Encyclopedia > Plesiochronous

  Article Content

Plesiochronous

The term plesiochronous is derived from the Greek plesio, meaning near, and chronos, time, and refers to the fact that plesiochronous systems run in a state where different parts of the system are almost, but not quite perfectly, synchronised.

According to ITU-T standards, corresponding signals are plesiochronous if their significant instants occur at nominally the same rate, with any variation in rate being constrained within specified limits. In general, plesiochronous systems behave similarly to synchronous systems, except that they must have some means to cope with "sync slips", which will happen at intervals due to the plesiochronous nature of the system.

The most common example of a plesiochronous system design is the Plesiochronous Digital Hierarchy networking standard.

The modern tendency in systems engineering is towards using systems that are either fundamentally asynchronous (such as Ethernet), or fundamentally synchronous (such as SDH), and layering these where necessary, rather than using a mixture between the two in a single technology.

See also:

Contains material from FOLDOC, used with permission



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Northwest Harbor, New York

... are 65 years of age or older. The median age is 41 years. For every 100 females there are 98.0 males. For every 100 females age 18 and over, there are 96.5 males. The ...

 
 
 
This page was created in 38.8 ms