| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem where it is necessary to surely discriminate preamble from noise by lengthening preamble for reducing noise malfunction, and that the effective speed of communication is decreased in an amount due to process in a preamble detecting circuit to be used for a communication system. SOLUTION: An input signal is oversampled and then delayed by sample units, and the number of times of level differences between the input signal and the delay signal is counted, and the count value is compared with a reference value decided according to a preamble. Thus, it is not necessary to complete the training of a clock reproducing circuit in advance, and it is possible to judge preamble according to waveform information whose time resolution is high. |
