--- title: "Line coding 1001101101 (unipolar NRZ, polar RZ, AMI, Manchester)" subject: "Communication Systems" chapter: 6 key: "semester_6/communication_systems:line-codes-1001101101" source: https://www.bctengineer.com/q/semester_6/communication_systems/line-codes-1001101101 site: BCT Engineering --- # Line coding 1001101101 (unipolar NRZ, polar RZ, AMI, Manchester) Communication Systems · Chapter 6: Baseband Digital Data Transmission - Asked in: 2081 Bhadra (CS II), 1.5+1.5+1.5+1.5 marks - Video: [Line coding in digital communication- Polar, Unipolar, Bipolar, RZ ,NRZ in simple way | HINDI](https://www.youtube.com/watch?v=rHPa0VU27l0) — Electronics Subjectified - 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-1001101101 - Whole chapter: https://www.bctengineer.com/md/semester_6/communication_systems/chapter-6 ## Question Represent given binary sequence 1001101101 in unipolar NRZ, polar RZ, AMI, and Manchester codes. ## Short answer For 1001101101: Unipolar NRZ: 1→+V full bit, 0→0 V. Polar RZ: 1→+V half-bit then 0, 0→-V half-bit then 0. AMI: 0→0 V, 1s alternate +V,-V starting +V. Manchester: 1→+V then -V, 0→-V then +V, with mid-bit transition. ## Answer Bit sequence: **1 0 0 1 1 0 1 1 0 1**, bit period $T_b$, levels $\pm V$. #### Unipolar NRZ 1 → +V for the full bit, 0 → 0 V. **Unipolar NRZ** ```text 1 0 0 1 1 0 1 1 0 1 +V ────| |───────| |───────| |─── 0 |───────| |───| |───| ``` #### Polar RZ 1 → +V for half the bit, 0 → −V for half the bit, then 0. **Polar RZ** ```text 1 0 0 1 1 0 1 1 0 1 +V ──| |─| |─| |─| |─| |─| 0 |─| |─| |─| |─| |─| |─| |─| |─| |─| |─ -V |─| |─| |─| |─| ``` #### AMI 0 → 0 V. The 1s are half-width pulses of alternating polarity: + − + − + −. **AMI (RZ)** ```text 1 0 0 1 1 0 1 1 0 1 +V ──| |─| |─| 0 |─────────| |─| |─────| |─| |─────| |─ -V |─| |─| |─| ``` #### Manchester 1 → +V then −V, 0 → −V then +V. There is a transition at every mid-bit. **Manchester** ```text 1 0 0 1 1 0 1 1 0 1 +V ──| |─| |───| |─| |───| |─| |───| -V |───| |─| |─| |───| |─| |───| |─ ``` ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. How does unipolar NRZ send a 0? A. 0 V for the full bit B. Half-bit pulse C. -V D. Alternating pulse Answer: A. Unipolar NRZ sends +V for the full bit for 1 and 0 V for 0. (Key point: Unipolar NRZ) 2. For 1001101101 (six 1s), the AMI pulses are: A. - + - + - + B. + - - + + - C. + - + - + - D. + + + + + + Answer: C. AMI alternates polarity on each 1, so six 1s give + - + - + -. (Key point: AMI polarity) 3. Polar RZ returns to zero after: A. The full bit B. Never C. Half the bit for both 1 and 0 D. Only for 1 Answer: C. Both 1 (+V) and 0 (-V) last half the bit and then return to 0. (Key point: Polar RZ) 4. Why is Manchester useful for synchronisation? A. It uses one level B. It has no transitions C. Zero average and a transition in every bit D. It needs less bandwidth Answer: C. Every bit has a mid-bit transition, giving clock information. (Key point: Manchester timing) ## 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 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× - [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 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× ## 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×