| 摘要 |
PROBLEM TO BE SOLVED: To provide the eye pattern amplitude measurement device that uses only logic circuits to measure an eye pattern amplitude. SOLUTION: The device is provided with a digital full wave rectifier circuit 11 that receives an eye pattern signal, selects whether binary data other than the MSB are outputted as they are or the complements of the binary data are outputted based on the MSB so as to conduct the same processing as full wave rectification, a comparator 12 that compares the quantity of an output signal of the digital full wave rectifier circuit 11 with that of reference data to provide an output of an UP enable (ENB) or a DOWN ENB signal, a random walk filter 13 that receives output signals of the comparator 12 at separate counters, provides an output of an UP ripple carry-out (RCO) or a DOWN RCO signal depending whether which of the counters reaches a full state, nullifying both the counts so as to make similar processing to smoothing, and an up-down counter 14 whose count is increased/decreased depending on the output of the random walk filter 13 and provides an output of a resulting count to a CPU 15. |
