| 摘要 |
The video signal stretcher comprises a signal adjusting circuit for adjusting a ratio of a synchronizing signal range to a video signal range, which video signal composes a composite picture signal together with the synchronizing signal, to become a predetermined value, whereby the DC level of the synchronizing signal is brought to coincide with the DC level of the video signal for stretching the black level of the video signal down to the pedestal level, further a composite picture signal having a set-up black level is stretched at the signal adjusting circuit so that a range of black and white levels becomes "100" against the synchronizing signal range of "40", and a DC level of a blanking period is set to a pedestal level of the composite picture signal whilst the black level of the video signal is stretched to the pedestal level, thus providing a stretched video signal having a range of 0-100 IRE with which a picture with no raised black can be displayed on a picture screen.
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