JP3361672B2 - Playback device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus which reproduces a recording signal by scanning an oblique track on which a signal is recorded while being inclined in a longitudinal direction of a magnetic tape, by a rotary head.

[0002]

2. Description of the Related Art In a reproducing apparatus for reproducing an information signal recorded on an oblique track which is inclined in the longitudinal direction of a magnetic tape, during the reproduction, a helical scan is usually performed by a rotary head. On the other hand, the information signal recorded on the magnetic tape is divided into tracks for convenience of this reproducing system.

At this time, there are cases where there is a reference signal with which the reproduction signal from the magnetic tape should be synchronized, such as in the run-up section of joint recording. In such a case, the reference signal and the signal reproduced from the magnetic tape are directly or indirectly compared in phase, and the result is reflected in the tracking control to achieve synchronization.

In the case of a consumer VTR (VHS (registered trademark) or the like), one field of an image is one track, two.
One frame composed of fields is recorded as two tracks. When reproducing this, as a control (hereinafter abbreviated as CTL) signal, a frame signal of 1 pulse per frame is usually recorded on a linear track provided on a magnetic tape separately from the diagonal track. The tracking control is performed so as to synchronize this with the reference signal.

There is also an example in which one frame is divided into 20 to 24 tracks like a commercial digital VTR (D1 etc.). Also in this case, there is a CTL track, and a servo signal of 1 pulse per drum rotation (corresponding to 4 tracks) and a frame signal of 1 pulse per frame are recorded. The same control as a consumer VTR was performed using a frame signal (for example, magazine "Broadcasting Technology" 1990, Vol. 4).
3, No. See 12).

As described above, in a VTR that performs tracking control using a frame signal, it is necessary to synchronize with a reference at the start of reproduction, but the synchronization pull-in speed is limited by the frame frequency. A VTR or the like whose frequency is 30 Hz in NTSC may not be able to achieve a sufficient pull-in speed. In particular, in the joint shooting, since the operator issues a recording start instruction at the time when the operator confirms the image to be recorded, the time required for each operation of the start and the frame synchronization is directly connected to the missing of the recorded image.

Therefore, in order to speed up frame synchronization from the tape running stop state, for example, Japanese Patent Laid-Open No. 5-159 has been proposed.
Japanese Patent No. 422 also discloses a method in which the stop position is recorded when the tape running is stopped, and thereby the start timing is adjusted with respect to the reference signal at the start.

A conventional reproducing apparatus will be described below with reference to an example thereof. FIG. 7 is a block diagram showing the structure of a conventional reproducing apparatus. In FIG. 7, reference numeral 4 is a reference signal generating means for generating a reference signal synchronized with the frame period, 1 is a magnetic tape having an information signal recorded on an oblique track, 7 is a capstan motor for sending the magnetic tape 1, and 3 is a reference signal. A drum rotating the head in synchronization with the reference signal from the generating means 4 to reproduce the magnetic tape 1, 2 is a capstan motor driving means, and 9 is an FG detector for detecting the FG signal magnetized by the capstan motor 7. , 80 is the F from the FG detector 9
FG tooth number counting means for counting the number of teeth of the G signal within a certain period, and 65 is timing control means for controlling the timing of switching to the traveling state based on the speed information of the speed information output means 15.

The operation of the reproducing apparatus configured as described above will be described below. In the running state of the magnetic tape 1, the FG tooth number counting means 80 counts up the FG tooth number of the capstan motor 7 and is reset by the reference signal. As a result, in the stopped state of the magnetic tape 1, the current stop position of the magnetic tape 1 is predicted using the count value of the number of FG teeth. At the start of running the magnetic tape 1, the timing controller 65 starts the capstan motor 7 in consideration of the timing synchronized with the reference signal from the reference signal generator 4 and the delay time calculated from the predicted value of the stop position. It sends a start command and tries to synchronize immediately after starting.

[0010]

However, in the conventional reproducing apparatus as described above, when the tape is running, the F
Since the count value of the number of G teeth is reset by the reference signal that is not directly correlated with the recording position on the magnetic tape, tracking deviation or offset is likely to occur, which causes the head to stop when the tape is stopped. There was a problem that the detection error of the relative position of the oblique track with respect to was large.

For this reason, in particular, in a VTR which records at a high density with a narrow track width, it is not possible to immediately perform on-track on a predetermined track, the image is disturbed immediately after start-up, and the track becomes thin at the editing point during joint recording. Had the problem.

The present invention solves the above problems and can reduce the detection error of the relative position of the oblique track with respect to the head in the tape stopped state. Provided is a playback device capable of preventing a track from becoming thin at an editing point.

[0013]

In order to solve the above problems, in the reproducing apparatus according to the first aspect of the present invention, a signal consisting of data of a predetermined length is recorded by dividing it into a plurality of diagonal tracks. At the same time, a magnetic tape on which a CTL signal is recorded on a linear track is run in the longitudinal direction by a capstan motor, and the oblique track is scanned from the magnetic tape by a rotating head to reproduce the recorded signal. In the apparatus, reference signal generating means for generating a reference signal serving as a rotation reference of the head, and an FG signal having a frequency detected by the capstan motor and corresponding to the rotation speed of the capstan motor in the running state of the magnetic tape. The number of teeth of the FG is reset by the CTL signal reproduced from the magnetic tape. Timing control for controlling the tape running start timing based on the number of teeth of the FG signal counted by the FG tooth number counting means and the reference signal from the reference signal generating means when the magnetic tape is stopped. And means.

According to this structure, in the tape running state, the F which corresponds to the rotation of the capstan motor at that time.
The number of G teeth is always counted, and the count of the number of FG teeth is reset by the CTL signal recorded on the linear track on the magnetic tape.

At the time of starting, the starting timing is controlled based on the stop position detected when the tape running is stopped.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION A reproducing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

First, a reproducing apparatus according to the first embodiment of the present invention will be described. FIG. 1 is a block diagram showing the configuration of the reproducing apparatus according to the first embodiment. In FIG. 1, reference numeral 4 is a reference signal generating means for generating a reference signal synchronized with a frame period, and 1 is 10 pieces of information for one frame.
A magnetic tape in which a CTL signal is recorded on a linear track that is dividedly recorded on a diagonal track of a book and formed in the running direction,
Reference numeral 7 is a capstan motor for sending the magnetic tape 1, 3 is a drum for rotating the head in synchronization with the reference signal from the reference signal generating means 4 to reproduce an oblique track of the magnetic tape 1, 2 is capstan motor driving means, 9 Is an FG detector that detects the FG signal magnetized by the capstan motor 7, 12 is a fixed head that reproduces the CTL signal recorded on the magnetic tape 1, and 8 is a fixed period of the FG signal from the FG detector 9. FG tooth number counting means for counting the number of teeth in the inside and resetting the count each time a CTL signal is input, and 6 is a timing control means for controlling the timing of switching to the running state based on the speed information of the speed information output means 15. Is.

The operation of the reproducing apparatus configured as described above will be described below with reference to FIG. First, the operation when the magnetic tape 1 shifts from the running state to the stopped state will be described.

FIG. 2 is a time chart showing the operation when the state is changed from the normal reproduction state to the stop state.
Note that, here, as shown in FIG. 2A, a case is shown in which numbers 0 to 9 are assigned to 10 tracks which are information for one frame.

As shown by the solid line in FIG. 2D, in the running state of the magnetic tape 1, the FG tooth number counting means 8 counts the FG tooth number of the FG signal detected from the magnetic tape 1 by the FG detector 9. It is raised and reset by the CTL signal reproduced by the fixed head 12 as shown in FIG. When the magnetic tape 1 is immediately decelerated and stopped as shown in FIG. 2E by the tape feed stop command shown in FIG. 2B, the FG count value counted by the FG tooth number counting means 8 is magnetic. C on tape 1
The value from the TL signal reproduction position is shown. Therefore, F
The stop position of the magnetic tape can be accurately detected based on the FG count value by the G tooth number counting means 8.

On the other hand, as shown in FIG. 7, in the conventional example in which the FG count value by the FG tooth number counting means 80 is reset at the timing synchronized with the reference signal from the reference signal generating means 4, FIG. As indicated by the alternate long and short dash line, since the stop position is predicted based on the reference signal that has no direct correlation with the recording position on the magnetic tape 1, a detection error due to tracking deviation or offset occurs.

Next, the operation when the magnetic tape 1 shifts from the stopped state to the activated state will be described. FIG. 3 schematically shows the relationship between the relative positions of the rotary head mounted on the drum 3 and the tracks recorded on the magnetic tape 1.

FIG. 3A shows the relationship between the relative position of the rotary head and the track when the tape is stopped. Figure 3
In (a), the dotted line shows the ideal stop position. The solid line shows the actual stop position.

As shown in FIG. 3B, when starting is performed at the timing synchronized with the reference signal from the reference signal generating means 4, immediately after the starting, the solid line is actually compared to the ideal state shown by the dotted line. As shown in, reproduction is performed with the tracking deviated.

Therefore, as shown in FIG. 3C, the start timing is delayed according to the position deviation calculated from the FG count value to deviate from the ideal position indicated by the dotted line, so that the start as shown by the solid line is started. Even immediately after that, it is possible to control so as to perform tracking accurately.

FIG. 4 schematically shows the relationship between the relative positions of the rotary head and the track when the search and slow conditions are changed to the steady running condition (1 × speed). As shown in FIG. 4A, when the search is shifted to the steady running, the deceleration timing is set by considering the deceleration time determined by the speed information and the delay time corresponding to the deviation from the ideal position. , Tracking can be performed accurately.

Also, when the slow speed shifts to the steady running, similarly, as shown in FIG. 4 (b), the start time portion determined by the speed information and the delay time portion corresponding to the deviation from the ideal position are similarly set. By setting the activation timing in consideration, tracking can be performed with high accuracy.

As described above, in the reproducing apparatus according to the first embodiment, the number of FG teeth corresponding to the rotation of the capstan motor is counted when the magnetic tape is running, and the count is recorded on the linear track on the magnetic tape. CTL
By resetting with a signal, it is possible to accurately detect the relative position of the track with respect to the rotary head when the tape is stopped.

Further, at the time of start-up, by controlling the start-up timing based on the stop position detected when the tape running is stopped, it is possible to immediately perform on-track immediately after start-up and obtain a stable image.

Further, C on the magnetic tape is fixed by the fixed head.
By detecting the TL signal, the tape position can be accurately detected even during a transition due to the brake mechanism or the like.

Further, even when the magnetic tape is running at a speed different from the steady running, such as in the search or slow state, the tracking control can be performed with high accuracy when shifting to the steady running. .

Next, a reproducing apparatus according to the second embodiment of the present invention will be described. FIG. 5 is a block diagram showing the structure of the reproducing apparatus according to the second embodiment. It should be noted that components having the same functions as those of the reproducing device according to the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 5, reference numeral 1 denotes a magnetic tape in which information for one frame is divided into 10 diagonal tracks, a pilot signal is multiplex-recorded in the information, and a CTL signal is recorded in the traveling direction. Is a tracking control means for detecting a pilot signal included in the reproduction signal from the drum 3 and outputting a tracking error signal, and 11 is a CT
A CTL phase shift detecting means 20 for comparing the L signal with a reference signal to detect and store a phase shift of the CTL signal, 20 selects a CTL signal from the fixed head 12 and a tracking error signal from the tracking control means 10. When the tracking control is performed by using the CTL signal, the capstan motor driving means 60 for controlling the phase shift with respect to the output of the CTL phase shift detecting means 11 as an error signal is used for the CTL phase shift detection. Means 11
Is a timing control means for controlling the running start timing of the magnetic tape 1 based on the output of the above, the FG tooth number count value from the FG tooth number counting means 8 and the reference signal from the reference signal generating means 4.

The operation of the reproducing apparatus configured as described above will be described below with reference to FIG. In FIG. 6, the capstan motor drive means 20 selects the tracking error signal from the tracking control means 10,
FIG. 9 is a time chart diagram showing a phase relationship between a reference signal and a CTL signal in a state where TF tracking reproduction is performed.

In FIG. 6, the phase of the CTL signal reproduced from the magnetic tape 1 by the fixed head 12 deviates from the design phase shown by the solid line due to the change over time such as expansion and contraction of the magnetic tape 1, and the DC shown by the broken line. Has an offset. Therefore, by correcting the detection position by the offset amount, it is possible to eliminate the deterioration of the detection accuracy due to the phase shift of the CTL signal.

The reproducing apparatus according to the second embodiment described above has the following effects in addition to the effects of the reproducing apparatus according to the first embodiment. CT during ATF tracking control
By detecting and storing the phase shift of the L signal, the offset of the CTL signal due to the expansion and contraction of the magnetic tape is removed, and the position detection when the tape is stopped is made accurate with respect to the change over time due to the expansion and contraction of the magnetic tape. In addition to being able to do so, it is possible to improve accuracy even when compatible.

CTL at the time of ATF tracking control
By detecting and storing the phase shift of the signal, when the rotary head is clogged, the control is switched to the control using the CTL signal, whereby accurate tracking control can be realized.

[0038]

As described above, according to the present invention, the F which corresponds to the rotation of the capstan motor in the tape running state.
The count of the number of G teeth can be reset by the CTL signal recorded on the linear track on the magnetic tape. Therefore, it is possible to accurately detect the stop position when the tape running is stopped.

In the tape running state, the number of FG teeth corresponding to the rotation of the capstan motor at that time can always be counted. Therefore, the stop timing of the magnetic tape can be set arbitrarily.

Further, at the time of starting, the starting timing can be controlled based on the stop position detected when the tape running is stopped. Therefore, the track can be immediately turned on immediately after the start-up, and a stable image can be obtained. Especially, a VTR recorded with high density in a narrow track width
It is possible to realize stable high-speed pull-in.

Further, the ATF control and the CTL control can be used together to monitor and store the phase shift of the CTL signal due to a change with time such as expansion and contraction of the magnetic tape during the ATF control. Therefore, the accuracy of detecting the stop position when the tape running is stopped can be further improved.

As described above, it is possible to prevent the disturbance of the image immediately after the start-up and the thinning of the track at the editing point at the time of joint recording.

[Brief description of drawings]

FIG. 1 is a block diagram of a playback device according to a first embodiment of the present invention.

FIG. 2 is a time chart diagram in the same embodiment.

FIG. 3 is an explanatory diagram of a transition operation from stop to steady running in the same embodiment.

FIG. 4 is an explanatory diagram of a shift operation from search throw to steady running in the same embodiment.

FIG. 5 is a block diagram of a playback device according to a second embodiment of the present invention.

FIG. 6 is an operation explanatory diagram of CTL phase shift detection means in the same embodiment.

FIG. 7 is a block diagram of a conventional playback device.

[Explanation of symbols]

2 Capstan motor drive means 3 drums 4 Reference signal generating means 6 Timing control means 8 FG Number of teeth counting means 12 fixed head

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Rishi Nishida 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Yoshio Sakakibara 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (56) References JP-A-4-11345 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B 15/467

Claims (6)

(57) [Claims] 1. A magnetic tape on which a signal consisting of a predetermined length of data is divided into a plurality of diagonal tracks and recorded, and a CTL signal is recorded on a linear track is run in the longitudinal direction by a capstan motor. In the reproducing device for reproducing a recording signal by scanning the diagonal track from the magnetic tape by a head which rotates, a reference signal generating means for generating a reference signal serving as a rotation reference of the head, and a running state of the magnetic tape. Then, the number of teeth of an FG signal having a frequency detected by the capstan motor and corresponding to the rotation speed of the capstan motor is counted, and the count is reproduced from the magnetic tape.
Based on the FG tooth number counting means reset by the L signal and the number of teeth of the FG signal counted by the FG tooth number counting means while the magnetic tape is stopped and the reference signal from the reference signal generating means, A playback device comprising a timing control means for controlling the timing at the start of traveling. 2. A magnetic tape on which a signal consisting of a predetermined length of data is divided into a plurality of diagonal tracks and recorded by a capstan motor is run in the longitudinal direction, and the diagonal tracks are moved from the magnetic tape. In a reproducing apparatus for reproducing a recording signal by scanning with a rotating head, a capstan motor driving means for driving the capstan motor so that the capstan motor runs a magnetic tape in its longitudinal direction, and a head for rotating the head, A drum for outputting a reproduction signal reproduced from the magnetic tape by the scanning by the rotary head, a reference signal generating means for generating a reference signal serving as a rotation reference of the head , and a CTL signal recorded in the running direction on the magnetic tape. Before being detected by the capstan motor while the fixed head to be reproduced and the magnetic tape are running. The number of teeth of the FG signal having a frequency corresponding to the rotation speed of the capstan motor is counted,
The CTL whose count is reproduced by the fixed head
FG tooth number counting means reset by a signal,
With the magnetic tape stopped, the timing at which the tape is started by the capstan motor driving means is controlled based on the number of teeth of the FG signal counted by the FG tooth number counting means and the reference signal from the reference signal generating means. And a timing control means for controlling the reproduction apparatus. 3. A speed information output means for outputting speed information for rotating a capstan motor in correspondence with the running speed in an unsteady running state where the speed is different from the steady running of the running state of the magnetic tape. The timing control means, based on the speed information and the number of teeth of the FG signal counted by the FG tooth number counting means and the reference signal from the reference signal generating means, shifts to the normal running of the magnetic tape by the capstan motor. The playback device according to claim 1, wherein the playback device is configured to control timing. 4. A magnetic tape, in which a signal composed of data of a predetermined length and a pilot signal are multiplexed by a capstan motor and divided into a plurality of diagonal tracks and recorded, is run in its longitudinal direction, In a reproducing device for reproducing a recording signal by scanning a diagonal track from a magnetic tape with a rotating head, a capstan motor driving means for driving the capstan motor so that the capstan motor runs the magnetic tape in its longitudinal direction. A drum for rotating the head, outputting a reproduction signal reproduced from the magnetic tape by the scanning by the rotary head, reference signal generating means for generating a reference signal as a rotation reference of the drum, and running the magnetic tape on the magnetic tape. A fixed head for reproducing the CTL signal recorded in the direction, and a reproduction signal from the drum. Based on the pilot signal generated, the amount of deviation is detected from the reference signal of the CTL signal reproduced by the fixed head, and tracking control means for performing tracking control of the capstan motor and the magnetic tape through the capstan motor drive means. And a CTL phase shift detecting means for storing the information. 5. The number of teeth of an FG signal having a frequency detected by the capstan motor and corresponding to the rotation speed of the capstan motor is counted while the magnetic tape is running, and the count is reproduced by the fixed head. The FG signal number counting means reset by the CTL signal, the shift amount obtained from the CTL phase shift detecting means and the number of teeth of the FG signal counted by the FG tooth number counting means and the reference signal generation when the magnetic tape is stopped. 5. The reproducing apparatus according to claim 4, further comprising a timing control unit that controls the timing of the tape running start by the capstan motor drive unit based on the reference signal from the unit. 6. A speed information output means for outputting speed information for rotating a capstan motor in accordance with the running speed in an unsteady running state in which the speed is different from the steady running of the running states of the magnetic tape. , Said speed information and CT
Based on the shift amount obtained from the L phase shift detecting means, the number of teeth of the FG signal counted by the FG tooth number counting means, and the reference signal from the reference signal generating means, the magnetic tape is normally run by the capstan motor driving means. 5. The reproducing apparatus according to claim 4, further comprising a timing control unit that controls the transition timing of the.