Optimized High Speed Digital Tutorial
34 Pages
English
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Optimized High Speed Digital Tutorial

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Downloading requires you to have access to the YouScribe library
Learn all about the services we offer
34 Pages
English

Description

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 ...

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Language English

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High Speed Digital Interconnects and Signal Integrity
1
0
Digital Signal Integrity
This is what we would like to have:
1
0
This 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 Aberrations
We 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 Levels Possible Bit Error
The Signal Voltage must make into the “End Zone”
within the allotted period of time.
Pulse Risetime
Risetime is the most important factor in determining Bandwidth requirements.
Differential Signaling
Immunity from Ground Noise
Immunity to Electromagnetic Interference
Works with low Voltages, saves Power
Differential Mode
Common Mode
Twinax / Quadrax
Field Patterns
Twinax Electric Field
Twinax Magnetic Field
Eye Pattern
The Eye Pattern is simply a bunch 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 Mask
High 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 be taken into account in order to preserve the Signal Integrity. Understanding High Frequency Design Techniques requires understanding the basics of Transmission Line Theory. First, we need to understand the High Frequency content of the Digital Signal…
Frequency Content of the Digital Signal
Mother Nature can’t create Square Waves, she can only create Sine Waves.
Waves of any other shape are Composed of Overlapping Sine Waves.
Square Waves are composed of a Superposition of Odd Harmonic Sine Waves.