Transcript Document 7750779

ECE 4006 Presentation on
Preliminary Results
Group: G3
Member: Karen Cano, Scott Henderson, Di Qian
Overview
STEP
VCSEL
PD
1 Component Purchase
Completed
Mostly Completed
2 Circuit Layout Design
Completed
Completed
Etched PCB Board
3
Design
Completed
Not Completed
1) RadioShack Board
Completed
Not Completed
2) Etched PCB Board
Not Completed Not Completed
Procedure Name
4 Circuit Assembly for
5 Circuit Testing for
1) RadioShack Board
Completed
Not Completed
2) Etched PCB Board
Not Completed Not Completed
Circuit Layout for PD
• Optical connection on top, (SC - Light In).
Electrical connections on left and right (SMA)
• R=1/(2*pi*f*CDET), where CDET = 1.5 pF (from
spec. sheet). So, R = 53.1Ω.(impedance of PD).
• Capacitors were chosen based on their frequency
response at 1.25 GHz. From Murata’s site: C =
.01uF.
Circuit Layout for the VCSEL
• Electrical connections on the left (SMA - In),
optical connections on the right (SC - Light Out).
• Constraint: Circuit’s RTOT has to be 50Ω, due to
equipment requirements.
• VCSEL’s RTYPICAL=25Ω (from spec.sheet)
• So, a 25Ω resistor was placed in series with the
VCSEL.
Constructing the VCSEL Board
• Radio Shack purchased “through” boards
• SMA connectors, SMT components, and
VCSELs
• Impracticalities of initial design
• Remedy for small holes and lack of a drill
• Problem: GTS-1250’s outputs are ACcoupled
• Bias-T applied and shown in new circuit
VCSEL Testing Procedure
• GTS-1250
• New VCSEL
board
• Old opto-board
• Scope
• Electrical
connections
and optical
loop
Testing Results
• IEEE 802.3z standard
mask application
• Bit error rate settings
in scope
• New VCSEL vs. old
VCSEL
• Failure of complete Tx
module thus far
VCSEL PCB Design
• Five components:
- SMT Resistor,
- LED,
- Power Connector,
- 2K ohms Resistor,
- SMA Connector
VCSEL PCB Design (Con’t)
•
•
•
•
SMT Resistor – 0.1 inch
LED – Two Leads
2K Ohms Resistor – 0.5 inch
Power Connector – hole 0.2 x 0.1 inch
VCSEL PCB Design (Con’t)
SMA Connector Bottom
View
Conclusion (Short term goals)
• Ensure the delivery of the connectorized PD
• Making and testing the PCB for VCSEL
• Intergrating with modules from other
groups.