JPH0782683B2 - Magnetic recording / playback device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic recording / reproducing apparatus of azimuth recording and guard bandless helical scan system, for example, a VTR.

[Prior Art] FIG. 4 is a schematic diagram showing a configuration of an automatic tracking system in a conventional VTR. The VTR is a capstan motor (2) for running a magnetic tape (1) and a cylinder drum (3). And a drum motor (4) for rotating the.

A pair of recording / reproducing heads (5) are provided on the cylinder drum (3), and a PG head (6) for detecting the phase is attached to the drum motor (4).

Further, the VTR is equipped with a control head (7) for picking up a control signal for controlling the running speed of the magnetic tape (1).

Further, the VTR has an electric circuit (8) as shown in FIG. 5, and the recording / reproducing head (5) is connected to a head amplifier (9) for amplifying a signal.

The head amplifier (9) has a reproduction signal processing circuit for performing a predetermined process on the reproduction signal reproduced by the recording / reproducing head (5).
The 8109 is connected to a level detector (11) for detecting the reproduction signal reproduced by the recording / reproducing head (5).

Further, the level detector (11) is connected to an optimum pattern recognition circuit (12) for recognizing whether or not the reproduction signal detected by the reverb detection is optimum.

Furthermore, on the magnetic tape (1), video tracks (13) of different azimuths are arranged alternately and without gaps,
A control signal (14) for controlling the traveling speed is recorded on the lower end of the magnetic tape (1).

Next, the operation will be described.

The magnetic tape (1) is run by the capstan motor (2), the control signal (14) recorded on the magnetic tape (1) is read by the control head (7), and the magnetic signal is generated based on the control signal (14). The capstan motor (2) is controlled so that the tape (1) runs at a predetermined speed.

The cylinder drum (3) is rotated by the drum motor (4), and the phase of the drum motor (4) is detected by the PG head (6).

Further, a pair of recording / reproducing heads (5) provided on the cylinder drum (3) trace a video track (13) on the magnetic tape (1) to obtain a reproduction signal (100).

This reproduction signal (100) is amplified by the head-up (9), subjected to predetermined processing by the reproduction signal processing circuit (10), and sent to the television as a reproduction video signal (101) to reproduce the video on the screen. To do.

At this time, the reproduced signal (100) amplified by the head amplifier (9) is detected by the level detector (11),
Based on the output of the level detector (11), the optimum pattern recognition circuit (12) recognizes whether or not the level-detected reproduction signal is optimum, and when it is not optimum, that is, the control signal (14).
The servo circuit controls the drum motor (4) and the capstan motor (2) so that the distance (X value) traced by the recording / reproducing head (5) on the cylinder drum (3) is accurately matched.

[Problems to be Solved by the Invention] Since the conventional magnetic recording / reproducing apparatus is configured as described above, in the case of the guard bandless, the width of the recording / reproducing head (5) is larger than the width of the drag (13). Therefore, the recording / reproducing head output when the tracking is changed changes as shown in FIG. 3, and the position (a) is the same head position as that at the time of recording, and the reproduction image quality is the best. When the position is traced, there is a risk that the image quality may be greatly impaired by being leftward from the position (a) due to an error in the detection circuit or the like. Further, in the case of a magnetic tape recorded by another VTR, there is a problem that the linearity of the tracks does not match and it is difficult to clearly determine the position of (a). Further, even if the position of (b), the position of (c) and the head position change, the reproduction output is constant due to the relationship of the head width, and there is a problem that it is not possible to determine whether or not it is the optimum position only by the head output. there were.

The present invention has been made to solve the above problems. When the position (a) is close to the tracking value at the time of recording, tracking can be fixed at the position (a) to optimize the image quality. An object is to obtain a magnetic recording / playback device.

[Means for Solving the Problem] A magnetic recording / reproducing apparatus according to the present invention comprises a traveling means for traveling a magnetic tape, a magnetic head provided on a rotating cylinder drum for recording / reproducing an image on the magnetic tape, and a magnetic recording medium. It is provided with a detection means for detecting the reproduction output of the head and a control means for inputting the reproduction output of the magnetic head detected by the detection means. Based on the reproduction output of the magnetic head detected by the detection means, the control means controls the traveling means for traveling the magnetic tape so that the reproduction output of the magnetic head becomes optimum, and the reproduction output of the magnetic head becomes optimum. When the phase of the rotary cylinder drum with respect to the control signal on the tape is within a predetermined range, the rotary cylinder drum is controlled so as to be held at the same predetermined phase as during recording.

[Operation] In the magnetic recording / reproducing apparatus according to the present invention, the magnetic tape is run by the running means, and an image is recorded / played on / from the magnetic tape by the magnetic head provided on the rotating cylinder drum.
The reproduction output of the magnetic head is detected by the detection unit, and the reproduction output of the magnetic head detected by the detection unit is input to the control unit. The control unit outputs the reproduction output of the magnetic head based on the reproduction output of the magnetic head detected by the detection unit. Is controlled so that the magnetic tape travels optimally, and when the phase of the rotary cylinder drum with respect to the control signal on the magnetic tape that optimizes the reproduction output of the magnetic head is within a predetermined range, The rotating cylinder drum is controlled so as to maintain the same predetermined phase.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the structure of a VTR according to an embodiment of the present invention. The VTR is a pair of recording / reproducing heads (5) provided on a cylinder drum (3) and heads for amplifying signals. It is connected to the amplifier (9).

The head amplifier (9) detects a level of the reproduction signal processing circuit (10) for performing a predetermined process on the reproduction signal reproduced by the recording / reproducing head (5) and the reproduction signal reproduced by the recording / reproducing head (5). And a level detector (11) as a detecting means.

Further, the level detector (11) is connected to an optimum pattern recognition circuit (12) as a control means which is composed of a microcomputer for recognizing whether or not the level-detected reproduction signal is optimum. Circuits (12)
A self-recording / replaying pattern memory (13) as a storage means for storing the self-recording tracking value is connected to the.

Next, the operation of this embodiment will be described.

In the guard bandless mode such as triple mode, the magnetic tape (1) is run by the capstan motor (2) and the control signal (1) recorded on the magnetic tape (1) is used.
4) is read by the control head (7), and based on this control signal (14), the capstan motor (2) is caused to run the magnetic tape (1) at a predetermined speed.
To control.

The cylinder drum (3) is rotated by the drum motor (4), and the phase of the drum motor (4) is detected by the PG head (6).

Further, a pair of recording / reproducing heads (5) provided on the cylinder drum (3) trace a video track (13) on the magnetic tape (1) to obtain a reproduction signal (100).

This reproduction signal (100) is amplified by the head amplifier (9), subjected to predetermined processing by the reproduction signal processing circuit (10), and sent to the television as a reproduction video signal (101) to reproduce the video on the screen. To do.

Again, the reproduction signal (100) amplified by the head amplifier (9) is level-detected by the level detector (11),
The output of the level detector (11) is the optimum pattern recognition circuit (1
Entered in 2).

The optimum pattern recognition circuit (12) inputs the self-recording tracking value to the self-recording / replaying pattern memory (13) during recording.

Next, the operation when the optimum pattern recognition circuit (12) performs automatic tracking adjustment will be described with reference to the flowchart of FIG.

The optimum pattern recognition circuit (12) sequentially changes tracking to obtain a head output change pattern (Step 1).

Then, it is judged whether or not the maximum point of the head output is 1 (Step
2) If it is determined that the number of points is one, the head output is held at the maximum tracking amount (Step 3).

At this time, the track width and the head width match.

When it is determined that the maximum point of head output is not 1 (see FIG. 3), the optimum pattern recognition circuit (12) uses the self-recording tracking value stored in the self-recording / replaying pattern memory (13) ( a) Judge whether the points are close (Step 4),
When it is determined that the point (a) is close to the self-recording tracking value, cylinder drum control and capstan control are performed so as to fix the self-recording tracking value (Step 5).

As a result, the optimum image quality with minimum crosstalk interference from another adjacent azimuth track can be obtained.

Generally, the head width is selected so that the crosstalk is minimized at the frequency of recording at the azimuth angle where the difference between the head width and the track width is given. Therefore, the crosstalk interference is most reduced at the position of the point (a), as compared with the case where the crosstalk is subtracted.

Furthermore, when it is determined that the point (a) is not close to the self-recording tracking value stored in the self-recording / replaying pattern memory (13), the point (a) between the points (a) and (c) Position (for example, the position of 1: 3) is selected, and the cylinder drum control and the capstan control are performed so as not to move to the left of (a) (Step 6).

As described above, according to the present invention, based on the reproduction output of the magnetic head, the traveling means for traveling the magnetic tape is controlled so that the reproduction output of the magnetic head becomes optimum, and at the same time, the magnetic head. When the phase of the rotating cylinder drum with respect to the control signal on the magnetic tape for which the reproduction output of is optimum is within a predetermined range, the rotating cylinder drum is controlled so as to be held at the same predetermined phase as during recording. In the case of guard bandless, the self-recording tracking value can be traced to obtain the optimum reproduction image quality.
Even in the case of a magnetic tape recorded by another VTR, the optimum tracking value can be traced to obtain the optimum reproduction image quality. Further, the optimum head position can be selected according to the tracking amount and the head output to obtain the optimum reproduction image quality.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a magnetic recording / reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a flow chart showing the operation of the embodiment of the present invention, and FIG. 3 is a relationship between head output and tracking. FIG. 4 is a diagram showing the relationship between the head and the track, FIG. 4 is a schematic diagram of the automatic tracking system, and FIG.
FIG. 1 is a block diagram showing the configuration of a conventional magnetic recording / playback device,
FIG. 6 is a diagram showing a pattern of a magnetic tape. In the figure, (1) is a magnetic tape, (2) is a capstan motor, (3) is a cylinder drum, (5) is a recording / reproducing head,
(11) is a level detector, (12) is optimum pattern recognition means,
(13) is a video track. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A magnetic recording of a helical scan system from azimuth recording to guard bandless, comprising a traveling means for traveling a magnetic tape and a magnetic head provided on a rotating cylinder drum for recording and reproducing an image on the magnetic tape. The reproducing apparatus includes a detection unit for detecting the reproduction output of the magnetic head and a control unit for inputting the reproduction output of the magnetic head detected by the detection unit, and the control unit is the reproduction output of the magnetic head detected by the detection unit. Based on the above, the traveling means for traveling the magnetic tape is controlled so that the reproduction output of the magnetic head becomes optimum, and the phase of the rotary cylinder drum with respect to the control signal on the magnetic tape where the reproduction output of the magnetic head becomes optimum has a predetermined range. If it is within the range, the rotary cylinder drum is controlled so as to maintain the same predetermined phase as during recording. Gas-recording and reproducing apparatus.