Skew (electronics)
The English term skew , in German analogous to time offset , is used in electronics to describe the time difference between signals on different conduction paths.
Signals that are transmitted in an electronic system travel with a finite speed on their line from the source to the sink. The time it takes for a signal to travel from source to sink is the signal transit time . In the case of cables, this is mainly determined by the material used, the speed (v), the speed of light (c), the dielectric constant (ε r ) and the length .
If several signals are transmitted in parallel on different lines as part of the parallel data transmission, the individual signals arrive at the sink at slightly different times due to slightly different signal transit times. The skew is calculated from the difference in the running times; the maximum skew is of interest here.
This can be remedied by making the various parallel lines as identical as possible, in particular with exactly the same length. Another possibility is the general avoidance of parallel data transmission and the use of serial data transmission methods with high bit rates, also known as SerDes . On the physical layer, there is then only one transmission line, for example according to the LVDS standard , which eliminates the problem of time delay.
See also
literature
- Eric Bogatin: Signal Integrity - Simplified . Prentice Hall, 2003, ISBN 978-0-13-066946-9 .
- Dieter Sautter, Hans Weinerth: Lexicon Electronics and Microelectronics. 2nd edition, Springer Verlag, Berlin / Heidelberg 1997, ISBN 978-3-5406-2131-7 .
- Luciano Lavagno, Igor L. Markov, Grant Martin, Louis K. Scheffer (Eds.): Electronic Design Automation for IC Implementation, Circuit Design, and Process Technology. 1st edition, Taylor & Francis Group, London 2016, ISBN 978-1-4822-5460-0 .