--- title: "Encode 1101001 with polar NRZ, AMI, Manchester" subject: "Data Communication" chapter: 5 key: "semester_5/data_communication:line-coding-1101001" source: https://www.bctengineer.com/q/semester_5/data_communication/line-coding-1101001 site: BCT Engineering --- # Encode 1101001 with polar NRZ, AMI, Manchester Data Communication · Chapter 5: Data Encoding and Modulation - Asked in: 2069 Asar, 3 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-1101001 - Whole chapter: https://www.bctengineer.com/md/semester_5/data_communication/chapter-5 ## Question Encode the following bit stream using polar NRZ, Bipolar AMI and Manchester encoding techniques 1101001. ## Short answer Polar NRZ-L: +V +V –V +V –V –V +V. Bipolar AMI: +V –V 0 +V 0 0 –V (alternating polarity on 1s, first 1 +V). Manchester: L→H L→H H→L L→H H→L H→L L→H (mid-bit transition, 1 low-to-high, 0 high-to-low). ## Answer Bit stream: 1 1 0 1 0 0 1 **Conventions used:** - Polar NRZ-L: 1 = +V, 0 = −V for the whole bit time. - Bipolar AMI: 0 = zero level; 1s alternate between +V and −V (first 1 is +V). - Manchester: transition in the middle of every bit; 1 = low-to-high, 0 = high-to-low. ```text NRZ-L 1 1 0 1 0 0 1 +V ────────────┐ ┌─────┐ ┌───── 0 │ │ │ │ -V └─────┘ └───────────┘ AMI 1 1 0 1 0 0 1 +V ──────┐ ┌─────┐ 0 │ ┌─────┘ └───────────┐ -V └─────┘ └───── Manchester 1 1 0 1 0 0 1 +V ┌──┐ ┌─────┐ ┌─────┐ ┌──┐ ┌── 0 │ │ │ │ │ │ │ │ │ -V ───┘ └──┘ └─────┘ └──┘ └─────┘ ``` **Reading the waveforms:** - NRZ-L: +V, +V, −V, +V, −V, −V, +V. - AMI: +V, −V, 0, +V, 0, 0, −V (the four 1s alternate +, −, +, −). - Manchester: bits give L→H, L→H, H→L, L→H, H→L, H→L, L→H. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. For 1 1 0 1 0 0 1, which polar NRZ-L level sequence is correct? A. +, +, -, +, -, -, + B. +, -, +, +, -, -, + C. +, +, 0, +, 0, 0, + D. -, -, +, -, +, +, - Answer: A. 1 = +V and 0 = -V for the whole bit. (Key point: NRZ-L levels) 2. For 1 1 0 1 0 0 1, what is the AMI sequence? A. +, +, 0, +, 0, 0, + B. +, -, 0, +, 0, 0, - C. +, -, 0, -, 0, 0, + D. -, +, 0, -, 0, 0, + Answer: B. The four 1s alternate + - + -. (Key point: AMI levels) 3. What does Manchester give for bits 0 and 1 here? A. 0 = H to L, 1 = L to H B. 0 = L to H, 1 = H to L C. 0 = 0 V, 1 = +V D. Transition only on 1 Answer: A. Mid-bit transition in every bit; 1 low-to-high, 0 high-to-low. (Key point: Manchester) ## Close variants set in other exams - [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× - [Encode 10110001110 with unipolar, polar, bipolar codes](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aline-coding-10110001110-68c) — 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 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 - [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 1010011001 with five line codes](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aline-coding-1010011001) — Data Communication, chapter 5 - [Line coding: properties; encode 01001100011](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aline-coding-01001100011) — Data Communication, chapter 5 ## Related in other subjects - [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 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 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 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×