JPH0646798B2 - Video tape recorder - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an azimuth recording type helical scan type video tape recorder, and more particularly to dividing a field period on a track pattern of a recorded tape into two. The present invention relates to a video tape recorder capable of a field division insert mode in which a new video signal is recorded in one area of a divided field period.

(Prior Art) In a general video tape recorder, when trying to record another new video signal on a recorded magnetic tape, conventionally, as shown in FIG. 6, all tracks in the mode are rewritten. Was going by. In the figure, area A is an insert track and area B is a recorded track.

However, such a method is inconvenient because it is not possible to insert a title or the like in the recorded image.

Therefore, recently, various devices capable of inserting such a signal as a title into a recorded video signal have been proposed (for example, JP-A-60-206385 and JP-A-59-138174). No. With these devices, a signal such as a title can be inserted on the upper side or the lower side of the screen.

In this case, when the horizontal sync signal of the newly recorded signal and the horizontal sync signal of the originally recorded video signal are deviated at the joint portion, the horizontal sync fluctuation occurs. Therefore, as shown in FIG. 7, a skew may appear on the monitor screen due to this, but the conventional apparatus described above has not taken any measures against this skew.

Therefore, as a measure to take such a measure, Japanese Patent Laid-Open No.
The insert circuit described in Japanese Patent No. 1-80982 has been proposed.

This insert circuit describes a configuration for performing H alignment at the start of insertion as a means for preventing skew. That is, in FIG. 1 of the publication, H matching is performed by a combination of circuits such as monomulti MM4, MM5, trapezoidal wave generation circuit 26, sampling hold circuit 27, AND circuit 23, APC circuit 7, switches 28 and 33. It has become.

(Problems to be Solved by the Invention) As described above, in the conventional insert circuit, although the skew at the joint portion is prevented by the H-matching, a complicated circuit configuration is required for that and the cost is high. It was a thing.

The present invention was devised to solve the above problems, and an object thereof is to provide a video tape recorder which reliably prevents the occurrence of skew at the joint portion of insert recording with an extremely simple circuit configuration. .

(Means for Solving the Problems) In order to solve the above problems, the video tape recorder of the present invention is applied to a helical scan type video tape recorder of the azimuth recording system, and a track of a recorded tape is recorded based on an insert mode signal. In the field division insert mode in which the field period on the pattern is divided into two and a new video signal is recorded in one area of the divided field period, a new video signal input terminal and a new video signal input from this input terminal are input. Video signal processing circuit for performing signal processing of a video signal according to a predetermined recording format, a recording signal switching circuit for appropriately switching the output of the video signal processing circuit and outputting to each head, the input terminal and the video It is inserted between the signal processing circuit and the newly input video signal and already recorded on the recorded tape. A blanking video signal creating circuit for creating a blanking video signal to be inserted in a connection portion with the existing video signal, and the switching timing of the recording signal switching circuit based on the insert mode signal and the head switching pulse signal. A recording timing signal generating circuit for generating a recording timing signal and generating a blanking timing signal for controlling a blanking video signal generating period by the blanking video signal generating circuit.

(Function) A blanking video signal creating circuit for creating a blanking video signal to be inserted in a connecting portion between a newly input video signal and a video signal already recorded on a recorded tape is provided with an input terminal and a video signal. Insert between the processing circuit.

On the other hand, the recording timing signal generation circuit generates a recording timing signal for controlling the switching timing of the recording signal switching circuit based on the insert mode signal and the head switching pulse signal, and the blanking video signal generated by the blanking video signal generation circuit. Generates a blanking timing signal for controlling the creation period of.

The blanking video signal creation circuit creates a blanking video signal by the blanking timing signal generated by the recording timing signal generation circuit only for the period during which the signal is being output, and a new blanking video signal input from the input terminal is generated. Insert it in the video signal. As a result, a new video signal in which the blanking video signal is inserted at the joint between the recorded video signal and the blanked video signal is obtained at the output of the blanking video signal generation circuit.

This new video signal is applied to each head through the recording signal switching circuit that can be switched appropriately by the recording timing signal from the recording timing signal generating circuit, so that the playback screen is a newly recorded video and a new one. A blanking image intervenes at the joint between the recorded image and the reproduced image. That is, the occurrence of skew at the joint portion is prevented by using the blanking image.

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

FIG. 1 is a block diagram showing the electrical configuration of the main part of the video tape recorder of the present invention.

In the figure, reference numeral 7 is a new video signal (video signal).
The input terminal 7 is a blanking video signal for creating a blanking video signal to be inserted into a joint portion between a video signal newly input, a video signal already recorded on the magnetic tape 8 and a video signal already recorded on the magnetic tape 8. It is connected to the production circuit 10. Then, the blanking video signal generation circuit 10
Of the video signal processing circuit 1 that performs signal processing of a new video signal that is input so as to follow a predetermined recording format. The output of the video signal processing circuit 1 is the recording amplifier 2 and the recording signal. Each head 5, through the switching circuit 3,
Guided by 6.

Further, the output of the recording timing signal generating circuit 11 to which the insert mode signal S ₁ and the head switching pulse signal S ₂ are guided is guided to the recording signal switching circuit 3 and the blanking video signal generating circuit 10.

The recording timing signal generation circuit 11 generates a recording timing signal S ₅ for controlling the switching timing of the recording signal switching circuit 3 based on the insert mode signal S ₁ and the head switching pulse signal S _2, and also creates a blanking video signal. A blanking timing signal S ₉ for controlling the blanking video signal generation period by the circuit 10 is generated.

Next, the operation of the video tape recorder having the above configuration will be described in the second
This will be described with reference to the timing chart shown in the figure and the waveform chart shown in FIG. However, FIG. 2 (a) shows the insert mode signal S ₁ , and FIG. 2 (b) shows the head switching pulse S 1.
₂ , (c) is a switching pulse edge signal S ₃ , (d) is a recording timing delay signal S ₄ , (e) is a recording timing signal S ₅ , and (f) is a head 5. recording current control signal S _{6 of} FIG. (g) shows a recording current control signal S ₆ of the head _6, FIG. (h) is a blanking timing signal S _9, respectively. 3 (a) is a new video signal S ₁₀ input to the input terminal 7, FIG. 3 (b) is an enlarged version of the blanking timing signal S9 shown in FIG. 2 (h), FIG. 3C shows the video signal S ₁₁ output from the blanking video signal generation circuit 10.

When the mode of the video tape recorder becomes the field division insert mode, the drum servo system controls the head drum (not shown) so that the inserted video signal is recorded in the area D shown in FIG. 4 on the track pattern. The capstan servo system reproduces the control signal recorded on the recording tape 8 while controlling the rotation in the recording mode (a mode in which the vertical synchronization signal of the newly input video signal is synchronized with a certain phase difference). A capstan (not shown) is controlled for rotation in a reproduction mode for tracking. Here, the field division insert mode means that the field period on the track pattern of the recorded tape is divided into two, and a new signal is recorded in one area of the divided field period. This makes it possible to match the recording pattern of the video signal to be inserted.

Each servo system is set to the above mode, and another video signal is input from the input terminal 7 to the blanking video signal generation circuit 10.

At this time, from the recording timing signal generation circuit 11 to FIG.
A blanking timing signal S ₉ as shown in (h) is input to the blanking video signal creation circuit 10. Therefore, the blanking video signal creation circuit 10 creates a blanked video signal S ₁₁ as shown in FIG. 3 (c) based on the blanking timing signal S ₉ .
It is output to the video signal processing circuit 1 in the next stage.

The video signal processing circuit 1 processes the input video signal S ₁₁ so as to follow a predetermined recording signal format,
After being appropriately amplified by the recording amplifier 2, recording is performed on the magnetic tape 8 via the recording signal switching circuit 3 and the heads 5 and 6.

Here, the recording signal switching circuit 3 controls the recording timing by the recording timing signal S ₅ shown in FIG. 2 (e). That is, the period of the recording timing signal S ₅ (a portion of one field), figure in the head 5 and the head 6 (f), by passing a recording current respectively at the timing of the control signals S6, S7 shown in (g), A blanking video signal and a new video signal can be recorded on the magnetic tape 8 in the state shown in FIG. In FIG. 4, an area D with a horizontal line is an insert portion, an area E with a vertical line is a recorded portion, and an area F sandwiched between both areas D and E is a blanking recording portion.

Further, FIG. 5 shows a state on the monitor screen when the magnetic tape 8 on which two video signals are superposed and recorded in this manner is reproduced. In the figure, the upper half of the screen is a reproduced image of the video signal originally recorded, the lower half of the screen is a reproduced image of another newly recorded video signal S ₁₀ (for example, a title, etc.), and the central part of the screen is displayed. A reproduced image 15 of the blanking video signal in which the strip portion is inserted is formed. That is, the blanking video signal is recorded at the joint portion of the video signal S ₁₀ that has been divided and inserted, and the skew at the joint portion can be eliminated.

That is, in the video tape recorder of the present invention, the blanking video signal generating circuit 10 is inserted between the input terminal 7 and the video signal processing circuit 1, and the recording timing signal generating circuit 4 is inserted.
With the extremely simple circuit configuration in which the blanking video signal generating circuit 10 is controlled by the blanking timing signal ₉ generated in step 1, the skew at the joint portion can be eliminated.

(Effects of the Invention) The video tape recorder of the present invention inserts a blanking video signal creating circuit between the new video signal input terminal and the video signal processing circuit, and based on the insert mode signal and the head switching pulse signal. With a very simple circuit configuration such as controlling the blanking video signal creation circuit by the blanking timing signal generated in the recording timing signal generation circuit, it is possible to realize high-quality insert recording without skew at the joint part. is there.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a main part of a video tape recorder of the present invention, FIG. 2 is a timing chart, FIG. 3 is a waveform diagram of input / output signals of a blanking video signal generation circuit, and FIG. FIG. 5 is a diagram schematically showing a state in which another new video signal is inserted into a magnetic tape that has been recorded by the video tape recorder of the present invention. FIG. 5 shows a reproduction of a magnetic tape on which two video signals are superposed and recorded. FIG. 6 is a diagram showing a state on the monitor screen at this time, FIG. 6 is a diagram schematically showing a state in which another video signal is inserted into a magnetic tape already recorded by a conventional video tape recorder, and FIG.
It is a figure which shows the image on a monitor screen when a skew has generate | occur | produced in the joint part of one image signal. 1 ...... video signal processing circuit 2 ...... recording amplifier 3 ...... recording signal switching circuit 10 ...... blanking video signal generating circuit 11 ...... recording timing signal generator circuit S 1 _...... insert mode signal S 2 _...... head switching pulse Signal S ₅ …… Recording timing signal S ₉ …… Blanking timing signal

Claims (1)

[Claims] 1. A helical scan type video tape recorder of the azimuth recording system, in which a field period on a track pattern of a recorded tape is divided into two based on an insert mode signal, and a new field is added to one of the divided field periods. In the field split insert mode for recording a video signal, a new video signal input terminal, and a video signal processing circuit for processing the new video signal input from this input terminal so as to follow a predetermined recording format, A recording signal switching circuit for appropriately switching the output of the video signal processing circuit to output to each head, and a newly input video signal inserted between the input terminal and the video signal processing circuit and the recorded tape. Create a blanking video signal to be inserted at the joint with the video signal already recorded in And ranking the video signal generating circuit, together with the basis on the insert mode signal and the head switching pulse signal and generates a recording timing signal for controlling the switching timing of the recording signal switching circuit,
A video tape recorder, comprising: a recording timing signal generation circuit for generating a blanking timing signal for controlling a blanking video signal generation period by the blanking video signal generation circuit.