JPH0191301A - Magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To enable the recording and reproduction of a video signal in a wide band by making a rotary cylinder diameter the same as that of the rotary cylinder of a two-head helical scanning system, and arranging four magnetic heads in the intervals of 90 deg., and making the relative speed of the magnetic head and a magnetic tape into 2/3 times. CONSTITUTION:The four magnetic heads 5-8 are attached to the rotary cylinder 4 of the same diameter as the two-head helical scanning system in the intervals of 90 deg.. The magnetic tape 2 is wound around the outer circumference of the cylinder 4 by tape guides 1,3 in an oblique direction and at the angle of the sum of 270 deg. and an overlap angle. Then, the relative speed of the head to the tape is made to be 2/3 of that of the two-head helical scanning system. Thus, the carrier of FM recording can be shifted to a higher part, and horizontal resolution can be increased, and the recording and the reproduction can be made into the wide band.

Description

[Detailed Description of the Invention] (Technical Field) The present invention is applicable to VTR (video tape recorder) and DAT.
The present invention relates to magnetic recording/reproducing devices (including those only for recording or only for reproducing) such as (digital audio tape recorders).

(Prior Art) FIG. 3 is a schematic diagram showing the rotary cylinder and magnetic head of a household VTR currently in widespread use, such as a 172-inch VTR or an 8-mm VTR.

4 is a rotating cylinder, and each rotating cylinder 4 has 1
Two magnetic heads 9°10 are provided at positions 80 degrees apart, and an 8-rotation cylinder 4 rotates together with the rotary cylinder 4.
A magnetic tape 2 guided by guides 1 and 3 is wound obliquely over an angle of 180 degrees and α around the outer periphery of the magnetic tape. α is the overlap angle.

The rotating cylinder 4 functions as a tape guide and a scanner, and rotates at approximately 30 Hz.

In this way, video signals for one field are recorded on the magnetic tape 2 in diagonal tracks track by track.

On the other hand, the video signal recording/reproducing characteristics of an 8 mm VTR has a horizontal resolution of about 240 to 250 lines. On the other hand, since the horizontal resolution of video signals transmitted from TV broadcasting stations is 320 lines, conventional 8mm VTRs do not faithfully record and reproduce TV signals.

Furthermore, improvements in CCD imagers and other technologies have led to the emergence of video cameras with horizontal resolutions of over 350 lines.
With the performance of current VTRs, it is not possible to take full advantage of the capabilities of such high-performance cameras.

Therefore, in order to perform wider band recording and playback using the conventional 8mm VTR mechanism, it may be possible to shift the FM recording carrier to a higher frequency, but this method has limitations in electromagnetic conversion characteristics. , will not be sufficient.

Another method is to record a wideband video signal by, for example, doubling the rotational speed of the magnetic head to increase the relative speed between the magnetic tape and the magnetic head. However, in this case, the magnetic heads are switched at the center of the screen, which causes problems such as skew distortion and differences in image quality due to differences in characteristics of the magnetic heads.

On the other hand, in the VHS type home VTR system, a VH3-C type device has been put into practical use, in which four magnetic heads are mounted on a rotary cylinder to reduce the size and weight of the rotary cylinder. However, in that method, the conventional 2
In order to maintain compatibility with head type equipment, the rotating cylinder diameter has been changed to 2 times the diameter of the conventional two-head type rotating cylinder.
While the rotation speed is set to 73 times, the rotation speed is set to 372 times.

As a result, in the VH3-C system, the video recording/playback characteristics are the same as those of the conventional 1/2 inch type, and wideband recording/playback is not performed.

(Objective) An object of the present invention is to provide a magnetic recording/reproducing device that can record and reproduce broadband video signals using a rotating cylinder having the same diameter as a conventional VTR.

(Structure) The present invention makes it possible to record and reproduce video signals over a wide range by focusing on the fact that by using four heads, the relative speed between the magnetic head and the magnetic tape can be increased by 372 times with the same rotating cylinder diameter. .

That is, in the present invention, the diameter of the rotating cylinder is the same as that of a conventional rotating two-head helical scan type magnetic recording/reproducing device, four magnetic heads are arranged at 90 degree intervals, and the magnetic tape winding angle is 270 degrees. and the overlap angle, and the relative speed between the magnetic head and the magnetic tape was set to 3/2 times that of the conventional two-head helical scan system.

Examples will be specifically described below.

FIG. 1 represents one embodiment.

The rotary cylinder 4 has the same diameter as the rotary cylinder of the conventional two-head helical scan type (see Figure 3).Four magnetic heads 5 to 8 are attached to the zero-rotation cylinder 4 at 90 degree intervals. It is being The magnetic head 5 is called channel A, the magnetic head 6 is called channel B, the magnetic head 7 is called channel A', and the magnetic head 8 is called channel B'.

The magnetic tape 2 is wound diagonally around the outer periphery of the rotary cylinder 4 by the tape guides 1 and 3 over an angle of 270 degrees and 10 α (α is the overlap angle). The arrow indicates the moving direction of the magnetic tape 2, and the magnetic heads 5 to 8 also rotate in the same direction. Since the magnetic heads 5 to 8 adopt the azimuth recording method, the magnetic heads 5 and 7 are arranged at 180 degrees apart from each other and have the same azimuth angle, and the magnetic heads 6 and 8 are arranged at 180 degrees apart from each other. They have the same azimuth angle.

Next, the operation of this embodiment will be explained with reference to FIG.

Track 1 is recorded on the magnetic tape 2 by the magnetic heads 5 to 8.
3-1.13-2. Recording is performed as shown by <, 11 indicates the magnetic tape feeding direction, and 12 indicates the moving direction of the magnetic head.

From the state shown in FIG. 1, track 13-1 of channel A is recorded by magnetic head 5, the magnetic head for primary recording is switched to magnetic head 8, track 13-2 of channel B' is recorded, and then track 13-2 of channel B' is recorded. The magnetic head for recording is switched to magnetic head 7, and track 13-3 of channel A' is recorded, and then the magnetic head for recording is switched to magnetic head 6, and track 1 of channel B is recorded.
3-4 is recorded. Thereafter, this recording pattern is repeated, and the principle of this recording is the same as that of the VH5-C system.

Generally, the relative speed between the magnetic head and the magnetic tape is V r
, the recording wavelength is λ, and the recording signal frequency is f, the relationship λ=V r /f holds true. Therefore, in the present invention, Vr is 3/
When doubling, λ also becomes 3/2 times, so the conventional 8mm V
It is possible to achieve a recording/reproducing capacity 3/2 times that of TR. Therefore, it becomes possible to shift the carrier of FM recording to a higher side by the increase in recording/reproducing ability, and the horizontal resolution also increases, 240 x 3/2 = 36
This makes it possible to achieve a wide band of 0 lines.

(Effects) In the present invention, the diameter of the rotating cylinder is the same as that of the conventional rotating two-head helical scan type magnetic recording/reproducing device, four magnetic heads are arranged at 90 degree intervals, and the magnetic tape winding angle is (270+α) degrees and
Since the relative speed between the magnetic head and the magnetic tape is 3/2 times that of the conventional rotary two-head helical scan system, it is possible to record and reproduce broadband video signals. As a result, even when dubbing signals recorded with a video camera for editing purposes, there is no deterioration in image quality, unlike with conventional 1/2 inch VTRs or 8 mm VTRs.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of a rotating cylinder section showing one embodiment;
FIG. 2 is a diagram showing a recording pattern according to the same embodiment, and FIG. 3 is a schematic plan view of a rotary cylinder section in a conventional VTR. 1.3... Tape guide, 2... Magnetic tape, 4... Rotating cylinder. 5-8...Magnetic head.

Claims (1)

[Claims] (1) Four magnetic heads are arranged at 90 degree intervals on a rotary cylinder with the same diameter as the rotary cylinder of a helical scan type magnetic recording/reproducing device, and the overlap angle of the magnetic tape is set to 270 degrees. In addition, the relative speed of the magnetic head and the magnetic tape is set to the above-mentioned rotation 2.
A magnetic recording and reproducing device that is 3/2 times as powerful as the head helical scan method.