| 摘要 |
PURPOSE:To change a wide band video signal into a narrow band video signal without giving any damage on the video information, by using an image receiving tube of multi beam type and, at the same time, by delaying the reading out speed from a memory more than the writing speed in the memory. CONSTITUTION:A multiple beam type image receiving tube which is arranged in such a way that N (>=2) pieces of electron beams make simultaneous scannings on different horizontal lines, is used as an image receiving tube 1. Then, a video signal S1 is written in a memory 6 after it is A/D converted by an A/D converter 4 and the data is read out at a frequency which is 1/N of the frequency at the time of writing. The read out data are D/A converted by D/A converters 7A and 7B which are corresponded to the N pieces horizontal lines and, at the same time, supplied to the image receiving tube 1. |
