| 摘要 |
PURPOSE:To constitute a stable automatic gain loop without sampling and holding circuits, by flickering a light source in a prescribed cycle when a printed matter passes through a detection position and lighting the light source continuously when the printed matter does not pass through the detection position. CONSTITUTION:The output of a banknote tracking circuit 5 is supplied to a lamp driving circuit 8 to light continuously an exciting light source 7 when a passage signal is not outputted from the circuit 5 and to flicker the exciting light source 7 in a prescribed cycle when the passage signal is outputted from the circuit 5. When a banknote P does not pass through a detection position 2, the light source 7 is lit continuously, and the output of a standard light emitting plate 6 is always inputted to an amplifier 10 through a comparator 12 and a holding circuit 14 to control the gain. When the banknote P passes through the detection position 2, the circuit 8 and the holding circuit 14 are controlled by the passage signal, and the circuit 8 flickers the light source 7 only during the passage period, and the holding circuit 14 holds the value before passage. |
