JPS62207092A - Method and device for video signal recording and reproducing - Google Patents

Abstract

PURPOSE:To extremely simplify in terms of the mechanism and circuitry by providing memories to store a video signal during a period longer than the vertical synchronization period of the video signal for two channels, making the time of one rotation of a rotary cylinder equal to the length of the vertical synchronization period, and recording/reproducing a brightness signal and a color signal that are time base compressed. CONSTITUTION:A brightness signal (c) undergoes a vertical synchronizing signal detecting circuit and reaches the first memory, and the time base compressed color signal (d) reaches the second memory. A vertical synchronizing signal enters a memory- read/write timing controlling signal to determine the read/write timing of the first and the second memories. The signal (e) outputted from the memories consists of signals c' and d' which are generated by compressing the time bases of the signals (c) and (d) by two times, and it enters an FM modulator. An output signal from the modulator is recorded on a magnetic tape by a magnetic head. The rotary cylinder turns one time during one vertical synchronization period of the signals (c) and (d), so that a recording track pattern is recorded as a tape pattern in which a brightness signal track and a color signal track are independent of each other.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a video signal recording and reproducing apparatus such as a video tape recorder for recording and reproducing video signals and audio signals, and a reproducing method thereof.

2. Description of the Related Art In the field of conventional commercial and broadcast video tape recorders (abbreviated as VTR), there is a method for recording and reproducing a color video signal by separating it into two channel component signals, a luminance signal and a color signal. being developed. For example, there is a VTR called M format or BCAM, a recording method described in Broadcasting Technology Magazine, IO issue, 1988, pages 872-890, and a recording method called M11 formant from the Television Society of Japan. Technical report VR70-2,7~
This is the recording method described on page 12. In these two-channel component type VTRs, the recording track recorded on the magnetic tape has a chrominance signal track adjacent to the luminance signal track. Two dedicated magnetic heads are used for reproduction, resulting in a complex head arrangement in which a total of four magnetic heads are placed on the rotating cylinder for recording and reproducing luminance signals and color signals. There is a problem that it has become .

An example of the conventional two-channel component type VTR mentioned above will be described below with reference to the drawings. Third
The figure is a block diagram of the main parts of a conventional two-channel component TR. In FIG. 3, a luminance signal as shown in FIG. 2A, for example, is input to the input terminal 18.

Further, to the input terminal 19, for example, a time-base compression multiplexed color signal as shown in FIG. 2B is input. Here, as an example of the conventional technique, a two-channel component signal is formed by a luminance signal and a time-base compression multiplexed color signal.

The luminance signal input from the input terminal 18 is sent to the FM modulator 20.
The magnetic heads 22 and 2 are frequency modulated (FM).
The reproduced luminance signal recorded on the magnetic tape at 4 and reproduced by the magnetic heads 22 and 24 during reproduction is demodulated by the FM demodulator 27 and output from the output terminal 29. On the other hand, the time-base compression multiplexed color signal inputted from the input terminal 19 reaches the FM modulator 21 where it is FMed and recorded on a magnetic tape by the magnetic heads 23 and 25. Also, during playback, the color signal is transmitted to the FM modulator 21 and recorded on the magnetic tape by the magnetic heads 23 and 25. The reproduced time-base compressed multiplex signal is demodulated by the FM demodulator 28 and outputted from the output terminal 30. In the conventional example, for example, FIG. 2(a) shows.

(The recording patterns of the luminance signal and the time-axis compressed color signal indicated by bl on the magnetic tape 29 are 401, 403, 405 and 402, 404 in FIG. 4, respectively.
, 406.

Problems to be Solved by the Invention In the conventional two-channel component VTR, a total of four magnetic heads are used for recording and reproducing the luminance signal and color signal, each of which is arranged on a rotating cylinder. ing.

Generally, the position of the magnetic head on the rotating cylinder determines the recording trunk pattern of the signal, so the positional accuracy of the magnetic head on the rotating cylinder is in the order of micrometers (μm). That is, the positions of the plurality of magnetic heads on the circumference of the rotating cylinder, the relative heights between the magnetic heads, etc. are determined by preference. Since a two-channel VTR has four magnetic heads for recording and reproducing video signals, namely a luminance signal and a color signal, there is a problem in that the installation and adjustment of these heads is extremely complicated. Additionally, since there are four magnetic heads, four channels of rotary transformers (RT) are required, and four regenerative amplifiers are also required, making the mechanical and circuit configurations around the VTR's electromagnetic conversion system extremely complex. There is a problem.

In view of the above-mentioned problems, the present invention provides a two-channel component VTR having two magnetic heads for recording and reproducing a luminance signal and a chrominance signal, which is extremely hour-like in both mechanical and circuit terms.

Means for Solving the Problems In order to solve the above problems, in the present invention, two channels of memory are prepared for storing video signals for a period longer than the vertical synchronization period of the video signals, and one rotation time of the rotating cylinder is is made equal to the length of the vertical synchronization period, and time-axis compressed luminance signals and color signals are recorded and reproduced.

Operation The present invention has the above-described configuration, and although it is a 2-channel VTR, the rotating cylinder, which requires precision because it has two magnetic heads for recording and reproducing video signals, is mechanically and circuit-wise. This also makes it possible to realize a VTR with an extremely simple configuration.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of main parts in one embodiment of the present invention. In FIG. 1, a luminance signal as shown in FIG. 2 (al) is input to input terminal 1, and a time-axis compressed color signal as shown in FIG. 2 (tb+) is input to input terminal 2. Figures 2c and d show the luminance signal a and the color signal at the time level of the vertical synchronization period, respectively.In Figure 1, the luminance signal c (at passes through the vertical synchronization signal detection circuit 3). The time-axis compressed color signal d (bl) reaches the second memory. The vertical synchronization signal detected by the vertical synchronization signal detection circuit enters the memory/read/write timing control circuit 11 and is transmitted to the first memory. The read/write timing of the first memory and the second memory is determined.Then, the signals output from the first memory and the second memory are as shown in Fig. d' becomes e and enters the FM modulator 6. The output signal of the FM modulator 6 is recorded on the magnetic tape by magnetic heads 7 and 8, and the rotating cylinder rotates once in one vertical sync period at C and d. Moreover, the recording track pattern is recorded so that the luminance signal trunk and the chrominance signal trunk become independent tape patterns as shown in FIG. 4. That is, the signal C' is recorded as 401, 403,
405..., the signal of d' is 402, 404,
406... is recorded. 1 rotating cylinder
C' rotates once during the vertical phase.

Since d' is a signal obtained by doubling the time axis of c and d,
It is easy to obtain a recording pattern as shown in FIG. However, the rotational phase of the rotary cylinder is controlled by a rotary cylinder rotational position control circuit 10 which is controlled by a signal obtained from a memory/read/write timing control circuit 11. In other words, it is a 2-channel component VTR that records and reproduces images using two magnetic heads and four magnetic heads.
The exact same magnetic tape track pattern can be obtained. Therefore, by changing the system configuration, compatibility with general two-channel component VTRs is also possible.

During reproduction, the signals reproduced by the magnetic heads 7 and 8 enter the FM demodulator 12, undergo FM demodulation, pass through the vertical synchronization signal detection circuit 13, and reach the third memory 14 and the fourth memory 15. The output signals from the third memory and the fourth memory are respectively shown in FIG. 2 c (al, d (bl
The read/write timing of the memory is controlled so that the signal of FIG.
Therefore, the reproduced signal shown in FIG. 2d [b] is output from the output terminal 17.

Note that in the above explanation, the luminance signal and the time axis compression multiplexed color signal were used as signals handled by the video signal recording device that records each of the video signals divided into two channels. A similar effect can be obtained even in the case of a signal in which two color difference signals are frequency multiplexed. That is, the present invention is applied to a recording device for video and audio signals that handles input signals that can be converted into two-channel signals. That is, the input signals to the recording circuit system may be a luminance signal and two types of color signals, or may be an R signal, a G signal, and a B signal. Furthermore, the present invention can be applied to a single channel signal such as a MAC signal in which a luminance signal and a line-sequential color signal are time-base compression multiplexed. The present invention can also be applied to signals obtained by adding FM-modulated audio signals or digitally modulated signals to the various signals described above, if the signals are ultimately divided into two channels.

Furthermore, in the embodiment, the time axis compression ratio of the signals output from the first memory and the second memory is twice, and the output time width is two vertical periods, but it is also possible to deflect these values. be.

Effects of the Invention In conventional two-channel component type VTRs, four magnetic heads are required to record and recompress video signals, and the electromagnetic conversion system has a complicated structure both mechanically and in terms of circuitry. be. However, the present invention has the great advantage that the four magnetic heads described above are simplified to two, and the configuration of the electromagnetic conversion system is greatly simplified. Also, the accuracy of mounting the magnetic head on the rotating cylinder is μ
However, since the number of magnetic heads has been halved, the installation also has the advantage that adjustment and maintenance operations are greatly simplified.

Additionally, by adding a system, it becomes possible to make it compatible with general business VTRs.

[Brief explanation of drawings]

FIG. 1 is a block diagram of main parts in an embodiment of the present invention, FIG. 2 is a signal waveform diagram of each part in FIGS. 1 and 3,
FIG. 3 is a diagram showing a main part of a conventional configuration, and FIG. 4 is a diagram showing recording track patterns on a magnetic tape in the conventional example and an embodiment of the present invention. 1.2...Input terminal, 9.26...Rotating cylinder rotation direction, 16.17...Output terminal, 34...1 track pinch, 35・・・・・・
...Track width, 36...Gart band, 37
...IH (1 horizontal opening period). Name of agent: Patent attorney Toshio Nakao Figure 3

Claims (3)

[Claims] (1) In a two-channel component helical scan type video signal recording and reproducing device that records and reproduces each of the video signals divided into two channels, two input
means for storing a channel video signal and a second channel video signal in a memory 1 and a memory 2, respectively; and converting the two-channel signals stored in the memories 1 and the memory 2 into a single-channel signal for each vertical synchronization period of the channel signals; A video signal recording and reproducing device characterized by comprising means for recording and reproducing with time axis compression. (2) The time-base compressed one-channel signal is arranged on a circumference that is almost symmetrical about the center of a rotating cylinder that rotates once every vertical synchronization period of the channel signal before time-base compression. The video signal recording and reproducing apparatus according to claim 1, wherein recording and reproducing are performed using two magnetic heads. (3) In a two-channel component helical scan video signal recording and reproducing device that records and reproduces each of the video signals divided into two channels, the two input first
A channel video signal and a second channel video signal are stored in memories 1 and 2, respectively, and the 2-channel signals stored in the memories 1 and 2 are converted into 1-channel signals on the time axis for each vertical synchronization period of the channel signals. A video signal recording and reproducing method characterized by compressing and recording and reproducing.