JPH0253206A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To execute dubbing at high speed by respectively specifying the diameter of a rotary head drum, the read angle of the rotary head drum, and the tape speed of a magnetic tape at the time of recording and reproducing. CONSTITUTION:A diameter D of the rotary head drum can be expressed with an expression I, a read angle theta of the rotary head drum can be expressed with an expression II, and a tape speed V1 of the magnetic tape at the time of recording and reproducing can be expressed with an expression III, respectively. In the expressions I to III, fv represents a field frequency, W represents a video width recorded on the magnetic tape, theta0 represents a video track angle, Tp represents a video track pitch, phi [rad] represents a tape winding angle for the rotary head drum equivalent to the video width, and K (K is an integer, and K>=2) represents the number of the magnetic heads. Thus, dubbing can be executed at high speed in the 1/K time of source tape recording time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording and reproducing apparatus tK that records and reproduces central signals by winding a magnetic tape around a rotating head drum at a predetermined angle.

Conventional technology Camera-integrated VTRs, in which a video tape recorder (hereinafter referred to as a VTR) and a camera are integrated, have recently become more and more popular on the market, and there has been a growing need for home-made video software recorded with a camera. ing. - Projectionally, I would like to use two VTRs as a semi-relay, and one as the source Dave's playback VTR.
The other is used as a recording VTR and the necessary parts are dubbed.

Furthermore, in the commercial field, it has traditionally been necessary to copy a large amount of video software from a single master tape in order to supply it to the market in large numbers. Therefore, one method is to prepare a large number of commercially available low-cost VTRs and record on them in parallel.

Problems to be Solved by the Invention However, using a commercially available VTR is inexpensive, but if you try to copy a program recorded for 2 hours, for example, it will take 2 hours.
This method requires time, and when copying in large quantities, it takes a considerable amount of time and efficiency cannot be improved, and when a large number of VTRs are used, the entire system becomes expensive.

In view of the above-mentioned problems, the present invention provides a magnetic recording and reproducing apparatus that can perform dubbing at high speed in a recording time of 3A or less compared to the recording time of a source tape.

Means for Solving the Problems In the present invention, the field frequency is fv, the video width recorded on the magnetic tape is W, the video track angle is θ, and the video track pitch is T1. The tape winding angle on the rotating head drum corresponding to the video width is defined as φ [rad], and the device records or plays simultaneously with magnetic heads (K is an integer of 2 or more), and the diameter of the rotating head drum is φ [rad]. The lead angle θ of the rotating head drum is controlled by the tape speed V during recording and reproduction of the magnetic tape. When playing back on a master VTR and dubbing at high speed, both the master VTR and the dubbing VTR feed the tape at a speed twice the tape speed at which the source tape was recorded (K is an integer of 2 or more), and then increase the tape speed. The cylinder lead angle θ and cylinder radius are set so that even if the tape and head change, the relative speed of the tape and head and the angle of the video head scanning trajectory are the same as when recording the source tape, and the magnetic By simultaneously playing back one track on the master VTR using the head, and simultaneously recording on the dubbing VTR using the K (l! I can do things.

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

FIG. 1 is a diagram showing a traveling locus of a magnetic head 2 on a magnetic tape 1. As shown in FIG. In the figure, 3 indicates the running direction of the magnetic tape 1, and 4 indicates the scanning direction of the magnetic head 2. Note that FIG. 1 is a view from the magnetic surface. The trajectory indicates a video track, and the video trunk angle θ3=6° 5B'99'. Tape speed v, t is 33, 346 msd/e
Since one field of signals is recorded on one track at c, the tape advances by l while the magnetic head 2 scans one track. Therefore, the lead angle θ2 of the cylinder is θ2-6056'74". Locus a
is the head scanning trajectory when the tape is stopped. This is the lead length of the rotating head drum.

When the tape speed is tripled, while the magnetic head 2 scans one track, the magnetic tape 1 moves #,=3X6.
Go forward only. Therefore, the scanning trajectory by the magnetic head 2 is C
becomes. Even if the magnetic tape 1 is sent at three times the tape speed, in order for the magnetic head 2 to scan the video track b,
It is sufficient to construct the magnetic head 2 so that the magnetic head 2 scans the trajectory θ when the tape is stopped. In other words, the rotary head drum 6 may be provided with a lead that is inclined in the tape traveling direction by a portion corresponding to 43 from video track b (C=l,'). θ.

is the lead angle at 3x speed. Also, L2 is the length of the lead, which must be a length that can be scanned while the rotary head drum 6 rotates 34 times, so the diameter of the rotary head drum 6 is smaller than the diameter of the conventional rotary head drum. It has to be big.

Next, the diameter of the rotating head drum 6 and the lead angle θ1 of the rotating head drum 6. The formula for determining the tape speed vt1 of the magnetic tape 1 will be explained with reference to FIG.

First, the lead angle θ will be explained.

Let's say that the video of one field is W.

W/-θ, = d3'-)-(W/-〇,)...(1)
becomes.

Letting the video track pitch be T, and when three tracks are simultaneously reproduced by three magnetic heads as shown in Fig. 2, and the number of heads is expressed as K (in this case, = 3), then 131-(T , XK )/Yu θ.

・・・・・・・・・・・・).

Substituting equation (t2) into equation (1), Next, the diameter of the rotating head drum 6 is determined.

The video track length (lead length of the rotary head drum 5) L2 when the tape is stopped is L2''=(1,'+1)2+12-〇.

・・・・・・・・・(4) (2) Substituting Eq.

If the tape winding angle on the rotary head drum 5 corresponding to the video 4w is φ [rad], then Ll is L2==D,X
φ/2 ・・・・・・・・・・・・(6)

Substituting equation (6) into equation β), the diameter D3 of the rotating head drum 5 is the tape speed vt, and the field frequency is f.An example in which the lead angle θ5, etc. are set as described above is shown in Fig. 2. This will be explained with reference to FIG.

Magnetic tape 1 is rotated at 270°=3//
2 [rad] It is wound. The magnetic head 2 is made of Ga
, Gb, Gc, and Gd are arranged at equal intervals of 90° on the same plane. The rotating head drum 5 is rotating at 270 Or, p, m in the direction of the arrow 4,
Each head forms one field as one track during 2700 revolutions.

Further, the magnetic tape 1 is running in the direction of the arrow 3 at a tape speed of vt. FIG. 6 shows an operation timing chart of each head. FIG. 4: is a corresponding tape pattern diagram.

In this way, any three of the four magnetic heads perform recording or reproduction simultaneously. Since the tape speed vt1 is three times the normal speed, these four magnetic heads scan independent tracks in the ridge shown in FIG.

Next, a second embodiment will be explained with reference to FIGS. 6 and 7. Similarly, the magnetic head 2 is mounted on the rotating head drum 6.
b, Ha, H (1 and 4) are arranged equally divided into 90' and rotated at 1800 r, p, m. The magnetic tape 1 is wound around the rotating head drum by π [rad]. Magnetic tape 1 is also a normal tape 7
``Twice the speed. θ is the track angle,
θ4 is the lead angle. When viewed as a magnetic tape pattern, it becomes as shown in FIG. 7, and each head scans an independent track. A head operation timing chart is omitted, but as in the first embodiment, two heads are always in operation, enabling simultaneous two-channel recording and reproduction.

For the above two embodiments, the specifications are calculated as shown in the table below.

Note that the field frequency fv = 59.94 (Hz), and the video track pitch Tp = 57.857 (μm).

Bidet No. 4 W = 10, 0771171, video track angle θ. =6658'9.9'.

Conventional 1 is a type used in general stationary VTRs, and Conventional 2 is a small-diameter drum type used in summer for camera-integrated VTRs.

The recording/reproducing apparatus of Embodiment 1 or Embodiment 2 constructed in this manner is arranged as shown in FIG. One of the VTRs is designated as a master VTR 10 and plays back a master tape cassette 2° recorded in a predetermined format. Similarly, dubbing VTRs 11 and 12 having dubbing tape 21,
13... are prepared, and recording is performed in phase with the reproduction of the master VTR 10.

Effects of the Invention As described above, according to the present invention, dubbing can be done at high speed in % or % of the actual time even when using a source tape that has been recorded for 2 hours, which conventionally required only 2 hours of real time. You can dub.

Furthermore, by increasing the number of simultaneous channels K, dubbing can be performed in a short recording time of less than 2%.

[Brief explanation of the drawing]

FIG. 1 is a traveling locus of the magnetic head of a magnetic recording/reproducing device according to an embodiment of the present invention, FIG. 2 is a plan view of the rotary head drum of the first embodiment, and FIGS. 3 and 4 are patterns of the magnetic tape. 6 is a timing chart of the head switching, FIG. 6 is a plan view of the rotary head drum of the second embodiment, and FIG. 7 is a diagram of the magnetic tape pattern, VRA
The figure is a block diagram showing the configuration of the dubbing system, and FIG. 9 is a tape 7 format diagram for explaining the operation. 1... Magnetic tape, 2... Magnetic head, 6.6... Rotating head drum. Name of agent: Patent attorney Shigetaka Awano, 11 people

Claims (1)

[Claims] The field frequency is f_v, the video width recorded on the magnetic tape is W, the video track angle is θ_o, the video track pitch is T_p, and the tape winding angle on the rotating head drum corresponding to the video width W is φ_ [_r_a_d_
], the magnetic recording/reproducing device simultaneously records or reproduces information using K magnetic heads (K is an integer of 2 or more), and the diameter D of the rotating head drum is expressed as D=(2√((T_p
×K+Wcosθ_o/cosθ^2)^2+W^2)
/φ The lead angle θ of the rotary head drum is θ=tan^-^1 ((Wsinθ_o/T_p×K+
W cos θ_o)) A magnetic recording and reproducing apparatus characterized in that a tape speed V_t during recording and reproducing of the magnetic tape is set to V_t=(T_p×K×f_v/sin θ_o).