| 摘要 |
<p>There is disclosed a vibration frequency setting mechanism of an engraving device provided with air pen. The vibration frequency setting mechanism comprises an engraving device provided with an air pen (11) vibration frequency of which is varied in response to compressed air to be supplied to the holder (12), a vibration frequency detector (12) for detecting the vibration frequency of the air pen (11) and providing a pulse signal (21) corresponding to the vibration frequency, a counter (4) for counting the pulse signal (21), a pressure regulator (1) provided with a regulating terminal (2), a vibration frequency setting circuit (5) for setting the vibration frequency (22) of the air pen(11), a comparator (6) for receiving the output of the counter (4) and the vibration frequency (22) and providing a logical "1" if the output of the counter (4) is greater than the vibration frequency (22) and a logical "0" if the output of the counter (4) is less than the vibration frequency (22), an output circuit (7) for receiving the output of the comparator (6) and decrementing the analog output at a given step if the output of the comparator (6) is a logical "1" and incrementing the analog output at a given step if the output of the comparator (6) is a logical "0", whereby the analog output of the output circuit (7) is supplied to the regulating terminal (2) so that the compressed air is supplied to the holder (12).</p> |
