JPH03219485A - Magnetic recorder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a digital video tape recorder (hereinafter referred to as D-VTR) that records and reproduces digital image signals and the like on a magnetic tape using a rotating magnetic head.

[Conventional technology]

FIG. 3 is a simplified diagram of the tape format of a D-VTR, known as the conventional D-2 format, as shown in, for example, "Broadcasting Technology July 1986 Composite Digital VTRDVR-10". 9 is a magnetic tape, 10 is a magnetic tape traveling direction, 11 is a rotating magnetic head scanning direction, 12 is a track pattern recorded on the tape, 13 is a recording head width, and 14 is a track pitch.

Figure 4 shows the tape track pattern near the cutout after insert editing in the same D-2 format; 9 to 11 are the same as in Figure 4;
5 is a track pattern recorded by insert editing, 16 is a track pattern recorded before insert editing, and 17 particularly shows a track pattern immediately after cutout.

FIG. 5 is a diagram showing the head arrangement in the D-2 format as well, where 9.10 is the same as in FIG. 4, 18 is a rotating drum, 19 is the rotation direction of the drum 18, and 20a to 20d.
are recording heads fixed to the drum 18, 21a to 21d;
is a reproducing head that can be displaced in a direction perpendicular to the drum rotation direction 19.

Next, the operation will be explained.

The 768 samples excluding the horizontal sync signal part of the input video signal are divided into odd and even samples alternately, and the 1/3 field (85 lines) excluding the vertical sync signal part is divided into odd and even samples.
Collect and shuffle.

Two types of error correction codes, inner and outer, are added to the shirted data, a sync pattern and an ID code are added, and the data is recorded on tape 1 for each channel. That is, the screen of one field is divided into three (called segments), each divided into even and odd samples, and recorded on separate tracks, so one field has six tracks.

In the recording heads 20a to 20d in FIG. 5, odd field segments are recorded with 20a and 20b.
The next field is recorded as 20c and 20d. D-
In the two types of D-VTRs, azimuth recording is used to reduce tracking errors, guard bands are eliminated, and a mirror square (M2) code is used as a recording code.

Since the M2 code has no long wavelength component in the recording signal and can be overwritten, the head width 13 of the recording head in FIG.
m) Make it wider and record overlapping parts of adjacent tracks without guard bands. In this case, it is not necessary to use a pre-rotating erasing head, and when insert editing is performed as shown in FIG. 4, the track 17 immediately after the cutout is cut out and narrowed due to overlap.

[Problem to be solved by the invention]

The recording device of a conventional D-VTR is configured as described above, so when insert editing is performed, the track immediately after the cutout is cut out and narrowed due to the overlap from the right and left tracks (recording head width is 45 μm). ,
) When the rack pitch is 39 μm, the track width is 33 μm.
), there is a problem in that while the playback head is tracing on a narrow track, the playback output decreases and the playback data error rate increases.

This invention was made to solve the above-mentioned problems, and even when insert editing is performed, the track immediately after quadruple-out does not become narrower than other tracks, and the screen is smoothly displayed at the cut-out point. The purpose is to obtain a magnetic recording device that can be connected.

[Means to solve the problem]

The magnetic recording apparatus according to the present invention is capable of varying the width of the recording head so as not to cause the head recording the track at the end of the insert i collection to overlap the track immediately after cant-out.

[Effect]

The recording device of this invention records the last track during insert editing using a recording head whose head width can be varied so as not to overlap the track immediately after the cutout, so that the track immediately after the cutout is narrowed due to the overlap. Therefore, it is possible to prevent an increase in error rate due to a decrease in output during reproduction.

〔Example〕

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

FIG. 1 shows the configuration of a recording head in which the recording head width can be varied in a magnetic recording apparatus according to an embodiment of the present invention, where 1a is the front core of the first head, and 1b is the front core of the second head.
The front core of the head, 2a is the back core of the first head, 2b is the back core of the second head, 3a is the coil of the first head, 3b is the coil of the second head, 4 is the head gap, and 5a is the first head. 5b is the recording head end when only the first head is used.

FIG. 2 is a circuit diagram showing the connection of the recording head shown in FIG. 1, and 6a and 6b are switchboards for switching whether or not to connect the coil 3a of the first head and the coil 3b of the second head.
ν, 7 is a recording current input terminal, and 8 is a terminal for inputting a head switching signal that turns the switches 6a and 6b upward only for the last track of insert editing, and downward at other times.

Next, the operation will be explained.

Shuffled in the signal processing section of the D-VTR,
If the digital video signal data to which an error correction code, ID code, and sync pattern are added is capable of azimuth overwriting recording such as M2 code, the switches 6a and 6b are tilted downward and the coils 3a and 3b are connected in series. The first head consisting of la, 2a, and 3a and the first
The second head consisting of the heads b, 2b, and 3b operates as if it were one recording head, and records a track pattern on the tape as a recording head having the head width 5a shown in FIG.

On the other hand, when performing insert editing on a D-VTR,
Only for the last track of insert editing, switches 6a and 6 are connected to the head switching signal input terminal 8 in Fig. 2.
A signal is input that causes switch b to be turned upward, and switches 6a and 6b are
falls upward, coil 3b is connected to GND, and coil 3
Both ends of a are connected to the recording current input terminal 7. As a result, the second head consisting of lb, 2b, and 3b shown in FIG. 1 does not operate, and the recording head 1a, 2a, and 3b shown in FIG.
Only the first head consisting of a is operated and performs a recording operation as a recording head having a head width of 5b.

When used in the D-2 system D-VTR shown in the conventional example,
The head width 5a is set to 45 μm, which is the same as the recording head width of the I)-2 type D-VTR, and the head width 5b is set to 39 μm, which is the same as the track pitch. Narrowing due to overlap can be prevented.

In the above embodiment, the video signal is digitized, signal processed, and recorded on tape using a recording code that can be overwritten. It goes without saying that the present invention can also be applied to tape recorders (DAT).

〔Effect of the invention〕

As described above, according to the present invention, in a D-VTR that records digital video signals on tape by overwriting without guard bands, only the last track during insert editing uses a recording head whose head width is variable. Since the magnetic recording device is configured to record at the cutout point, the track immediately after the cutout is not narrowed due to overlap, which prevents an increase in the error rate due to a decrease in the playback output, which has the effect of smoothly connecting images at the cutout point. be.

[Brief explanation of drawings]

FIG. 1 is a top and side view of a recording head constituting a magnetic recording device according to an embodiment of the present invention, FIG. 2 is a circuit diagram of the magnetic recording device, and FIG. 3 is a conventional magnetic recording head without a guard band. A tape format diagram of a D-VTR using the D-2 system that performs overwriting recording. FIG. 4 is a diagram showing the tape track pattern near the insert editing cutout in the above D-VTR. FIG. - It is a diagram showing the head arrangement of a VTR. In the figure, 1 is the front core, 2 is the back core, 3 is the coil, 4 is the head gap, 5 is the head width, 6 is the switch,
7 is a recording current input terminal, 8 is a head switching signal input terminal, 9 is a magnetic tape, 10 is a tape traveling direction, 11 is a head scanning direction, 120 is a track pattern, 13 is a recording head width, 14 is a track pitch, 15 is a Track 1 with insert recording
6 is a recorded track before insert recording, 17 is a track immediately after cutout, 18 is a rotating drum, 19 is a drum rotation direction, 20 is a recording head, and 21 is a reproduction head. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (2)

[Claims] (1) It has a signal processing circuit that digitizes the video signal, shuffles the video signal data, and adds an error correction code, ID code, sync pattern, etc., and modulates the video signal into a recording code that can be overwritten. , a magnetic recording device that uses N recording heads (N is a natural number) to record azimuthally on the tape while gradually overlapping without a guard band, the recording head whose head width can be varied for the last track during insert editing. A magnetic recording device characterized in that it records with a head width that does not overlap the recorded track immediately after cutout. (2) A recording head whose head width can be varied is formed by laminating a first head with a head width that matches the track pitch and a second head that has a head width that matches the overlap width, and 2. The magnetic recording apparatus according to claim 1, further comprising a switch for switching between a state in which only the head is operated and a state in which both the first and second heads are operated.