Multiplexers revision

What are multiplexers?
Multiplexers are logic devices which choose an output from among several possible inputs based on the value of a select signal.

What is the short name for a multiplexer?
The short name for a multiplexer is a mux.

What is the other name for the signal that controls the output of a multiplexer?
The other name for the signal that controls the output of a multiplexer is the control signal.

What variable is used to represent the control signal?
The variable used to represent the control signal is .

Wider multiplexers

In general, the number of data inputs (represented with ...) is an integer power of ...
In general, the number of data inputs (represented with ) is an integer power of two.

How many select lines does a multiplexer need based off of the number of input lines ?
The number of select lines a multiplexer needs based off of the number of input lines is .

Wider multiplexers (2)

What are the two ways that a 4:1 multiplexer can be built?
The two ways that a 4:1 multiplexer can be built are:

  1. Sum Of Products (SOP) logic.
  2. Three 2:1 multiplexers.

What is the truth table for a 4:1 multiplexer?
The truth table for a 4:1 multiplexer is:
0 0
0 1
1 0
1 1

Wider multiplexers (3)

How can you use to make a 16:1 multiplexer?
You can use five 4:1 multiplexers a make a 16:1 multiplexer.

What can multiplexers be used as to implement any logic function?
Multiplexers can be used as lookup tables to implement any logic function.

Multiplexer logic

How do you implement an AND2 gate using a 4:1 multiplexer?
To implement an AND2 gate using a 4:1 multiplexer:

  1. Assign the two control signals to and .
  2. Pull the inputs to low.
  3. Pull the input high.

Multiplexer logic (2)

What size of input multiplexer can be used to implement any -input logic function?
A multiplexer with an input size of can be used to implement any -input logic function.

How do you implement an AND2 gate using a 2:1 multiplexer?
To implement an AND2 gate using a 2:1 multiplexer:

  1. Assign to the control signal.
  2. Assign to input .
  3. Pull input low.