Digital Logic · Unit 6
Multiplexers and Demultiplexers
Exam-focused notes for Multiplexers and Demultiplexers (Digital Logic, BIT103): what the TU syllabus asks and how it has actually been tested, with 5 solved past questions from this unit.
What this unit covers
- Multiplexer design and operation
- Multiplexer implementation using smaller multiplexers
- Function implementation using multiplexers
- Demultiplexer circuits
Multiplexer implementation using smaller multiplexers
Define multiplexer. Implement 8 × 1 multiplexer using 2 × 1 multiplexer. [1+4]
A multiplexer (MUX) is a combinational circuit that selects one of many input lines and forwards it to a single output line based on select lines. It is also called a data selector. - An n-input multiplexer has: - 2^n data input lines - n select lines - 1 o...
Full solved answer →What is decoder? Implement 8 x 1 MUX using 2 x 1 MUX. [5]
--- A decoder is a combinational logic circuit that converts binary information from n input lines to a maximum of 2ⁿ unique output lines. - It takes an n-bit binary code as input and activates exactly one of the 2ⁿ output lines. - A decoder with n inputs a...
Full solved answer →What is decoder? Implement 8 x 1 MUX using 4 x 1 MUX. [5]
--- A decoder is a combinational logic circuit that converts binary information from n input lines to a maximum of 2ⁿ unique output lines. - It "decodes" a binary code into individual signals. - For each input combination, exactly one output is active (HIGH...
Full solved answer →Design 8 to 1 Multiplexer using two 4to 1 Multiplexers. [5]
An 8-to-1 MUX has: - 8 data inputs: I₀ to I₇ - 3 select lines: S₂, S₁, S₀ - 1 output: Y A 4-to-1 MUX has: - 4 data inputs - 2 select lines - 1 output --- To build an 8-to-1 MUX from two 4-to-1 MUXes, we need a two-level hierarchy: - MUX 1 (Upper): handles i...
Full solved answer →Demultiplexer circuits
Write short notes on: a) De-Multiplexer b) Excitation table [0+2.5+2.5]
A De-Multiplexer is a combinational logic circuit that takes a single input line and routes it to one of several output lines based on the selection inputs. - It is the reverse operation of a Multiplexer. - A DEMUX with n selection lines can route the input...
Full solved answer →Make Unit 6 stick
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