Skip to main content

Encode 1001101110 with unipolar, polar, bipolar codes

Short answer

Unipolar: + 0 0 + + 0 + + + 0. NRZ-L: + – – + + – + + + –. NRZ-I (from –V): + + + – + + – + – – (toggle on 1). RZ: +0 –0 –0 +0 +0 –0 +0 +0 +0 –0. Manchester: ↑ ↓ ↓ ↑ ↑ ↓ ↑ ↑ ↑ ↓. AMI: + 0 0 – + 0 – + – 0.

Encode the bit stream 1001101110 using unipolar, polar (NRZ-I, NRZ-L, RZ, Manchester), bipolar (AMI) encoding techniques.

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.
bits: 1001101110
unipolar
   1   0   0   1   1   0   1   1   1   0   
+V ────┐       ┌───────┐   ┌───────────┐   
0      └───────┘       └───┘           └───
-V                                         

NRZ-L
   1   0   0   1   1   0   1   1   1   0   
+V ────┐       ┌───────┐   ┌───────────┐   
0      │       │       │   │           │   
-V     └───────┘       └───┘           └───

NRZ-I
   1   0   0   1   1   0   1   1   1   0   
+V ────────────┐   ┌───────┐   ┌───┐       
0              │   │       │   │   │       
-V             └───┘       └───┘   └───────

RZ
   1   0   0   1   1   0   1   1   1   0   
+V ──┐         ┌─┐ ┌─┐     ┌─┐ ┌─┐ ┌─┐     
0    └─┐ ┌─┐ ┌─┘ └─┘ └─┐ ┌─┘ └─┘ └─┘ └─┐ ┌─
-V     └─┘ └─┘         └─┘             └─┘ 

Manchester
   1   0   0   1   1   0   1   1   1   0   
+V   ┌───┐ ┌─┐   ┌─┐ ┌───┐   ┌─┐ ┌─┐ ┌───┐ 
0    │   │ │ │   │ │ │   │   │ │ │ │ │   │ 
-V ──┘   └─┘ └───┘ └─┘   └───┘ └─┘ └─┘   └─

AMI
   1   0   0   1   1   0   1   1   1   0   
+V ────┐           ┌───┐       ┌───┐       
0      └───────┐   │   └───┐   │   │   ┌───
-V             └───┘       └───┘   └───┘   

Level sequences (per bit):

  • Unipolar: +, 0, 0, +, +, 0, +, +, +, 0
  • NRZ-L: +, −, −, +, +, −, +, +, +, −
  • NRZ-I: + (toggled from −), +, +, −, +, +, −, +, −, −
  • RZ: +0, −0, −0, +0, +0, −0, +0, +0, +0, −0
  • Manchester: ↑, ↓, ↓, ↑, ↑, ↓, ↑, ↑, ↑, ↓
  • AMI: +, 0, 0, −, +, 0, −, +, −, 0

NRZ-I and AMI depend on history; NRZ-L, RZ and Manchester depend only on the present bit.

✓ Answer checked by Claude Sonnet 5.5

All Data Communication chapter 5 questions →