| 摘要 |
PURPOSE:To prevent frame step-out occurring in spite of the normal operation of a circuit by providing a selector circuit to switch a frame to the one to which the load signal of a window generation circuit is inputted when a power source is applied and the cutoff of an input signal is recovered. CONSTITUTION:When the power source is applied and the cutoff of the input signal is recovered, the selector circuit 5 selects the frame FP1 generated from an input clock CLK1 by the input of a power-on-reset signal POR and an input signal cutoff detecting signal REC, and a counter 7 in the WIND (window) generation circuit 6 is loaded by the frame. Therefore, it is possible to align the phase of the frame FP1 generated from the input clock CLK1 with that of the frame FP2 generated from the output clock CLK2 of a PLL2. In such a way, the phases between the frames can be set at the optimum level when the power source is applied and the cutoff of the input signal is recovered, and it is possible to prevent malfunction such as a code error in a device as a whole due to the step-out of the frame while performing an operation occurring. |
