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Optical Gigabit Ethernet. Group F.O.R.E. March 31, 2005 Ronen Adato. Progress Overview. Completed Midterm Report Soldered and Tested 2 Conservative Design Boards. Conservative Board 1. Soldered all components and tested the Rx circuit for a clear eye
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Optical Gigabit Ethernet Group F.O.R.E. March 31, 2005 Ronen Adato
Progress Overview • Completed Midterm Report • Soldered and Tested 2 Conservative Design Boards
Conservative Board 1 • Soldered all components and tested the Rx circuit for a clear eye • Errors in part selection prevented BER testing for the Rx circuit, and any Tx circuit testing Rx Circuit Test Setup Eye Produced by Rx Circuit, Signal PRBS 7
Conservative Board 1 • QMAs were sent instead of SMAs • We elected to attempt and use these incorrect parts • A clear eye was produced by the Rx circuit, but the coaxial cables had to be held tightly into the QMAs • BER testing of the Rx circuit was impossible as a consistent signal could not be achieved with the QMAs • Tx circuit was not tested as this would have been very difficult with the QMAs
Conservative Board 2 • SMAs were removed from the test board to be used in the prototype • The QMAs were removed from the original board • Attempts to insert the SMAs into the holes occupied by the QMAs resulted in the destruction of a trace Board 1 With QMAs Removed The Destroyed Trace
Conservative Board 2 • The VCSEL and ROSA were de-soldered and a new board was constructed • The VCSEL was recycled while a new ROSA was used • The Limiting Amplifier (MAX3264) was incorrectly placed and had to be removed and re-soldered The Second Conservative Board
Conservative Board 2 • The Rx circuit failed to produce an eye • It was determined that the LA (MAX3264) had been damaged Rx Circuit Waveform Measured Before LA Rx Circuit Waveform Measured After LA
Conservative Board 2 • The Tx circuit was tested and does not work • The VCSEL is not lasing • Voltage measurements were taken throughout the circuit • In general, the entire loop around the VCSEL has a 5V dc voltage • Potentiometer adjustments changed nothing • We suspect our VCSEL may not be functioning
Tasks for Next Week • Replace the LA in the Rx circuit and retest, including BER measurements • Fix and test the Tx circuit • The VCSEL will probably be replaced • Loop-back test the entire board • Solder and test the aggressive design