JPS621382A - Video tape recorder for high definition television signal - Google Patents

Abstract

PURPOSE:To allow a magnetic head to track just each track by running a magnetic tape in a half or a third of the tape speed for recording and reproducing the tape with a drum device having a shape corresponding to this speed. CONSTITUTION:The magnetic tape 5 of a reproducing part 6 is run in a 1/N of the tape speed for recording. While the tape is run in the lower speed in this manner, a drum diameter D and a still angle phiPB of the drum device are adjusted to allow the magnetic head to track just each recording track. A video signal PBTV reproduced in this manner is written in a picture memory 8 through a time base compensating device 7. The signal read out from the picture memory 8 is given to an electron beam scanning controller, and pictures are recorded on a film for movie by the output beam.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a video tape recorder for high-definition television signals, and is particularly suitable for application to a film printing device for printing high-definition television signals onto motion picture film. It is.

B. Summary of the Invention The present invention provides a video tape recorder for high-definition television signals that uses N magnetic heads to reproduce high-definition television signals from a magnetic tape in order to record the high-definition television signals on film. The tape is run at a speed that is 1/N of the tape speed during recording, and various parameters of the tape running system are selected so that each magnetic head can just track the video track while running at that tape speed, and the magnetic heads respond accordingly. By using the high-definition television signal played only when scanning the video track to be used as the signal for film recording,
A sufficient amount of time can be secured for the film recording operation, and high-quality television signals can be recorded on the film without including so-called noise bars.

C. Prior Art This type of film printing apparatus uses an electron beam. However, simply printing motion picture film with an electron beam results in a black and white image.

In order to obtain a color image, a high-definition television signal videotape recorder (HDVTR) is used as shown in Figure 3.
) 1, the primary color signals R, G, and B are sequentially read out and the luminance information RNsGW and BN of each of the primary color signals R, G, and B is once recorded on the intermediate film 2 using an electron beam. Each recorded luminance information RN
, GM , 1-envelope component rays LR, LG corresponding to BM,
LB is applied from behind the intermediate film 2 and these light rays LR
, LG, and LB are introduced to a predetermined frame KN of the movie film 3 and exposed.

In this way, in order to print a color image on the motion picture film 3, it is necessary to first print it on the intermediate film 2, which takes a lot of processing time. )
It is actually difficult to record the video signals (R, G, B) obtained by running the film on the motion picture film 3;
R1 is configured to run the magnetic tape at low speed and reproduce the video signal.

Problems to be Solved by the Invention Generally speaking, in a VTR, recording tracks are formed diagonally on the tape.
In the image reproduced by running the magnetic tape at low speed, a so-called noise bar appears in the horizontal scanning direction at a position corresponding to the guard band, and the image cannot be recorded on the motion picture film 3 as it is. Therefore, even when the magnetic tape is running at a low speed, the film printing system is designed to prevent noise bars from occurring by allowing the magnetic head to just track the recording track (the magnetic head accurately traces the recording track). It is especially necessary in

Therefore, it is conceivable to use a dynamic tracking head (DT head) as the magnetic head so that just tracking can be performed while running the magnetic tape at a low speed.

However, in the case of a high-definition television signal, the tape pattern of the magnetic tape 5 for the video signal consists of one field of component signals G1 and G2, as shown in FIG.
, R, and B using four video tracks, standard formats (NTSC format, SECA
V for reproducing television signals of M system, PAL system)
Compared to TR, the distance that the DT head has to jump is significantly longer (in fact, about twice as long). Moreover,
For high-definition television signals, the video track width is 1
Because a large number of tracks are used in the field, the track width is narrower than in a standard television signal (in practice, it is
Therefore, in the case of high-definition television signals, the DT head is required to have the ability to jump long distances and just track narrow tracks.

However, in practice, it is difficult to realize such a DT head, and in particular, the head chip is equipped with four heads stacked one on top of the other so that four tracks can be recorded in one scan. difficult to obtain.

Therefore, there is a need for a VTR that can perform just tracking with a fixed head without using a DT head. In order to solve this problem, the recording side VTR and the playback side VT
A system has been proposed that allows just tracking on the playback VTR even when the drum diameter differs between the R and R (Japanese Patent Application Laid-Open No. 101579/1983), but this is aimed at the normal playback mode and cannot be used as is. It cannot be applied to slow playback mode.

The present invention has been made in consideration of the above points, and provides a video tape recorder for high-quality television signals that allows a fixed head to just track without using a DT head when running a magnetic tape at low speed. This is what we are trying to provide.

E Means for Solving the Problem In order to solve this problem, the present invention uses N magnetic heads (N is 2 or more) to record high-definition television signals on a magnetic tape. In a high-definition television signal video tape recorder 1 that reproduces high-definition television signals, the magnetic tape is run at a tape speed that is 1/N of the tape speed at the time of recording, and when the magnetic tape is running, the video The drum radius and still angle φPm of the drum device are selected so as to just track the track, and the high-definition television signal picked up only when each magnetic head is scanning the video track corresponding to the magnetic head is imaged. The above-mentioned high-definition television signal is written into the memory, and the high-definition television signal to be recorded on film is read out from the image memory and output.

In order to ensure sufficient operating time to record high-definition television signals on the two-action film, the magnetic tape is run at a low speed to reproduce the high-definition television signals.

In this way, even when the magnetic tape is running at low speed, the magnetic head just tracks the video track.
The tape speed is selected to be 1/the number of heads, and the amount of tape feed per scan is made equal to the distance between tracks.The drum diameter and still angle are selected according to the speed, and the tape is scanned at the recording angle during running. I did it like that.

In this way, each magnetic head scans all the video tracks, and the number of times the video track corresponding to the magnetic head is scanned is reduced to 1/N. Therefore, an image memory is used to control writing and reading so that the reproduced high-definition television signal is output only when the magnetic head is scanning the corresponding video track.

As a result, sufficient time can be secured for the film recording operation, and high-definition television signals can be recorded on the film without including so-called noise bars.

G example Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

When the magnetic tape 5 has a tape pattern recorded by scanning one field of high-definition television signals (Gl, G2, RlB) with four magnetic heads as shown in FIG. 4, the tape is moved at a low speed. In order to run the magnetic tape 5 so that the magnetic head scans only all the tracks including the corresponding track and does not scan the guard band, the magnetic tape 5 must be moved at a speed that is 1/(the number of heads) compared to the tape speed during recording. In this case, it is necessary to run the vehicle at a speed of 1/4).

Choosing the tape speed in this manner causes each magnetic head to move the distance between adjacent tracks on the tape with each scan, and is capable of moving from track to guardband.

In addition, in order to prevent the head from deviating from the track even if the head scans progress, even if the tape speed Vll during playback becomes 1/4 of the tape speed Vttc during recording, as shown in Figure 1. As shown in , the recording angle θF during reproduction is the recording angle θ□ during recording. It needs to be equal to .

For example, the video track length is L1 and the video width is W.

When the field frequency is fv, the still angle φF when a drum device that scans the video track at the tape speed VPII in playback mode is applied can be expressed as W...-(1) as shown in the following equation. (For the sake of simplicity, it is assumed that a video track having a length is formed by rotating the head 360 degrees.)

In equation (1), L cos θ□ is the length of the video track in the longitudinal direction of the tape, and Vpl/f is the distance that the magnetic tape 5 actually travels during one revolution of the head.
Therefore, L coSθPI-Vl''II/fV represents the distance that the head moves in the longitudinal direction of the tape when the head makes one rotation with the magnetic tape 5 stationary. Also, when the magnetic tape 5 is stationary, Also, speed vP,
When the magnetic head rotates once, the magnetic head moves by the video width W in the tape width direction.

Therefore, in the still state, the magnetic head moves in the longitudinal direction of the tape by L cos θ□-VPI/fV,
Since the tape moves by W in the tape width direction, the angle that the trajectory TR makes with the tape longitudinal direction, that is, the still angle φ2. is (1)
It comes to be expressed in the formula.

Also, with the magnetic tape 5 stationary, the magnetic head 1
When it rotates, a trajectory TR is formed, so this trajectory TR
The length of is equal to the length of rotation of the head, that is, the length of the circumference of the drum device on which the head is attached. Therefore, if the drum diameter is D, the length of the trajectory TR can be expressed as πD.

By considering a right triangle formed by this locus TR and the still angle φF, the drum radius can be expressed by the following equation.

Thus, the tape speed V□ during recording. Even if the tape speed V□ during playback is selected to be one-th of the number of heads, a drum device with a drum radius that follows equation (2) is used, and a still magnetic tape 5 that follows equation (1) for the drum device is used. By winding the magnetic head at an angle φF, each magnetic head can be caused to scan over each track during reproduction.

In the video tape recorder 1 for high-definition television signals, which has the tape speed VPI selected in this way and is equipped with the playback unit 6 to which the above-described drum device is applied, the playback video of the component output from the playback unit 6 is used. Signal P
BTV has a time base correction device (TBC) as shown in Figure 2.
After the time axis fluctuations are corrected via the image data 7, the image is provided to the image memory 8.

The image memory 8 writes the playback video signal PBTV when the write command signal WT arrives from the write control circuit 9, and outputs a successive command signal RD in synchronization with the operation of the film printing mechanism such as the feeding mechanism of the intermediate film 2 (FIG. 3). When the video signal PBTV arrives, the replay video signal PBTV is sequentially read out for each component signal.

Here, since the reproducing unit 6 runs the tape at a speed V□ which is 1/1/the number of heads of the tape speed V IEe during recording, each magnetic head scans each track shown in FIG. The magnetic head scans the corresponding track once every several times the head scans. Therefore, the write control circuit 9 determines whether or not each magnetic head is scanning the corresponding track in accordance with the control signal CON from the reproduction section 6, and outputs the reproduced video signal PBTV reproduced by the magnetic head from the corresponding track. The write control signal WT is applied to the image memory 8 at a timing that causes only the image to be written into the image memory 8.

In the above configuration, the video tape recorder l for high-definition television signals runs the tape at a speed that is one-th of the number of recording heads, and has a playback unit 6 that has a drum device with parameters selected according to the speed. The reproduced video signal PBTV is obtained from T.
After time axis correction and extraction of necessary portions via the BC 7 and image memory 8, the image is provided to an electron beam scanning controller.

The electron beam thus obtained is scanned over the intermediate film 2 in the same way as before, and each component signal is once recorded as black and white information, and then a light beam having the color components of each component signal is applied from behind the intermediate film 2. An image corresponding to the video signal PBTV, which is synthesized, exposed and reproduced on the same frame of the movie film 3, is recorded.

According to the embodiments described above, since the tape speed is made slower than the normal speed, a sufficient amount of time can be obtained for the film printing process. In addition, even if the tape speed is slowed down, each parameter that determines the drum device is selected accordingly, so the magnetic head can be precisely tracked on the track with high precision, and the images recorded on motion picture film can be maintained. can eliminate noise bars from being included.

In the above-described embodiment, a high-definition television signal is separated into component signals, and four magnetic heads are simultaneously scanned to reproduce a recorded magnetic tape. However, the present invention The present invention is not limited to this, and can be widely applied as needed to devices that simultaneously scan a plurality of magnetic heads to reproduce a magnetic tape on which a high-quality television signal is recorded.

H Effects of the Invention As described above, according to the present invention, the magnetic tape can be run at a tape speed that is one-th of the number of heads compared to the tape speed at which high-definition television signals are recorded on the magnetic tape, and Since playback is performed using a drum device whose shape corresponds to the tape speed, it is possible to just track each track of the magnetic tape, and it is possible to obtain an image that does not include noise bars. It is possible to obtain a video tape recorder for high-definition television signals that can sufficiently lengthen the processing time of the burning operation compared to the conventional one.

[Brief explanation of drawings]

FIG. 1 is a route diagram for explaining how to determine the drum diameter and still angle in an embodiment of a high-definition television signal layer video cheap recorder according to the present invention, and FIG. 2 is a route diagram showing an embodiment of the present invention. FIG. 3 is a route map for explaining the processing procedure for printing a high-definition television signal onto a film, and FIG. 4 is a route map showing an example of a tape pattern of the high-definition television signal. l...Video tape recorder for high-definition television signals, 3...Film, 5...Magnetic tape, 6...Reproducing section, 8... ...Image memory, 9...Write control circuit, D...
Drum diameter, φ□・・・Still angle.

Claims (1)

[Claims] For high-definition television signals, in which the high-definition television signals are reproduced from a magnetic tape using N magnetic heads (N is 2 or more) in order to record the high-definition television signals on a film. In the video tape recorder, the magnetic tape is run at a tape speed that is 1/N of the tape speed at the time of recording, and the drum diameter of the drum device is adjusted such that the video track is just tracked while the magnetic tape is running. Select a still angle, write the high-definition television signal picked up only when each magnetic head is scanning the video track corresponding to the magnetic head into an image memory, and record from the image memory onto the film. A video tape recorder for high-definition television signals, characterized in that the high-definition television signal is read out and output.