JPH03286450A - Magnetic picture recording/reproducing device - Google Patents

Abstract

PURPOSE:To optimize the quality of a picture by controlling a magnetic tape running device so that the reproduced output of a magnetic head detected by a detecting means becomes optimum, and simultaneously, controlling a rotary cylinder drum so that the same phase as the stored phase at the time of recording is held. CONSTITUTION:A control means 12 controls the running means to run a magnetic tape so that the reproduced output of the magnetic head 5 detected by the detecting means 11 becomes optimum. Simultaneously with this, when the phase of the rotary cylinder drum for a control signal on the magnetic tape in which the reproduced output of the magnetic head 5 becomes optimum is within a prescribed range, it controls the rotary cylinder drum so that the same prescribed phase as at the time of the recording stored by a storage means 13 is held. Thus, optimum reproduced picture quality can be obtained by tracing an optimum tracking value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an azimuth recording and guard bandless helical scan type magnetic recording and reproducing apparatus, such as a VTR.

[Prior Art] Fig. 4 is a schematic diagram showing the configuration of an automatic tracking system in a conventional VTR. and a drum motor (4) that rotates the drum.

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

The VTR also has a control head (
7).

Furthermore, the VTR has an electric circuit (8) as shown in FIG.
The recording/reproducing head (5) is connected to a head amplifier (9) that amplifies the signal.

The head amplifier (9) includes a playback signal processing circuit (10) that performs predetermined processing on the playback signal played back by the recording/playback head (5), and a playback signal processing circuit (10) that detects the level of the playback signal played back by the recording/playback head (5). A level detector (11) is connected thereto.

The level detector (11) also includes an optimal pattern recognition circuit (12) that recognizes whether the level-detected playback signal is optimal or not.
) are connected.

Further, on the magnetic tape (1), video tracks (13) of different azimuths are lined up alternately and without any gaps, and at the bottom end of the magnetic tape (1) there is a control signal (13) for controlling the running speed. 14) is recorded.

Next, the operation will be explained.

The magnetic tape (1) is run by a capstan motor (2), and the control signal (14) recorded on the magnetic tape (1) is read by a control radar (7), and based on this control signal (14) A capstan motor (2) is controlled to run the magnetic tape (1) at a predetermined speed.

Further, the cylinder drum (3) is rotated by a drum motor (4), and the drum motor (4) is connected to the PG head (
6), the phase is detected.

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

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

At this time, the level of the playback signal (100) which has been increased by l by the head amplifier (9) is detected by the level detector (11), and the optimal pattern recognition circuit (12) detects the level based on the output of the level detector (11). It is recognized whether the detected playback signal is optimal or not, and if it is not optimal, the control signal (14) and the recording/playback head (5) on the cylinder drum (3) are detected.
) so that the distance (X value) traced by
A servo circuit controls the drum motor (4) and capstan motor (2).

[Problems to be Solved by the Invention] Since the conventional magnetic recording and reproducing apparatus is configured as described above, in the case of guard bandless, the convergence of the recording/reproducing head (5) is larger than the width of the track (13). Therefore, when the tracking is changed, the recording/playback head output changes as shown in Figure 3. Position (a) is the same head position as during recording, and has the best playback quality, but position (a) If the position was to be traced, there was a risk that the image would be leftward from the position (a) and the image quality would be significantly degraded due to errors in the detection circuit.

Furthermore, in the case of magnetic tapes recorded with other VTRs, there was a problem in that the linearity of the tracks did not match, making it difficult to clearly determine the position in (a). Furthermore, even if the head position changes from position (b) to position (C), the playback output remains constant due to the head width, and there is a problem that it is not possible to determine whether or not the position is optimal based on the head output alone. there were.

This invention was made to solve the three problems mentioned above. If the position (a) is close to the tracking value at the time of recording, tracking is fixed at the position (a) to optimize the image quality. The purpose is to scale the magnetic recording and playback device that can be used.

[Means for Solving the Problems] A magnetic recording and reproducing device according to the present invention includes a traveling means for traveling a magnetic tape, a magnetic head provided on a rotating cylinder drum for recording and reproducing images on the magnetic tape, and a magnetic head for recording and reproducing images on the magnetic tape. a detection means for detecting the playback output of the head; a storage means for storing the phase of the rotating cylinder drum in response to a controller/roll signal on the magnetic tape during recording; and a control for manually controlling the playback output of the magnetic head detected by the detection means. equipped with the means.

The control means controls the running means for running the magnetic tape so that the reproduction output of the magnetic head is optimized based on the reproduction output of the magnetic head detected by the detection means, and also controls the magnetic tape running means so that the reproduction output of the magnetic head is optimized. If the phase of the rotary cylinder drum relative to the control signal on the tape is within a predetermined range, the rotary cylinder drum is controlled so as to maintain the same predetermined phase as during recording stored in the storage means.

[Function] The magnetic recording and reproducing device of the present invention runs a magnetic tape by a running means, records and reproduces images on the magnetic tape by a magnetic head provided on a rotating cylinder drum,
The detection means detects the reproduction output of the magnetic head, the storage means stores the phase of the rotating cylinder drum relative to the control signal on the magnetic tape during recording, and the reproduction output of the magnetic head detected by the detection means is manually input to the control means. , the control means is based on the reproduction output of the magnetic head detected by the detection means,
A running means for running the magnetic tape is controlled so that the reproduction output of the magnetic head is optimized, and the phase of the rotating cylinder drum relative to the control signal on the magnetic tape is within a predetermined range so that the reproduction output of the magnetic head is optimized. In this case, the rotating cylinder drum is controlled so as to maintain the same predetermined phase as that during recording stored in the storage means.

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

Figure TS1 is a block diagram showing the configuration of a VTR according to an embodiment of the present invention.
) are connected to a head amplifier (9) for amplifying the signal.

The head amplifier (9) includes a playback signal processing circuit (10) that performs predetermined processing on the playback signal played back by the recording/playback head (5), and a playback signal processing circuit (10) that detects the level of the playback signal played back by the recording/playback head (5). A level detector (11) as a detection means is connected.

In addition, an optimal pattern recognition circuit (12) as a control means is connected to the level detector (11) and is configured with a microcomputer that recognizes whether the level-detected playback signal is optimal or not. Circuit (1
2) is connected to a self-recording/reproducing pattern memory (13) as a storage means for storing self-recorded tracking values.

Next, the operation of this embodiment will be explained.

In case of guard bandless mode such as 3x mode, magnetic tape (
1) is driven by a capstan motor (2) and receives a control signal (14) recorded on a magnetic tape (1).
) is read by the control head (7), and the capstan motor (2) is operated to run the magnetic tape (1) at a predetermined speed based on this control signal (14).
control.

Further, the cylinder drum (3) is rotated by a drum motor (4), and the drum motor (4) is connected to the PG head (
6), the phase is detected.

Furthermore, a pair of recording/reproducing heads (5) provided on the cylinder drum (3) trace the video track (13) on the magnetic tape (1) to obtain a reproduction signal (1,00).

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

At this time, the level of the reproduced signal (100) amplified by the head amplifier (9) is detected by the level detector (11), and the output of the level detector (11) is input to the optimum pattern recognition circuit (12).

In addition, the optimal pattern recognition circuit (12) performs the following during recording.
The self-recorded tracking value is stored in the self-recorded and replayed pattern memory (13
).

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

The optimal pattern recognition circuit (12) sequentially changes tracking to obtain a pattern of changes in head output (Stapl).
).

Then, it is difficult to judge whether the maximum point of the head output is 1 point or not.
ep2), if it is determined that it is one point, the tracking amount is held at the maximum head output (Step 3).

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

Further, if it is determined that the maximum point of the head output is not one point (see Fig. 3), the optimal pattern recognition circuit (12) changes the self-edge tracking value stored in the self-recording/reproducing pattern memory (13) to ( a) To judge whether the points are close or not, S t
e p4), (a) If it is determined that the point is close to the self-edge tracking value, cylinder drum control and capstan control are performed to fix it at the self-edge tracking value (S
step 5).

This provides optimal image quality with minimal crosstalk interference from adjacent azimuth tracks.

Generally, the head width is selected so that crosstalk is minimized at the frequency recorded at the azimuth angle given the difference between the head width and the track width. Compared to the case where the crosstalk is obtained from the point (a), the crosstalk interference is reduced the most at the position of point (a).

Furthermore, if the point (a) is not close to the self-edge tracking value stored in the self-recording/reproducing pattern memory (13), t,1
If one break occurs, select a position between points (a) and (c) that is closer to point (a) (for example, a 1:3 position), and control the cylinder drum so that it does not deviate to the left of point (a). and capstan control (Step 6).

[Effect of the Invention 1] As explained above, according to the present invention, the running means for running the magnetic tape is controlled based on the reproduction output of the magnetic head so that the reproduction output of the magnetic head is optimized, and the magnetic head If the phase of the rotary cylinder drum relative to the control signal on the magnetic tape is within a predetermined range for optimal reproduction output, the rotary cylinder drum is controlled to maintain the same predetermined phase as during recording. In the case of guardbandless, self-edge tracking values can be traced to obtain optimal playback quality. Furthermore, even in the case of magnetic tapes recorded with other VTRs, the optimum tracking value can be traced to obtain the optimum reproduced image quality. Furthermore, the optimum head position can be selected based on the tracking amount and the head output to obtain the optimum reproduction image quality.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a magnetic recording and reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a flowchart showing the operation of an embodiment of the invention, and FIG. 3 is a diagram showing the relationship between head output and tracking. Figure 4 is a schematic diagram of the automatic tracking system; Figure 5 is a diagram showing the relationship between the head and the track;
The figure is a block diagram showing the configuration of a conventional magnetic recording and reproducing device.
FIG. 6 is a diagram showing the pattern of the 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 an optimal pattern recognition means, and (13) is a video track. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] In a helical scan type magnetic recording and reproducing device that performs azimuth recording and does not have a guard band, it is equipped with a traveling means for traveling a magnetic tape and a magnetic head provided on a rotating cylinder drum for recording and reproducing images on the magnetic tape. A detection means for detecting the reproduction output of the head, a storage means for storing the phase of the rotating cylinder drum with respect to a control signal on the magnetic tape during recording, and a control means for inputting the reproduction output of the magnetic head detected by the detection means. The control means controls the running means for running the magnetic tape so that the reproduction output of the magnetic head is optimal based on the reproduction output of the magnetic head detected by the detection means, and also controls the traveling means for running the magnetic tape so that the reproduction output of the magnetic head is optimal. If the phase of the rotating cylinder drum with respect to the control signal on the magnetic tape is within a predetermined range, the rotating cylinder drum is controlled so as to maintain the same predetermined phase as that at the time of recording stored by the storage means. Recording and playback device.