JPH0955911A - Frame synchronizing method and magnetic recording/ reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speed up the pull-in of tracking without losing tracking once pulled in and to immediately make the phase of a reproduction frame match the reference frame. SOLUTION: When a tape 100 to be reproduced stops, a microcomputer 6 detects that track number of a stop position by a track number detection circuit 4 and stores it in a memory. When a comer and is given to shift to the reproduction, the microcomputer 6 starts a capstan motor 10 by a motor drive circuit 9 at a timing based on the track number in the memory. Thus, the phase of the reproduction frame is adjusted to that of the reference frame outputted from a frame pulse generation circuit 7 from the beginning, and the system can be moved to the reproduction mode, thereafter, only the pull-in of tracking is controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus for recording digital data by composing one frame with even-numbered tracks, and more particularly to a frame synchronization method for performing tracking control and adjusting a frame phase.

[0002]

2. Description of the Related Art Conventionally, as a frame synchronization method for aligning the phase of a reproduction frame and the phase of a reference frame of this type, one frame is composed of 10 tracks of data by a helical scan method as disclosed in, for example, Japanese Patent Laid-Open No. 4-285746. 2. Description of the Related Art There is a magnetic recording / reproducing apparatus that records as configured and also records a pilot signal for controlling tracking so as to make a cycle of four tracks. In such a magnetic recording / reproducing apparatus, first, while performing normal tracking control in the reproduction mode, the recorded track information (track numbers 0 to 9 of the reproduction frame) is detected, and as a result, the phase of the reproduction frame is detected. If the phase is different from the phase of the reference frame, the tape feed is forcibly accelerated or decelerated according to the phase difference, the tracking is broken once, and then the phase of the playback frame is adjusted to the phase of the reference frame. Taking the method.

The reason for carrying out such frame synchronization is that the reproduction data of the magnetic recording / reproducing apparatus having the above-mentioned track structure is composed in units of frames, and error correction processing and data shuffling processing are carried out within the frame. Therefore, if the frame phase is shifted, the data will not be established, so that it is necessary to perform frame alignment.

FIG. 5 is an example of a timing chart for explaining the above-mentioned conventional frame synchronization method. As shown in FIG. 5 (A), when the tape travel is stopped, the tape reproduction track is track number No. It is assumed that the vehicle is stopped at the position 6 as shown in FIG. Thereafter, as shown in FIG. 5D, when a capstan motor (not shown) is turned on at the timing of (a) and the tape starts to run in the reproduction mode, tracking pull-in is performed after the time point of (a). , Tracking is pulled in at a certain point of time (a) to time (b).

After the tracking is pulled in, the track number is detected, and at the point (b), for example, the track N
o. 4 is detected, the capstan motor is turned off as shown in FIG. 5 (D) to temporarily stop the tape. After that, the reference frame pulse (FRP) shown in FIG.
The tape is stopped until the phase of the next track (here, track No. 5) is located, that is, at the time point (C). Then, the capstan motor is restarted at the timing of time point (C) to cause the tracking to be pulled in again, so that the reproduction track shown in FIG. 5 (E) is transferred to the phase of the reference frame pulse shown in FIG. 5 (B). And the same phase as the reference track shown in FIG. 5C, and the phase matching is completed.

However, when the frame synchronization method as described above is used, it is necessary to break the tracking once in order to match the reproduction frame with the reference frame. The procedure is as follows: (1) reproduction mode transition (deep running), (2) Tracking pull-in, (3) Track number detection, (4)
After forcibly stopping the tape at the detected track number, restarting the capstan so that it can be synchronized with the reference frame pulse, aligning the frame phase, and (5) performing a number of procedures such as re-pulling tracking. There is a drawback that it takes a long time to finish the frame alignment and lock the tracking, and the start-up at the time of reproduction is slow.

[0007]

In the conventional frame synchronization method as described above, in order to match the phases of the reference frame and the reproduction frame, first, tracking control is performed,
After confirming the phase of the playback frame by detecting information such as the recorded track number, if the playback frame is different from the phase of the reference frame, the tape feed is forcibly accelerated or decelerated and the tracking is performed once. However, after adjusting the frame phases of both, the tracking has to be drawn in again, and it takes a long time to finish both the frame adjustment and the tracking pull-in, and there is a drawback that the start-up during playback is slow.

Therefore, the present invention solves the above-described problems, and the tracking pull-in can be performed quickly without breaking the tracking once pulled in, and at the same time,
It is an object of the present invention to provide a frame synchronization method capable of immediately matching the phase of a reproduction frame with the phase of a reference frame and a magnetic recording / reproducing apparatus using this method.

[0009]

According to a first aspect of the present invention, when a magnetic tape having a plurality of tracks, one frame of which is reproduced by a magnetic recording / reproducing apparatus, a phase of a reproduction frame and a phase of a reference frame are matched with each other. In the synchronization method,
When the magnetic tape is stopped, the track number of the tape at the stopped position is detected, and when the playback mode is entered, the start timing of the tape running start with respect to the reference frame is set according to the detected track number. Then, the method of starting the tape running at this start timing is adopted.

According to a second aspect of the present invention, when the track number of the tape at the stopped position is not detected when the magnetic tape is stopped, the stopped tape is moved by a predetermined amount and then stopped. The method of detecting the track number of the tape at the position is adopted.

According to a third aspect of the present invention, the operation of detecting the track number of the tape at the stop position by moving the stopped tape by a predetermined amount and stopping the tape is determined in advance until the track number is detected. It adopts a method that repeats up to the number of times.

The invention of claim 4 employs a method in which the predetermined amount for moving the tape is 1/2 track.

According to a fifth aspect of the present invention, there is provided a frame synchronization method for aligning the phase of a reproduction frame and the phase of a reference frame when reproducing a magnetic tape having a plurality of tracks in one frame by a magnetic recording / reproducing apparatus. When a specific track number on the tape is detected when the magnetic tape is stopped, the magnetic tape is stopped at the detection position, and when the reproduction mode is entered, the reference frame is read from the reference frame according to the predetermined track number. A method is used in which the start timing of the tape running start is determined and the tape running is started at this start timing.

According to a sixth aspect of the present invention, there is provided a magnetic recording / reproducing apparatus for aligning a phase of a reproduction frame with a phase of a reference frame when reproducing a magnetic tape in which one frame is composed of a plurality of tracks. The phase of the reference frame is matched by the frame synchronization method according to any one of claims 1 to 5.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of a magnetic recording / reproducing apparatus using the frame synchronization method of the present invention. Reference numeral 1 is a reproduction head for helically scanning the reproduction tape 100 to reproduce recorded information, 2 is a recording / reproduction amplifier for amplifying a reproduction signal reproduced by the reproduction head 1, and 3 is a reproduction signal input from the recording / reproduction amplifier 2. The data processing circuit for processing 4 is the tape 100 currently being reproduced from the reproduction signal inputted from the recording / reproducing amplifier 2.
A track number detecting circuit for detecting the upper track number (number), 5 is a tracking error detecting circuit for detecting a tracking error from a pilot signal in the reproduction signal input from the recording / reproducing amplifier 2, and 6 is frame synchronization control or tracking control. With a microcomputer that
It controls the cylinder motor and reel motor (not shown) including the capstan motor 10. Reference numeral 7 is a frame pulse (FRP) generation circuit for generating a reference frame pulse based on a vertical synchronizing signal, 8 is a mode input section for inputting various mode states of the apparatus to the microcomputer 6, and 9 is a capstan motor 10 A motor drive circuit for rotating the tape based on a control signal from the microcomputer 6, 10 is a capstan motor for running the tape 100 to be reproduced, and 11 is a capstan motor 10
The rotational speed detector 100 detects the rotational speed of the recording medium, and reference numeral 100 is a reproduced tape in which a signal is recorded in which one frame is composed of a plurality of (even times) tracks.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. When a stop mode shift command for stopping the running of the tape 100 to be reproduced is input from the mode input section 8 to the microcomputer 6, the microcomputer 6 controls the motor drive circuit 9 in step 201 to stop the capstan motor 10. By doing
Enter stop mode. At this time, since the drum (not shown) is rotating, the reproducing head 1 is reproducing the track on the reproduced tape 100 at the stop position. The reproduction signal thus obtained is input to the data processing unit 3 and the track number detection circuit 4 through the recording / reproduction amplifier 2. Therefore, the microcomputer 6 executes step 202.
Then, the track number information at the tape stop position is inputted through the track number detecting circuit 4, and it is judged at step 203 whether or not the track number can be detected. As a result, when the track number can be detected, the process proceeds to step 209, the detected track number is stored in the internal memory, the process is terminated, and the reproduction mode waiting is started.

On the other hand, if the track number cannot be detected in step 203, the process proceeds to step 204, in which the microcomputer 6 drives the motor while monitoring the rotation speed of the capstan motor 10 obtained from the rotation speed detector 11. The circuit 9 is controlled to slightly rotate the capstan motor 10 to move the tape to be reproduced 100 by 1/2 track and stop, and the tape 1 to be reproduced at this stop position.
The operation of detecting the track number on track 00 through the track number detection circuit 4 is performed, and it is further determined in step 205 whether the track number can be detected.

If the track number cannot be detected in step 205, the microcomputer 6 controls the motor drive circuit 9 again to slightly rotate the capstan motor 10 so that the tape 100 to be reproduced is ½ track. Then, the track number on the tape 100 to be reproduced at this position is detected again by the track number detection circuit 4 and the operation is performed again. As a result, it is determined in step 207 whether or not the track number can be detected. If the track number can be detected, the process proceeds to step 209. If the track number cannot be detected, the process ends, and the reproduction mode transition command waits. If the track number on the tape is not detected in step 207, the microcomputer 6 determines that there is no recorded data on the reproduced tape 100,
The process ends.

FIG. 3 is a flow chart showing the frame synchronization control by the microcomputer 6 described above.
In the playback mode waiting state after shifting to the stop mode, the playback mode shift command is issued from the mode input unit 8 in step 301.
Is supplied to the microcomputer 6, the microcomputer 6 causes the motor drive circuit 9 to rotate the capstan motor 10 at a predetermined speed to run the tape 100 to be reproduced and start control for shifting to the reproduction mode. . At this time, the microcomputer 6 determines in step 302 whether or not the track number at the stop position of the tape to be reproduced 100 is stored in the internal memory, and if it is not stored, the process proceeds to step 306 and is stored. If so, go to step 303. At step 303, the microcomputer 6 sets a uniform timing corresponding to the track numbers stored in the memory, and at this timing starts the capstan motor 10 through the motor drive circuit 9. As a result, the reproduction frame is synchronized with the reference frame generated by the frame generation circuit 7, and the tape running is started.

After that, the microcomputer 6 controls the rotation speed of the capstan motor 10 by the motor drive circuit 9 based on the tracking error information detected by the tracking error detection circuit 5 to perform the tracking pull-in operation, and the tracking is performed. When locked, the reproduction mode transition process ends. On the other hand, step 3
When it is determined in 02 that the track number is not stored in the memory and the process proceeds to step 306, the microcomputer 6 starts the capstan motor 10 to enter the reproduction mode while adopting the conventional frame synchronization method. Transition.

FIG. 4 is a time chart for explaining the frame synchronization procedure of this embodiment described above. When the tape to be reproduced 100 is stopped, that is, when the capstan drive signal shown in FIG. 4C is at a low level and the capstan motor 10 is stopped, the tape is stopped from the reproduction frame shown in FIG. 4D. The track number of the position is detected and stored in the above-mentioned memory in the microcomputer 6. here,
Track number 6 is stored. Therefore, when the reproduction frame is synchronized with the phase of the reference frame pulse shown in FIG. 4 (A), it becomes exactly 6 which is the same as the track number of the reference track in FIG. 4 (B). , Fig. 4
By setting the capstan control signal shown in (C) to a high level, the reproduction target tape 100 starts to be conveyed.
At this time, since the frame matching has already been completed, after that, only the tracking pull-in is performed to enter the reproduction mode.

According to this embodiment, the phase of the reproduction frame and the reference frame has already been aligned when the tape to be reproduced 100 is started when shifting to the reproduction mode, and only the tracking pull-in is performed after the start. Therefore, after all, the tracking pull-in can be performed quickly without breaking the tracking pull-in once, and the phase of the reproduction frame can be immediately matched with the phase of the reference frame. As a result, the magnetic recording / reproducing apparatus can be quickly started up.

Unlike the above embodiment, when a tape stop mode transition command is input from the mode input section 8, the microcomputer 6 reproduces the reproduced tape 100 in the reproduction mode, and at the time of reproduction, the track number is reproduced. When the detection circuit 4 detects a specific track number on the tape 100 to be reproduced, the capstan motor is stopped and the stop mode is entered. By doing so, the next time the mode is changed to the reproduction mode, the stop position of the tape to be reproduced 100 is always at the position of the above-mentioned specific track number, so that the microcomputer 6 is a capstan for adjusting the reproduction frame to the reference frame. The start timing of the motor 10 can be set to be the same every time, and the smooth transition to the reproduction mode and the frame alignment can be always performed.

[0024]

As described above, claims 1 to 5 are as follows.
According to the frame synchronization method of any one of claims, tracking pull-in can be performed quickly without breaking the tracking pull-in once, and the phase of the reproduction frame can be immediately adjusted to the phase of the reference frame. .

According to the magnetic recording / reproducing apparatus of the fifth aspect, the rise at the time of reproducing the data can be performed quickly.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a magnetic recording / reproducing apparatus of the present invention.

FIG. 2 is a flowchart showing a frame synchronization processing procedure by the microcomputer shown in FIG.

FIG. 3 is a flowchart showing a reproduction mode transition processing procedure by the microcomputer shown in FIG.

FIG. 4 is a time chart explaining frame synchronization timing by the microcomputer shown in FIG.

FIG. 5 is a time chart illustrating frame synchronization timing according to a conventional method.

[Explanation of symbols]

1 ... Playback head 2 ... Playback amplifier 3 ... Data processing circuit 4 ... Track number detection circuit 5 ... Tracking error detection circuit 6 ... Microcomputer 7 ... Frame pulse generation circuit 8 ... Mode input section 9 ... Motor drive circuit 10 ... Capstan motor 11 ... Rotational speed detector

Claims (6)

[Claims] 1. A frame synchronization method for aligning a phase of a reproduction frame and a phase of a reference frame when reproducing a magnetic tape having one track composed of a plurality of tracks by a magnetic recording / reproducing apparatus, and stopping the magnetic tape. At this time, the track number of the tape at the stopped position is detected, and when the reproduction mode is entered, the start timing of the tape running start with respect to the reference frame is obtained according to the detected track number. A frame synchronization method characterized in that the tape running is started at. 2. When the magnetic tape is stopped, when the track number of the tape at the stopped position is not detected, the stopped tape is moved by a predetermined amount and stopped, and the track of the tape at the stopped position is detected. The frame synchronization method according to claim 1, wherein a number is detected. 3. The operation of detecting the track number of the tape at the stop position by moving the stopped tape by a predetermined amount and stopping the tape within a predetermined number of times until the track number is detected. The frame synchronization method according to claim 2, wherein the frame synchronization method is repeated. 4. The predetermined amount for moving the tape is 1 /
4. The frame synchronization method according to claim 2, wherein the frame synchronization method is two tracks. 5. A frame synchronization method for aligning the phase of a reproduction frame and the phase of a reference frame when a magnetic tape having a plurality of tracks forming one frame is reproduced by a magnetic recording / reproducing apparatus, wherein the magnetic tape is stopped. When a specific track number on the tape is detected, the magnetic tape is stopped at the detected position, and when the reproduction mode is entered, the tape running start with respect to the reference frame is started according to the predetermined track number. Find the startup timing,
A frame synchronization method characterized in that the tape running is started at this start timing. 6. A magnetic recording / reproducing apparatus for aligning a phase of a reproduction frame and a phase of a reference frame when reproducing a magnetic tape having one frame composed of a plurality of tracks,
6. A magnetic recording / reproducing apparatus, wherein the phase of the reproduction frame and the phase of the reference frame are matched by the frame synchronization method according to claim 1.