NRZ (Non-Return to Zero)

Definition

NRZ (Non-Return to Zero) is a binary encoding scheme where binary 1 is represented by one significant condition (usually a positive voltage) and binary 0 by another (usually a negative or zero voltage), with no neutral or rest condition between bits.

Detailed Explanation

NRZ encoding comes in two main variants: NRZ-L (Level) and NRZ-I (Invert).

NRZ-L (Level):

  • Binary 1: Positive voltage
  • Binary 0: Negative voltage
  • Most straightforward encoding method
  • Used in short-distance, low-speed communications

NRZ-I (Invert):

  • Change in voltage level represents 1
  • No change represents 0
  • Better for long sequences of same bits
  • Provides some self-synchronization

Advantages:

  • Simple to implement
  • Efficient bandwidth usage
  • Easy to decode

Limitations:

  • No error detection
  • Loss of synchronization during long sequences of same bit
  • DC component present
  • Not suitable for high-speed communication over long distances