PURPOSE: To avoid a faulty operation of a cylinder motor, by detecting the missing of a horizontal synchronizing signal, and then using this detected output to gate the sampling pulse.
CONSTITUTION: When a decoded synchronizing signal (a) has a missing, the "L" level period is increased for an output signal (b) of a monostable-multivibrator 1. A monostable-multivibrator 9 is triggered at the fall edge of the signal (b), and the fall edge of a produced signal (g) is set so that the signal (b) may kept at an "H" level in the normal state. However, the output Q of a D-FF7 is inverted to an "L" level since the signal (b) attains an "L" level. As a result, an AND gate 8 closes to produce no sampling signal (j). As a result, the previous sampling voltage is held even through the signal (a) is missed due to the noise.
KOBORI YASUNORI
FUKUSHIMA ISAO
GOTOU KATSUHIKO
