Non return to zero

In telecommunication, a non-return-to-zero (NRZ) line code is a binary code in which "1s" are represented by one significant condition and "0s" are represented by the other significant condition, with no other neutral or rest condition. The pulses have more energy than a RZ code. Unlike RZ, NRZ does not have a rest state. NRZ is not inherently a self-synchronizing code, so some additional synchronization technique (perhaps a run length limited constraint, or a parallel synchronization signal) must be used to avoid bit slip.
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A code in which "1s" are represented by one significant condition and "0s" are represented by another, with no neutral or rest condition, such as a zero amplitude in amplitude modulation (AM), zero phase shift in phase-shift keying (PSK), or mid-frequency in frequency-shift keying (FSK). (188 ) Note 1: Contrast with Manchester code, return-to-zero. Note 2: For a given data signaling rate, i.e., bit rate, the NRZ code requires only one-half the bandwidth required by the Manchester code.