The document discusses different methods for representing binary sequences including unipolar, bipolar, return-to-zero, biphase or Manchester, and alternate mark inversion encoding. Unipolar encoding represents 1s as positive current and 0s as no current. Bipolar encoding represents 1s as positive current and 0s as negative current. Return-to-zero encoding uses positive or negative pulses half the width of bipolar that return to zero before the next bit. Biphase or Manchester encoding represents 1s as a transition from positive to negative current and 0s as a transition from negative to positive current. Alternate mark inversion encoding represents 1s as return-to-zero pulses that alternate between positive and negative levels

1. Binary Signals Tayyab Arif Allama Iqbal Open University Islamabad Mob: 03445064252 Email: leopk01@yahoo.com

2. Binary Signals 4.5.1 Representation of Binary Sequences: Uni-polar Bipolar Return-to-Zero Bi-phase or Manchester Alternate mark inversion (AMI)

3. Binary Signals Unipolar: For 1s Positive Current Flows. For 0s no current flows. Requires most power.

4. 00110101 Unipolar encoding Time Amplitude 0 0 0 0 1 1 1 1

5. Binary Signals Bipolar: For 1s positive Current flows. For 0s negative Current flows. Most used in electric Circuits.

6. 00110101 Bipolar encoding Time Amplitude 0 0 0 0 1 1 1 1

7. Binary Signals Return-to-zero: Bits are represented by a positive or a negative current pulse that is one half the width of bipolar signals. The current level returns to zero before thenext bit in the sequence is handled.

8. 00110101 Polar encoding – Return to Zero: RZ Time Amplitude 0 0 0 0 1 1 1 1

9. Binary Signals Biphase or Manchester: A 1 is a positive current that changes to a negative current. A 0 is a negative current that changes to a positive current. Changeover occur exactly at the middle of the bit period. Reduces the chance for error.

10. 00110101 Polar encoding – Biphase - Manchester Time Amplitude 0 0 0 0 1 1 1 1

11. 00110101 Polar encoding – Biphase - Manchester Time Amplitude 0 0 0 0 1 1 1 1 0 1

12. Binary Signals Alternate mark inversion (AMI): 1s are represented by return-to-zero pulses that alternate between positive and negative levels. 0s are represented by the absence of puses.

13. 00110101 Bipolar encoding – AMI (alternate mark inversion) Time Amplitude 0 0 0 0 1 1 1 1

14. Tayyab Arif Allama Iqbal Open University Islamabad Mob: 03445064252 Email: leopk01@yahoo.com Ref: Telecommunication Primer Signals, Building Blocks and networks by E.Bryan