--- title: "Encode 10110001110 with unipolar, polar, bipolar codes" subject: "Data Communication" chapter: 5 key: "semester_5/data_communication:line-coding-10110001110-68c" source: https://www.bctengineer.com/q/semester_5/data_communication/line-coding-10110001110-68c site: BCT Engineering --- # Encode 10110001110 with unipolar, polar, bipolar codes Data Communication · Chapter 5: Data Encoding and Modulation - Asked in: 2068 Chaitra, 6 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 Sonnet 5.5 on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_5/data_communication/line-coding-10110001110-68c - Whole chapter: https://www.bctengineer.com/md/semester_5/data_communication/chapter-5 ## Question Encode the following bit stream using unipolar (NRZ), polar (NRZ-L, NRZ-I, RZ, Manchester), bipolar (AMI) 10110001110. ## Short answer Unipolar NRZ: + 0 + + 0 0 0 + + + 0. NRZ-L: + – + + – – – + + + –. NRZ-I (from –V): + + – + + + + – + – –. RZ: +0 –0 +0 +0 –0 –0 –0 +0 +0 +0 -0. Manchester: ↑ ↓ ↑ ↑ ↓ ↓ ↓ ↑ ↑ ↑ ↓. AMI: + 0 – + 0 0 0 – + – 0. ## Answer **Conventions used:** - Unipolar NRZ: 1 = +V, 0 = 0 V. - NRZ-L: 1 = +V, 0 = −V (level depends on the bit value). - NRZ-I: a 1 causes a transition at the start of the bit, a 0 keeps the previous level (starting level assumed −V). - RZ: 1 = +V for the first half then 0; 0 = −V for the first half then 0 (returns to zero in every bit). - Manchester: mid-bit transition; 1 = low-to-high, 0 = high-to-low. - Bipolar AMI: 0 = zero; 1s alternate +V and −V, first 1 is +V. ```text unipolar 1 0 1 1 0 0 0 1 1 1 0 +V ────┐ ┌───────┐ ┌───────────┐ 0 └───┘ └───────────┘ └─── -V NRZ-L 1 0 1 1 0 0 0 1 1 1 0 +V ────┐ ┌───────┐ ┌───────────┐ 0 │ │ │ │ │ -V └───┘ └───────────┘ └─── NRZ-I 1 0 1 1 0 0 0 1 1 1 0 +V ────────┐ ┌───────────────┐ ┌───┐ 0 │ │ │ │ │ -V └───┘ └───┘ └─────── RZ 1 0 1 1 0 0 0 1 1 1 0 +V ──┐ ┌─┐ ┌─┐ ┌─┐ ┌─┐ ┌─┐ 0 └─┐ ┌─┘ └─┘ └─┐ ┌─┐ ┌─┐ ┌─┘ └─┘ └─┘ └─┐ ┌─ -V └─┘ └─┘ └─┘ └─┘ └─┘ Manchester 1 0 1 1 0 0 0 1 1 1 0 +V ┌───┐ ┌─┐ ┌───┐ ┌─┐ ┌─┐ ┌─┐ ┌─┐ ┌───┐ 0 │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ -V ──┘ └───┘ └─┘ └─┘ └─┘ └───┘ └─┘ └─┘ └─ AMI 1 0 1 1 0 0 0 1 1 1 0 +V ────┐ ┌───┐ ┌───┐ 0 └───┐ │ └───────────┐ │ │ ┌─── -V └───┘ └───┘ └───┘ ``` **Level sequences (per bit):** - Unipolar NRZ: +, 0, +, +, 0, 0, 0, +, +, +, 0 - NRZ-L: +, −, +, +, −, −, −, +, +, +, − - NRZ-I: + (toggled from −), +, −, +, +, +, +, −, +, −, − - RZ: +0, −0, +0, +0, −0, −0, −0, +0, +0, +0, −0 - Manchester: ↑, ↓, ↑, ↑, ↓, ↓, ↓, ↑, ↑, ↑, ↓ - AMI: +, 0, −, +, 0, 0, 0, −, +, −, 0 The long run of three 0s (bits 5 to 7) gives a flat line in unipolar, NRZ-L (at −V), NRZ-I and AMI, which is a synchronization problem. RZ and Manchester still have transitions in every bit. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What are the levels for unipolar NRZ in this answer? A. 1 = +V, 0 = 0 V B. 1 = +V, 0 = -V C. 1 = 0 V, 0 = +V D. Alternating Answer: A. Unipolar uses only one polarity. (Key point: Unipolar) 2. Starting at -V, what is the NRZ-I sequence for 1 0 1 1 0 0 0 1 1 1 0? A. +, +, -, +, +, +, +, -, +, -, - B. +, -, +, +, -, -, -, +, +, +, - C. +, +, +, -, -, +, +, -, -, +, + D. -, -, +, -, -, -, -, +, -, +, + Answer: A. Each 1 toggles; each 0 keeps the level. (Key point: NRZ-I sequence) 3. Why is the run of three 0s a problem for NRZ-L, NRZ-I, unipolar and AMI? A. Flat line, so no transitions for clock recovery B. It creates a DC offset only C. It doubles bandwidth D. It causes alias Answer: A. No transitions gives a synchronisation problem; RZ and Manchester still transition each bit. (Key point: Sync problem) 4. What is the AMI sequence for the bit stream? A. +, 0, -, +, 0, 0, 0, -, +, -, 0 B. +, 0, +, +, 0, 0, 0, +, +, +, 0 C. +, 0, -, -, 0, 0, 0, +, +, -, 0 D. +, 0, -, +, 0, 0, 0, +, -, +, 0 Answer: A. 1s alternate + - + - + -. (Key point: AMI) ## Close variants set in other exams - [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× - [Encode 1001101110 with unipolar, polar, bipolar codes](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aline-coding-1001101110) — Data Communication, chapter 5, asked 3× ## Related in Data Communication - [Polar, unipolar, bipolar, Manchester; encode 101000111011](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aline-coding-101000111011) — 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 10110001110 with five line codes](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aline-coding-10110001110) — Data Communication, chapter 5 - [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 10010110001 with NRZ-L, NRZ-I, diff. Manchester](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aline-coding-10010110001) — Data Communication, chapter 5 - [Encode 1010011001 with five line codes](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aline-coding-1010011001) — Data Communication, chapter 5 ## Related in other subjects - [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 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 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 - [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×