JPH04268265A - Method for recording image signal and device using the same method - Google Patents

Abstract

PURPOSE:To prevent the degradation in the reliability on the editing function when the track pitch is made narrow and the high-density recording is performed in a recording method of a digital signal in a medium. CONSTITUTION:A guard track is provided between the signal track 5 groups formed between the units of field, etc., of the image signal. The guard track is formed by stopping the recording operation of one head among plural heads 3. In the start of the editing or in the finished point, the width of one portion of the signal tracks becomes narrow and the quality of the recorded image signal, etc., does not degrade.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for digitizing video signals and at least recording them on a magnetic tape medium.

0002

[Prior Art] As a digital VTR, for example, "Digital Video Recording Technology" by Eto Gai, Nikkan Kogyo Shimbunsha 1.
As described in 133rd to 155th editions published in August 1990, D1VTRs whose recorded signals are component signals and D2VTRs whose recorded signals are composite signals have been put into practical use. These two VTRs are characterized in that they can reliably record and reproduce vast amounts of digital video signal data, and that the original image quality hardly deteriorates even after repeated editing and dubbing. On the other hand, although these VTRs have the above-mentioned characteristics, they are large-scale devices, and in order to spread widely, it is desired that they be made smaller.

[0003] In addition, in order to miniaturize digital VTRs, there is a method of compressing data to reduce the amount of data to be recorded by utilizing the characteristics of video signals, and a method of recording digital data signals with higher density on magnetic tape. It goes without saying that if these two methods are used simultaneously, a smaller and more attractive digital VTR can be realized. According to the former method, the video signal to be recorded will be slightly distorted compared to the original signal, and the image quality will deteriorate if editing or dubbing is repeated several times. There is no practical problem if the amount is small.

0004

[Problem to be Solved by the Invention] However, in the latter method, there is a problem in that the reliability of the editing function is significantly reduced, especially when the width of the signal track for recording video signals etc. is made extremely small. . In other words, in assemble editing or insert editing, it is ideal for the signal tracks to form a regular pattern even at the editing start and end points, but mechanical deviations and variations in the VTR are unavoidable, and the width of some signal tracks may The recording quality may be significantly degraded due to a decrease in the recording quality or a track offset occurring in the signal track pattern.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, namely, to provide a digital VTR that has a highly reliable editing function in a VTR that narrows the signal track width and records digital data of video signals at high density. .

[0006]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a signal track group formed by a plurality of rotating heads as one unit (field, frame, etc.) of a video signal; A guard track is formed between a group of signal tracks corresponding to one unit of adjacent video signals by prohibiting the recording operation of some of the rotary heads among the plurality of rotary heads.

[0007]

[Operation] The guard track serves to prevent additionally recorded signal tracks from overlapping existing signal tracks due to mechanical deviations or the like at the start and end points of editing. As a result, the width of existing signal tracks does not become narrower due to the overlapping signal tracks, and the quality of recorded video signals and the like does not deteriorate.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a diagram showing the configuration of a VTR for achieving the recording method according to the present invention, and FIG. 2 is a diagram showing the configuration of a VTR shown in FIG. V
It is a figure showing the composition of the drum of TR. In the figure, 1 is a drum, 2 is a drum motor, 3 is a head, 4 is a tape,
5 is a signal track, 6 is a capstan, 7 is a capstan motor, 8 is a drum motor control circuit, 9 is a capstan motor control circuit, 10 is a timing generation circuit, 11 is a recording signal processing circuit, and 12 is a recording gate circuit. be. Furthermore, as shown in FIG.
b).

FIG. 3 is a diagram showing operating waveforms of the recording gate circuit 12 according to the first embodiment of the present invention, and FIG.
FIG. 3 is a diagram showing a pattern of signal tracks according to the embodiment.

The operation will be explained below. In this embodiment, the rotational frequency of the drum 1 is described as twice the field frequency of the video signal, but the present invention is not particularly limited to this.
It goes without saying that the present invention can also be applied to a case where the rotation frequency is N times the field frequency (which will be explained later, but does not necessarily have to be an integer).

A video signal (which may include an audio signal or sometimes only an audio signal, but will simply be referred to as a video signal in the following description) is input to a timing generation circuit 10 and a recording signal processing circuit 11. The timing generation circuit 10 generates the following three timing signals (generally a group of timing signals) based on the timing of the field period and horizontal scanning period of the video signal and the rotational phase signal of the drum 1.

(1) A rotational phase reference signal used for synchronizing the rotational phase of the drum 1 with the video signal is sent to the drum motor control circuit 8.

(2) The recording signal is sent to the recording signal processing circuit 11, which includes, for example, a video signal data compression circuit and an error correction parity code addition circuit, and converts the video signal into a data format suitable for recording on the tape 4. Sends various timing control signals for processing.

(3) The tape 4 actually passes through the head 3.
A gate signal is sent to the recording gate circuit 12 to determine whether or not to record a signal on the recording gate.

Further, the capstan motor control circuit 9 causes the tape 4 to run at a constant speed in the longitudinal direction of the tape via the capstan motor 7 and the capstan 6.

Furthermore, as shown in FIG. 3, the recording gate circuit 12 uses the gate signal from the timing generating circuit 10 to cause the head A (3a) and head B (3b) to each have a high level period (indicated by REC) in the figure. At this point, the signal is actually recorded on the tape 4. Conventionally, in sub-intervals (denoted T1 to T4) that divide the field period into four, head A (3a) can record signals at T1 and T3, but in the first T1, , disable signal recording. Naturally, the recording signal processing circuit 11 uses a memory circuit (not shown) provided in the recording signal processing circuit 11 so that data to be recorded is output only in the T2 to T4 intervals excluding the T1 interval. After performing appropriate processing such as time axis compression, the recording gate circuit 12 prevents any signal from being supplied to the head 3. More generally, the recording gate circuit 12 performs recording signal processing. It may be considered as part of the circuit 11.

As a result, the signal track pattern shown in FIG. 4 is realized on the tape 4. That is, in FIG. 4, 4a is a signal recording area where the helical signal track 5 is formed, 4b is a cue track in the longitudinal direction,
Similarly, 4c is a control track, and 4d is a time code track.
An area for one signal track is allocated, of which one
Its duty is to serve as a guard track 5a with a signal track corresponding to an adjacent field.

According to the embodiment described above, any starting point or ending point of editing (in the case of insert editing)
Also, since the guard track 5a can absorb mechanical deviations and variations, the reliability of the editing function is improved without causing the problem of the width of some signal tracks becoming extremely narrow. Can be secured.

Next, a second embodiment of the present invention will be explained using FIGS. 5 and 6. FIG. 5 is a diagram showing a signal track pattern on the tape 4 according to the second embodiment, and FIG.
2 is an operational waveform diagram of the recording gate circuit 12 shown in FIG. 1. FIG.

The difference between this embodiment and the first embodiment is that a track in the longitudinal direction is not particularly required as shown in FIG. (sections 5b and 5c in the figure). Similarly to the first embodiment, in this embodiment as well, four signal tracks 5 are allocated to one field of video signals, one of which is a guard track 5a. However, in the sections (5b, 5c) allocated for tracking signals, etc. in the signal track 5, signals such as the tracking signal are recorded regardless of the guard track 5a, and the continuity of the tracking information is maintained. , realizes stable tape running.

In order to realize the above-mentioned signal track pattern, the recording gate signal corresponding to the head A (3a) is used in the section (5b, 5c) in which tracking signals etc. are to be recorded, as shown in FIG. T of the signal field
The level is set high so that even one section can be recorded. Of course, although not shown, in a mode such as insert editing where tracking information is not intentionally rewritten, the gate signal needs to be at a low level in this section.

FIG. 7 shows a modification of the second embodiment of the invention. In the figure, a part of the signal track pattern is shown enlarged for clarity. This example differs from the previous example shown in FIG. 5 because on the signal track 5, a guard space 5
The reason lies in the fact that c. The guard space 5c is
In insert editing or the like, when only a video signal or the like is additionally recorded, it is made so that it does not overlap with an adjacent section of a tracking signal or the like.

FIGS. 8 to 12 show a third embodiment and a fourth embodiment of the present invention. These two examples are:
The difference between the first and second embodiments is that the head 3 has multiple channels. Further, the configuration of the VTR shown in FIG. 1 can be applied to the first to fourth embodiments. Furthermore, FIG. 8 is a diagram showing the drum shown in FIG. 1, and is common to the third and fourth embodiments described below.

In FIG. 8, the head 3 is a head A (
3a), head B (3b), head C (3c), and head D (3d). Head A (3a)
and head C (3c) as a pair, head B (3b)
and head D (3d) perform recording at substantially the same timing as another pair of heads facing each other at 180 degrees. The third and fourth embodiments below will be explained using the drum configuration shown in FIG. For example, when a pair of head groups consists of four heads,
It goes without saying that the present invention can also be applied to four pairs of head groups separated by degrees.

FIG. 9 shows an operational waveform diagram of the recording gate circuit 12 of the third embodiment, and FIG. 10 shows a signal track pattern. In this embodiment, the rotation speed of the drum 1 is 1.5 times, and each field period is divided into three equal parts (
T1 to T3), the guard track 5a shown in FIG. 9 is formed by head A (3a) in the first T1 period of the odd field and head B (3b) in the first 1T period of the even field. Therefore, the recording gate signal is set to a low level.

As a fourth embodiment, FIG. 11 shows an operating waveform diagram of the recording gate circuit 12, and FIG. 12 shows a signal track pattern. .25 times. Therefore, as shown in FIG. 11, in the interval T1 to T10, which is obtained by dividing four times the field period (2 frames) into 10 equal parts, head A (3a) is set in the T1 interval, and head C (3c) is set in the T3 interval.
The guard track 5a shown in FIG. 12 is formed by preventing the head B (3b) from recording alternately in the T6 interval and by the head D (3d) in the T8 interval.

As explained above in the third and fourth embodiments, it can be seen that the rotational frequency of the drum does not necessarily have to be an integral multiple of the field frequency of the video signal. Furthermore, if the third and fourth embodiments are used, video signals with different numbers of scans, that is, a 625/50 system with 625 horizontal scanning lines and a field frequency of 50Hz, and a 625/50 system with 625 horizontal scanning lines and a field frequency of 50Hz, can be used. This is a 525/60 system with a field frequency of 60Hz, and the configuration of the VTR shown in FIG. VTR
It will be possible to achieve this. That is, if the rotational speed of the drum 1 is 75 Hz, the third embodiment corresponds to the 625/50 system, and the fourth embodiment corresponds to the 525/60 system.

Further, in FIGS. 13 and 14, in order to realize better performance in the editing function, a rotary erasing head (see FIG. An example of the configuration of a drum on which middle parts 13a to 13d) are mounted is shown. In FIG. 13, head A (3a)
The signal tracks formed by the rotary erasing head A (13a
), the rotating erasing head B (13b) rotates the head B (
Erase the signal track formed in step 3b). Similarly, Figure 1
4, for four heads A to D (3a to 3d)
Two rotating erasing heads A to D (13a to 13d) are one-to-one.
corresponds to Furthermore, the driving of the rotary erasing heads A to D (13a to 13d) in FIGS. 13 and 14 is similar to the driving of the heads A to D (3a to 3d) in the section corresponding to the guard track 5a. ban it.

In the above description of the embodiments of the present invention, it has been explained that the video signal is treated in units of one field, but the present invention can also be considered in units of one frame or color frames (two frames). There is no problem in applying it.

[0031]

As described above, according to the present invention, guard tracks can be formed between fields of a video signal as a signal track pattern on a tape. Therefore, even if the track pattern of the additionally recorded video signal deviates from the originally existing signal track pattern due to mechanical deviation or variation at the editing point such as during insert editing, the added signal track There is almost no chance of overlapping the originally existing signal track and reducing the width of the originally existing signal track, and the reliability of the editing function in a small VTR is greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a VTR that implements the recording method of the present invention.

[Fig. 2] A diagram showing the configuration of a drum applicable to the first and second embodiments.

[Fig. 3] Operation waveform diagram of the recording gate circuit of the first embodiment

[
Figure 4: Signal track pattern diagram of the first embodiment

[Figure 5]
Signal track pattern diagram of the second embodiment

[Fig. 6] Operation waveform diagram of the recording gate circuit of the second embodiment

[Fig. 7] Modification of the second embodiment shown in Fig. 5

FIG. 8 is a diagram showing the configuration of a drum applicable to the third and fourth embodiments.

[Fig. 9] Operation waveform diagram of the recording gate circuit of the third embodiment

[
FIG. 10: Signal track pattern diagram of the third embodiment

[Figure 1
1] Operation waveform diagram of the recording gate circuit of the fourth embodiment

[Figure 1
2] Signal track pattern diagram of the fourth embodiment

[Figure 13]
A diagram showing a configuration in which a rotating erasing head is mounted on the drum shown in Figure 2.

[Fig. 14] A diagram showing a configuration in which a rotating erasing head is mounted on the drum shown in Fig. 8.

[Explanation of symbols]

1...Drums, 3...Head, 4...Tape, 5...Signal track, 5a...Guard truck, 5b...section of tracking signal, etc. 5c...guard space, 10...timing generation circuit, 11...recording signal processing circuit, 12... Recording gate circuit

Claims (4)

[Claims] Claims: 1. A video signal recording method in which a helical signal track is formed on a tape-shaped recording medium by a rotary head, in which a helical signal track is formed adjacent to a group of signal tracks formed as one unit, such as one field or one frame of the video signal. A method for recording a video signal, characterized in that a guard track is provided between a group of tracks. 2. The video signal recording method according to claim 1, wherein the tracking information of the helical signal track is recorded not only as a part of the helical signal track but also on the guard track. video signal recording method. 3. The video signal recording method according to claim 1, wherein the guard prohibits recording by one rotary head of a plurality of rotary heads at the connection of one unit of the video signal. A method of recording video signals that form tracks. 4. An apparatus using the video signal recording method according to claim 1, 2, or 3.