| 摘要 |
<p>PURPOSE:To decrease the number of component parts of a clock signal switching circuit and to simplify the circuit constitution, by using two 2-input data selectors, two fall edge trigger type FF circuits, and a single 4-input data selector. CONSTITUTION:When 'H' of a clock selection signal S is supplied, the output signals (e) and (f) of the FF 13 and 14 are set at 'H' and a clock signal A is delivered to an output terminal 10 of a 4-input data selector 15. At the same time, the signals (a) and (b) of the same types as clock signals A and B are delivered to the outputs Y of 2-input data selectors 11 and 12 respectively. When the signal S is changed to 'L', the FF 13 is sampled at the fall edge of the signal (a). Then the signal (f) is set at 'L' and the signal B is delivered to the terminal 10. Thus a switching action is through between signals A and B. As a result, the number of FF circuits can be decreased and the constitution of a clock signal switching circuit is simplified.</p> |
