Optimized High Speed Digital Tutorial

High Speed Digital Interconnects and Signal Integrity10Digital Signal IntegrityThis is what we would like to have:10This is more like what we get in real life:This would be considered to be a “clean” signal.In real life, it is not always 1,0,1,0…Signal AberrationsWe are trying to create a Square Wave, but Mother Nature just won’t let us do it!It is Physically Impossible to create a perfect Square Wave!Logic LevelsPossible Bit ErrorThe Signal Voltage must make into the “End Zone” within the allotted period of time.Pulse RisetimeRisetime is the most important factor in determining Bandwidth requirements.Differential Signaling• Immunity from Ground Noise• Immunity to Electromagnetic Interference• Works with low Voltages, saves PowerDifferential ModeCommon ModeTwinax / Quadrax Field PatternsTwinax Electric Field Twinax Magnetic FieldEye PatternThe Eye Pattern is simply abunch of pulses, both positive and negative, chopped up and overlaid upon each other.It is an easy way to evaluate the Signal Integrity of Thousands of pulses at a glance.The shape of each pulse is affected by the whether the previous pulse was a 1 or 0.This is why we need to use a Pseudo Random Bit Stream (PRBS) to simulate an actual data stream.Eye Pattern MaskHigh Speed Digital & Signal Integrity• What makes High Speed Digital different than old fashion digital?• The High Frequency content of the Digital Signal requires that High Frequency Design Techniques ...