Wolmer’s
Upper and Lower Six Teacher: Mrs. McCallum-Rodney
MULTIPLEXERS
In electronics, a multiplexer or mux is a device that performs multiplexing; it selects one of many analog or digital input signals and outputs that into a single line.
An electronic multiplexer makes it possible for several signals to share one expensive device or other resource, for example one A/D converter or one communication line, instead of having one device per input signal.
A multiplexer of 2n inputs has n select bits, which are used to select which input line to send to the output. Therefore, if the multiplexor has 8 inputs (which is 23), then there will be 3 selectors.
QUESTION 1: Considering the 8-1 multiplexer above, show which of the inputs will be selected for the following:
|
S2 |
S1 |
S0 |
Input to be selected |
|
1 |
0 |
0 |
|
|
0 |
1 |
0 |
|
|
0 |
0 |
0 |
|
|
0 |
1 |
1 |
|
|
1 |
1 |
1 |
|
|
1 |
0 |
1 |
|
QUESTION 2: Now consider the following table, that gives values to A, B, C, D, E, F, G and H.
|
S2 |
S1 |
S0 |
A |
B |
C |
D |
E |
F |
G |
H |
X (out) |
|
1 |
0 |
0 |
1 |
1 |
0 |
1 |
0 |
1 |
1 |
0 |
|
|
0 |
1 |
1 |
1 |
0 |
0 |
1 |
0 |
0 |
1 |
1 |
|
|
0 |
0 |
0 |
0 |
0 |
0 |
1 |
1 |
0 |
1 |
1 |
|
|
1 |
1 |
1 |
0 |
1 |
0 |
1 |
1 |
0 |
0 |
1 |
|
|
0 |
1 |
0 |
1 |
1 |
0 |
0 |
0 |
1 |
1 |
0 |
|
|
1 |
1 |
0 |
0 |
0 |
1 |
1 |
0 |
1 |
0 |
1 |
|
|
0 |
0 |
1 |
1 |
1 |
1 |
0 |
1 |
0 |
0 |
1 |
|
|
1 |
0 |
0 |
1 |
0 |
1 |
0 |
0 |
1 |
1 |
0 |
|
|
1 |
0 |
1 |
0 |
0 |
0 |
1 |
1 |
0 |
1 |
1 |
|
|
0 |
1 |
1 |
0 |
1 |
0 |
1 |
1 |
0 |
0 |
1 |
|
QUESTION 3: Draw a 4-1bit MUX. How many selectors will there be in this MUX. How many combinations are there for there for the selectors and what are they (be specific for each selector).
QUESTION 4: Draw a 2 – 1 bit MUX.
QUESTION 5: Draw a 16 – 1 bit MUX.
