April 8, 2010 -- Impedance mismatches on PCBs (printed-circuit boards) and backplanes can cause reflections that impair high-speed chip-to-chip connections. These reflections also create ISI (intersymbol interference), an echo of a previous bit superimposed on the current bit, which causes your system to become unreliable. To overcome the interference, you can employ various signal-processing techniques, including de-emphasis, in which you predistort the signal before transmission. You use an analog filter to make a CTE (continuous-time equalizer) in the transmission path in just a few minutes.
By Sanjeev Gupta. (Gupta is a signal-integrity-applications manager at Agilent EEsof.)
This brief introduction has been excerpted from the original copyrighted article.