Introduction to DEMUX | Number System and Code | Digital Circuit Design in EXTC Engineering

TL;DR

A demultiplexer routes one data input to one of many outputs according to its select-line values. For M select lines, it has N = 2^M outputs; for example, two select lines produce a 1-to-4 DEMUX with outputs Y0 through Y3. Only the selected output is activated at a time, and each output can be expressed with select variables and the data input. Read on for the truth table and output expressions.

Transcript

click the bell icon to get latest videos from Akira hello friends now we are going to discuss the introduction to the demultiplexers let's start the discussion for demultiplexer so friends here heading is demultiplexer now the main features of demultiplexer are it has only one input and many outputs in other way you can say 1 is to n D MUX we're N ... Read More

Key Insights

• 🔠 Demultiplexers have one input and multiple outputs, allowing for data distribution based on input conditions.
• 🫥 The number of outputs in a demultiplexer is determined by the select lines, which can be any power of two.
• ⌛ Only one output is activated at a time, based on the input condition.
• 😑 The expression for each output can be designed using logic gates.
• 📡 Demultiplexers can be used in various applications, such as data transmission and signal routing.
• 😑 Understanding the truth table and expressions for each output allows for effective demultiplexer design.
• 🫥 Select lines play a crucial role in determining which output is activated.

Questions & Answers

Q: What is a demultiplexer and how does it work?

A demultiplexer has one input and many outputs, so it distributes input data among multiple output paths. Its select-line values determine which single output is activated at a time.

Q: How many outputs does a demultiplexer have for a given number of select lines?

The number of outputs is N = 2^M, where M is the number of select lines. Two select lines give four outputs, while three select lines give eight outputs.

Q: What is a 1-to-4 DEMUX?

A 1-to-4 DEMUX has one data input and four outputs: Y0, Y1, Y2, and Y3. It uses two select lines, labeled A and B in the explanation.

Q: What is the truth table for a 1-to-4 DEMUX?

When A and B are 00, Y0 is selected; for 01, Y1 is selected. The combinations 10 and 11 select Y2 and Y3, respectively, while the remaining outputs stay inactive.

Q: Why is only one DEMUX output activated at a time?

Each select-line combination corresponds to one specific output. The input data therefore appears only at that selected output, while the other outputs remain inactive.

Q: What are the output expressions for a 1-to-4 DEMUX?

The expressions are Y0 = A̅B̅Din, Y1 = A̅BDin, Y2 = AB̅Din, and Y3 = ABDin. Each expression combines the data input with the select-line condition assigned to that output.

Q: What role does the data input Din play in the DEMUX expressions?

Din is the single input distributed by the demultiplexer. It appears in every output expression, but it reaches only the output enabled by the current select-line combination.

Q: How can a 1-to-4 DEMUX be designed with logic gates?

First define the four select-line combinations for A and B, then write one output expression for each combination. Those expressions, A̅B̅Din, A̅BDin, AB̅Din, and ABDin, provide the logic needed to design the four outputs.

Summary & Key Takeaways

• Demultiplexers have one input and multiple outputs, with the number of outputs determined by the select lines.

• Only one output is activated at a time based on the input conditions.

• The expression for each output can be designed using logic gates.