Differential Manchester encoding
Differential Manchester encoding:
Encoding in which
(a) data and clock signals are combined to form a single self-synchronizing data stream,
(b) one of the two bits, i.e., “0″ or “1″, is represented by no transition at the beginning of a pulse period and a transition in either direction at the midpoint of a pulse period, and
(c) The other is represented by a transition at the beginning of a pulse period and a transition at the midpoint of the pulse period.
In differential Manchester encoding, if a “1″ is represented by one transition, a “0″ is represented by two transitions, and vice versa.
In differential Manchester encoding, the transition at the middle of the bit is used only for synchronization. The bit representation is defined by the inversion or no inversion at the beginning of the bit.
- Mid-bit transition is ONLY for clocking.
- 1 = absence of transition at the beginning of the bit interval
- 0 = presence of transition at the beginning of the bit interval
- Differential Manchester is both differential and bi-phase.
- The coding is the opposite convention from NRZI.
Used in 802.5 (token ring) with twisted pair.
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