GIGABIT ETHERNET DESIGN ECE164.02 - Spring 2004 Presentation #3

Introduction Tested Transmitter Evaluation Board Eye Testing BER Testing Built Practice Board Receiver Intro to Design Exposure to Surface Soldering Tested Practice Board Attenuation Effects Modified Gantt Chart

Evaluation - Transmitter Testing Test Setup for Reading in Scope

Evaluation - Transmitter Testing Ugly Eye Shown No attenuation Ran out of “film” Disk Problems with Oscilloscope

More Problems Evaluation - Transmitter Testing Poor BER High Error Rate Again, no more space on digital camera

Evaluation – Receiver Testing Test Setup to Scope for the Evaluation Receiver Circuit

Evaluation – Receiver Testing Very Descent Eye No attenuation Small Undesirable Line on Right-hand Side No detectable errors

Adding Attenuation As expected, the eye degrades with more and more attenuation (20 dB shown for eye) (34 dB shown for BER) BER = 4.8E-07

Getting Our Feet Wet Soldering Flux is Useful for surface that are not “sticky” Need good contact for a good signal

Building Receiver Better feel for how the circuit works and where the signal is going Surface Soldering is not frustrating Proper Power Supply Connectors Unavailable – Used wires to begin testing

Practice – Receiver Testing Setup for eye testing in oscilloscope

Practice – Receiver Testing Differential Outputs Verification Pretty much symmetric waveforms

Practice – Receiver Testing Poor Eye with no attenuation But…

Practice – Receiver Testing Adding 10 dB attenuation results in a very clean eye Why?

Practice – Receiver Testing 20 dB 40 dB 50 dB 30 dB

Practice – Receiver Testing BER insignificant for 10-30 dB range (as shown), but was high when no attenuation was applied

Circuit Design & Layout Building the Practice Board introduces Circuit Design & Layout by way of example These are scheduled in later weeks

Gantt Chart

Next Week Optical Link Budget has been delayed, It will be a top concern in the coming week Transmitter Construction & Assembly PCB Design & Layout