is inputted into an amplifier circuit 2, and the reproducing levels of the signals S1-S4 are raised to the signal reproducing level on the entire width of the track. The signals are made binary by a waveform-shaping circuit 3 and given to a dislocation detection circuit 5. An output of the circuit 3 becomes a signal as shown in the figure when there is no or little dislocation. However, if dislocation occurs, some of the signals are omitted. Thus, according to the time relation between the output of the circuit 3 and the index signal, the detection circuit 5 detects dislocation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting misalignment between a recording medium and a head in a magnetic recording device such as a floppy disk device, an optical recording device such as an optical disk recording device, and the like.

If the recording/reproducing head is misaligned with respect to the track of the recording medium, correct recording/reproducing cannot be performed and compatibility with other devices is lost. For example, when such a positional shift occurs in a floppy disk device, the conventional method is to play an adjustment disk on which a special signal is recorded and make adjustments based on this playback signal, which is a hassle. was unavoidable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method that can detect positional deviation using a normal disk and eliminate the above-mentioned troubles.

The positional deviation detection method according to the present invention includes recording a predetermined signal on a predetermined track of a recording medium at a plurality of different positions in the width direction of the trunk and in the relative movement direction with respect to the head;
The present invention is characterized in that the positional deviation between the recording medium and the head is detected based on the reproduction state of these signals.

Embodiments will be specifically described below based on drawings showing examples. 1st
The figure shows the reference track of a floppy disk, which is normally used even if it has 9 cylinders (tracks) and does not have cylinders (trunk).
It may be.

As shown in Figure 1, both edges of this track in the width direction are
8, H7, the position that divides this into 5 equal parts is H1H2 + H3
, Hf. A signal S□ to be reproduced over a period of ΔL from the time t1 has elapsed since the index signal is obtained is recorded in the I area of Ha = H2, and from the time t2 has elapsed from the time when the index signal is obtained, the signal S□ is
The signal S2 to be reproduced over a period of time t is expressed as H8 to H3.
Similarly, a signal S3 to be reproduced for a time Δt from the time t3 has elapsed is recorded in an area H2 to H4, and a signal S3 to be reproduced for a time ΔL from the time t has elapsed. The desired signal S4 is recorded in the areas H3 to H1. Signals 81 to s4 are uniform signals that provide a constant level of reproduction output.

FIG. 2 shows the configuration of a reproduction system of a floppy disk device to which the method of the present invention is applied. The signal reproduced by the head 1 is input to an amplifier 2 and then to a waveform shaping circuit 3, and the output of the waveform shaping circuit 3 is input to a regenerative data processing circuit 4 or a positional deviation detection circuit 5.

When reproducing the data of the bird, the reproduced signal binarized by the waveform shaping circuit 3 is input to the reproduced data processing circuit 4, whereas in this mode, the signal recorded on the reference track is to be reproduced. When the device is operated, a signal GU instructing the amplifier circuit 2 to increase its gain is input from a control circuit (not shown) to the amplifier circuit 2. The signals 81 to S recorded on the reference track do not have the full width of the track, unlike normal recording signals, and the reproduction level of the head 1 is low. However, the amplifier circuit 2 compensates for the level by increasing the gain and amplifying the signal GO, and increases the level of the output of the amplifier circuit 2 when reproducing the signals S, ~S, to the level when reproducing the signal of the full trunk width. . The output of the amplifier circuit 2 is then binarized by the waveform shaping circuit 3, and the binarized output is given to the positional deviation detection circuit 5.

FIG. 3 shows the output of the waveform shaping circuit 3. When there is no positional deviation or there is little positional deviation, this output is changed from the index signal to tl+t2. as shown in the figure. The signal is such that a pulse with a time width Δt appears after t3+t4, but if a positional shift occurs, one of the signals will be missing.

For example, if the head 1 is shifted to the H5 side and the recording in the area between Ho'' and H2 cannot be reproduced, the signal S1 will not be reproduced.

Further, even if a partial region between H O = H2 is not reproduced, the signal S1 will not appear at the output of the waveform shaping circuit 3 depending on the threshold value set in the waveform shaping circuit 3. On the other hand, if head 1 is shifted to the H1 side, signal S4
is not played. The positional deviation detection circuit detects the deviation of the head 1 based on the time relationship between the output of the waveform shaping circuit 3 and an index signal input separately, and outputs the detected deviation by appropriate means.

In this way, the present invention uses a part of the trunk of a normal floppy disk to record signals for detecting positional deviations, so there is no need to create a special disk for detecting positional deviations, and this greatly reduces maintenance work. It's convenient.

Note that the number of divisions in the width direction of the trunk is not limited to the above-mentioned example, and may be any number; the more subdivided the trunk, the more accurately the amount of positional shift can be detected. Also, in the above example, the missing signal can be identified using the time 'l+t2... from the index signal.
・Although this is not limited to this, the signal recorded at the center of the width direction where there is no actual dropout (
For example, when the area is divided into six areas in the width direction, the identification may be made based on signals recorded over the 3rd and 4th areas). Furthermore, the present invention is equally applicable to optical recording systems. Furthermore, it goes without saying that the present invention can also be applied to a reproduction-only machine.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is an explanatory diagram of a recording format on a reference track, FIG. 2 is a block diagram of a device to which the method of the present invention is applied, and FIG. 3 is a time chart of reproduced signals. It is. 1...Head 2...Amplification circuit 3...Waveform shaping circuit 5...Position shift detection circuit patent Applicant: Sanyo Electric Co., Ltd. Agent Patent attorney: Noboru Kono

Claims (1)

[Claims] 1. In a signal reproducing device that reproduces a signal recorded on a track having a predetermined width of a recording medium using a head that moves relative to the signal, the signal is recorded on a predetermined track of the recording medium in the width direction of the track and the head. 1. A positional deviation detection method comprising recording predetermined signals at a plurality of different positions in a direction of relative movement with a head, and detecting a positional deviation between a recording medium and a head based on the reproduction state of these signals.