| 摘要 |
<p>PURPOSE:To digitally realize a hold over function without using the voltage control circuit of analog constitution. CONSTITUTION:A phase difference detecting means 21 detects phase difference between a reference signal SR and a regenerative signal SP, and an information delay means 22 delays information corresponding to this detection output only for prescribed time by using a memory 221. Then, an information holding means 23 holds this delayed information and based on this held information, the oscillation frequency of an oscillating means 24 is controlled. At occurrence of abnormality, the operation of fetching the information in the information holding means 23 is inhibited and according to the information already held in this information holding means 23, the oscillation frequency of the oscillating means 24 is controlled.</p> |
