Multiplexers and Demultiplexers
297
3. Determine the function performed by the combinational circuit of Fig. 8.29.
Figure 8.29 Problem 3.
4-to-1 multiplexer
4. Implement a full subtractor combinational circuit using a 3-to-8 decoder and external NOR gates.
Fig. 8.30
3-to-8
Decoder
2
2
2
1
2
0
Difference
Borrow Out
0
1
2
3
4
5
6
7
A
B
B in
Figure 8.30 Answer to problem 4.
297
3. Determine the function performed by the combinational circuit of Fig. 8.29.
Figure 8.29 Problem 3.
4-to-1 multiplexer
4. Implement a full subtractor combinational circuit using a 3-to-8 decoder and external NOR gates.
Fig. 8.30
3-to-8
Decoder
2
2
2
1
2
0
Difference
Borrow Out
0
1
2
3
4
5
6
7
A
B
B in
Figure 8.30 Answer to problem 4.