| 摘要 |
PROBLEM TO BE SOLVED: To realize high-speed processing by simple structure by conducting skew calibration individually for respective drivers. SOLUTION: When a relay switch 106 is closed by the control of a CPU 114 and a first signal Sin ' is inputted, a signal Sout ' with delay of zero is outputted from a phase shift circuit 103 and it is fetched by a phase comparator 107. When the phase of the signal Sout ' advances ahead of the phase of a reference clock So ', a value of a judgment signal becomes 1, 0 and 0, and a count value Sc of a counter 112 increases by only one, and a specified delay value is outputted from a memory 113, then the phase shift circuit 103 makes the signal Sin ' to be delayed. On the other hand, when the phase of the signal Sout ' is behind the reference clock So ', the value of the judgment signal becomes 0, 1 and 0, so that the count value Sc is not changed and the output from the memory 113 is not changed as well, therefore the phase shift circuit 103 does not change the delay time of the clock signal Sin '. Then the CPU 114 judges that the skew calibration is completed, and opens the switch 106. |
