• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a multi video cassette recorder capable of reproducing video signals of video tapes recorded in NTSC and PAL systems, and more particularly, to a multi video cassette recorder capable of normally reading NTSC and PAL video signals of video tapes. Relates to a video head switching device. According to the present invention, a tab is formed in the NTSC video head width, and a tab is formed in a portion corresponding to the PAL video head width of the NTSC video head width to determine whether it is a NTSC-type playback signal. Alternatively, it is determined whether the PAL system is a playback signal, and if the PAL system is a PAL playback signal, the tap is formed to be grounded at a portion corresponding to the PAL video head width. If the type of the reproduction signal is an NTSC type reproduction signal, the PAL type signal and the NTSC type signal can be normally reproduced by switching the tap formed in the portion corresponding to the NTSC video head width to ground. Therefore, the present invention has the effect of preventing the skew phenomenon that occurs during the special playback of the signal recorded in the SP mode in the multi-video cassette recorder.
    公开号:KR19990056453A
    申请号:KR1019970076448
    申请日:1997-12-29
    公开日:1999-07-15
    发明作者:곽효명
    申请人:전주범；대우전자 주식회사；
    IPC主号:
    专利说明:

    Video head switching device for multi video cassette recorder
    The present invention relates to a multi video cassette recorder capable of reproducing video signals of video tapes recorded in NTSC and PAL systems, and more particularly, to a multi video cassette recorder capable of normally reading NTSC and PAL video signals of video tapes. Relates to a video head switching device.
    The video cassette recorder is a video device that has a recording function for recording a broadcast video signal input through a tuner or the like and a playback function for reproducing the video signal recorded on the video tape so that the user can watch it at any time.
    On the other hand, the television broadcasting system can be divided into NTSC, PAL and SECAM system, accordingly video cassette recorder is also divided into NTSC, PAL and SECAM system.
    Here, the NTSC (National Television System Committee) method is widely adopted mainly in Japan, the United States, Canada, and the like. The color signal, that is, the R, G, and B signals is converted into one luminance signal (Y) and two color differences (I). M), and then modulate a subcarrier with a frequency of 3.58 MHz in the video band with two color difference signals. The composite signal obtained by combining the modulated color difference signal and the luminance signal modulates and transmits a carrier having a higher frequency and has 525 scan lines.
    On the other hand, PAL (Phase Alteration Line) method is adopted by Europe and China such as UK, Germany, Italy, Switzerland, and two-phase right angle of color subcarrier by two color difference signals BY and RY different from NTSC method. The modulated signal is transmitted in addition to the luminance signal by inverting its polarity by 180 ° per scan line 1H. The receiving side reproduces the color difference signal by the sum and difference of the color difference signals. In the PAL method, the number of scanning lines is 625, whereas the number of scanning lines is 525, which is called the PAL-M method.
    SECAM (Sequential Couleur A Memory) method is east of France. In the method employed in the former Soviet Union, the color subcarriers are alternately frequency-modulated into two color difference signals for each scanning line 1H, and the modulated color difference signals are superimposed on the luminance signal and transmitted every 1H, and the receiving side transmits the signal every 1H. It is a color television system that reproduces colors on the same scan line by delaying.
    Among the above-described television broadcasting systems, since only NTC and PAL systems have differences in the processing of color difference signals and scanning lines, a multi-video cassette recorder capable of selecting and processing both methods has been developed and used.
    In other words, in NTSC and PAL, the difference between the frequency bands of the color subcarriers of the video signal (3.58 MHz for NTSC and 4.43 MHz for PAL) and the frequency of the synchronization signal (difference in the number of scan lines) are used in the multi-video cassette recorder. As a result, a difference occurs in the frequency of the synchronization signal. The multi-video cassette recorder is configured to handle both of these methods.
    As shown in Fig. 1, the multi-video cassette recorder is configured such that only one of the NTSC video head SP (R) or PAL video head PAL (R) can be mounted.
    That is, the video head attached to the drum is a PAL video head and the tape playback signal is an NTSC signal, or the drum video head is an NTSC video head, and the tape playback signal is a PAL signal. In case of special playback of signals recorded in SP mode, for example, when performing CUE / Review, STILL, SLOW mode, the SKEW phenomenon that the upper part of the playback screen is bent in the horizontal direction is not possible. There was a problem that occurred.
    SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to provide a video head of a video cassette recorder for accurately reproducing an NTSC signal and a PAL signal as an NTSC video head in a multi video cassette recorder. It is to provide a switching device.
    The present invention for achieving the above object is a head amplifier; An NTSC video head having one end connected to the head amplifier and having a size of an NTSC video head width, and having a tab formed at a portion corresponding to the PAL video head width; A switch for selectively grounding a tap formed in the PAL video head width or a tap formed in the NTSC video head width according to a switching signal; A head amplifier for amplifying and providing a signal reproduced by the NTSC video head; A synchronization detector for detecting and providing a vertical synchronization signal from a reproduction signal provided from the head amplifier; And a micom that determines the type of the reproduction signal scheme according to the vertical synchronization signal provided by the synchronization detector, and provides a switching signal accordingly to the switch.
    The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the invention described below with reference to the accompanying drawings by those skilled in the art.
    1 is a view showing the mounting position of the video head of the multi-video cassette recorder,
    2 is a block diagram showing the configuration of a video head switching device of a multi-video cassette recorder according to the present invention.
    <Description of the symbols for the main parts of the drawings>
    10: video head 20: head amplifier
    30: synchronization detection unit 40: micom
    50: switch
    Hereinafter, with reference to the accompanying drawings will be described in detail the operation of the preferred embodiment according to the present invention.
    Fig. 2 is a block diagram showing the configuration of the video head switching device of the multi-video cassette recorder according to the present invention. The video head 10 for NTSC, the head amplifier 20, the synchronization detector 30, the microcomputer 40, and the switch are shown. It consists of 50.
    In the present invention, an NTSC video head reproduces an NTSC signal and a PAL signal.
    At this time, the NTSC video head 10, as shown in the figure, when the NTSC video head width is 58 µm, the PAL video head width is set to 48 µm, and the 48 µm portion of the 58 µm head width. A tab is formed on the PAL to set the video head width for the PAL.
    Usually, since the radius of the drum is 32 mm, the drum radius is 201.0619 mm. Therefore, the distance moving to 1H is 0.32169 mm for the PAL video head, and 0.38297 mm for the NTSC video head.
    Therefore, since the drum 2H mounting position, that is, NTSC (2H) -PAL (2H) = 0.12257 mm, the PAL video head width is set to 48 µm of the NTSC video head width as described above.
    The head amplifier 20 is connected to the NTSC video head 10 and once a signal is reproduced by the NTSC video head 10 to amplify it and provide it to the synchronization detector 30.
    At this time, the synchronization detector 30 detects the vertical synchronization signal from the reproduction signal provided from the head amplifier 20 and provides it to the microcomputer 40, and the microcomputer 40 provides the vertical synchronization signal provided from the synchronization detector 30. The type of reproduction signal is determined from the.
    That is, when the power source frequency corresponding to the vertical synchronization signal detected by the synchronization detector 30 is 50 kHz, the microcomputer 40 determines that the playback signal is a PAL signal and selects a tap formed in the PAL video head width. The switch 50 is controlled to switch the switching signal, that is, the ground terminal to the terminal side (A).
    If the power source frequency according to the vertical synchronization signal detected by the synchronization detector 30 is 60 kHz, the microcomputer 40 determines that the signal is an NTSC signal and selects a switching signal for selecting a tap formed in the NTSC video head width. The switch 50 is controlled to switch the ground terminal to the (B) terminal side.
    As described above, the video head switching apparatus of the multi-video cassette recorder according to the present invention adjusts the size of the NTSC video head width to reproduce the NTSC type signal and the PAL type signal normally so that a skew phenomenon occurs. There is an effect that can be prevented.
    While the invention has been shown and described with respect to certain preferred embodiments, it will be apparent to those skilled in the art that various modifications, changes and omissions can be made without departing from the spirit and scope of the invention.
    权利要求:
    Claims (1)
    [1" claim-type="Currently amended] Head amplifier;
    An NTSC video head having one end connected to the head amplifier and having a size of an NTSC video head width, and having a tab formed at a portion corresponding to the PAL video head width;
    A switch for selectively grounding a tap formed in the PAL video head width or a tap formed in the NTSC video head width according to a switching signal;
    A head amplifier for amplifying and providing a signal reproduced by the NTSC video head;
    A synchronization detector for detecting and providing a vertical synchronization signal from a reproduction signal provided from the head amplifier;
    And a microcomputer for determining a type of a reproduction signal method according to a vertical synchronization signal provided by the synchronization detector and providing a switching signal according to the vertical synchronization signal.
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    同族专利:
    公开号 | 公开日
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1997-12-29|Application filed by 전주범, 대우전자 주식회사
    1997-12-29|Priority to KR1019970076448A
    1999-07-15|Publication of KR19990056453A
    优先权:
    申请号 | 申请日 | 专利标题
    KR1019970076448A|KR19990056453A|1997-12-29|1997-12-29|Video head switching device for multi video cassette recorder|
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