JPS63136383A - Video tape recorder - Google Patents

Abstract

PURPOSE:To write a partial video such as a title on a remaining part while part of signals previously recorded is left by recording a new signal on one area of a field period split by a recording means. CONSTITUTION:With the mode of a video tape recorder at a field split insert mode, a drum servo system controls a head drum with respect to driving at the time of recording mode so that the inserted video signal is recorded on a D area on a track pattern. Then the capstan is controlled with respect to the driving at the time of reproducing mode where the control signal recorded on the recording tape 8 and the capstan servo system is reproduced and subjected to tracking. Then another video signal is inputted from an input terminal 7 to the video signal processing circuit 1 and the video signal is subjected to signal processing so as to be in match with the prescribed recording signal format, amplified properly by a recording amplifier 2 and recorded on the magnetic tape 8 via the recording signal switching circuit 3 and heads 5, 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an azimuth recording type helical scan video tape recorder.

(Prior Art) In a general video tape recorder, when trying to record another new video signal on an already recorded magnetic tape, conventionally, as shown in FIG. This was done by rewriting it. In the figure, area A is an insert track, and area B is a recorded track.

(Problem to be solved by the invention) However, when another new video signal is recorded in this way, there is a problem in that all previously recorded signals are erased during that mode. .

(Means for Solving the Problems) The video tape recorder of the present invention is a helical scan type video tape recorder using an azimuth recording method. The present invention includes a dividing means for dividing the field period into two, and a recording means for recording another new signal in one area of the field period divided by the dividing means.

(Function) The dividing means divides the field period on the track pattern into two without changing the track pattern of the signal already recorded on the magnetic tape, and the recording means divides the field period into two into one area of the divided field period. By recording a new signal, it is possible to leave a part of the previously recorded signal and write a partial video, such as a title, in the remaining part.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of a video tape recorder according to the present invention.

In the figure, 1 is a video signal processing circuit, 2 is a recording amplifier, 3 is a recording signal switching circuit, 4 is a recording timing signal generation circuit, 5 and 6 are heads, and 7 is an input terminal for a new video signal (video signal). , 8 is a magnetic tape.

Next, the operation of the video tape recorder having the above configuration will be explained with reference to the timing chart of FIG. Figure 2 (a
) is the insert mode signal S1%, (b) is the head switching pulse signal Sg, fc) is the switching pulse edge signal S3, (d) is the recording timing delay signal S4, and +e) is the recording timing. Signal SS,
FIG. 5(f) shows the recording current control signal S6 for the head 5, and the figure (phantom is the recording current control signal S for the head 6), respectively.

When the mode of the video tape recorder becomes the field division insert mode, the drum servo system will insert the video signal into the track pattern D9 shown in Figure 3.
In order to record in the i area, the head drum (not shown) is controlled to rotate in the recording mode (a mode in which it is synchronized with a certain phase difference with the vertical synchronization signal of the newly input video signal), and the capstan servo is The system is recording tape 8
A capstan (not shown) is controlled to rotate during a playback mode in which tracking is performed by playing back a control signal recorded in the drive. Here, the field division insert mode refers to dividing a field period on a track pattern of a recorded tape into two, and recording a new signal in one area of the divided field period. This allows the recording pattern of the inserted video signal to match the track pattern of the recorded video signal.

With each servo system set to the above mode, another video signal is input from the input terminal 7 to the video signal processing circuit 1, where the video signal is processed to conform to a predetermined recording signal format, and the recording amplifier 2 After being appropriately amplified, the signal is recorded on the magnetic tape 8 via the recording signal switching circuit 3 and the head 5.6. Here, the recording timing of the recording signal switching circuit 3 is controlled by a recording timing signal S shown in FIG. 2 (8). That is, this recording timing signal S,
period (part of 1 field), head 5 and head 6
The control signals S&, S? shown in (f) and (g) of the same figure are shown in FIG. By flowing recording currents at the respective timings, a new video signal can be recorded on the magnetic tape 8 in the state shown in FIG. In FIG. 3, the horizontally lined area is the insert portion, and the vertically lined area E is the recorded portion. Further, FIG. 4 shows the state on the monitor screen when the magnetic tape 8 on which two video signals are superimposed and recorded in this manner is reproduced. In the figure, the upper half of the screen is a reproduced image of an originally recorded video signal, and the lower half of the screen is a reproduced image (for example, a title, etc.) of another newly recorded video signal.

Note that the recording timing delay signal S shown in FIG. 2(d)
By changing the timing of step 4, it is possible to arbitrarily change the positional relationship between the inserted video signal and the originally recorded video signal on the monitor screen.

On the other hand, when two signals are recorded on the magnetic tape 8 as described above, the horizontal synchronization signal of the newly recorded video signal and the horizontal synchronization signal of the originally recorded video signal are misaligned at the joint. If this occurs, periodic fluctuations in horizontal synchronization occur, which may cause skew to appear on the monitor screen (see FIG. 8). This skew can be eliminated by constructing the video tape recorder as shown in FIG.

That is, in the same figure, a blanking video signal generation circuit 10 is connected between the input terminal 7 and the video signal processing circuit 1, and a blanking timing signal generation circuit 10 is connected to the blanking video signal generation circuit 10 from the recording timing signal generation circuit 11. It is configured to output a signal S. The rest of the configuration is the same as that shown in FIG. 1, so the same circuits are given the same reference numerals.

Next, the operation of the video tape recorder having the above configuration will be explained with reference to FIGS. 6 and 7. FIG. 6(a) shows the insert mode signal SI% (bl is the head switching pulse signal S, FIG. 6(d) is the recording timing delay signal S, and FIG. 6(d) is the switching pulse edge signal S'.
4. fQ) in the same figure is the recording current switching timing signal Sll.
, the same figure (fl indicates the blanking timing signal S), and FIG. 7(a) shows the video signal 5IO1 input to the terminal 7, and FIG. Blanking timing signal S.

A partially enlarged view of FIG. 10) shows the video signal S11 output from the blanking video signal generation circuit 10.

That is, when the mode of the video tape recorder becomes the field division insert mode, the blanking timing signal S shown in FIG. 6(f) is input from the recording timing signal generating circuit 11 to the blanking video signal generating circuit 10. , a blanked video signal 311 as shown in FIG. 7(C) is created. This blanked video signal Sl+ is input to the video signal processing circuit 1, where the video signal is processed to comply with a predetermined recording signal format, and after being appropriately amplified by the recording amplifier 2, the recording signal switching circuit 3 and heads 5 and 6 onto a magnetic tape 8. At this time, the switching timing of the recording signal switching circuit 3 is determined by the switching timing signal S8 shown in FIG.
controlled by As a result, a blanking signal is recorded at the joint portion of the divided and inserted video signals, so that skew at this joint portion can be eliminated. That is, in FIG. 9 showing the monitor screen, reference numeral 15 is the blanking recording area.

(Effects of the Invention) As explained above, according to the video tape recorder of the present invention, it is possible to leave a part of the signal already recorded on the magnetic tape and write another new signal to the remaining part. It is something that can be done.

[Brief explanation of the drawing]

Fig. 1 is a schematic block diagram of the video tape recorder of the present invention, Fig. 2 is a signal waveform diagram of each part, and Fig. 3 is a diagram of inserting another new signal into a magnetic tape already recorded by the video tape recorder of the present invention. 4 is a diagram schematically showing the state, FIG. 4 is a diagram showing a monitor screen, FIG. 5 is a schematic block diagram of the video tape recorder of the present invention with a circuit for removing skew on the monitor screen, and FIGS. Figure 7 is a signal waveform diagram of each part, Figure 8 is a diagram showing the image on the monitor screen when skew occurs at the joint between two video signals, and Figure 9 is a diagram showing the blanking signal recorded. FIG. 10 is a diagram schematically showing a state in which another signal is inserted into a magnetic tape already recorded by a conventional video tape recorder. 1... Video signal processing circuit 2... Recording amplifier 3...
- Recording signal switching circuit 4.11... Recording timing signal generation circuit 10...
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Claims (1)

[Claims] 1) In a helical scan video tape recorder using an azimuth recording method, dividing means divides a field period on a track pattern into two without changing the track pattern of a signal already recorded on a magnetic tape. and recording means for recording another new signal in one area of the field period divided by the dividing means.