Self-synchronizing code

Not to be confused with self-clocking signal.

In telecommunications, a self-synchronizing code^[1] is a line code in which the symbol stream formed by a portion of one code word, or by the overlapped portion of any two adjacent code words, is not a valid code word. Put another way, a set of strings (called "code words") over an alphabet is called a self-synchronizing code if for each string obtained by concatenating two code words, the substring starting at the second symbol and ending at the second-last symbol does not contain any code word as substring.

A synonym for self-synchronizing code is comma-free code.^[2] However, sometimes the term comma-free code is used in the meaning of prefix code.^[3] The latter is a broader concept: every self-synchronizing code is a prefix code, but not all prefix codes are self-synchronizing.

A self-synchronizing code permits the proper framing of transmitted code words provided that no uncorrected errors occur in the symbol stream; external synchronization is not required. Self-synchronizing codes also allow recovery from uncorrected errors in the stream; with most prefix codes, an uncorrected error in a single bit may propagate errors further in the stream and make the subsequent data unreadable.

Examples

• High-Level Data Link Control (HDLC)
• Advanced Data Communication Control Procedures (ADCCP)
• UTF-8

See also

• Framing (telecommunication)
• Bit slip
• Self-clocking signal

Notes

1. ^ US Federal Standard 1037C
2. ^ Berstel, Jean; Perrin, Dominique (1985), Theory of Codes, Academic Press 
3. ^ US Federal Standard 1037C

References

•  This article incorporates public domain material from the General Services Administration document "Federal Standard 1037C" (in support of MIL-STD-188).

This article related to telecommunications is a stub. You can help Wikipedia by expanding it.v · Categories: Line codes Synchronization Telecommunications stubs Wikimedia Foundation. 2010. Игры ⚽ Поможем написать реферат Security management Semiautomatic switching system Look at other dictionaries: Self-clocking signal — In telecommunications and electronics, a self clocking signal is one that can be decoded without the need for a separate clock signal or other source of synchronization. This is usually done by including embedded synchronization information… …   Wikipedia Code point — Not to be confused with Point code. In character encoding terminology, a code point or code position is any of the numerical values that make up the code space (or code page).[1] For example, ASCII comprises 128 code points in the range 0hex to… …   Wikipedia Line code — An example of coding a binary signal using rectangular pulse amplitude modulation with polar non return to zero code …   Wikipedia List of electronics topics — Alphabetization has been neglected in some parts of this article (the b section in particular). You can help by editing it. This is a list of communications, computers, electronic circuits, fiberoptics, microelectronics, medical electronics,… …   Wikipedia Non-return-to-zero — The binary signal is encoded using rectangular pulse amplitude modulation with polar non return to zero code In telecommunication, a non return to zero (NRZ) line code is a binary code in which 1 s are represented by one significant condition… …   Wikipedia Run length limited — or RLL coding is a technique that is used to store data on recordable media. Specifically, RLL prevents long stretches of repeated bits from causing the signal recorded on media to not change for an excessive period, by modulating the data. RLL… …   Wikipedia Symbol rate — In digital communications, symbol rate (also known as baud or modulation rate) is the number of symbol changes (waveform changes or signalling events) made to the transmission medium per second using a digitally modulated signal or a line code.… …   Wikipedia Syncword — In computer networks, a syncword, sync character or preamble is used to synchronize a transmission by indicating the end of header information and the start of data. Contents 1 Examples 2 Alternatives 3 Preamble 4 …   Wikipedia Comparison of synchronous and asynchronous signalling — Synchronous and asynchronous transmissions are two different methods of transmission synchronization. Synchronous transmissions are synchronized by an external clock, while asynchronous transmissions are synchronized by special signals along the… …   Wikipedia Frame synchronization — While receiving a stream of framed data, frame synchronization is the process by which incoming frame alignment signals, i.e. , distinctive bit sequences (a syncword), are identified, i.e. , distinguished from data bits, permitting the data bits… …   Wikipedia 18+ © Academic, 2000-2024 Contact us: Technical Support, Advertising Dictionaries export, created on PHP, Joomla, Drupal, WordPress, MODx. Mark and share Search through all dictionaries Translate… Search Internet Share the article and excerpts Direct link … Do a right-click on the link above and select “Copy Link”