| 摘要 |
<p>An image is formed on the target of a vidicon tube and is read by several electron beams sweeping it point by point. The signals are analysed and compensation provided for defocalisation of the reading beam. a logic circuit (3) controls a generator (4) to determine the times during which the target of an analysis tube (1) is swept by a focussed beam and a defocussed beam. The video signal from the tube is preamplified (5) and passed to two amplifiers (6,7) with inputs gated from the logic circuit so that the respective beam signals are amplified separately. The signals are mixed (9) after one (7) has been memorised (8) to provide a standardised delay for the particular TV system line sweep frequency.</p> |
