Johnson Counter

Duration: 3 min

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Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
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  9. Computer Fundamentals, IT Basics & Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Register Transfer and Microoperations, Control Unit Design, Programming the Basic Computer, Terms & Abbreviations, MS Office Applications, Instr Formats & Modes, Floating Point Rep, कंप्यूटर के मूल सिद्धांत / Computer Fundamentals, साइबर सुरक्षा / Cyber Safety and Security, कंप्यूटर सॉफ़्टवेयर / Computer Software, ऑपरेटिंग सिस्टम / Operating System, वर्ड प्रोसेसिंग (MS Word) / Word Processing (MS Word), कंप्यूटर नेटवर्क / Computer Networks, प्रेज़ेंटेशन (MS PowerPoint) / Presentation Software (MS PowerPoint)
  10. Python Language: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis
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  13. Mathematics - I, II, III, IV: Permutation and Combination, Logarithm, Linear Algebra, Algebra, Calculus, Trigonometry, Vectors, Set Theory, Functions, Relations, Propositional and Predicate Logic, Research Process Steps, Graph Theory, समुच्चय, संबंध, फलन और विविक्त गणित / Sets, Relations, Functions and Discrete Mathematics, संख्या पद्धति और संख्या सिद्धांत / Number Systems and Number Theory, यूक्लिडीय ज्यामिति और क्षेत्रमिति / Euclidean Geometry and Mensuration, सांख्यिकी और प्रायिकता / Statistics and Probability, निर्देशांक ज्यामिति, सदिश और त्रिविमीय ज्यामिति / Coordinate Geometry, Vectors and 3D Geometry, बहुपद, समीकरण और सम्मिश्र संख्याएँ / Polynomials, Equations and Complex Numbers, समतल क्षेत्रमिति / Plane Mensuration, प्रतिचयन / Sampling, प्रतिशत / Percentage, सरलीकरण, घातांक और करणी / Simplification, Indices and Surds, अनुपात और समानुपात / Ratio and Proportion
  14. Computer Graphics, Multimedia & Mobile Computing: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, 3-D Object Representation, Geometric Transformations and Viewing, Multimedia
  15. Emerging Trends: Emerging Tech Trends, Knowledge Representation, Natural Language Processing, व्यापार, विपणन एवं उपभोक्ता संरक्षण / Trade, Marketing and Consumer Protection
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  18. Basis of Physics: वैज्ञानिक उपलब्धियाँ और अनुसंधान / Scientific Achievements and Research
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AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video lecture introduces the Johnson Counter, also known as a Twisted Ring Counter or Switch-tail Ring Counter. The instructor explains that while a standard k-bit ring counter provides k distinguishable states, a switch-tail configuration doubles this number. The defining characteristic is a circular shift register where the complemented output (Q-bar) of the last flip-flop is connected to the input (D) of the first flip-flop. The instructor uses a 4-bit D flip-flop diagram to illustrate this feedback loop. He then begins to construct a state table to demonstrate the counting sequence, starting with an initial state of 0000. Finally, he derives the formula for the total number of states in a Johnson counter, which is 2n, and calculates it for a 4-bit system.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor defines the Johnson Counter using on-screen text that describes it as a 'circular shift register with the complemented output of the last flip-flop connected to the input of the first flip-flop.' He points to a diagram of four D flip-flops connected in a shift register, highlighting the feedback path from the inverted output of the last stage to the input of the first. He then draws a state table with columns for CLK, Q0, Q1, Q2, and Q3. He populates the initial row (CLK 0) with zeros (0000) and draws arrows to visualize the shifting of bits from one flip-flop to the next, preparing to trace the sequence.

  2. 2:00 – 2:44 02:00-02:44

    The instructor focuses on calculating parameters for this specific counter configuration. He writes the general formula '2^n - 2n' on the board. He substitutes n=4 into the equation, writing '2^4 - 2(4) = 16 - 8'. This calculation highlights the relationship between the total possible states (2^n) and the valid states (2n) for a Johnson counter. He emphasizes this formula as a key property of the switch-tail ring counter.

The lecture progresses from a theoretical definition to a practical calculation. It starts by distinguishing the Johnson Counter from a standard ring counter based on its feedback mechanism (complemented output). The instructor visually demonstrates the circuit structure and begins the process of analyzing its state sequence using a table. The lesson culminates in a mathematical derivation of the counter's modulus (number of states), establishing the formula 2n as a critical takeaway for exam preparation.

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