isochronous definition
<communications> /i:-sok'rn-*s/ A form of multiplexing that
guarantees to provide a certain minimum data rate, as
required for time-dependent data such as video or audio.
Isochronous transmission transmits asynchronous data over a
synchronous data link so that individual characters are only
separated by a whole number of bit-length intervals. This is
in contrast to asynchronous transmission, in which the
characters may be separated by arbitrary intervals, and with
synchronous transmission [which does what?].
An isochronous message protocol assigns each data source a
fixed amount of time to transmit (its "slot") within each
cycle through the sources. That guarantees that each source
will have regular opportunities to transmit the latest
information. If a source has no more data to transmit, then
the rest of its time slot is wasted. If it has more to send
than will fit in its slot, it has to either store the excess
data and transmit it in its next slot, or discard it.
Note that whether messages are isochronous or asynchronous is
independent of whether the transmision of individual bits is
synchronous or asynchronous.
Isochronous communication suits applications where a steady
data stream is more important than completeness and accuracy,
e.g. video conferencing.
Asynchronous Transfer Mode and High Performance Serial Bus
can provide isochronous service.
Compare: plesiochronous.
[ANIXTER, LAN Magazine 7.93]
(2006-06-13)
Nearby terms:
ISO 9735 « ISOC « ISO C « isochronous » isochronous transfer » ISODE » ISO Development Environment
|
