JPH02161679A - Video tape recorder - Google Patents

Abstract

PURPOSE:To prevent erroneous recording by arranging plural magnetic heads being in relation of same azimuth at a constant interval of angle of rotation and in relation of different azimuth at the half interval of the above on a rotary cylinder, and reproducing a track recorded by one of magnetic heads out of the magnetic heads of same azimuth by a following magnetic head at the time of performing recording. CONSTITUTION:The plural magnetic heads 6a and 6c being in relation of same azimuth at the interval of angle theta1 of rotation and in relation of different azimuth at the interval of angle theta1/2 of rotation are arranged on the rotary cylinder. And the track recorded by one of magnetic heads 6a and 6c of same azimuth is reproduced by following magnetic head 6c and 6a at the time of performing the recording. In such a way, it is not required to provide a new head dedicated for reproduction to perform simultaneous reproduction, and it is possible to prevent the erroneous recording occurring only by applying change and addition on a circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a video tape recorder (hereinafter abbreviated as VTR) that can prevent recording errors by simultaneously playing back data during recording.

BACKGROUND OF THE INVENTION FIG. 4 is a plan view showing the head arrangement of a conventional VTR that enables simultaneous playback.

In FIG. 4, 1 is a rotating cylinder, 2'&.

2b is a recording/reproducing head disposed on the rotating cylinder 1 at a distance of 180 degrees and has opposite azimuths to each other; 3a is a magnetic head 2;
3a and 3b are read-only heads having the same azimuth as the magnetic head 2b, and 4 is a magnetic tape wound around the rotary cylinder 1 over 180 degrees, and the arrow indicates the direction of rotation of the rotary cylinder 1.

The magnetic heads 3a and 3b are magnetoelectric heads 2a and 2b.
The magnetic head 2a is provided so as to follow the magnetic head 2a.

Transfer the 1-rack immediately after recording with 2b to the magnetic head 3.

3b to check whether recording is being performed normally or not, thereby preventing recording errors. This can be applied to a VTR with a two-head type large-diameter cylinder, as long as it is a VIIS type VTR.

On the other hand, the VH3-c type VTR, which is a VTR with an integrated camera, uses a small-diameter cylinder in order to downsize the device, and has four magneto-electric heads arranged at 90-degree intervals.
In addition, the magnetic tape is wound over 270 degrees or more.

FIG. 5 is a plan view showing the head arrangement in a VH3-C type VTR, in which recording and reproducing heads ea-6d are arranged at 90-degree intervals on each small-diameter cylinder 5'', and the magnetic tape 7 is placed on the small-diameter cylinder 5''. It is wound over 2 degrees of 6. The magnetic heads 6a and ec, and the magnetic heads eb and 6d, which are located about 180 degrees from each other, have the same azimuth relationship! /c leg, ea, sc and 6b, 6d have a reverse leg relationship.

FIG. 6 shows the 1-record formed by this small diameter cylinder 5.
It is a rack pattern diagram, and a to d are each magnetic head 6a to 6a.
This is a track recorded with 6d.

Here, L represents the track pitch and β represents the track width.

Since a video signal for one field is recorded on one track, the small diameter cylinder 5 rotates at 46 revolutions per second. Therefore, compared to the 30 rotations per second of a two-head type VTR, the rotation speed is set to be 1.5 times higher.

FIG. 7 is a block diagram showing an example of a recording/reproducing circuit,
FIG. 8 is a timing chart of head switching signals of the same circuit.

First, during recording, the recorded video signal S1 is passed through the recording circuit 8 to the recording system switching circuit (hereinafter referred to as SW) 91! L~9
d, and R of the recording/reproduction selector switches 10a to 10d.
Current is applied to the 'C magnetic heads 6a to 6d through the side to cause a recording current to flow.

Next f, during playback, selector switch IC) a to 10d R
From the side, the reproduction output of the magnetic heads 6a to 6d is output to the 5W of the reproduction system.
11a to 11d, and the respective switching outputs are passed to the reproducing circuit 12 to obtain a reproduced video signal S2. In addition,
Signal S3 records changeover switches 10a to 10d (R')
This is a recording/reproduction switching signal that must be switched with and playback (P).

Here, switching signals S a j to Sd1 having waveforms shown in FIG. 8 are inputted to 5W9a to 9d, respectively, to perform head switching during recording. This is the magnetic head 6a~
6d is necessary for sequentially recording and forming the desired tracks a%d shown in FIG. Turtle in the waveform diagram
d indicates the correspondence with each track a to d. For example, Sa
1 is for recording on track a, and Sb2 is for playing back on track b.

That is, since each head is configured to wrap around at an angle of 270 degrees and record video signals for one field, when one head, for example 6a, is in the recording state, it is energized, and the other heads 6b to 6d are energized. The current is cut off. and,
After recording by 61L is completed, power is applied to 6b, and the other heads are similarly cut off. Similarly, (3
C, 6d.

62L, . . . are sequentially energized and recorded. However, in reality, as shown by diagonal lines in the waveform diagram, the current is applied for a period of 2 degrees or more to enable overlap recording.

Waveforms Sa2 to Sd2 in FIG. 8 are switching signals for switching the head output during reproduction, and this is a signal that switches exactly every 270 degree period.

That is, the reproduction system switching signals 5IL2 to Sd2 are signals having almost the same timing as the recording system switching signals $a1 to Sd+.

Problems to be Solved by the Invention However, in the above-mentioned conventional configuration, in a VH3-C type VTR, if simultaneous playback is to be performed during recording to prevent recording errors, playback is performed on each of the recording and playback heads 6a to θd. A dedicated head must be provided, and a total of eight magnetic heads are required. Therefore, the number of heads increases, which increases costs, and the number of channels of the rotary lance that relays between the heads and the circuit also increases, which causes many problems such as increasing the size of the device and increasing costs. Ta.

The present invention solves the above-mentioned conventional problems.
It is an object of the present invention to provide a video tape recorder which enables simultaneous reproduction during recording without providing a reproduction-only head in a C-type VTR.

Means for Solving the Problems To achieve this object, the video tape recorder of the present invention has a plurality of magnetic heads disposed on a rotary cylinder L at the same azimuths of θ1 at intervals of θ1 and at different azimuths at intervals of i. During recording, the track recorded by one of the magnetic heads of the same azimuth is reproduced by the following magnetic head.

The present invention also provides a standard mode in which a plurality of magnetic heads having the same azimuth of θ1 at intervals of θ1 and different azimuths at intervals of i are arranged on the rotating cylinder, and and a long-time mode in which a plurality of magnetic heads are arranged at a predetermined interval with respect to the head position of the standard mode,
When recording in the one mode, reproduction is performed by a magnetic head of the same azimuth following the other mode.

Effect: With this configuration, the video tape recorder of the present invention has the following functions:
There is no need to provide a new dedicated head for simultaneous reproduction, and recording errors can be prevented by simply making circuit changes and additions.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a recording/reproducing circuit according to an embodiment of the present invention, and FIG. 2 is a timing chart of a head switching signal of the same circuit.

As shown in FIG. 1AK, during recording, the recorded video signal S1
is supplied to the SWs 13a to 13d via the recording circuit 8, and the magnetic heads 6a to 6d are energized to flow the recording stream 11. During playback, the playback output of the magnetic ☆C head 6δ, ~...-6d is sent to 5W11a~1 via SWl 31L~13d.
1d, and the respective switching outputs are passed through the reproducing circuit 12 to obtain a reproduced video signal S2.

The basic operation of recording and reproducing is completely the same as the conventional example, and the switching signals Sε71 to Sd1 and 5a7 shown in FIG.
-5a2 are 5W13a, ~13d and SWl respectively
1a to 11d. These switching signals are
Sa4 to Sd4 and 5a via the circuits shown in Figure 1 B and C.
5-Si2.

This is a configuration for realizing simultaneous playback in the present invention.

That is, in FIG. 1B, 5W14 & -14d are set to the fixed level "'L" and the switching signal 52 by the recording/reproducing switching signal S3.
Selectively switch and take out L1 to Sd1 and output Sa
4 to obtain Sd4. The fixed level "L" is output during reproduction, and the switching signals Sa1 to Sd1 are output during recording.

In addition, in Fig. 1C, 'tl'% SWl 5a ~ 1
f5d is switched to the switching signal Sa by the simultaneous reproduction switching signal S4.
2~Sd2 and Sa5he-3a3 are selectively switched and taken out to obtain Sa5~Si2.

The switching signals Sa2 to Sd2 are output during normal reproduction, and the switching signals Sa5 to Sd are output during simultaneous reproduction.

Here, the switching signals Sa3 to Sd3 are signals for realizing simultaneous reproduction in the present invention, and the waveform Sa5 in FIG.
This is a signal generated at the timing shown in ~Sd. These switching signals Sa3 to Sd5 do not reproduce tracks a to d, but tracks c and d.

This is a signal for switching to reproduce a and b respectively. However, the timing is based on the recording switching signal Sat~S.
d, the rotation angle of the small diameter cylinder is delayed by L7 by 180 degrees. This is because the magnetic heads 6a and 60 and 6b and 6d, which have the same azimuth relationship with each other, are configured to reproduce each other's tracks.

By doing the above, simultaneous reproduction can be made possible by selection using the simultaneous reproduction switching signal S4 at the time of recording.

It should be noted that the configuration of the recording/reproducing circuit shown in FIG. 1 is merely an example thereof, and it goes without saying that any structure can be used as long as the object of the present invention can be achieved.

FIG. 3 is a track pattern diagram for explaining the conditions necessary to realize the present invention.

In the figure, (3L, 60 indicates the scanning position of the magnetic head, and the magnetic head 6C has a rotation angle of 1 with respect to 6a.
It's 80 degrees behind. Therefore, the magnetic head 6C is used as opposed to the track head of the magnetic head 6a. Therefore, in order to enable simultaneous reproduction, it is necessary for the magnetic head 6C to be able to reproduce at least a part of track a of 6a, and the magnetic head 6C must be able to reproduce at least a part of track a of track pitch L, track width β, and rotation angle θ1. The conditions for this are determined between θ2 and θ2. Here, β1 is the rotation angle at which the magnetic head of the same azimuth is arranged, β2 is the angle of the effective winding of the magnetic tape υ, and in the example, θ, :=1SO degree,
θ2-270 degrees.

The conditions necessary to realize the present invention are as follows.

(1) Single recording mode (2) Two modes: standard mode and long-time mode (each with its own dedicated head), with track pitch Ll, L2, and track width β1°7!2 When the relative height of the magnetic head in long-time mode with respect to standard mode is y (21) When recording in standard mode and simultaneously reproducing with the head in standard mode (22) When recording in standard mode and for a long time In the case of simultaneous playback with heads in the mode β1 L 1 o , ” y < β1 , β1 < β2 (23
) When recording in long-time mode and playing back simultaneously with a head in standard mode (24) When recording in long-time mode and playing back simultaneously with a head in long-time mode As explained above, the present invention performs simultaneous playback. Since there is no need to provide a dedicated head for playback, and the head used for normal recording and playback can be used for simultaneous playback during recording, this can be achieved by simply making changes and additions to the circuit. .

In addition, the playback output obtained by simultaneous playback is the playback video signal S
2. In addition to displaying images, depending on the output level, for example, the I and ED light emitting elements may be turned on when the output level exceeds a certain level, or a warning sound may be emitted via a buzzer when the output level is below a certain level. Of course, you can comb it.

Effects of the Invention As described above, the present invention eliminates the need to provide a new head exclusively for reproduction when simultaneous reproduction is not possible, and thereby eliminates the need to add a rotary transformer to relay between the head and the circuit.
In addition, recording errors can be prevented with an extremely simple configuration that requires only circuit changes and additions, and its practical effects are significant.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a recording/reproducing circuit of a video tape recorder according to an embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the operation of the circuit shown in FIG. 1, and FIG. A track pattern diagram for explaining the recorder conditions, Figure 4 is a conventional 2-head type V
5 is a plan view showing the head arrangement of a VH3-C type VTR, and FIG. 6 is a plan view showing the head arrangement of a VH3-C type VTR.
FIG. 7 is a block diagram showing a conventional recording/reproducing circuit, and FIG. 8 is a waveform diagram for explaining the operation of the circuit shown in FIG. 7. 6a to 6d...recording/playback head, 7...
・Magnetic tape, 8 ・---Recording circuit, 11a-1
1d, 13&~13d, 141! L~14d and 1
6a to 15d...Switching circuit, 12...
regeneration circuit. Name of agent: Patent attorney Shigetaka Awano (1 person) Figure c13 Figure 1 - Daisho Shiritsutta? . , 2b - Commemorative playback head 3α, 3b - Head for playback 4 - Selection tape 2゜Tomi figure Figure 5 - J\ diameter cylinder Aa, tb, 6C, 6d - 1st grade student head 71 Magnetic tape

Claims (3)

[Claims] (1) A plurality of magnetic heads having the same azimuth at intervals of θ_1 and different azimuths at intervals of θ_1/2 are arranged on a rotating cylinder, and during recording, one of the magnetic heads with the same azimuth A video tape recorder characterized in that tracks recorded with a magnetic head are played back using a trailing magnetic head. (2) A standard mode in which a plurality of magnetic heads having the same azimuth at an interval of θ_1 and different azimuths at an interval of θ_1/2 are arranged on a rotating cylinder; a long-time mode in which a plurality of magnetic heads are arranged at predetermined intervals with respect to the head position of the standard mode, and when recording in the one mode, the recording mode follows the other mode. A video tape recorder characterized by playing back with a magnetic head of the same azimuth. (3) The video tape recorder according to claim 1 or 2, wherein θ_1 is 180 degrees.