JPH06251566A - Magnetic tape device and its controlling method - Google Patents

Abstract

PURPOSE:To attain a searching by group-managing minute data groups and using a high-speed running jointly. CONSTITUTION:The block number of a data block consisting of plural tracks 8 and the group number of a group consisting of plural data blocks are recorded in all tracks as sub-code information in a magnetic tape 1. At the time of searching a data block specified with a group number and a block number, the searching is finished by detecting the group number with a high-speed running and thereafter detecting the block number in the group with a middle-speed running.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape device for reproducing digital data on a magnetic tape and a control method thereof.

[0002]

2. Description of the Related Art An apparatus for digitally recording data on a predetermined track of a magnetic tape has been put into practical use, for example, R-DA.
It is known as the T (Rotating Digital Audio Tape Recorder) system. Unlike conventional analog recording, this digital magnetic tape unit has less signal deterioration due to recording / playback, so high-density recording is possible, and follow-up recording, high-speed search using subareas, and various editing such as song selection are easy. It has the advantage that it can be done. Therefore, such a digital magnetic tape device can be applied not only to audio recording such as the above-mentioned R-DAT but also to recording and reproducing of graphics and other digital data.

In a digital magnetic tape device represented by such an R-DAT, as shown in FIGS. 10A and 10B, the rotary head normally scans the traveling magnetic tape obliquely. A so-called helical scan method is used. In FIG. 10, the magnetic tape 1
Is from the supply reel 4 to the take-up reel 5 while being in contact with the cylindrical rotating drum 3 provided with the rotating shaft 2 slightly inclined with respect to the direction perpendicular to the magnetic tape running direction at a wrap angle of 90 degrees.
To be sent to. Two magnetic heads 6 are provided on the circumferential surface of the rotating drum 3 so as to face each other by 180 degrees.
A straight long track 8 (see FIG. 11) slightly inclined in the tape running direction 7 is formed on the magnetic tape 1.

A track in such a helical scan system is generally a tape composed of a PCM (main) area for digitally recording data and a sub area for digitally recording a subcode signal showing the characteristics of the data. It has a format, and data is recorded by sequentially forming it on the magnetic tape 1.

Further, each data is managed by a subcode signal of a subarea provided in each track. For example, when the data to be recorded is a plurality of data blocks, the number of each data block and the information for controlling each data block will be recorded in the necessary sub-area of the track.

Here, the data block number is sequentially recorded in a subcode area of a required track for each divided data, and this is sequentially searched to record / reproduce a desired data block. It is possible. In particular, in order to enable the audio search operation, it is recommended that one song be 1,200 tracks or more (equivalent to 18 seconds in normal playback), and the beginning signal causes the magnetic tape to run at high speed. In order to make it possible to identify even in the case of, it is defined as 600 tracks (corresponding to 9 seconds in normal reproduction).

Further, during reproduction of the magnetic tape, a recording signal is output when data is recorded on the magnetic tape, so it can be detected that a recording signal is present, and no recording signal is output when no data is recorded. Therefore, it can be detected that there is no recording signal. By utilizing this fact, the magnetic tape device can recognize the last part of the data recorded on the magnetic tape, that is, the point where the recording signal changes to the absence of the recording signal, which is particularly effective when additional recording of data is performed. is there.

[0008]

In the conventional magnetic tape, the problem that the data block group cannot be managed as a group, and when searching for a minute data block, high speed magnetic tape running is used for the search. There were problems such as difficulty.

In the conventional magnetic tape device, when the traveling direction or traveling speed of the magnetic tape is switched, the magnetic tape sags, and the head touch becomes unstable. When the recording signal on the magnetic tape is immediately detected in this state, it is easy to falsely detect that there is no recording signal, even though there is a recording signal. Particularly, as shown in FIG. 12, data recorded on the magnetic tape is detected. There has been a problem that a false detection is made when the last part is detected.

The present invention has been made in order to solve the above-mentioned problems, and makes it possible to manage a group of data blocks in groups and to search for minute data blocks using high-speed magnetic tape running. The purpose is to do.

Another object of the present invention is to provide a magnetic tape device capable of accurately detecting the absence of a recording signal on the magnetic tape when the running direction and running speed of the magnetic tape are switched.

[0012]

According to a method of controlling a magnetic tape device according to the present invention, a plurality of tracks on which a main digital signal and a sub coat as management information are recorded are combined to form a data block, and a plurality of data are recorded. A magnetic tape in which blocks are grouped together to form a group, and a group number for identifying each group and a block number for identifying each data block in each group are recorded as subcodes on each track are the above subcodes. When searching for the specified group number and block number in the one that is made to run at high speed or medium speed while detecting, the search is performed at high speed until the specified group number is detected, and then The block number specified at medium speed is searched.

Further, when searching the designated group number and block number, if the current position is a group before and after the designated group number, the search is started at medium speed, and if it is not a preceding and succeeding group, the search is performed forward and backward. The search is performed at high speed until the group number is detected, and then at medium speed.

In the magnetic tape device according to the present invention, the magnetic tape on which the search information is recorded is made to run and rewind between the supply reel and the take-up reel. When the search operation is performed after the running direction or running speed of the magnetic tape has been switched, the magnetic tape is run in the direction to be searched and the supply reel and take-up reel are The control means is provided so as to start the search operation after rotating a predetermined number of rotations.

[0015]

According to the present invention, it becomes possible to manage groups of data blocks. In addition, it becomes possible to search for minute data blocks. Furthermore, when the running direction and running speed of the magnetic tape are switched, even if the magnetic tape is slack and the head touch is unstable, the magnetic tape is run until the slack is removed to obtain a good head touch. After that, the presence / absence of a recording signal on the magnetic tape is started, so that the presence / absence of a recording signal can be reliably detected.

[0016]

【Example】

Example 1. Hereinafter, the first embodiment of the present invention will be described in detail. FIG. 1 is a block circuit diagram of the first embodiment, and the same reference numerals as those in FIG. 10 denote the same parts.

The apparatus is provided with a signal processing section 9, and under the control of the system control circuit 10, the input digital recording signal is subjected to predetermined signal processing and output. The system control circuit 10 includes a subcode generator 11
Is connected, and the subcode output from this is added to the output of the signal processing unit 9 by the adder 12 and input to the modulator 13.

The signal which has undergone the predetermined modulation by the modulator 13 is
After being amplified to a predetermined level by the recording amplifier 14, it is inputted to the recording / reproducing section 16 via the switching circuit 15 and supplied to the two magnetic heads 6 which are held 180 degrees opposite to the rotary drum 3. It has become. A head switching signal (not shown) synchronized with the rotation of the rotary drum 3 is input to the switching circuit 15 from the system control circuit 10, and the two magnetic heads 6 are switched at this timing.

The magnetic head 6 is in contact with the magnetic tape 1 traveling from the supply reel 4 to the take-up reel 5 whose rotation is controlled by a drive motor (not shown), and traverses the magnetic tape 1 at a predetermined angle with respect to its traveling direction. It is designed to scan helically. As a result, a track is formed on the magnetic tape 1 at this angle, and the data is sequentially recorded.

In the vicinity of the supply reel 4 and the take-up reel 5, sensors 17 and 18 for detecting the respective rotation speeds are attached, and a pulse signal 19 having a frequency corresponding to the rotation speeds is provided.
20 is output to the system control circuit 10.

A mechanism control circuit 21 is connected to the recording / reproducing section 16, and under the control of the system control circuit 10,
The supply reel 4, the take-up reel 5 and the like are controlled.

As shown in FIG. 11, the tracks 8 formed on the magnetic tape 1 are formed on the magnetic tape 1 so that a large number of tracks 8 are formed adjacent to each other so as to form an angle θ with the tape running direction. ing. Each track 8 has a PCM area 22 provided in the center and ATFs provided on both sides of the PCM area 22.
(Automatic track finding) Area 2
3 and subareas 24 provided on both sides thereof
Composed of. Of these, the PCM area 22 is an area for recording the digital data itself, the ATF area 2
Reference numeral 3 is an area for recording information necessary for tracking, and subarea 24 is an area for recording information for controlling a group number, a block number and a data block.

A reproduction amplifier 25 is connected to the switching circuit 15 in FIG. 1 so as to amplify a reproduction signal input from the recording / reproducing unit 16 via the switching circuit 15. The signal amplified by the reproduction amplifier 25 is demodulated by the demodulator 26.
After being demodulated by, the signal is input to the signal processing unit 27. The reproduction signal input to the signal processing unit 27 is subjected to predetermined signal processing under the control of the system control circuit 10 and output as a digital signal.

The signal processing section 27 includes a subcode detecting section 2
8 is connected to the system control circuit 1 to detect various subcode signals from the reproduced signal input to the signal processing unit 27.
It is designed to be sent to 0. System control circuit 10
Controls each unit based on an instruction input from the operation unit 29, controls operations such as reproduction, recording, and high-speed search, and displays various information on the display unit 30.

A storage unit 31 is connected to the system control circuit 10 to store various programs and data relating to reproduction and recording operations.

The group number and block number recorded in the sub area 24 can be detected. Further, it is possible to detect the presence or absence of a recording signal while the magnetic tape is running.

FIG. 2 is a perspective view showing the outer appearance of the magnetic tape device according to the first embodiment. On the operation panel 32 of this apparatus, a plurality of operations are performed as an insertion opening 33 for attaching and detaching a magnetic tape cassette, a power switch 34 for turning on the power of the apparatus, a display section 30 for displaying various information, and an operation section 29. A key 35 and a ten-key pad 36 for inputting numerical data are provided. As the operation keys 35, for example, a reproduction key, a stop / eject key, a search key, etc. are provided.

FIG. 3 is a conceptual diagram of a recording state on the magnetic tape used in the first embodiment. A plurality of tracks 8 form a data block, and a plurality of data blocks form one group. Each data block is identified by a block number, and each group is identified by a group number.

The block number may be a number that can be identified only within the group. Therefore, the specific data block can be designated by the group number and the block number. The code indicating the group number and the block number is recorded as subcode information in the subarea 24 of all tracks 8 to be recorded on the magnetic tape 1 at the same time as the main digital signal.

Next, the operation of the first embodiment will be described with reference to FIG. A conceptual diagram of the recording state on the magnetic tape 1 is shown in FIG. A data block on the magnetic tape 1 can be designated by a group number and a block number. Here, when searching for a certain data block, the magnetic tape can be operated at high speed or medium speed as shown in FIG. 4B. Run 1 and run. Note that FIG. 4B is a diagram showing an operation when the data block j is searched for in the group x in FIG. 4A. First, the magnetic tape 1 is run at high speed until the target group number (group number of group x) is detected. When the target group number is detected, the magnetic tape 1 is switched to medium speed to run, and when the target block number is detected, the search ends.

The above operation will be described in detail with reference to the flow charts of FIGS. 1, 2, 4, and 5. The group number and the block number of the target data block are input using the ten keys 36 of the operation unit 29. When the search key of the operation keys 35 is pressed (S100), the system control circuit 1
0 makes full use of the mechanism control drive circuit 21 to rotate the supply reel 4 and the take-up reel 5 to run the magnetic tape 1 at high speed (S101). Then, the system control circuit 10
Monitors the subcode information obtained from the subcode detection unit 28 and detects the target group number (S102:
Y), making full use of the mechanism control drive circuit 21, the supply reel 4 and the take-up reel 5 are rotated to run the magnetic tape 1 at a medium speed (S103). Furthermore, the system control circuit 1
0 monitors the subcode information obtained from the subcode detector 28 and detects the target block number (S10).
4: Y), by making full use of the mechanism control drive circuit 21, the magnetic tape 1 is stopped by stopping the supply reel 4 and the take-up reel 5 (S105), and the search is completed.

Example 2. Embodiment 2 of the present invention will be described with reference to FIG. FIG. 6 is a conceptual diagram of a recording state on the magnetic tape 1. As shown in FIG. 6, from the group (group m) currently located to the adjacent group (group l to
When searching the data blocks in the group n), the magnetic tape 1 is run only at a medium speed. As a result, the number of times to switch the running mode of the magnetic tape 1 from high speed to medium speed is reduced, and the search time is shortened.

The above operation is shown in FIGS. 1, 2, 6 and 7.
This will be described in detail with reference to the flowchart of. Enter the group number and block number of the target data block on the operation unit 2
When the search key of the operation key 35 is pressed by inputting from the ten key 36 of 9 (S110), the system control circuit 10
Determines whether or not the target group is adjacent to the currently located group, and if it is adjacent (S11
1: Y), by making full use of the mechanism control drive circuit 21, the supply reel 4 and the take-up reel 5 are rotated to run the magnetic tape 1 at a medium speed. (S112).

If they are not adjacent (S111:
N), by making full use of the mechanism control drive circuit 21, the supply reel 4 and the take-up reel 5 are rotated, and the magnetic tape 1 is run at high speed (S113). Then the system control circuit 10
Monitors the subcode information obtained from the subcode detection unit 28, and detects the target group number (S11
4: Y), making full use of the mechanism control drive circuit 21, the supply reel 4 and the take-up reel 5 are rotated to run the magnetic tape 1 at a medium speed (S115).

Further, the system control circuit 10 monitors the subcode information obtained from the subcode detection unit 28, and when it detects the target block number (S116: Y), it makes full use of the mechanism control drive circuit 21 to supply the reel 4 The magnetic tape 1 is stopped by stopping the take-up reel 5 (S117), and the search is completed.

Example 3. A third embodiment of the present invention will be described with reference to FIG. A conceptual diagram of the recording state on the magnetic tape 1 is shown in FIG. When the presence / absence of a recording signal on the magnetic tape 1 is detected after the traveling direction and traveling speed of the magnetic tape 1 are switched, the detection of the presence / absence of a recording signal is once interrupted, and the magnetic tape is switched at the traveling direction and traveling speed to be switched. At the same time as running 1, the detection of the pulse generated with the rotation of the supply reel 4 and the take-up reel 5 is started. By measuring both of the pulses by a predetermined amount, it is determined that the slack of the magnetic tape 1 that has occurred when the traveling direction and the traveling speed are switched is removed, and the detection of the presence or absence of a recording signal on the magnetic tape 1 is restarted.

FIG. 8B is a conceptual diagram showing the detection start timing of the presence / absence of a recording signal on the magnetic tape 1 after switching the traveling direction and traveling speed at the current position.

The above operation will be described in detail with reference to the flow charts of FIGS. 1, 8 and 9. When a request for switching the running direction and running speed of the magnetic tape 1 is generated, the system control circuit 10 interrupts the detection of the presence or absence of a recording signal on the magnetic tape 1 (S120), makes full use of the mechanism control drive circuit 21, and the supply reel 4 and The take-up reel 5 is rotated to run the magnetic tape in the running direction and the running speed to be changed (S121). At the same time, the pulse 1 generated from the sensors 17 and 18 as the supply and take-up reels rotate.
The measurement of 9 and 20 is started (S122). When both the pulses 19 and 20 are measured by a predetermined amount (S123:
Y), that the magnetic tape 1 has traveled a predetermined amount, the slack of the magnetic tape 1 that has occurred when switching the traveling direction and traveling speed is removed, and a good contact state between the magnetic tape 1 and the rotary head 6 is secured. The judgment is made and the detection of the presence or absence of a recording signal on the magnetic tape 1 is restarted (S124).

[0039]

As described above, according to the present invention, it is possible to search a minute data block designated by a group number and a block number by running a magnetic tape using both high speed and medium speed. In addition, there is an effect that it is possible to shorten the search time into the adjacent group.

Further, even when the magnetic tape sags when the traveling direction and traveling speed of the magnetic tape are switched,
Since the magnetic tape is run until the slack of the magnetic tape is removed, and the detection of the presence or absence of the recording signal on the magnetic tape is started after a good head touch is obtained, erroneous detection of the presence or absence of the recording signal is detected. There is an effect that it is possible to prevent, and in particular, it is possible to surely recognize the last part of the data recorded on the magnetic tape.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing a magnetic tape device according to each embodiment of the present invention.

FIG. 2 is a perspective view showing an appearance of a magnetic tape device according to each embodiment.

FIG. 3 is a diagram showing a concept of a data structure recorded on a magnetic tape.

FIG. 4 is a diagram for explaining a search operation in the first embodiment.

FIG. 5 is a flowchart of the first embodiment.

FIG. 6 is a diagram for explaining a search operation in the second embodiment of the present invention.

FIG. 7 is a flowchart of a second embodiment.

FIG. 8 is a diagram for explaining a search operation in the third embodiment of the present invention.

FIG. 9 is a flowchart of a third embodiment.

FIG. 10 is a diagram showing a magnetic tape running system of the magnetic tape device.

FIG. 11 is a diagram showing a recording format of a magnetic tape used in a magnetic tape device.

FIG. 12 is a diagram for explaining one usage example in which it is necessary to detect the presence or absence of a recording signal.

[Explanation of symbols]

 1 magnetic tape 3 rotating drum 4 supply reel 5 take-up reel 6 magnetic head 8 track 10 system control circuit 16 recording / reproducing section 17 sensor 18 sensor 21 mechanism control drive circuit 22 PCM area 23 ATF area 24 sub area 28 sub code detecting section 29 Operation unit 30 Display unit

Claims (3)

[Claims] 1. A data block is formed by collecting a plurality of tracks on which a main digital signal and a sub-code as management information are recorded, and a group is formed by collecting a plurality of data blocks to identify each group. A magnetic tape having a group number and a block number for identifying each data block in each group recorded as a subcode on each track is made to run at high speed or medium speed while detecting the subcode. When searching the specified group number and block number, the search is performed at high speed until the specified group number is detected, and then the specified block number is searched at medium speed. A method for controlling a magnetic tape device, which is characterized. 2. A data block is formed by collecting a plurality of tracks on which a main digital signal and a sub-code as management information are recorded, and a group is formed by collecting a plurality of data blocks to identify each group. A magnetic tape having a group number and a block number for identifying each data block in each group recorded as a subcode on each track is made to run at high speed or medium speed while detecting the subcode. When searching the specified group number and block number, if the current position is the group before and after the specified group number, the search starts at medium speed, and if it is not the previous and next group number, the next and previous group numbers Searches at high speed until is detected, then at medium speed A method for controlling a magnetic tape device, comprising: 3. A magnetic tape on which search information is recorded is run and rewound between a supply reel and a take-up reel, and means for detecting the number of revolutions of the supply reel and the number of revolutions of the take-up reel. In addition, when the search operation is performed after the running direction or running speed of the magnetic tape has been switched, the magnetic tape is run in the direction to be searched, and the supply reel and take-up reel are rotated by a predetermined number of revolutions. A magnetic tape device comprising means for controlling so as to start a search operation after the above.