Decoders

Duration: 5 min

This video lesson is available to enrolled students.

Return to /learn/UP-LT-GRADE-ASSISTANT-TEACHER-2025/digital-logic-circuits-discrete-math-structures/combinational-circuit/demux-decoder-encoder/asset-decoders after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. CS | 01 | Digital Logic and Circuits and Discrete Mathematical Structures: Digital Systems & Boolean Basics, Number System, Number Representation, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic, Permutation and Combination
  3. CS | 02 | Computer Organization and Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Multiprocessors
  4. CS | 03 | Data Structures and Algorithm: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Complexity Theory, Advanced Algorithms
  5. CS | 04 | Problem Solving through C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  6. CS | 05 | Object Oriented Techniques: Object Oriented Technology, Java
  7. CS | 06 | Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Windows OS, Unix OS
  8. CS | 07 | Database Management Systems: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Algebra, SQL, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, Database Security & Authorization, Query Processing & Optimization, File Organization & Indexing
  9. CS | 08 | Computer Networks: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics
  10. CS | 09 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  11. CS | 10 | Internet Technology, Web Design and Web Technology: Internet Fundamentals, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security, Emerging Technologies, JavaScript-Basics, HTML Basics
  12. CS | 11 | System Analysis And Design: Fundamentals of Systems and Information Systems, SDLC and Development Approaches, Software Documentation and Software Requirements Specification (SRS), SDD and Quality Assurance, Security, Risk Management & Maintenance
  13. CS | 12 | Information Security and Cyber Laws: Cyber Threats and Malware Attacks, Role of Internet and Web Services, Security in Mobile and Wireless Computing, Electronic Data Interchange and E-Commerce, Physical Security and Cryptography Basics, Intrusion Detection Systems (IDS), Cyber Safety and Security
  14. CS | 13 | Computer Graphics: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, 3-D Object Representation, Geometric Transformations and Viewing
  15. GS Paper | 01 | Indian and World Geography: Geography
  16. GS Paper | 02 | History: History
  17. GS Paper | 03 | Indian Economy & Social Development: Indian Economy
  18. GS Paper | 04 | General Science: Biology, Chemistry, Physics
  19. GS Paper | 05 | Elementary Maths: Number System, Divisibility Rules, HCF LCM, Percentage, Profit and Loss, Simple Interest and Compound Interest, Ratio and Proportion (Ratios), Average, Time and Work, Speed Time and Distance, Algebra, Mensuration and Geometry, Data Interpretation, Arithmetic, Statistics, Probability, Sequence and Series (Series), Mixture and Alligation, Calculus, Trigonometry, Vectors
  20. GS Paper | 06 | Indian Polity and Governance: Polity
  21. GS Paper | 07 | Current Events: GK- Current Affairs
  22. UPLT Live Classes Notes: UPLT Live Classes
  23. UPLT Full Mock Tests Tier 1:
  24. UPLT Full Mock Tests Tier 2:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture demonstrates how to construct a 4-to-16-line decoder using two 3-to-8-line decoders with enable inputs. The instructor begins by drawing a block diagram for the target 4x16 decoder, labeling its four inputs as I0 (LSB) through I3 (MSB) and its sixteen outputs as D0 to D15. The solution involves using the three lower-order bits (I0, I1, I2) as common data inputs to both 3x8 decoder blocks. The most significant bit (I3) is used to control the enable inputs of each decoder: when I3=0, the upper decoder is enabled to produce outputs D0-D7; when I3=1, an inverter allows the lower decoder to be enabled to produce outputs D8-D15. This method effectively doubles the output capacity of a 3x8 decoder to create a 4x16 decoder.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor introduces the problem of connecting two 3-to-8-line decoders to form a 4-to-16-line decoder. A block diagram for the target '4x16 Decoder' is drawn on the whiteboard, with inputs labeled I0 (LSB) to I3 (MSB) and outputs D0 to D15. The instructor then begins drawing the first 3x8 decoder block, labeling its inputs I0, I1, I2 and an enable input E.

  2. 2:00 – 5:00 02:00-05:00

    The instructor draws a second 3x8 decoder block in green ink, stacking it below the first. The inputs I0, I1, and I2 are connected to both decoders. The MSB (I3) is circled in red and wired to the enable inputs of both decoders. An inverter is added between I3 and the upper decoder's enable pin, while a direct connection is made to the lower decoder. The outputs are labeled D0-D7 for the upper block and D8-D15 for the lower block.

  3. 5:00 – 5:19 05:00-05:19

    The final diagram is completed, showing the logic conditions for each decoder. The instructor writes 'I3=0' and 'I3=1' to indicate the enable states. The outputs of both 3x8 decoders are connected to the final 4x16 decoder block, demonstrating how the MSB selects which half of the output range is active based on the enable logic.

The core concept taught is decoder expansion using enable inputs. By sharing the lower-order address lines (I0-I2) across multiple smaller decoders and using the higher-order bit (I3) to control their enable pins, a larger decoder can be synthesized. The use of an inverter on one enable line ensures that only one 3x8 decoder is active at any given time, preventing output conflicts and correctly mapping the 4-bit input to one of sixteen unique outputs.

Loading lesson…