1. a clock is logic 0 for 20 ns and logic 1 for 50 ns. a) (2 points) what is the period t? b) (2 points) what is frequency f? c) (2 points). what is the duty cycle? 2. (3 points) briefly explain the difference between a combinational and a sequential digital circuit. - 3. (3 points) briefly explain the difference between a level-triggered device and an edge triggered device. - 4. (3 points) for latch circuits, briefly describe the significance of a setup time and a hold time. -