I will use two flip-flops uv, and two input variables xy, and make the following encodings for states and input:
State encoding:
| uv | |
| s | 00 |
| a | 01 |
| r | 10 |
Input encoding:
| xy | |
| 0 | 00 |
| 1 | 01 |
| . | 10 |
I will then transcribe the state-transition table
| 0 | 1 | . | |
| s | a | a | r |
| a | a | a | s |
| r | r | r | r |
to the bit values
| 00 | 01 | 10 | |
| 00 | 01 | 01 | 10 |
| 01 | 01 | 01 | 00 |
| 10 | 10 | 10 | 10 |
Finally I will create two Karnaugh maps, one corresponding to next-state value of u and one to v:
Map for next u:
| 0 | 0 | d | 1 |
| 0 | 0 | d | 0 |
| d | d | d | d |
| 1 | 1 | d | 1 |
Map for next v:
| 1 | 1 | d | 0 |
| 1 | 1 | d | 0 |
| d | d | d | d |
| 0 | 0 | d | 0 |
Now I can derive the simplified logic equations from these maps as:
next u = u + v'xy'
next v = u'x'