| 摘要 |
PROBLEM TO BE SOLVED: To provide a preemphasis adjustment system for properly adjusting the strength of preemphasis in accordance with attenuation by a transmission path. SOLUTION: The preemphasis adjustment system performs: a first adjustment step in which a threshold of an input buffer circuit is caused to match a deemphasis voltage at a receiving end of the input buffer circuit; a second adjustment step in which an output buffer circuit is caused to transmit random data; and a third adjustment step in which the first and second adjustment steps are repetitively implemented while changing the strength of the preemphasis of the output buffer circuit until an output value of a flip-flop is always "0". Alternatively, the preemphasis adjustment system performs: the above first adjustment step; a second adjustment step in which the output buffer circuit is caused to repetitively transmit pattern data and latching of an output signal from the input buffer circuit is performed for the plurality of number of times while a variable delay unit changes an amount of delay of a clock; and a third adjustment step in which the first and second adjustment steps are repetitively implemented while changing the strength of the preemphasis of the output buffer circuit until the number of "0s" output from the flip-flop reaches a prescribed number. COPYRIGHT: (C)2008,JPO&INPIT
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