JP2564938B2 - Magnetic disk recording method - Google Patents

Description

The present invention relates to a magnetic disk recording method, and more particularly to a format recording method in perpendicular magnetic recording.

[Prior Art] Conventionally, a pull-in signal area (hereinafter referred to as a sync signal) used for magnetic recording of a magnetic recording medium (hereinafter referred to as a medium) has a continuous minimum bit interval used in a data area, that is, FM. Whether all “1” is continuous in recording, is “00” or “11” in MFM recording, or is continuous with maximum bit interval, that is, all “0” is continuous in FM recording and “10” is continuous in MFM recording. One of the
Called) was tuned to the data frequency in this area, and was also in phase with the data.

[Problems to be Solved by the Invention]

However, since this Syquimbite is written at the same frequency, it is easy for VFO to synchronize, but it is not possible to judge the quality of the data, and especially in the case of perpendicular magnetic recording, the peak shift of the read data is a characteristic of the medium. Is significantly affected by. This is due to the correlation between the characteristics of the medium and the magnetic head to be read, and it is necessary to correct the read circuit side. However, as described above, it was not possible to determine how to correct the sync signal in the conventional format.

[Means for solving the problem]

The present invention first writes a fixed number of sync signals at the same bit interval (the minimum or maximum of the data bits used), completes the pull-in of VFO in this written area, and is used subsequently. By writing a fixed number of data with the minimum bit interval and the maximum bit interval of the data bits alternately, the written signal has the maximum peak shift, so adjust the phase relationship between the VFO sync signal and the read data in this area. A recording method of a format that can be used for recording is provided.

That is, according to the present invention, in a recording format written on a magnetic disk medium, a signal having a certain number of bit intervals in a sync area for facilitating synchronization with a phase synchronization circuit that generates a sampling clock synchronized with a read signal. And then write a fixed number of signals of the maximum bit interval and the minimum bit interval of the data bit intervals to be used alternately, or write a specific number of a specific pattern that maximizes the bit shift. This is a magnetic disk recording method.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

First, the recording format of the medium and the contents of the sync area of the conventional medium will be described with reference to FIGS. 2 and 3. In FIG.
GAP1 is an area for absorbing uneven rotation of the medium, and is located between the ID section 2 and the data section 3 and between the data section 3 and the ID section 2. In the ID section 2, information corresponding to the name tag of the next data section 3 is written. The data unit 3 is so-called information. Sync area 4
It is written at the beginning of the ID section 2 and the data section 3, and the VFO circuit makes it easy to generate a sampling clock signal in which the frequency and the phase are matched with the signal of the ID section 2 or the data section 3 written on the medium. It is a thing. Conventionally, all "0" or all "1" is written in the content of the sync area 4 as shown in FIG.

FIG. 1 shows the sync area 4 of the present invention. The figure shows MFM
Describes the recording method. In this invention,
At the beginning, the minimum bit interval "00" or "11" signal is written continuously, and then the minimum bit interval and the maximum bit interval are alternated so that the peak shift of the signal becomes maximum. The pattern of "110110" that occurs is repeatedly written. It should be noted that a specific pattern that maximizes the bit shift may be written instead of this pattern.

FIG. 5 shows a read signal in the conventional sync area. With this signal, at high density, it is almost a sine wave and it is difficult to distinguish it regardless of the medium or magnetic head.

FIG. 4 shows a read wave number waveform in the vicinity of the switching of the “00” or “11” pattern and the subsequent “110” pattern in the sync area of the present invention. With this method, after the VFO is synchronized with the read signal, the peak shift of the signal written in the data section or ID section that follows can be predicted,
By using the sampling clock of VFO synchronized with the frequency, it becomes possible to adjust the readout circuit in the sync area so that the phases match.

〔The invention's effect〕

As described above, according to the present invention, the sync area in the recording format is followed by a fixed number of signals with a constant interval, and then a fixed number of signals with a minimum bit interval and a maximum bit interval used in the data area are alternately written. , Or by writing a certain number of specific patterns that maximize the bit shift,
There is an effect that information can be read without error when the density is increased.

[Brief description of drawings]

FIG. 1 is a diagram showing a recording format in a sync area according to an embodiment of the present invention, FIG. 2 is a diagram showing a recording format in a medium, and FIG. 3 is a figure showing a recording format in a sync area according to a conventional example. 4, FIG. 4 is a waveform diagram of the read signal in the sync region of FIG. 1, and FIG. 5 is a waveform diagram of the read signal in the sync region of FIG. 1 ... GAP part, 2 ... ID part, 3 ... data area, 4 ...
Sync area

Claims (1)

(57) [Claims] 1. A predetermined number of pull-in signals are written at the same bit intervals in a recording area for recording the format of a magnetic recording medium to facilitate synchronization with a synchronizing circuit which generates a sampling clock signal synchronized with a read signal. Writing a predetermined number of signals of the minimum bit interval and the maximum bit interval used in the data area alternately after the predetermined number of writes, or writing a predetermined number of specific patterns that maximize the bit shift. And a magnetic disk recording method.