1. Mealy Machine outputs state

2. State table of Mealy Machine

3. X1/Y1 X2/Y2 S1 X2/Y1 S2 S3 X1/Y2 X2/Y3 X1/Y3 Mealy Machine Graph

4. X1 X2 X2 X1 X2 S1/Y2 S2/Y1 S3/Y3 X1 Moore Machine Graph

5. Natural language formulation of a problem Design a control unit for ligth signalization on the railway with car sensors in positions A, B, C. The cars can go BA, AB i AC. In direction BA go only car sets of length larger than the distance between sensors B and A. In directions AB and AC go only single cars of length smaller than distance between sensors A and B and A and C, respectively. The designed circuit should light lamp z=1 if there are no cars between sensors A and B or sensors A and C Sensors A, B, C generate signals a=1, b=1 and c=1 respectively, when sets of cars or single cars occur to be in their close distance.

6. Timing Diagram Specification

7. Transition and output table for light signalization circuit

8. 010 6/1 110 1/0 100 7/1 2/1 000 000 000 100 8/1 001 5/1 3/1 010 4/1 Moore Machine graph for the analyzed device 000

9. asynchronous flip-flop sr

10. Asynchronous srflip-flop

11. Asynchronousflip-flop sr

12. Negated sr FF This version has negated inputs This FF realizes the function:

13. Negated sr FF

14. Negated sr FF