JPH027233A - Recording medium - Google Patents

Abstract

PURPOSE:To improve the accuracy of position detection by arranging a track having two marks and a track having three marks alternately, and providing two marks on adjacent two tracks at the same bit position and a remaining mark adjacently to either two marks. CONSTITUTION:The mark on the track T1 is the one in which the mark 4 at the bit position #4 neighboring to the mark 5 is added on the marks 3 and 5 at the same bit positions #1 and #5 as the mark of the track T0, and the mark on the track T2 is formed in the same patterns as that of the mark in which the mark at the bit position #5 is eliminated from the mark on the track T1. Here, since the difference of arrangement of the marks arranged on arbitrary adjacent tracks is one at maximum, it is possible to suppress a reading error within one even when mark detection in seeking is performed not accurately. In such a way, it is possible to identify the track with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a recording medium having a plurality of tracks and recording or reproducing information along each track.

2. Description of the Related Art In recent years, recording media such as optical discs, which have a large storage capacity and also have excellent information retrieval capabilities, have been appearing.

An example of the conventional recording medium mentioned above will be described below with reference to the drawings.

FIG. 4 shows a block diagram of the main parts of a conventional recording medium. In FIG. 4, 10, 11, 12.degree. 13 are marks, respectively, and mark 1O and mark 11. Marks 12 and 13 are arranged along the same track. Furthermore, the mark 10 is placed at a position shifted by one bit from the mark 11. Marks are provided at regular intervals along the track, and information is recorded in these gaps.

The operation of the recording medium configured as described above will be explained below.

Each mark is used as a guidepost for each track. That is, when recording and reproducing information along each track, marks are detected at regular time intervals and tracking correction is applied in a sampling manner. mark 12
The reason why the information is shifted by l bit from the mark lO is because when the information recording/reproducing head jumps from one track to another (+/rack seek), the position of the moving head is checked. This is to make it easier. In other words, this means that a Gray code with an inter-symbol distance of 1 is composed of a plurality of marks. Fifth
As shown in the figure, the trajectory of the head during track seeking diagonally traverses the tracks on the recording medium. The position of the head at this time can be found by multiplying the number of tracks crossed by 'A'. However, with this sampling-based track position detection method, a track can only be identified when marks placed at certain intervals along the track are detected. Sometimes I fail to read a certain mark. Therefore, 2 +! with different bit positions! I
! By alternately arranging racks with similar mark patterns, multiple tracks can be made into blocks.
This allows for a certain amount of skipping. Does it actually have marks at the same bit positions as marks 10 and 11 as shown in FIG. 5? Does it have a mark at the same bit position as M number of tracks and mark 12 and mark 13? il is arranged alternately with several tracks to allow skipping of multiple tracks.

(For example, "Nikkei Electronics 1-ronics" 19B6.12
．． 15 (no, /+10)).

Problems to be Solved by the Invention However, the above configuration has a problem in that the maximum seek speed and position detection accuracy are in a contradictory relationship, as described below. That is, as the seek speed increases, the number of skipped tracks also increases. In order to avoid errors in position detection due to this, it is necessary to have a sufficiently large number of similar tracks. However, on the other hand, the accuracy of position detection becomes more ambiguous by the number of tracks.

In view of the above-mentioned problems, the present invention provides a recording medium having bit marks that can increase the seek speed without reducing the 811 degrees of position detection.

Means for Solving the Problems In order to solve the above problems, the recording medium of the present invention has a track in which a mark is placed at a certain bit position, and then a mark is placed at both that bit position and the adjacent bit position. A marked track is arranged, and then a track in which an adjacent bit position is marked in place of the previous previous bit position is arranged.

Effect The present invention has the above-described configuration, so that the mark pattern is one.
A relatively long lap around a track with different bits! 111 in sequence, and the pattern is L'2
By performing EFk, the track can be identified with good accuracy.

EXAMPLE Hereinafter, a recording medium according to an example of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 each show a partial configuration diagram of a main part of a recording medium in a first embodiment of the present invention. In FIG. 1, marks 1, 2, 3, 4.5, and 6.7 are arranged along the track, and the arrangement thereof is explained as follows. On track Tl, mark l and mark 2 are bit #1 and focus #5, respectively.
It is located at Mark 3. is on the adjacent track Tl. Mark 5 is bit #l and bit #5 respectively
Focus #4 where mark 4 is adjacent to bit #5
It is located at the location of Furthermore, the next truck T2
1, marks 6 and 7 are provided at the positions of bit #1 and bit #4, respectively. In other words, the mark on track TI is at the same bit position #1 as the mark on track To. Marks 3 and 5 in #5 are added with mark 4 at bit position #4 adjacent to mark 5, and the mark on track T2 is obtained by removing the mark at bit position #5 from the mark on track T1. It has the same pattern. Mark placement is determined from track T3 to track T15 using the same rules. Furthermore, according to this rule, the next track after track T15 has the same arrangement as track TO, so this mark Bakuts is 1
This will be repeated every 6 tracks.

The operation of the recording medium configured as described above will be explained below with reference to FIGS. 1, 2, and 3.

According to this, if the speed is within the speed at which 15 tracks are skipped, the track being sought can be identified within the error range of at most one track. In other words, since the arrangement of marks placed on any adjacent tracks differs by at most one mark, even if mark detection during seek is ambiguous, the reading error can be kept within one line. For example, as shown in FIG. 3, when the head passes between tracks T1 and T2, whether a mark at bit position #50 is detected or not, the determination is that it is track TI or T2. The probability that another track is determined to be HA is extremely small.

Furthermore, the features of this embodiment are as follows! The word length of a track mark that can identify 6 tracks can be realized with only 6 bits. If we try to identify 16 tracks using two marks using the conventional extension technique, the word length will be 16.
More than one bit will be required.

As described above, according to this embodiment, tracks having two and three marks for identifying the tracks are arranged alternately,
Two marks on two adjacent tracks are provided at the same bit position,
By providing the remaining one adjacent to either of the other two, the head position can be detected within an error range of at most one track even during high-speed seek.

Effects of the Invention As described above, the present invention allows a mark to be placed at a certain bit position. =
Next to the track marked by J, place a track that is marked both at its focus position and at the bit position adjacent to it, and then place a mark at the adjacent focus position in place of the previous previous bit position. By arranging marked tracks, the mark pattern becomes one.
Tracks with different bits can be sequentially arranged over a relatively long period, and by recognizing the pattern, the tracks can be identified with high accuracy.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of main parts of an embodiment of the present invention, Fig. 2 is a partial block diagram of an embodiment of the present invention, Fig. 3 is an explanatory diagram of the operation of the present invention, and Fig. 4 is a main part of a conventional example. FIG. 5 is a diagram illustrating the operation of a conventional example. 1.2, 3, 4, 5. (i, 7...marks. Agent's name Patent attorney Toshio Nakao Haka 1 person Kure 1 Figure #4 F5 @2 Figure

Claims (2)

[Claims] (1) A recording medium having a Gray code that periodically numbers tracks by marking at least one of a plurality of bit positions and changing the mark position for each track, the Gray code places a track with a mark at a bit position followed by a track with a mark on both that bit position and an adjacent bit position, then replaces the given bit position with the adjacent bit position. 1. A recording medium characterized in that the recording medium is configured such that tracks with marks attached thereto are arranged. (2) The recording medium according to claim (1), wherein tracks each having two and three Gray code marks are arranged alternately.