RZ vs NRZ vs manchester-Difference between RZ,NRZ,manchester code

Digital signals are usually sequencial binary information in the form of zeros and ones. Each of this binary digits are represented by some pulse width. This pulse width vary based on the transmission data rate requirements. There are three signal types used in digital transmission of binary information. They are NRZ, RZ and manchester codes. This page describes RZ, NRZ, manchester code basics and mention difference between RZ, NRZ and manchester codes.

RZ vs NRZ vs manchester code

NRZ-Non Return to Zero

In the case of NRZ, binary digits change between H and L value and does not remain at ground or DC potential. Let us take assumption that H means High and L means Low. There are two types of NRZ waveforms viz. unipolar and bipolar.

In unipolar, H and L values are both either above zero or below zero potential. In bipolar, binary digits are both above as well as below zero potential. The bit time Tb is the time during which single digit of data is either low or high. Hence pulse width Tp is equal to Tb where in Tb is the bit period.

RZ-Return to Zero

In the case of RZ, after every binary digit, signal returns to the zero or ground potential. Hence here pulse width is half of the binary digit bit period.
Tp = Tb/2

Manchester code

manchester code

In the case of Manchester coding, edges are sensed and based on this meaning is provided to the digital data. When the transmission is from L to H , then the received bit is taken as zero (i.e. '0'). When the transmission is from H to L, then the received bit is taken as one (i.e. '1').
Refer Manchester vs Diff. Manchester encoding >> for more information.

Comparison between NRZ and RZ pulse shapes used in line coding

Line encoder and Line decoder

Refer RZ versus NRZ >> which mentions comparison between RZ and NRZ pulse shapes including their advantages and disadvantages. The RZ and NRZ line coding is used for digital communication and optical Duobinary transmission system.

Line coding techniques

Difference between Unipolar Polar and Bipolar coding    RZ vs NRZ vs Manchester coding    RZ vs NRZ pulse shapes    Advantages and disadvantages of NRZ encoding    RZ encoding    2B1Q coding    8B6T coding    4D PAM5 coding    MLT-3 coding    4B/5B encoding    8B/10B encoding    R8ZS scrambling    HDB3 scrambling   

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