| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent overflow in a buffer memory even if the interruption/ restoration of a reference clock is repeated. SOLUTION: An input interruption detection circuit 17 discriminates the normality of clocks in plural systems, which are extracted by clock extraction circuits 110-113, specifies the clocks in a prescribed priority among the normal clocks and selects them as reference clocks Ckref. A clock generation circuit 15 generates system clocks Cksys from the reference clocks Ckref and sets them to be read clocks for respective buffer memories 121-123. The input cut detection circuit 17 detects that the clock in an interruption state is restored, and sets write address/read address so that data is written and read from a position almost the half of memory capacity into the corresponding buffer memory at the time of detecting restoration.</p> |
