JPS60247826A - Video tape recorder for high-speed dubbing - Google Patents

Abstract

PURPOSE:To permit high-speed dubbing by maintaining the same relative speed between a head and tape and the tape pattern as those in the conventional method and increasing the tape speed according to the increase in the number of the heads. CONSTITUTION:The lead angle of a drum is made smaller than in the conventional practice when the tape speed is increased in the stage of realizing high-speed dubbing. The consequent change in the scanning length of the video head can be prevented simply by increasing the diameter of the drum to increase the video track length K in the tape feed direction so that the head scans across the video width W. The integer multiplication and the high-speed dubbing tape recorder at such magnification can be realized simply by attaching plural pairs of the heads equiv. to said integer multiplication to the rotary drum and constituting the heads in such a way that the same azimuth part of the video tracks is traced or recorded by each head at the number of the heads of integer times the one rotation of the drum. Each pair of the heads are installed at the height differently with respect to the horizontal reference plane of the rotary drum in this case.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement for high-speed dubbing in a video tape recorder, particularly a helical scan type video tape recorder.

[Conventional technology]

As is well known, dubbing of videotape requires the use of two videotape recorders, with one recorder playing back and the other recorder recording the playback signal. [Object of the Invention] An object of the present invention is to shorten the dubbing time by providing a video tape recorder capable of high-speed dubbing.

Another object of the present invention is to provide a video tape recorder which allows high speed dubbing with minimal structural changes and by using conventional electrical circuitry.

Still another object of the present invention is to provide a video tape recorder capable of dubbing at double speed, triple speed, or higher integral multiple speeds.

[Structure of the invention]

In order to achieve the above-mentioned objectives, this @IJ is installed on multiple pairs of rotating video head drums, and the relative speed between the head and the tape is adjusted according to the diameter of the drum, the lead angle, and the tape speed. Video track angle Y: determined to have a required value Kl, and by making the installation heights t of the video heads of each pair different from the drum horizontal reference plane on the rotating drum.

High-speed dubbing while maintaining the same relative speed and tape pattern between the head and tape as in the conventional method, and increasing the tape speed as the number of heads increases? This is a summary of what has been made possible.

The tape pattern of a helical scan power type video tape recorder is shown in FIG. In FIG. 3, l is the l field video track length and W is the video width.

FIG. 2 shows the relationship between the scanning force of the video head and the direction of the video track on the tape pattern. In Figure 4, a
is the center of the video track 11j1. on the tape pattern.
b is the center line of the video head scanning force when the tape is stopped when recording is performed by running the tape at a tape speed V.

Here θ. is the video track angle, and θl is the drum lead angle set so that the video head traces the video track a during standard running (tape speed V). nf is the field frequency, and D is the drum diameter.

A typical video tape recorder is provided with a drum having an outer diameter D and a lead angle θ1. In addition to achieving high-speed dubbing, as is clear from Figure 2, when the tape speed V is increased, the draft angle is made smaller than before, and in addition, the scanning length of the video head is not changed compared to that of JJK. The drum diameter may be increased so that the video track length K in the tape feeding direction is lengthened and the head scans over the video width W.

The actual values of these can be found from the following three formulas ◎ Pi=v/
7' knee w ding ten - y...(11n( π (/'g=si.-"inkstone...+31πD') To realize the speed dubbing video recorder of that magnification by multiplying the tape speed by an integer K is attached to 15 pairs of Hedon rotating drums, which are integral multiples of K.

Each head on the same azimuth area of the video track traces an integer multiple of the number per revolution of the drum.

Alternatively, it may be configured to record. However, the heads of each pair are set at different heights with respect to the horizontal reference plane of the rotating drum, as will be described later.

〔Example〕

FIG. 1 shows an embodiment in which the present invention is applied to a helical scan type video tape recorder.
is a rotating drum, 2 is a video head of the first channel a,
3 is a video head for the first channel b, 4 is a video head for the second channel a, and 5 is a video head for the second channel b.

It is. Arrow C in the figure represents the rotational direction of the drum 1, which is attached to the drum at intervals. Also, the drum diameter is as mentioned above (
Let the tape speed be Vv2V using the formula 11, +21.

FIG. 2 shows an example of a tape pattern recorded on a videotape used in the present invention. In the fourth case, e is the tape running force, f is the head scanning direction, and T is the track pitch.

The operation of reproducing the video tape having the tape pattern shown in FIG. 4 at double speed using the tape recorder shown in FIG. 1 will be described. From the above equation (3), when the tape is wound around the drum 1 in Fig. 1, which has a blind angle, at a tape speed of 2V,
The video head 2 scans the same azimuth track ■9♂, and when it reaches the W- position, the same azimuth head 3
The lower end O゛ of fkVC<. Note that the video head 3 is mounted at a position tK higher than the video head 2 by S with respect to the drum horizontal reference plane. This relative height S is.

Defined by. Here, J21: tape wrapping angle for video head scanning (180'), G': angle difference between a and b heads (
90''), V is 2VY: Give.

By attaching this 5H relative Hatake, video head 2
When the video head 3 reaches the position mentioned above, the video head 3 comes to the bottom of the track ■. Furthermore, video head 2 is at the top edge of W at position 1806, video head 3 is at position 906 of track ■ (then video head 4 is at the bottom edge of track ■). , and if the video head 5 is also installed in the same position as the video head 3, when the video comes to the 4th or 90th position* of the video head, the video head 5 will come to the lower end of the track 2 at the lower end of the track. As described above, each head can scan four trunks each time the drum 1 rotates once.Since the length of the tape traveled in one revolution is twice that of the conventional tape, the video head 2 can scan four trunks each time the drum 1 rotates once. Truck■
Start scanning from the bottom edge of . This allows double-speed playback.

The electric circuit for Niu l#j is given by the relative speed V of the video head and tape as v=l-n (151, and this value is usually IV
, since it is the same as ff R, al11ilb11ilIV
c. Two sets of the same technology as in the conventional technology are provided, and the Nyu-sou numbers obtained in the manner described above are sent separately to a recording audience video tape recorder. This recording side video tape recorder also has a playback side shown in Figure 1. With the same number of heads, each value is determined according to the above formula, and the recording circuit connected to each head is also the same as the conventional one, and two sets are separately provided on the a, Ill, and b sides to perform recording.

〔Effect of the invention〕

As described above, four video heads are installed on the rotating drum of the video recorder on the recording side and the playback side.
By doubling the drum diameter and determining the drum diameter as described above, it is possible to realize a video tape recorder dedicated to high-speed dubbing that can obtain dubbing Y Tx L in half the time compared to the conventional 2-head video recorder using two recorders. The same method as the method may be used.

Further, according to the method of the present invention, the number of heads is tripled and the number of chips is 7.
``High-speed video tape recorder for recording and playback that can be tripled and recording and reproducing in less than 100 hours'' and even faster taping'' (7) are also being developed. Voice No. 8 can be processed by directly applying the high-speed tabink force method already used in audio equipment.Furthermore, the method of the present invention can be applied to video chi recorders attached to recent audio head drums. Even though
It is possible to pass the number of heads.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a drum and a head according to an embodiment of the present invention. The second factor is a diagram showing an example of the head trace state of the 7° pattern of the video tape used in this embodiment, FIG. 3 is a diagram showing the tape pattern of helical scan VjR, and FIG. 4 is a diagram showing the video head scanning direction. FIG. 4 is a diagram showing the relationship between the video track direction and the tape pattern. ■...Rotating drum, 2~4...1st channel a~
Video head of second channel b. Figure 1

Claims (1)

[Claims] In a helical scan video tape recorder, a plurality of pairs of video heads are installed on a rotating drum, and the diameter and lead angle of the drum Y:, the relative speed between the head and the tape, and the video track are adjusted as the tape speed increases. Corner Y
: A video tape recorder for high-speed dubbing in which the height of each pair of video heads is set to be maintained at a predetermined value and the height of each pair of video heads relative to the drum horizontal reference plane on the rotating drum is set to be different.