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A comprehensive overview of multiplexers and demultiplexers, their types, functions, and applications in digital circuits.

Multiplexers

  • Definition: A multiplexer (MUX) is a digital switch that connects data from one of ( n ) sources to its output. It is also known as a data selector.
  • Components:
    • ( N ) control inputs
    • ( 2^N ) data inputs
    • 1 output
  • Function: Routes the selected data input to the output based on the value of the control inputs.

Types of Multiplexers

  • 2-to-1 Multiplexer:
    • 2 data inputs (( I0 ) and ( I1 ))
    • 1 select input (( S ))
    • 1 output (( Y ))
    • Truth table provided for different input combinations.
  • 4-to-1 Multiplexer:
    • 4 data inputs (( I0 ), ( I1 ), ( I2 ), ( I3 ))
    • 2 select inputs (( S0 ) and ( S1 ))
    • 1 output (( Y ))
    • Logic symbol and truth table provided.
  • 16-to-1 Multiplexer:
    • Constructed using multiple 4-to-1 multiplexers.
    • Select signals determine the output.

Logic Function Generation Using MUX

  • Efficient method for implementing a Boolean function using a MUX.
  • Example provided for implementing Boolean functions using suitable multiplexers.

Uses of Multiplexers

  • Data communications for multiple computers over one line.
  • Radio channel selection.
  • Routing data within a computer.
  • Function generation.

Demultiplexers

  • Definition: A demultiplexer (DEMUX) reverses the multiplexing function by taking data from one line and distributing it to multiple output lines. It is also known as a data distributor.
  • Components:
    • ( N ) control inputs
    • 1 data input
    • ( 2^N ) outputs

Types of Demultiplexers

  • 1-to-2 Demultiplexer:
    • 1 data input (( D ))
    • 1 select line (( S ))
    • 2 outputs (( Out0 ) and ( Out1 ))
  • 1-to-4 Demultiplexer:
    • 1 data input (( D ))
    • 2 select lines (( S0 ) and ( S1 ))
    • 4 outputs (( Out0 ), ( Out1 ), ( Out2 ), ( Out3 ))
    • Logic diagram and operation explained.
  • 1-to-8 Demultiplexer:
    • 1 data input
    • 3 select lines
    • 8 outputs

Applications of Demultiplexers

  • Reconstruction of parallel data from incoming serial data streams.
  • Routing data to multiple destinations.
  • Example provided for a single source multiple destinations selector.

Multiplexer and Demultiplexer – Lesson 12

Engineering Institute of Technology