| 摘要 |
PURPOSE:To reduce the disturbance of the start time of picture information output due to noise, by arranging a laser pulse generating plate, which has slits formed at prescribed intervals, and a photodetector in the nonpicture area to obtain a reference time signal. CONSTITUTION:A laser beam is moved in an equal speed V on slits formed at equal intervals on a laser pulse generating plate which is arranged in the nonpicture area. A reference time signal generating circuit 33 generates a reference time signal on a basis of a pulse train signal given from a photodetector 32. If a noise is inputted to the photodetector 32, every output pulse is delayed by a time delta. That is, the output of each gate 45 rises the time delta after the fall time of a monostable multivibrator 41. Thus, the center value, of the rise time of the output of each gate 45 namely, the median is obtained equivalently, and a reference time, that is the least probability of the influence of a normally distributed noise, is obtained. |
