| 摘要 |
<p>The reading unit has light sources and light-sensitive elements. The light sources (11) are placed on one side of the banknote (1) and transmit infra-red light within a wavelength interval which is less than ten per cent of the wavelength. The light-sensitive elements (12,13) are located so as to probe the light transmitted through the banknote. Components are provided to produce relative movement between light sources and sensitive elements on the one hand, and the banknote on the other. This permits reading at a number of points on the banknote. The positioning of the light sources and sensitive elements is in rows so that transmission and probing takes place over a rectangular area. Two memories are used -one storing digital values from the light sensitive elements, the other predetermined values, and a comparative circuit compares data from them. (Provisional Basic advised week J49)</p> |
