Self-clocking Signal - Implementations

Implementations

Example uses of self-clocking signal protocols include:

• Isochronous
  • Manchester code, where the clock signals occur at the transition points.
  • Plesiochronous Digital Hierarchy signals
  • Eight-to-Fourteen Modulation
  • 4B5B
  • 8b/10b encoding
  • HDLC
  • Modified Frequency Modulation
• Anisochronous
  • Morse code
  • Asynchronous start-stop

Most of these codes can be seen as a kind of Run Length Limited code. Those constraints on "runs" of zeros and "runs" of ones ensure that transitions occur often enough to keep the receiver synchronized.

Such self-clocking signals can be decoded correctly into a stream of bits without bit slip. To further decode that stream of bits and decide which bit is the first bit of a byte, often a self-synchronizing code is used.