JPS6019567B2 - How to print magnetic tape - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a recorded tape in which video signals of unit time are sequentially recorded on each magnetic track (a printing method for producing a duplicate tape from a master tape, and in particular, a printing method that enables high-speed printing). Usually, a master tape is manufactured in the following manner, for example: As shown in FIG. These rotating magnetic heads and 2 are arranged at intervals, and are driven by a motor at a frame frequency of 30 per second in the case of an NTSC video signal.
For example, it is rotated in the direction of arrow 5 at the rotation rate. The magnetic tape 4 is then obliquely wound around the rotating circumferential surface of the head and the guide drum 3 over an angular range of approximately 1800 degrees. Furthermore, the tape 4 is inserted between a capstan and a pinch roller (not shown), and is transported, for example, in the direction of the arrow 6 at a constant speed VT by the capstan motor. Although not shown, the rotating heads 1 and 2 are subjected to so-called rotational phase servo based on the vertical synchronization signal in the video signal, and these rotating heads 1 and 2 are used to rotate the magnetic tape as shown in FIG. 4, its widthwise length W
The video signal for one field at a time, for example, the odd field video signal ○, 02, . , T, 2... are sequentially formed and recorded, and even field video signals E,, E2...
. . is track T2,, L2, . . . by the head 2.
... are sequentially formed and recorded. In this case, a signal of 30 Hz, for example, is usually recorded as a control signal on the side edge of the tape 4, as indicated by TP in FIG. In order to print the tape 4 on which video signals have been recorded in this way as a master tape and to produce a slave tape having the same signal recording pattern, the number of rotating heads, their rotational speed, and tape speed must be equal. It is sufficient to prepare a playback machine and a recorder, play back a master tape with the playback machine, and record the playback signal on a slave tape with a mirror imager. In this case, unlike when making a master tape, for example, where the video signal from a television camera must be recorded as is, when making a duplicate tape, the same recording pattern as the original master tape is used. It is only necessary to form the data on the slave tape, and the time to scan one track does not need to be one field period, so the tape speed can be increased. Therefore, high-speed printing can be considered. The present invention aims to propose a new method for printing at a considerably high speed. That is, in this invention, the number of rotating heads is m times (
m is an integer), by using a rotating head device that increases the number of rotations by n (n does not have to be an integer).
This allows printing to be performed xn times faster. An example of the method of this invention will be described below with reference to the drawings. That is, in this example, as shown in FIG. 3, twice as many rotary heads as there are in the recording/playback machine M, ie, four rotary heads are used. And these four rotating heads 7A, 7B, 7C, 7D
The heads 7A, 7B, 7C, and 7D are rotated at a rotation speed twice that of the recorder/player M, that is, at a rate of 60 rotations per second, as indicated by the arrow 1 in the figure.
Rotate in the direction indicated by 0. Then, for such a rotary head device, the tape 9 is placed against the guide drum 8,
Wrap it over an angular range of approximately 180 degrees, and calculate the tape speed VT of the recorder/player M by (multiple of the number of heads) x (
If the magnetic tape 9 is run at a speed V'T that is a multiple of the number of rotations) = 2 x 2 = 4 times, each of the rotating heads 7A, 7B, 7C,
7D will draw a trajectory similar to the rotation trajectory of head 2 in FIG. In other words, if the tape speed is increased by 4, and the number of rotations of the rotary head is constant, the scanning pitch of each head in the longitudinal direction of the tape (track pitch P) will be four times as large, but if the number of rotations of the head is increased by 2. Since it is doubled, the scanning pitch is doubled. Therefore, as shown in FIG. 4, the rotating heads 7A and 7C move the tape so as to form tracks TA and Tc on which one field's worth of video signals are to be recorded, respectively, at a scanning pitch of 4P (track pitch). Scan above. On the other hand, since the rotating heads 7B and 7D are supposed to scan positions shifted by 1'2 pitches from the rotating heads 7A and 7C, the head 7B scans positions corresponding to one field shifted by P from the track T^. The head 7D scans to form a track TB on which the video signal is to be recorded, and the head 7D scans to form a track To on which the video signal for one field is to be recorded, which is shifted by P from the track Tc. In this case, the head 7B starts scanning the track TB when the head 7A has scanned half of the track T^, and the head 7C starts scanning the track Tc when the head 78 has scanned the track TB halfway, head 7c
The time relationship is such that the head 7D starts scanning the track TD when it has scanned half of the track Tc. Here, tracks T^, TB, Tc, and To formed by heads 7A, 7B, 7C, and 7D are
In order to be equal to the track formed by M and 2, the diameter of the guide drum must be different from that of the mirror image reproduction machine M. That is, in the green picture reproduction machine M, when the tape is running, the angle between the longitudinal direction of the tape and the scanning locus of the rotary head is 8, but when the tape is stationary, the angle is as shown in Figure 2. becomes. This is because when the tape runs, the tape moves only P while the head rotates half a rotation, so if the tape moving direction and the head scanning direction are as shown by the arrows in Figure 2, the end of the head scanning trajectory will be This is because only P differs between when the tape is running and when it is stationary. On the other hand, in the rotary head device used in the present invention, as described above, the tape moves by a large amount while the head makes half a rotation. Therefore, when the tape of each head 7A, 7B, 7C, and 7D is stationary, the angle formed between the scanning locus of the tape and the longitudinal direction of the tape is 8o', which is 8o that of the Zeniga player M. It is different from. Then, when the tape is stationary, the length of the scanning locus that the head scans over an area of length W in the width direction of the tape corresponds to the length of half the circumference of the guide drum. Therefore, if the diameter of the head guide drum 3 of the recorder/player M is D, the diameter D' of the guide drum 8 of the rotary head device used in the present invention can be determined as follows. That is, if the field frequency is Vf, the pitch P is p
= law ---・--(1} By the way, the pitch P' of the rotary head device according to the present invention is P'=Ataka;=...

[21
As mentioned above, Therefore, diameter 〇 scale 2 = sheep. C. Hada 20 (Ko. Sin 8.) 2 town = No. [Imo side 8. 10 laws) 20 Kuimo/Sina. )2 A3}. Also, if we know the angle 8 between the longitudinal direction of the tape and the track, we get (character) 22 Kutsuta 10 etc.> 20 W2. = Hanaba Tsuta 10th grade> 2 books I4'. Thus, in the rotating head device shown in FIG. 3, the diameter of the guide drum 8 is set as D', and the relative oblique winding angle between the tape and the guide drum 8 is set as 8o'=sin-1 turn. ^'TB'TC'TD. ... is truck T, . , L, , T, 2, T22, and so on. Therefore, when the master tape 4 is mounted on the rotary head device shown in FIG. 3 and put into playback mode, the rotary head 7A moves to the tracks T, . If the head 7B scans the track T2, the head 7B will move to the track T2.
, the head 7C sequentially scans the track T2, and the head 7D sequentially scans the track T22, and as shown in FIG. 5, sequential reproduction signals are always obtained from the two heads at the same time. It will be done. In this case, although not shown, a so-called tracking servo is controlled by a control signal (track TP), so that each head 7A, 7B, 7C, 7D is correctly operated on tracks T, . ,T2,,T,2,T of course, the crab is scanned. Then, if a recorder having the rotating head device shown in Fig. 3 is prepared, and the rotating head is rotated in synchronization with that of the playback device, and a slave tape is installed in this recorder, there will be no data on the slave tape. , track T^, TB, Tc
, To are formed to form a signal recording pattern that is exactly the same as that of the master tape. In this way, according to this example, compared to the recording/playback machine M, by increasing the number of heads (m = 2 times) and the number of rotations (n = 2 times), it is possible to print at a speed n x m = 4 times. . That is, compared to the speed of the recorder/player M, printing can be performed at a speed m×n times higher. In this case, when only the number of heads is increased, the limit is 4 times in terms of reliability, and when the number of rotations of the heads is increased, the limit is 5 times, but according to the method of this invention, 1 This has the remarkable effect of enabling high-speed printing that is faster than sound. Here, when the diameter 〇 of the drum of a rotary head device used as a printer is multiplied by the number of heads by m and the number of rotations is multiplied by n, the pitch P in the longitudinal direction of the tape between two heads separated by an angular interval of 180 degrees from each other is ′ is P′=m-imo-myoT
......■, so it is given as o = Gouuchi Tsutajumori) 20W2 Small]. As shown in Fig. 6, a machine for making slave tapes is equipped with a plurality of coaxial rotary head devices with the number of heads multiplied by m, and a slave tape is attached to each of them. , the common rotary shaft, and therefore each head of each rotary head device, is rotated in synchronization with the master tape player, so that the master tape playback signal is supplied to each of the rotary heads of each rotary head device. By doing so, a large amount of slave tapes can be produced at the same time. Note that the example in the figure is an example in which one field worth of video signal is recorded as one track, but it can also be applied to the case where one frame worth of video signal is recorded as one track. Furthermore, it goes without saying that the angular range in which the tape is wrapped around the guide drum is not limited to the 180-degree angular range, but can be selected as appropriate. By the way, as in the example shown in the figure, when obtaining a duplicate tape from a master tape on which one track is recorded with one field worth of video signals, the number of rotating heads as a rotating head device is larger than the number of rotating heads used for making a master tape. When using a fox-sized playback machine, if you choose to arrange each rotary head at an angular position that is divided into equal parts at a ratio that corresponds to the number of heads, you can monitor the playback signal from the playback machine. However, there is a drawback that normal playback images cannot be obtained. That is, for example, as in the example of FIG.
, 7B, 7C, and 7D are arranged at equally divided angular positions, as is clear from FIG. 5, the reproduced signal is always obtained simultaneously from the two rotary heads. . Therefore, when it is desired to monitor the reproduced signal, the reproduced signals of two heads separated by 180 degrees from each other, for example, heads 7A and 7C, are alternately switched every half rotation to extract the reproduced signals. can. However, as is clear from FIG. 5, the reproduced signals obtained from heads 7A and 7C are both odd field (or even field) video signals ○ and 02.
Therefore, when switching from the reproduction signal of head 7A to the reproduction signal of head 7C, or vice versa, the horizontal periodic signal section does not become IH (horizontal period) correctly, and as can be seen from the figure. The disadvantage is that the monitor image becomes distorted when the death occurs. Therefore, in such a case, when the angular positions are equally divided, the angular interval between the two heads that are separated by 180 degrees from each other should be reduced by an angular interval equal to an odd multiple of Q = back day than 180 degrees. Make it slightly different. For example, when the number of rotating heads is four, the heads 7A and 7C and the heads 78 and 7D are each set to be larger than 180 degrees by an amount corresponding to 180 degrees, as shown in FIG. In this way, even if the heads 7A and 7C always reproduce odd-field or even-field video signals, their angular positions differ by the same amount of time rather than 180 degrees. However, the horizontal synchronization signal section is always IH, and a normal monitor image can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of a rotary head device of a tin picture reproducing machine for producing a master tape, Fig. 2 is a diagram showing an example of a signal recording pattern of a master tape, and Fig. 3 is a diagram showing a rotating head device used in the method of this invention. FIG. 4 is a diagram showing an example of the signal recording pattern of the head device, FIG. 5 is a diagram showing the temporal relationship of the reproduced signals, and FIG. 6 is a diagram showing the rotation of the recorder used in the method of the present invention. A schematic diagram showing an example of a head device, and FIG. 7 is a diagram showing another example of a rotary head used in the method of this invention. 1, 2 and 7A, 7B, 7C, and 7D are rotating magnetic heads, respectively, and 3 and 8 are guide drums. Figure 1 Figure 3 Figure 2 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. Number of rotating heads M, number of rotations of this rotating head N,
When obtaining a duplicate slave tape from a master tape on which a video signal has been recorded at tape speed V_T, the master tape is transferred to the number of rotating heads M x m, the number of rotations of this rotating head N x n, and the tape speed V_T x. Play m×n,
This reproduction signal is recorded on a slave tape with the number of rotating heads M x m, the number of rotations of this rotating head N x n, and the tape speed V_T x m x n to obtain a plurality of slave tapes at a speed m x n times. A magnetic tape printing method that allows for