| 摘要 |
<P>PROBLEM TO BE SOLVED: To surely suppress EMI noise in a clock transmission device 61 that divides a clock CLK1 into a clock CLK2 with a frequency divider 14, and transmits it so as to suppress the EMI noise for sharing the clock CLK1 without frequency fluctuations between devices 11, 21. <P>SOLUTION: A frequency dividing ratio of the frequency divider 14 is made to be variable and is set with a setting circuit 19, and the information on the frequency dividing ratio is also transmitted to a multiplying circuit 22. Accordingly, even if the spectrum of EMI noise emitted from a clock transmission channel 16 differs from a designed value, the EMI noise level of the clock transmission channel 16 in a state in which circuits are actually connected and the clock CLK1 is in transit is measured, and the frequency dividing ratio is adjusted so that a favorable spectrum is obtained, thereby permitting to surely suppress the EMI noise. In addition, the frequency dividing ratio can be easily adjusted. <P>COPYRIGHT: (C)2003,JPO |
