JPH0831267B2 - Digital recording method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital recording method for recording a digital signal on a tape as an oblique track.

[Background of the Invention]

Searching the desired data at high speed from the signals recorded on the tape shortens the waiting time of the tape and greatly improves the operability of the recorder. FIG. 1 shows a random access means conventionally performed by analog. In FIG. 1, 1 is a tape, 2 is a head, 3 is an amplifier, 4 is a slice circuit, 5 is a microcomputer, 6 is a motor, 7 is a keyboard, and 8 is a servo circuit.

 Hereinafter, description will be given with reference to the drawings.

This data is once taken in by the microcomputer 5. The microcomputer 5 reaches the access side to rotate the motor 6 at high speed. The tape 1 is wound up at high speed. At this time, the head 2 is in contact with the tape 1 and reads the signal recorded on the tape 1. This signal enters the comparator 4 after the amplifier 3. The comparator 4 detects whether or not the signal from the head 2 exceeds a certain threshold. When the tape 1 approaches the track, no signal is recorded, so the comparator 4 detects this state. The detection signal is taken into the microcomputer 5. Here, when the number of songs input from the keyboard 7 and the number of detections between songs match, the microcomputer 5 switches the switch, and the servo circuit 8 based on the signal of the motor 6 starts normal running to move the head 2 To play the data.

However, random access by such a method cannot be detected when there is no silent section or when there is no silent section. When a digital signal is recorded, the digital signal corresponding to silence is recorded, and the above random access cannot be performed. Further, in the above random access method, in the case of overwriting, the order of subsequent songs may be out of order depending on the number of overwritten songs.

On the other hand, Japanese Patent Laid-Open No. 53-53916 discloses that an absolute address is recorded in a diagonal track together with a video signal for tape editing. According to this recording method, since the absolute address is recorded at the same time as the recording of the video signal, the recording is performed only in a time series, and therefore the tape cannot be randomly accessed at the time of recording.

[Object of the Invention]

It is an object of the present invention to provide a digital recording method that is more accurate and stable than the conventional random access means.

[Outline of Invention]

In the present invention, the control signal areas containing control information and the like are previously formatted at both ends of the diagonal tracks on the tape to form digital signal areas for recording digital signals between the control signal areas, and the same diagonal tracks are formed. The control information at both ends is the same control information. According to this, the control information at a position far away from both ends of the same diagonal track is unlikely to be lost at the same time, so that the control information can be reliably detected from each diagonal track.

Example of Invention

An embodiment according to the present invention is shown in FIG. 2, the same reference numerals as those in FIG. 1 have the same functions. 10 is a recording system for recording an address code, 11 is a head attached to a rotating cylinder, 12 is a head for detecting cylinder rotation, 13 is a cylinder, 14 is a random access circuit of a reproducing system, and 15 and 16 are switches. , 20 is a rotation detection pulse, and 21 is a recording signal.

The present invention is based on the premise that the access signal Sn is pre-formatted at the end of the diagonal track on the tape as shown in FIG. Such an access signal Sn further includes F ₀ and F ₁ for detecting an error.
It consists of a CRC code, and F ₁ is a signal for high speed random access. F ₀ is further divided into f _{0 to} f ₃ and indicates a flag indicating whether or not the music is in a silent section, an absolute address from the tape start, an absolute time, an error detection code, or an error correction code.

Initially, the cylinder 13 rotates, the head 11 is in a predetermined position,
Here, when the tape end portion is reached, the position detection pulse 20 is output. Based on this detection pulse 20, the servo circuit 8
To control the motor 6 to control the feed motor 6 for the tape 1.

On the other hand, the position detection pulse 20 triggers the recording system 10 that forms a tape format to format the access signal Sn on the tape 1.

Next, at the time of reproduction, the switch 16 is switched to detect the signal previously recorded on the tape 1 by the head 11, and the circuit of the feed motor 6 is controlled as an input of the servo circuit 8.

Further, at the time of random access, the absolute address f ₁ or the absolute time f ₂ recorded in the access signal Sn is fetched into the reproducing system 14, and the coincidence with the address signal input from the keyboard 7 is judged, and the switch 15 is set to the random access side. To control the rotation of the feed motor 6 for access.

FIG. 4 shows the inside of the recording system 10 in FIG. 10-1 is a synchronizing signal generation circuit, 10-2 is a counter for counting the absolute address of tape running from the tape start, 10-3 is a counter for counting the time from the tape start, and 10-4 is the content of the recording data. Data shown, 10-
Reference numeral 5 is a multiplexer for switching the output of each signal, and 10-6 is a correction generation circuit for generating a correction code.

When the head 11 reaches a predetermined position, the content of the counter 10-2 that counts the absolute address is incremented by 1, and the multiplexer 10-5 is sequentially switched to read each data serially. This data is recorded
It becomes the output of 10 and becomes the input of the correction generation circuit 10-6, and after all the data is read, the data of the correction generation circuit 10-6 is read to form the access signal Sn.

FIG. 5 is a diagram showing a tape pattern in one embodiment according to the present invention.

In FIG. 5, the access signal Sn is double-written and recorded on the tape 1. This is because the tape 1 travels faster than usual during random access, so the access signal Sn is double-written to improve reliability.

That is, in tracks obliquely formed on the tape, recording areas for the access signal Sn are provided at both ends of the track, and the same access signal Sn is recorded in the recording areas at both ends of the same track. Therefore, the number of times the access signal Sn is recorded increases, which increases the possibility that the access signal Sn will be reproduced favorably and increases the reliability. At this time, the access signal Sn is the synchronization signal (SYN
C), absolute track number (C ₁ ), absolute time (C ₂ ), and error correcting Parity. If there is an error in the absolute track number (C ₁ ) or absolute time (C ₂ ) during playback, it will be corrected by Parity, and the same access will be made even if there is a dropout that is too large for Parity to correct. Since the signals Sn are recorded at positions sufficiently distant from each other at both ends of the track, and it is almost impossible for these two access signals Sn to be uncorrectable at the same time, the access signal Sn always exists for each track. Will be done. Therefore, there is almost no track in which the access signal Sn cannot be detected, and all tracks can be randomly accessed.

In addition to this code, relative time (C ₃ ), song number (C ₄ ), Index
Overwrite (C ₅ ) and Page No. (C ₆ ).

FIG. 6 shows another embodiment according to the present invention. In this embodiment, at the time of random access, the tape 1 and the head 11
In some cases, the relative speed of and changes and the access signal Sn becomes difficult to reproduce during access.

Therefore, in this embodiment, an access head 18 and a switch 17 are provided to improve this. The portion of F ₁ of the access signal Sn is recorded with the recording frequency lowered. When the tape 1 runs at high speed during random access, the reproduction frequency of the F ₀ portion of the access signal Sn becomes high and the head 11 cannot read it, but the F ₁ portion is recorded with the recording frequency lowered. Therefore, the head 11 or 18 enables the tape 1 to be read out even when the tape 1 is running at high speed. Therefore, after the switch 17 is switched to the head 18 side for a rough access, the speed of the feed motor 6 is reduced and the switch 17 is switched to the head 11 side to feed the tape to a position to be accessed more accurately. According to this, it becomes possible to access faster.

〔The invention's effect〕

As described above, according to the present invention, the same control information is recorded at both ends of each diagonal track on which a digital information signal is recorded, with error detection and correction codes added thereto. The reading of the control information from the track becomes reliable, and the control by random access becomes reliable.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a conventional random access circuit, and FIG.
FIG. 4 is a block diagram showing an embodiment according to the present invention, FIG. 3 is a diagram showing a tape pattern which is the premise of the present invention, FIG. 4 is a block diagram showing an example of the configuration of a recording system, and FIG. FIG. 6 is a diagram showing an example of a tape pattern according to the present invention, and FIG. 6 is a block diagram showing another example according to the present invention. 1 ... tape, 2 ... head, 6 ... motor, 7 ... servo circuit, 10 ... recording system, 11 ... head, 13 ... cylinder, 14 ... reproduction system, 15,16,17 ... switch.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shoji Kobayashi 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Inside Electric Appliance Research Laboratory, Hitachi, Ltd. (72) Keiji Noguchi 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Inside the Hitachi Electric Appliances Research Laboratory (72) Inventor Takao Arai 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Inside the Hitachi Electric Appliances Research Laboratory (56) Reference JP-A-55-146676 (JP, A) 58-125278 (JP, A) JP-A-51-30709 (JP, A)

Claims (3)

[Claims] 1. A digital recording method for recording a digital signal as a diagonal track on a tape, in which a control signal area is previously formatted at both ends of each diagonal track and the digital signal is recorded between the control signal areas. An area is provided, and the control signal recorded in the control signal area is composed of a synchronization signal, a plurality of types of control information, and an error detection / correction code for detecting or correcting an error in these control information, and both ends of the same diagonal track. A digital recording method, wherein the control information recorded in the control signal area of a unit is the same control information. 2. The digital recording method according to claim 1, wherein the control information includes absolute position information on the tape and relative position information in the digital signal area. 3. The control information comprises first information including absolute position information on the tape and second information including information for high speed access. The digital recording method described in the item.