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Line Coding in Digital to Digital Conversion
about 8 years ago
Line Coding
Line coding consists of representing the digital signal to be transported, by a waveform that is optimally tuned for the specific properties of the physical channel (and of the receiving equipment).
The pattern of voltage, current or photons used to represent the digital data on a transmission link is called line encoding. The common types of line encoding are unipolar, polar, bipolar, and Manchester encoding.
Signal Comments NRZ–L Non return to zero level. This is the standard positive logic signal format used in digital circuits. 1 forces a high level
0 forces a low levelNRZ–M Non return to zero mark 1 forces a transition
0 does nothingNRZ–S Non return to zero space 1 does nothing
0 forces a transitionRZ Return to zero 1 goes high for half the bit period
0 does nothingBiphase–L Manchester. Two consecutive bits of the same type force a transition at the beginning of a bit period. 1 forces a negative transition in the middle of the bit
0 forces a positive transition in the middle of the bitBiphase–M There is always a transition at the beginning of a bit period. 1 forces a transition in the middle of the bit
0 does nothingBiphase–S There is always a transition at the beginning of a bit period. 1 does nothing
0 forces a transition in the middle of the bitDifferential Manchester There is always a transition in the middle of a bit period. 1 does nothing
0 forces a transition at the beginning of the bitThe conversion of the digital data into the digital signal is known as Line Coding. The data in digital is in the binary form. It is represented by the 1 and 0.
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