--- title: "Line coding 1101010011 (polar NRZ, polar RZ, Manchester, AMI)" subject: "Communication Systems" chapter: 6 key: "semester_6/communication_systems:line-codes-1101010011" source: https://www.bctengineer.com/q/semester_6/communication_systems/line-codes-1101010011 site: BCT Engineering --- # Line coding 1101010011 (polar NRZ, polar RZ, Manchester, AMI) Communication Systems · Chapter 6: Baseband Digital Data Transmission - Asked in: 2073 Chaitra (CS II), 4 marks - 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-1101010011 - Whole chapter: https://www.bctengineer.com/md/semester_6/communication_systems/chapter-6 ## Question Given the binary sequence 1101010011 represent in polar NRZ, polar RZ, Manchester and AMI codes. ## Short answer Polar NRZ: +V,+V,-V,+V,-V,+V,-V,-V,+V,+V. Polar RZ: +V0,+V0,-V0,+V0,-V0,+V0,-V0,-V0,+V0,+V0. Manchester: +V-V,+V-V,-V+V,+V-V,-V+V,+V-V,-V+V,-V+V,+V-V,+V-V. AMI: +V,-V,0,+V,0,-V,0,0,+V,-V. ## Answer Conventions (bit period $T_b$, amplitude $V$): - **Polar NRZ:** 1 → $+V$, 0 → $-V$ for the full bit. - **Polar RZ:** 1 → $+V$, 0 → $-V$ for the first half, then 0. - **Manchester:** 1 → $+V$ then $-V$; 0 → $-V$ then $+V$. - **AMI:** 0 → 0; 1s alternate $+V$, $-V$ (first 1 positive). Bit sequence: **1 1 0 1 0 1 0 0 1 1** ```text bits 1 1 0 1 0 1 0 0 1 1 Polar NRZ: +V |‾‾‾‾‾‾‾‾ ‾‾‾‾ ‾‾‾‾ ‾‾‾‾‾‾‾‾ 0 | -V | ____ ____ ________ Polar RZ: +V |‾‾ ‾‾ ‾‾ ‾‾ ‾‾ ‾‾ 0 | -- -- -- -- -- -- -- -- -- -- -V | __ __ __ __ Manchester: +V |‾‾ ‾‾ ‾‾‾‾ ‾‾‾‾ ‾‾ ‾‾‾‾ ‾‾ 0 | -V | __ ____ ____ ____ __ __ __ AMI (bipolar NRZ): +V |‾‾‾‾ ‾‾‾‾ ‾‾‾‾ 0 | ---- ---- -------- -V | ____ ____ ____ ``` Levels in each bit (a pair means first half, second half): | Code | 1 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | |---|---|---|---|---|---|---|---|---|---|---| | Polar NRZ | +V | +V | −V | +V | −V | +V | −V | −V | +V | +V | | Polar RZ | +V,0 | +V,0 | −V,0 | +V,0 | −V,0 | +V,0 | −V,0 | −V,0 | +V,0 | +V,0 | | Manchester | +V,−V | +V,−V | −V,+V | +V,−V | −V,+V | +V,−V | −V,+V | −V,+V | +V,−V | +V,−V | | AMI (bipolar NRZ) | +V | −V | 0 | +V | 0 | −V | 0 | 0 | +V | −V | Manchester and polar RZ have a transition in every bit (good timing), while AMI has zero average value because its marks alternate. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. In AMI coding, how are 1s and 0s represented? A. 1 alternates +V and -V, 0 is zero level B. 1 is +V, 0 is -V C. 1 is +V then -V, 0 is -V then +V D. 1 is +V, 0 is zero Answer: A. AMI sends 0 as zero level and alternate 1s with opposite polarity, starting with positive. (Key point: AMI rule) 2. For 1101010011, what are the AMI levels for the four 1s at positions 1, 2, 4, 6 (first four ones)? A. +V, +V, +V, +V B. +V, -V, +V, -V C. +V, -V, -V, +V D. -V, +V, -V, +V Answer: B. The first 1 is +V, then alternate: +V, -V, +V, -V (then +V, -V for the last two 1s). (Key point: AMI for the sequence) 3. In the convention used, how is a 0 sent in Manchester code? A. -V in the first half, +V in the second half B. +V then -V C. Zero for the whole bit D. -V for the whole bit Answer: A. Manchester: 1 is +V then -V, 0 is -V then +V; every bit has a mid-bit transition. (Key point: Manchester rule) 4. How is a 1 sent in polar RZ? A. +V for the full bit B. +V for the first half, then 0 C. +V then -V D. 0 for the first half then +V Answer: B. RZ returns to zero in the second half: 1 is +V then 0, 0 is -V then 0. (Key point: Polar RZ) ## Close variants set in other exams - [Line coding 1011001010 (polar NRZ, polar RZ, Manchester, AMI)](https://www.bctengineer.com/question.md?key=semester_6%2Fcommunication_systems%3Aline-codes-1011001010) — Communication Systems, chapter 6, asked 8× - [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 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×