Line code: Difference between revisions

Revision as of 18:36, 12 July 2005

Revision as of 18:01, 17 October 2005

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After line coding, the signal can directly be put on a transmission line, in the form of variations of the current. The common types of line encoding are [[Unipolar encoding|unipolar]], [[Polar encoding|polar]], [[Bipolar encoding|bipolar]] and [[Manchester encoding]].

A line coded signal must not contain a DC-component (the average signal level should be 0), because transport of a DC-component is impossible in case of long wires. An included DC-component would therefore lead to an offestoffset at the receiving end, and thus to a higher decoding error probability.

Line coding should make it possible for the receiver to synchronise itself to the [[phase]] of the received signal. If the synchronisation is not ideal, then the signal to be decoded will not have optimal differences (in amplitude) between the various digits or symbols used in the line code. This will increase the error probability in the received data.