JPS62275358A - Flag recording and reproducing system - Google Patents

Abstract

PURPOSE:To improve reliability for correction of flag errors by giving flags in 2-dimensional directions of time axis and track directions to a flag block formed by reproducing those flags recorded on each track of a magnetic recording medium and arraying such flag blocks for production of the specific data. CONSTITUTION:The data signal D is recorded in a block style where a single block 101 contains five frames 102 and with each frame 102 set to each track of a magnetic tape 1. Then a flag F and code error correcting redundant signals c1 and c2 are recorded to the specific areas of those five tracks 102 in a block 101. These flags F are successively reproduced out of plural adjacent blocks 101. In this case, the flags F form blocks 104 in both time base and track directions and these blocks 104 are arrayed to produce the specific data. Thus the flag block 104 contains flags F in both time base and track directions and the specific data are obtained from an array of the blocks 104.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] This invention relates to a flag recording and reproducing system for PCM (Pulse Sign Change? J4) signals.

[Traditional technique! ] Conventionally, PCM recorders have been divided into two main types: rotating head systems that convert PCM signals into TV signals and then recording them on a VTR, and fixed head systems that have the same tape running system as current analog recorders. Separated.

In the case of a fixed head type PCM recording device, in order to reduce the tape speed, a multi-track structure is used, and PCM signals are distributed to the multi-tracks and recorded.

On the other hand, when recording music information, there is information other than this music information that should be recorded on the tape. For example, (a) Emphasis 0N-OFF, Note 22 Change 2gl
Various parameters during recording operations in the recorder, such as identification of formats, etc. during recording operations in the recorder (b) Information on recording software such as performer, recording location, date, etc.

This information is recorded on tape at the same time as the PCM signal,
Based on this information during playback, for example, (c) when generating a PCM recorder, the emphasis is set to 0N-
(d) Control such as OFF, etc. (d) Display of performance conditions on the cathode ray tube display, etc. Such data is called a flag.

Figure 5 shows a conventional example of a method for recording flags on tape, in which (1) is magnetic tape and (2) is PCM.
The track (3) on which signals are recorded is a dedicated track on which flags are recorded. Although this method has the advantage of being able to record a large number of flags, it has the disadvantage of increasing track density because one extra track must be provided.

Therefore, conventionally, there is a method in which this flag track is not provided. PCM signals recorded on tape generally generate code errors due to dust or scratches on the tape. In order to correct this code error, the PCM signal is organized into block format.

Adding error correction redundant signals in the tape width direction and the tape longitudinal direction of this block is usually used in view of the distribution pattern of code errors occurring on the magnetic tape.

FIG. 6(X) shows the block (1
In the example of 01), one block (101) consists of, for example, five frames (102) as shown by diagonal lines, and each frame (102) is distributed to each track of the magnetic tape (1) by one frame (+02). and record it.

In FIG. 6(b), which is an enlarged view, S is a frame synchronization signal, and F is a flag, and each track has the same number of bits. p is PCM
A data signal consisting of one sample of the signal, CI, is a redundant signal for data error correction added in the longitudinal direction of the tape, and C2 is added in the width direction of the tape.

[Problems to be Solved by the Invention] However, although this method does not require a flag track to be provided on the magnetic tape (1), it has the drawback that the number of bits of the flag F that can be recorded is small.

This invention was made to improve the above drawbacks.
It is an object of the present invention to provide a flag recording and reproducing method that can record flags with a large number of bits and has an excellent flag error correction function.

Means for Solving Problem c] The flag recording and reproducing method according to the present invention records data signals in one
Each block is recorded in a block format consisting of a plurality of frames, each frame is distributed to each track of the magnetic recording medium, and flags and redundant signals for code error correction are recorded at specific locations on 8I tracks in one block. However, when reproducing flags sequentially from multiple adjacent blocks,
Each flag forms a block in the two-dimensional direction of the time axis direction and the track direction, and this flag block is arranged to become specific data, and a flag synchronization signal is recorded in each flag block, and adjacent flags are It is characterized in that it is configured to detect and correct errors in flag blocks based on matching of block patterns.

In this way, a flag block formed by reproducing flags recorded on each track of a magnetic recording medium has flags in the two-dimensional direction of the time axis direction and the track direction, and in this flag block, specific data and They are arranged as follows.

Therefore, even if a flag error occurs in the flag of the l track, for example, the error can be corrected by replacing it with the contents of another flag block, and the reliability of flag error correction can be improved.

Furthermore, if such a flag recording/reproducing method (hereinafter referred to as the margin) is used, it is possible to record information with different meanings depending on the position of the flag in the flag block, and if the flag changes slowly, The number of flags that can be recorded can be increased.

Furthermore, according to this flag recording and reproducing method, flag error correction for each flag block is detected during reproduction depending on whether or not the contents of adjacent flag blocks match. Since it is not necessary to record redundant signals for flag error correction in blocks, the number of flags that can be recorded in each flag block can be increased accordingly, and from this point of view as well, the reliability of flag error correction can be further improved. Can be done.

[Embodiments of the invention] Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1A and 1B show an example of recording in the flag recording/reproducing method according to the present invention.

Figure (L) is an example of a block (lot), for example 5
It consists of frames (102), each frame (102) being one frame (102) for each track of the magnetic tape (1).
Distribute and record.

That is, each block (101) is sequentially and continuously recorded on the magnetic tape (1) as shown by diagonal lines in FIG. recorded.

In addition, the same figure (C) shows a flag block (104),
When the flags (103) of each block (101) are taken out and rearranged, each flag (103) constitutes a flag block (100) as shown in the figure.

That is, each flag block (104) is constructed by sequentially storing the flag (103) in the memory during playback.
A flag synchronization signal is used to clarify the 00 break, and F is a flag.

Further, block numbers are sequentially assigned to the flag blocks (104). In Figure 1A, F (1)
is the first flag block (104), F(2)
.

F(3) is the second. Third flag block (104)
Then, the fourth and other 7-lag blocks (to4), which are not shown, continue, and as shown in FIG. 1B, the N-1st flag block F (n-1), the N-th flag block F(n), N+1st flag block F
(n+1),... and so on.

Figure 2 shows the flag blocks (10
4) is a circuit diagram of a flag processing section that performs the reproduction process.

In the figure, (4) is an input terminal for a PCM signal, (5) is an output terminal for a PCM signal, and (8) is a flag extractor for extracting flags, which extracts only the flag F of each block (101). (7), (8) and (8) are the first,
The second and third memories each have a storage capacity for l flag blocks (104), and each memory (7)
, (8) and (3) include the l flag block (
tOa) is stored from beginning to end.

(10) is a pattern matching detection unit that detects matching of patterns of each flag block (+04), and the memory (7)
, (8) Detect whether the stored contents are equal or not. (11) is a pattern match detection! A gate controlled by (to) is opened when the contents of memories (7) and (8) match, and the contents of memory (8) are stored in memory (8). A decoder (12) decodes the contents of the flag F stored in the memory (9) and outputs it to a predetermined circuit through a flag output terminal (13).

Now, the PCM No. 1 applied to the input terminal (4) extracts only 7 lags F in the flag extractor (ill), and stores the flag F of 1 flag block (104) in the memories (7) and (8). , flag block F (1) to block number (n+1), etc., are stored from beginning to end. The pattern matching detection unit (10) detects whether the contents stored in each of the memories (7), , (8) are the same, and determines whether the contents of the memory (7) and memory (8) match. When the gate (11) is opened, the contents of the memory (8) are stored in the memory (9). As a result, an incorrect flag F will not be stored in the contents of the memory (8).The contents of the flag block (104) stored in this memory (9) are decoded by the decoder (12) and output as a flag. It is output to a predetermined circuit through a terminal (13).

Normally, the rate of change of the flag is sufficiently slow, so that the contents of adjacent flag blocks F (n-1) and F (n) are exactly the same. Therefore, as mentioned above, when the contents of memories (7) and (8) are played back, the pattern matching circuit (10)
If there is a difference, it is assumed that there is a code error, and the adjacent flag blocks F(n-1) and F
(n), the preceding flag block F (n-1
), the contents of the subsequent flag block F (n) are stored in the memory (8).

Also, depending on the change in information, the subsequent flag block F (
If the contents of flag block F (n) have changed, the contents of the subsequent flag block F (n) are transferred to the memory (9) with the contents of the preceding flag block F (n-1) using the same procedure.
However, if drop error 1 does not occur, the subsequent flag block F (n-1
) and the preceding flag block F (n), it is detected that the flag has changed at the time of this comparison, and the flag block F (n) already stored in the memory (8) is detected. The contents of flag block F (n) are changed to F (n) and the contents of flag block F (n) are stored in the memory (8).

In that case, although detection of a change in flag F is delayed by one flag block, this does not pose a practical problem because the repetition frequency of each flag block is sufficiently high.

As described above, data signals are recorded in a block format in which one block (101) consists of five frames (102), and each frame (102) is distributed to each track of the magnetic tape (1). (101) 5
When flag F and code error correction redundant signals cl and c2 are recorded at specific locations on the track (lo2), and flags F are sequentially reproduced from adjacent blocks (101), each flag F is Blocks (100) are formed in the two-dimensional direction of the track direction, and this flag block (100
The data is arranged so that it becomes a specific data. (See Figure 1) In this way, the flag block (1) is formed by reproducing the flag F recorded on each track of the magnetic tape (1).
04) has flags F in the two-dimensional direction of the time axis and the track direction, and is arranged to become specific data in this flag block (104).

Therefore, for example, the flag F of l track (102)
Even if a flag error occurs, the contents of the flag block F (n) in which the flag error occurred will be replaced with the contents of the preceding flag block F (n-1) and will not be changed, and the subsequent flag Unless it matches the contents of block F (n-1), the preceding flag block F (
Since the content of n-1) always takes priority, its error can be corrected, and the reliability of flag error correction can be improved.

Furthermore, if such a flag recording and reproducing method is used, information with different meanings can be recorded depending on the position of the 7 lags F of the flag block (104), and if the changing speed of the flag F is slow, , the number of recordable flags F can be increased.

Furthermore, according to this flag recording and reproducing method, flag error correction of each flag block (1<14) is detected during reproduction depending on whether or not the contents of adjacent flag blocks (104) match. Therefore, it is not necessary to record a redundant signal for flag error correction in each flag block (1G4).

Therefore, the number of flags F that can be recorded in each flag block (104) can be increased accordingly, and from this point of view as well, the reliability of flag error correction can be further improved.

However, in this method, each flag block (104
) may cause frame synchronization malfunction.

For example, a pseudo frame synchronization signal having the same pattern as the frame synchronization signal 5ync of the flag block (104) is generated in the PCM signal in block (101) in FIG. 1(a). Such a fake frame synchronization signal is extracted as a correct frame synchronization signal 5ync by a flag extractor (8), and is stored in a memory (7).
, (8), if the flag block (1
04) frame synchronization malfunction occurs.

In order to solve this inconvenience, a known means using a synchronization gate can be adopted. FIG. This is a frame synchronization signal extracted from a pseudo frame synchronization signal (
al)-. (b) is a synchronization gate signal generated from the frame synchronization signal (&), and when the signal level is LOW (L), (11) is opened. (C) is a frame synchronization signal selected by the synchronization gate signal (b). Since the selection range is narrow, there is no selection of the fake frame synchronization signal (a1). Therefore, this frame synchronization signal (C) is reproduced. If used as a frame synchronization signal, malfunctions in frame synchronization of the flag block (104) can be effectively prevented.

The pseudo frame synchronization signal (al) is generated during the reproduction of the PCM signal, and as shown by the signal (d l) in FIG. When first extracted by the flag extractor (6) during playback, this false frame synchronization signal (d1) passes through the synchronization gate signal (e) and becomes the true synchronization gate signal (fl), After that, there is a risk that a fake frame synchronization signal will be selected at a certain period.

However, since the PCM signal is a random signal, it is almost impossible for another false frame synchronization signal to be generated. The true synchronous gate signal (g) extracted in (8) is selected and a normal cycle can be entered.

On the other hand, in the case of a flag block (100), the change of the flag signal F is slow, and this flag signal F is not a random signal but a fixed pattern, so once the flag synchronization signal of the flag synchronization signal 5ync is If this occurs, a false flag synchronization signal will be generated at regular intervals for a long period of time, and it may be extremely difficult to enter a normal cycle.

In such a case, instead of using the same type of synchronization pattern such as the flag synchronization signal 5ync in FIGS. 1A and 1B to clarify the break in the flag block (104), the synchronization pattern shown in FIGS. 4A and 4B is As shown, a plurality of different types of synchronization patterns 5(A)' and (B) may be sequentially and alternately used.

[Effects of the Invention] As described above, according to the flag recording and reproducing method according to the present invention, flag blocks formed by reproducing flags recorded on each track of a magnetic recording medium are aligned in the time axis direction and the track direction. It has flags in two-dimensional direction, and the flag block is divided into specific data, so it improves the reliability of flag error correction, allows recording of flags with a large number of bits, and It has an excellent flag error correction function that can record information with different meanings depending on the position of the flag in the block.

[Brief explanation of drawings]

1A and 1B are explanatory diagrams of an information recording format showing an example of the flag recording/reproducing method according to the present invention, and FIG. 2 is a flag processing for reproducing a flag block recorded using the flag recording/reproducing method according to the present invention. FIG. 3 is a time chart illustrating an example of means for preventing frame synchronization malfunctions of flag blocks that occur during reproduction of flag blocks in the flag recording/reproducing method according to the present invention, and FIGS. 4A and 4B. 5 is an explanatory diagram of an information recording format explaining another example of means for preventing malfunction of frame synchronization of flag blocks; FIG. 5 is an explanatory diagram of information recording showing an example of a conventional flag recording/reproducing method;
FIG. 6 is an explanatory diagram of an information recording format showing another example of the conventional flag recording/reproducing method. (1)...Magnetic recording medium, (101)...Data block, (102)...Frame, F, (103
)...Flag, (104)...Flag block, S
Ten nc...Flag synchronization signal. In addition, in the figures, the same reference numerals indicate the same or compatible parts.

Claims (2)

[Claims] (1) Data signals are recorded in a block format in which one block consists of multiple frames, and each frame is distributed to each track of a magnetic recording medium, and flags and code errors are set at specific locations on multiple tracks in one block. When a redundant signal for correction is recorded and flags are sequentially reproduced from multiple adjacent blocks, each flag forms a block in the two-dimensional direction of the time axis and the track direction. are arranged so that
1. A flag recording and reproducing system characterized in that each flag block has a flag synchronization signal, and errors in flag blocks are detected and corrected by matching patterns of adjacent flag blocks. (2) The flag recording and reproducing method according to claim 1, wherein the flag synchronization signal of each flag block is composed of a plurality of different types of synchronization signal patterns.