| 摘要 |
PURPOSE:To obtain a clear picture having reduced influence of noise even if the reading-out speed from an image pickup tube is reduced to narrow a frequency band by sampling a reading signal and A/D converting the sampled signal during the interruption time of reading beams from the image pickup tube. CONSTITUTION:When the video signal reading-out speed from the image pickup tube 14 is set up to 1/2 the usual speed, the time scanning an area corresponding to one picture element on the target surface of the image pickup tube is doubled and the size of a video signal from the image pickup tube is reduced by about a half. Therefore, the reading-out beam from the image pickup tube is interrupted by a half of one picture element period during the time of horizontal scanning and reading is executed only at the remaining half period. Consequently, the period reading out a video signal from an area corresponding to one picture element is the same as the usual speed and the video signal is almost the same as the video signal read out at a normal speed. |
