| 摘要 |
PURPOSE:To improve the form of a halftone spot and reduce the occurrence of the moire, by presetting a prescribed counter with every scanning line of one time. CONSTITUTION:Counters 13 and 14 are driven by clocks 11 and 12, and counters 15 and 16 are driven by the division outputs of the counters 13 and 14. The upper and lower addresses of a memory 17 are designated by the outputs of the counters 15 and 16. In this case, the fact that the counters 13 and 14 are used after presetting them means that the preset value of a memory address during the start of a scan can be set with the accuracy of 1 bit in case a front-stage counter is an 8-notation type forexample. Then the output of the memory 17 to which an address is designated receives a D/A conversion 18 and compared with a picture signal 19 to be turned into a halftone spot picture signal 21. The count value is preset with every scanning line of one time for the counters 13 and 14 respectively. |
