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PHYS245
Electricity and Electronics Syllabus - Classes - Assignments - Laboratory - Resources Class 28: Answers to Assignment |
Chapter 14
Exercise 4:
Hint:
Ans: The sequence of states Q0Q1Q2 is 111, 101, 100, 010, 001, 110, 011, and back to 111.
(000 is excluded and unfortunately does not enter into the sequence.)
Exercise S14-1:
Hint: Note that the starting output of each flip-flop is Q = 0 and Q' = 1.
Determine D1, D2, and D3 at the time of the positive edge of the clocking signal; find the resulting Qs for each flip-flop, then feed back two of the complemented outputs back into D1 with the AND gate.
Ans: see link.
Exercise S14-2:
Hint:
Going clockwise around the included states from 000, followed by going clockwise around the excluded states from 1111,
the truth table should be:
| Q0 | Q1 | Q2 | D0 | D1 | D2 | |
|---|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 1 | 0 | |
| 0 | 1 | 0 | 1 | 0 | 0 | |
| 1 | 0 | 0 | 1 | 1 | 0 | |
| 1 | 1 | 0 | 0 | 0 | 0 | |
| 1 | 1 | 1 | 0 | 0 | 0 | |
| 0 | 0 | 1 | 0 | 1 | 0 | |
| 0 | 1 | 1 | 1 | 0 | 0 | |
| 1 | 0 | 1 | 1 | 1 | 0 |
Ans: see link.