| 摘要 |
PURPOSE:To obtain a difference in the crossover timing by blocking the passing in the presence of an abnormality in the period of a load pulse and using an AND so as to gate a pulse whose count period is made coincident and an output of a NAND. CONSTITUTION:A load pulse M to be inputted is NANDed by an E pulse at a NAND 1 to block the passing in the presence of the abnormality in the period of the load pulse M. Moreover, the period is made coincident with the count period of an F pulse and the F pulse and an output of the NAND 1 are ANDed by an AND 2. As a result, a b-adic counter 3 is loaded by the load pulse M when the clock crossover is normal and the counter is loaded by the F pulse when the clock crossover is abnormal. Thus, the crossover function of the two clock frequencies different from each other is realized by a minimum circuit constitution. |
