1Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Infrared Avionics Signal Distribution: (Phase 2: Experimental Setup and Verification)
Mohammed AtiquzzamanSchool of Computer Science
Jim Sluss & Filip SlaveskiSchool of Electrical & Computer
Engineering
University of OklahomaNorman, Oklahoma
Final PresentationNASA Glenn Research Center, Cleveland, Ohio
July 16, 2002
Hung NguyenDuc Ngo
NASA Glenn Research CenterCleveland, Ohio.
2Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Introduction
n Pilots need to communicate with groundn Communications between aircraft and ground is Radio
Frequency (RF)n Signal Distribution within an aircraft is RFn Limited Communication within aircraft� Audio signal distribution� Telephone (new)� No video distribution� No communication between passengers and crew
3Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
RF Signal Distribution
n Coaxial Cables for RF signal distribution� Low bandwidth� Lossy
n Interference� Low signal to noise ratio
n Weight� Coaxial cables add weight to the aircraft
n Inflexible to future applications� passengers can select video to view� Internet browsing
4Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Optical Communications
n No Electromagnetic interference, low transmission loss and electrical isolation (no spark hazard)� signal security� safer aircrafts
n Lightweight� suitable for aircraft
n Lots of bandwidth� Good for future applications� Voice, video, data can be carried over the same infrastructure
n Difficult to multiplex and demultiplex signals
5Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Outline of presentation
n History of the project� Review of phase 1 (University of Dayton and NASA)
n Objectives of phase 2n Tests carried out in phase 2 (University of Oklahoma and
NASA)n Conclusions
6Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Review of Phase 1
7Infrared Avionics Signal Distribution
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Point to Point Fiber Communication
TX
RX
TX
RX
RX
TX
TX
RX
950 1450MHz 950 1450MHz
100 150 MHz
100 150 MHz4 channnes(Passenger)
4 channels(VHF Antenna 2)
24 channels (Cockpit) 24 channel
(UHF Antenna 1)OF
OF
OF(1.3/1.55 micron)OF
8Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Wavelength Division Multiplexing
TX
TX RX
RX
1280+1330nm1330 nm 1330 nm
1280 nm 1280 nm
(Cockpit) ( UHF Antenna 1)
(VHF Antenna 2) (Passenger)
OF
OF
OF
OF
OF
WAVELENGTHDEMUX
RX
RX TX
TX
1280+1330 nm
1330 nm 1330 nm
1280 nm1280 nm
( VHF Antenna 2) (Passenger)
(Cockpit) (UHF Antenna 1)
OF
OF
OF
OF
OF
WAVELENGTHDEMUX
n Signal extraction by splitters and wavelength demultiplexersn Signal injection by wavelength combiners
9Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Signal Broadcast
n Optical signal split into 8 equal parts by power splittersn Distribution tree by two or more levels of splitters
Rx Rx Rx Rx Rx RxRxRx Rx
Rp Rp Rp
Tx
VHF Antenna(4 channels)
Repeater (Rp)
10Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Optical fiber
AntennaPassenger
Optical Receiver
RF cable
Optical Transmitter
Cockpit
Optical combiner
Optical Splitter
Wavelength Demultiplexer
Optical Implementation in Aircraft
11Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Objectives of Phase 2
12Infrared Avionics Signal Distribution
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Project Objectives
n Assemble a prototype of the previous fiber optic transmission system design.
n Carry out measurements to verify proof of concepts and establish performance metrics.
n Based on experimental findings, make recommendations for “best practice” system architectures for use in aircraft.
13Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Basic Communications Link
ChannelSource Transmitter Receiver Destination
Noise Interference
14Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Basic Fiber Transmission Link
DriveCircuit
SignalRestorer
LightSource
AmpPhoto-detector
Transmitter Channel Receiver
Electrical OutputSignal
Electrical InputSignal
Attenuation Distortion
15Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Analog/Digital Transmission Link
16Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Wavelength Division Multiplexing (WDM)
WDM
1300 nm
1550 nm WDM 1550 nm
1300 nm
WDM1550 nm
1300 nm
WDM 1550 nm
1300 nm
Unidirectional
Bidirectional
• Insertion loss
17Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Dense WDM (DWDM)
TX
TX
TX
RX
RX
RX
λ1
λ2
λN
λ1
λ2
λN
.
.
.
.
.
.
WDM
(mux)
WDM
(demux)
Fiber
18Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Bus-based Fiber Backbone Using DWDM
C F
D
B
E
A
Fiber Fiber
Fiber Fiber Fiber
19Infrared Avionics Signal Distribution
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Phase 2 Deliverables
n Experimental data for various measurements taken for different modulation schemes.
n Proof of concepts validation.n Establishment of performance specifications.n Recommendations on “best practice” implementations for
incorporation into aircraft.
20Infrared Avionics Signal Distribution
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Tests Carried out in Phase 2
21Infrared Avionics Signal Distribution
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Tests Performed
n Power Test� Transmitted Power� Reflected Power
n Delay Measurementsn SNR Testn CNR Testn Signal Quality Testn Distortion Testn Laser Spectrum Testn Video Testn BERT
22Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Power Tests
23Infrared Avionics Signal Distribution
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Power Test Setup
n Power Measurements performed with the Network Analyzern Transmitted and Reflected Power measured for 1310 and 1550
nm
SPECTRUM ANALYZERTEKTRONIX
8554B
SPECTRUM ANALYZERTEKTRONIX
8554B
RF GENERATORFluke 6060B
RF GENERATORFluke 6060B
NETWORK ANALYZER
Agilent 8712ET
NETWORK ANALYZER
Agilent 8712ET
TX ORTEL3541C 1310 nm
TX ORTEL3541C 1310 nm
TX ORTEL1741A 1550 nm
TX ORTEL1741A 1550 nm
RX ORTEL4518B 1310 nm
RX ORTEL4518B 1310 nm
RX ORTEL2516A 1550 nm
RX ORTEL2516A 1550 nm
WDM WDM
fiber
WDM WDM
24Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Power Test Experimental Setup
25Infrared Avionics Signal Distribution
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Optical Tx and Rx
26Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
WDM
27Infrared Avionics Signal Distribution
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Transmitted Power in WDM
n Transmitted power averages:� – 45 dB for the 1310 nm� – 55 dB for 1550 nm
Power Measurements in WDM
-80
-70
-60
-50
-40
-30
-20
-10
0
0 200 400 600 800 1000 1200 1400
Frequency(MHz)
Pow
er (d
B)
Power for 1310 nm
Power for 1550 nm
1550 nm channel has greater insertion losses in the WDM network
Results comparable with literature: –50 dB for 1310 nm channel
28Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Reflected Power in WDM
Reflected Pow e r in WDM
-50
-40
-30
-20
-10
00 500 1000 1500
Fr e quency(M Hz)
Po
wer
(d
B)
R e f le c t e d P o we r in 13 10 n m
R e f le c t e d P o we r in 15 5 0 n m
n Reflected power is the power reflected from the circuit in our case due to the electrical to optical conversion
n Reflected power averages:� – 25 dB for the 1310 nm� – 30 dB for 1550 nm
Results comparable with literature: 20 to 30 dB loss for electrical to optical conversions
29Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Delay Measurements
30Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Delay Measurements in WDM
n Delay is due to:� Electrical components � Optical components
n Delay averages 60 ns for the 1310 and 1550 nmn Optical delay is approximately 50 ns
Delay in WDM
0.0E+00
2.0E-08
4.0E-08
6.0E-08
8.0E-08
1.0E-07
1.2E-07
1.4E-07
1.6E-07
1.8E-07
2.0E-07
0 200 400 600 800 1000 1200 1400
Frequency(MHz)
Del
ay(s
)
Delay 1310nm
Delay 1550nm
10 ns of electrical delay is very negligible and ensures low phase distortion
31Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
CNR and SNR Test
32Infrared Avionics Signal Distribution
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CNR and SNR Test Setup
n CNR and SNR measured with the spectrum analyzern FM and AM on 1310 nm and 1550 nm n Network Analyzer used to enable analog traffic on the second channel
SPECTRUM ANALYZERTEKTRONIX
8554B
SPECTRUM ANALYZERTEKTRONIX
8554B
RF GENERATORFluke 6060B
RF GENERATORFluke 6060B
NETWORK ANALYZER
Agilent 8712ET
NETWORK ANALYZER
Agilent 8712ET
TX ORTEL3541C 1310 nm
TX ORTEL3541C 1310 nm
TX ORTEL1741A 1550 nm
TX ORTEL1741A 1550 nm
RX ORTEL4518B 1310 nm
RX ORTEL4518B 1310 nm
RX ORTEL2516A 1550 nm
RX ORTEL2516A 1550 nm
WDM WDM
fiber
WDM WDM
33Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
SNR Test Results
n SNR for both AM and FM for the 1310 nm channel averages 55 dB n SNR for both AM and FM the 1550 nm channel is around 40 dB
SNR in WDM
20
30
40
50
60
70
80
90
100
100 200 300 400 500 600 700 800 900 1000
Frequency (MHz)
SNR
(dB)
SNR for AM in 1310nm
SNR for FM in 1310 nmSNR for AM in 1550 nm
SNR for FM in 1550 nm
nLiterature survey shows SNR of 57 dB for AM in 1310 nm fibernSNR of 30 dB is a good FM radio reception and CD quality audio is 98 dB
34Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
CNR Test Results
CNR in WDM
20
30
40
50
60
70
80
90
100
100 200 300 400 500 600 700 800 900 1000
Frequency (MHz)
CNR
(dB)
CNR 1330 nm
CNR 1550 nm
n CNR for the 1310 nm channel averages 65 dB n SNR for the 1550 nm channel is 52 dB
Literature survey shows CNR of 60 dB for AM in 1310 nm fiber
35Infrared Avionics Signal Distribution
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Signal Quality Test
36Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Signal Quality Test Setup
n Signal Quality measured with the digital oscilloscopen Input and Output AM and FM measuredn Network Analyzer used to enable analog traffic on the second channel
DIGITALOSCILLOSCOPE
TEKTRONIXTDS 784C
DIGITALOSCILLOSCOPE
TEKTRONIXTDS 784C
RF GENERATORFluke 6060B
RF GENERATORFluke 6060B
NETWORK ANALYZER
Agilent 8712ET
NETWORK ANALYZER
Agilent 8712ET
TX ORTEL3541C 1310 nm
TX ORTEL3541C 1310 nm
TX ORTEL1741A 1550 nm
TX ORTEL1741A 1550 nm
RX ORTEL4518B 1310 nm
RX ORTEL4518B 1310 nm
RX ORTEL2516A 1550 nm
RX ORTEL2516A 1550 nm
WDM WDM
fiber
37Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
AM Signal Quality Results
n AM modulation� Carrier: 2 MHz � Modulating signal: 200
KHz � Modulation Index:30%
A M In p u t a t 2 M H z
-8
-6
-4
-2
0
2
4
6
8
- 1 . 0 E - 0 5 - 5 . 0 E - 0 6 0 .0 E + 0 0 5 .0 E - 0 6 1 .0 E - 0 5
T im e ( s )
Am
plit
ud
e (V
)
A M O u tp u t a t 2 M H z
- 0 . 0 5
- 0 . 0 4
- 0 . 0 3
- 0 . 0 2
- 0 . 0 1
0
0 . 0 1
0 . 0 2
0 . 0 3
0 . 0 4
0 . 0 5
- 1 . 0 E - 0 5 - 5 . 0 E - 0 6 0 .0 E + 0 0 5 . 0 E - 0 6 1 . 0 E - 0 5
T im e ( s )
Am
plit
ud
e (V
)
n High signal quality of the AM signal is preserved in the output waveform.
n Output shows very little distortion, which is numerically measured and presented in the Distortion Test
38Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
FM Signal Quality Results
FM input for 100MHz
-6
-4
-2
0
2
4
6
-0.0005 -0.0003 -0.0001 0.0001 0.0003 0.0005
Time (s)
Ampli
tude
(V)
FM output at 100 MHz
-0.025
-0.02
-0.015
-0.01
-0.005
0
0.005
0.01
0.015
0.02
0.025
-0.0005 -0.0003 -0.0001 0.0001 0.0003 0.0005
Time (s)
Ampli
tude
(V)
n FM modulation� Carrier: 100 MHz � Modulating signal: 1000
Hz � Deviation:20 KHz
n High signal quality of the FM signal is preserved in the output waveform.
n Output shows very little distortion, which is numerically measured and presented in the Distortion Test
39Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Distortion Test
40Infrared Avionics Signal Distribution
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Power Spectrum of a Modulated Signal
n The peak is the carrier and smaller peaks are the sidebands.
41Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Distortion Basics
n a0: peak of the fundamental frequencyn a1: first harmonicn a2: second harmonicn a3: third harmonic
%100*(%)0
23
22
21
aaaa
THD++
=
42Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Distortion Test Setup
SPECTRUM ANALYZERTEKTRONIX
8554B
SPECTRUM ANALYZERTEKTRONIX
8554B
RF GENERATORFluke 6060B
RF GENERATORFluke 6060B
NETWORK ANALYZER
Agilent 8712ET
NETWORK ANALYZER
Agilent 8712ET
TX ORTEL3541C 1310 nm
TX ORTEL3541C 1310 nm
TX ORTEL1741A 1550 nm
TX ORTEL1741A 1550 nm
RX ORTEL4518B 1310 nm
RX ORTEL4518B 1310 nm
RX ORTEL2516A 1550 nm
RX ORTEL2516A 1550 nm
WDM WDM
fiber
WDM WDM
43Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Input Carrier Distortion Results
n Input carrier distortion generated by RF signal generatorn Input carrier distortion ranges between 0 and 0.2 %
I n p u t C a r r i e r D is t o r t i o n
0 . 0 0
0 . 0 5
0 . 1 0
0 . 1 5
0 . 2 0
0 . 2 5
0 . 3 0
1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 9 0 0 1 0 0 0
F r e q u e n c y ( M H z )
TH
D (
%)
In p u t C a r r i e r T H D fo r F M
In p u t C a r r i e r T H D fo r A M
Spec on the RF signal generator for THD is less than 1%
44Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Output Carrier Distortion Results
n Output carrier distortion ranges from 0 to 0.8 %
O u tp u t C a r r ie r D is to r t io n
0 . 0
0 . 1
0 . 2
0 . 3
0 . 4
0 . 5
0 . 6
0 . 7
0 . 8
0 . 9
1 . 0
1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 9 0 0 1 0 0 0
F r e q u n c y (M H z )
TH
D (
%)
F M o n 1 5 5 0 n m
A M o n 1 5 5 0 n m
F M o n 1 3 1 0 n m
A M o n 1 3 1 0 n m
nThe output carrier distortion is very low (less than 1%)
45Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Input Signal Distortion
Input Signal Distortion
0.0
0.5
1.0
1.5
2.0
2.5
3.0
100 200 300 400 500 600 700 800 900 1000
Frequency( MHz)
TH
D (
%)
Input S ignal THD for FM
Input S ignal THD for AM
n Input signal distortion generated by external modulator of RF signal generatorn Input carrier distortion ranges between 0 and 2 %
46Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Output Signal Distortion
n Output distortion level for the modulating signal ranges from 0 to 7%
Output Signal Distortion
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
20.0
100 200 300 400 500 600 700 800 900 1000
Frequency (MHz)
THD
(%)
FM on 1550 nm
AM on 1550 nm
FM on 1310 nm
AM on 1310 nm
Distortion is due to the high frequency range of operation and external modulation
47Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Laser Spectrum Test
48Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Laser Spectrum Test Setup
n Laser quality in the optical transmitters was measured with the optical spectrum analyzer
OPTICALSPECTRUM ANALYZERHP 71450B
OPTICALSPECTRUM ANALYZERHP 71450B
RF GENERATORFluke 6060B
RF GENERATORFluke 6060B
NETWORK ANALYZER
Agilent 8712ET
NETWORK ANALYZER
Agilent 8712ET
TX ORTEL3541C 1310 nm
TX ORTEL3541C 1310 nm
TX ORTEL1741A 1550 nm
TX ORTEL1741A 1550 nm
49Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Laser Spectrum Test Results
n 1310 nm shows peak wavelength at 1311 nm with narrow bandwidth of 1 nm
n 1550 nm shows peak wavelength at 1543 nm with narrow bandwidth of 1.5 nm
1310 nm 1550 nm
There is no overlap in the laser bandwidths since they are very narrow, which ensures no cross talk, no interference and no leakage.
50Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Video Test
51Infrared Avionics Signal Distribution
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Video Test Setup
n Video Tester provides a baseband test video signal to the Impathn The video signal goes through FDM and is output on a 1310 fiber in the Impathn Network Analyzer used as analog traffic on the second channel
VIDEO TESTERVIDEOTEK
VSG 21
VIDEO TESTERVIDEOTEK
VSG 21
NETWORK ANALYZER
Agilent 8712ET
NETWORK ANALYZER
Agilent 8712ET
TX IMPATH1310 nm
TX IMPATH1310 nm
TX ORTEL1741A 1550 nm
TX ORTEL1741A 1550 nm
TX IMPATH1310 nm
TX IMPATH1310 nm
RX ORTEL2516A 1550 nm
RX ORTEL2516A 1550 nm
WDM WDM
DIGITALOSCILLOSCOPE
TEKTRONIXTDS 784C
DIGITALOSCILLOSCOPE
TEKTRONIXTDS 784C
fiber
52Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Test Signal Picture Quality
n No visible distortion of the output picture quality
Input Output
53Infrared Avionics Signal Distribution
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Camera Picture Quality
n Camera snapshot input and output show identical qualityn No distortion in the output picture
Input Output
54Infrared Avionics Signal Distribution
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Input and Output Waveform Comparison
n Output amplification due to Impath TX
n Almost no distortion in the output waveform
Input for Multiburst Test Video Signal
-0.002
0
0.002
0.004
0.006
-3.0E-05 -2.0E-05 -1.0E-05 0.0E+00 1.0E-05 2.0E-05 3.0E-05 4.0E-05 5.0E-05
Time (s)
Am
plit
ud
e (V
)Output for Muliburst Video Test Signal
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
-4.0E-05 -3.0E-05 -2.0E-05 -1.0E-05 0.0E+00 1.0E-05 2.0E-05 3.0E-05 4.0E-05 5.0E-05
Time (s)
Am
plit
ud
e (V
)Cross correlation of the input and output =0.9984
55Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Input and Output Streaming Video
n Input Video Stream
n Output Video Stream
n Output video was the same quality as the input video from a human eye perspective.
56Infrared Avionics Signal Distribution
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Bit Error Rate Test (BERT)
57Infrared Avionics Signal Distribution
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BERT Setup
n BERT Tester supplies pseudo-random sequence to GDI TX via RS 232 port
n GDI TX converts the pseudo-random sequence into FSK modulated signal
n Network Analyzer provides analog traffic on the second channel
BERT TESTERDCB BT-1
BERT TESTERDCB BT-1
NETWORK ANALYZER
Agilent 8712ET
NETWORK ANALYZER
Agilent 8712ET
GDI FLD2SATX 1310 nm
GDI FLD2SATX 1310 nm
TX ORTEL1741A 1550 nm
TX ORTEL1741A 1550 nm
GDI FLD2SARX 1310 nm
GDI FLD2SARX 1310 nm
RX ORTEL2516A 1550 nm
RX ORTEL2516A 1550 nm
WDM WDM
fiber
58Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
BERT Experimental Setup
59Infrared Avionics Signal Distribution
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BERT Results
n Asynchronous BERT output:� Messages: ú ABC printable char.ú All 256 hex for 8 bit char.
(00 to FF)ú A “Quick brown fox” (QFB)
messageú 63,511, and 2047 bit random
sequence� Transmission speed:ú 9600 bpsú 14400ú 19200ú 38400
� Running Time: 30 min.
60Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
BERT Test Scenarios
19200 bps ABC
14400 bps QBF
9600 bps 00 to FF
38400 bps 511 seq.
61Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
BERT Test Remarks
n No bits received in error in all possible tests
n No interference between the digital and the analog channels
n No power loss on the analog side due to the digital transmission
62Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
Conclusions
n Measurements carried out on our WDM testbed.� Power Test� Delay Measurements� SNR Test� CNR Test� Signal Quality Test� Distortion Test� Laser Spectrum Test� Video Test� BERT
n Publications: � 1 conference paper accepted at DASC 2002 conference.� One journal paper planned.
63Infrared Avionics Signal Distribution
Atiquzzaman and Sluss
n Acknowledgements� NASA Glenn Research Center� Dr. Hung Nguyen and Dr. Duc Ngo - NASA Glenn� Ronald LaSpisa, Univ. of Oklahoma.
n Further InformationMohammed [email protected], (405) 325 8077
n These slides are available at www.cs.ou.edu/~atiq