| 摘要 |
PURPOSE:To obtain a stable revolution servomechanism by a method wherein the period from the rise to the next rise of a detection signal and the period from the fall to the next fall of the detection signal are separately measured to read the period of the detection signal. CONSTITUTION:The period from the rise to the next rise of a detection signal (a) which is detected by a detector 2 is measured by a first period measuring apparatus 3. The period from the fall to the next fall of the detection signal (a) detected by the detector 2 is measured by a second period measuring apparatus 4. The measured results are successively selected by a switching means 5 and converted into voltages by a period-voltage converting means 6 and outputted as control signals. The switching timing of the switching means 5 is such that, as the respective outputs of the first and second period measuring apparatuses 3 and 4 are alternately supplied with the phases opposite to each other, the output of the switched one between the first period measuring apparatus 3 and the second period measuring apparatus 4 is introduced into the period- voltage converting means 6. |
