--- title: "Line coding 1011001010 (polar NRZ, polar RZ, Manchester, AMI)" subject: "Communication Systems" chapter: 6 key: "semester_6/communication_systems:line-codes-1011001010" source: https://www.bctengineer.com/q/semester_6/communication_systems/line-codes-1011001010 site: BCT Engineering --- # Line coding 1011001010 (polar NRZ, polar RZ, Manchester, AMI) Communication Systems · Chapter 6: Baseband Digital Data Transmission - Asked in: 2073 Shrawan (CS II), 4 marks; 2070 Chaitra (CS II), 4 marks (asked 2 times) - Video: [Line Coding Techniques | RZ, NRZ, Unipolar, Polar, Bipolar & Manchester | Digital Communication](https://www.youtube.com/watch?v=daf9F9NC7zQ) — Engineering Funda - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_6/communication_systems/line-codes-1011001010 - Whole chapter: https://www.bctengineer.com/md/semester_6/communication_systems/chapter-6 ## Question Given the binary sequence 1011001010 represent it in Polar NRZ, Polar RZ, Manchester and AMI codes. ## Short answer Polar NRZ: + - + + - - + - + -. Polar RZ: +0 -0 +0 +0 -0 -0 +0 -0 +0 -0. Manchester: +- -+ +- +- -+ -+ +- -+ +- -+. AMI: + 0 - + 0 0 - 0 + 0 (1s alternate). ## Answer Bit sequence: **1 0 1 1 0 0 1 0 1 0**, bit period $T_b$, levels $\pm V$. Each bit is 4 characters wide in the drawings. Conventions used: Manchester sends 1 as a +V half followed by a −V half, and 0 as −V then +V (Lathi/Haykin; the IEEE 802.3 convention is the opposite). AMI sends alternate 1s as half-width +V and −V pulses, starting with +V, and 0 as no pulse. **Polar NRZ (1 → +V, 0 → −V, full bit)** ```text 1 0 1 1 0 0 1 0 1 0 +V ────| |───────| |───| |───| -V |───| |───────| |───| |─── ``` **Polar RZ (1 → +V, 0 → −V, for half bit, then 0)** ```text 1 0 1 1 0 0 1 0 1 0 +V ──| |─| |─| |─| |─| 0 |─| |─| |─| |─| |─| |─| |─| |─| |─| |─ -V |─| |─| |─| |─| |─| ``` **Manchester** ```text 1 0 1 1 0 0 1 0 1 0 +V ──| |───| |─| |─| |───| |───| |─ -V |───| |─| |───| |─| |───| |───| ``` **AMI (bipolar RZ)** ```text 1 0 1 1 0 0 1 0 1 0 +V ──| |─| |─| 0 |─────| |─| |─────────| |─────| |───── -V |─| |─| ``` AMI pulse polarities for the 1s: + − + − + (the 0s are 0). ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. For the sequence 1011001010, what are the AMI pulse polarities of the five 1s, starting with +? A. + + + + + B. + - + - + C. + - - + - D. - + - + - Answer: B. AMI alternates polarity on every 1, and the 0s are no pulse. (Key point: AMI polarities) 2. In the convention used (Lathi/Haykin), how is a 1 sent in Manchester code? A. -V then +V B. +V for the full bit C. +V for the first half then -V D. 0 then +V Answer: C. 1 is +V then -V, and 0 is -V then +V, giving a mid-bit transition in every bit. (Key point: Manchester convention) 3. How are bits represented in polar RZ? A. 1 is +V and 0 is -V for half a bit, then back to zero B. 1 is +V and 0 is zero C. 1 is +V for the full bit D. Alternating polarity for 1s Answer: A. Polar RZ uses +V/-V pulses lasting half the bit and returns to zero in the second half. (Key point: Polar RZ) 4. In polar NRZ, what is the level during the 0 bits? A. 0 V B. +V for half of the bit C. -V for the whole bit D. Alternates Answer: C. Polar NRZ sends 1 as +V and 0 as -V for the full bit period. (Key point: Polar NRZ) ## Close variants set in other exams - [Line coding 1101010111 (polar NRZ, polar RZ, Manchester, AMI)](https://www.bctengineer.com/question.md?key=semester_6%2Fcommunication_systems%3Aline-codes-1101010111-polar-ami) — Communication Systems, chapter 6, asked 8× - [Line coding 1101010011 (polar NRZ, polar RZ, Manchester, AMI)](https://www.bctengineer.com/question.md?key=semester_6%2Fcommunication_systems%3Aline-codes-1101010011) — Communication Systems, chapter 6, asked 8× - [Line coding 1001101101 (unipolar NRZ, polar RZ, AMI, Manchester)](https://www.bctengineer.com/question.md?key=semester_6%2Fcommunication_systems%3Aline-codes-1001101101) — Communication Systems, chapter 6, asked 8× - [Line coding 1001001101 (polar NRZ, polar RZ, Manchester, AMI)](https://www.bctengineer.com/question.md?key=semester_6%2Fcommunication_systems%3Aline-codes-1001001101) — Communication Systems, chapter 6, asked 8× - [Line coding 10110101 (polar NRZ, unipolar RZ, AMI, Manchester)](https://www.bctengineer.com/question.md?key=semester_6%2Fcommunication_systems%3Aline-codes-10110101) — Communication Systems, chapter 6, asked 8× ## Related in Communication Systems - [Line coding 100111010 (Polar RZ, bipolar NRZ, AMI, Manchester)](https://www.bctengineer.com/question.md?key=semester_6%2Fcommunication_systems%3Aline-codes-100111010) — Communication Systems, chapter 6 - [Line coding 1011000010000000001 (polar NRZ, AMI, Manchester)](https://www.bctengineer.com/question.md?key=semester_6%2Fcommunication_systems%3Aline-codes-polar-ami-manchester-long) — Communication Systems, chapter 6, asked 2× - [Definitions of unipolar, polar, bipolar, RZ, Manchester codes](https://www.bctengineer.com/question.md?key=semester_6%2Fcommunication_systems%3Adefine-line-codes) — Communication Systems, chapter 6, asked 2× - [Line coding 110011000001 (unipolar RZ, Manchester, HDB3)](https://www.bctengineer.com/question.md?key=semester_6%2Fcommunication_systems%3Aline-codes-110011000001) — Communication Systems, chapter 6 ## Related in other subjects - [Line coding and NRZ, RZ, AMI](https://www.bctengineer.com/question.md?key=semester_8%2Ftelecommunications%3Aline-coding-nrz-rz-ami) — Telecommunications, chapter 3 - [Line coding: polar RZ and bipolar AMI](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aline-coding-polar-rz-ami) — Data Communication, chapter 5 - [Encode 10101111000011 with NRZ, RZ, AMI, Manchester](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aline-coding-10101111000011) — Data Communication, chapter 5 - [Encode 1101001 with polar NRZ, AMI, Manchester](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aline-coding-1101001) — Data Communication, chapter 5, asked 3×