| 摘要 |
PURPOSE:To make it possible to reduce noise developing from a pulse motor by periodically modulating a motor drive frequency in a constant speed rotation period. CONSTITUTION:When a pulse motor is driven at a constant speed fo, it is driven by superimposing a signal, which has a modulation width DELTAf and varies at a cycle of 1/fs, on the constant drive speed fo. At this time, the relationship between fo and DELTAf is set so as to satisfy 1.0<=DELTAf/fs<=2.5 and DELTAf<=fo/10. In this way, the modulation of a drive frequency of the pulse motor results in reduced amplitude of noise of a basic frequency by virtue of frequency modulation effects. This causes peak values concentrated on a specific frequency to be reduced, and hence it becomes possible to reduce the entire noise level. |
