| 摘要 |
PURPOSE:To execute the convertion of size, by detecting the ratio of black and white data of a video signal in a period of time which is set by one period of a clock signal, and by changing the length of a period of time showing a black data in the video signal in accordance with its detected state. CONSTITUTION:A photoelectric converting circuit 4 reads a character of forms PA and generates a video signal VS. When the leading edge of a black data of a character pattern is detected, the VS becomes a high level, and an output signal of an FF42 becomes a high level. As a result, the first counter 48 starts to count. This counting operation is executed in accordance with a clock signal CB, and is stopped by a pulse of a clock signal CA. On the other hand, an output signal of an FF41 becomes a high level by a pulse of the CA. In this case, the first deciding circuit 50 decides whether a period of time of a black data is above a prescribed level or not in accordance with an expansion coefficient TD for designating an output CD1 of the counter 48 and the pattern size, outputs a pulse to an output signal J1 in case of being above the prescribed level, and sets an FF47, by which a converted video signal is made. |
