| 摘要 |
PURPOSE:To automatically select data with a safe phase and to eliminate dispersion in the delay of a clock distribution system and a data transmission system by detecting the noncoincidence of each data whose re-timing is taken with clocks delayed with different phases. CONSTITUTION:The data in which the re-timing of received data is taken with the positive phase of the clock, and the data in which the re-timing of the received data is taken with the negative phase of the clock and furthermore, the re-timing is taken with the positive phase of the clock are inputted to a selection circuit SEL. Also, the data in which the re-timing of the received data is taken with the clock whose phase is delayed by 1/4-phase than the clock of positive phase and the re-timing is taken with the clock whose phase is further delayed by 3/4-phase is compared EOR with the data in which the re-timing of the reception data is taken with the clock delayed by 3/4-phase. Noncoincidence information that is a comparison result is latched, and is set as the control signal of the circuit SEL, and the re-timing phase of the received data can be selected. |
