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Central Development Central Development LaboratoryLaboratory
(Adapted from (Adapted from John Webber’sJohn Webber’s Viewgraphs, Viewgraphs, April 2002April 2002
Presented tonight by Skip Thacker)Presented tonight by Skip Thacker)
IEEE TourApril 2003
IEEE CDL Tour April 2003 2
Block DiagramBlock DiagramSignals
from other antennas
Antenna
Local Oscillator
MixerIF
Amplifier
Correlator
Computer
Image
\\CVFILER\cv-cdl-pub\CDL Tour\RadioBlockDiagram.dwg
Feed
IEEE CDL Tour April 2003 3
CDL ActivitiesCDL Activities
Low-noise AmplifiersLow-noise AmplifiersPassive Electromagnetic DevicesPassive Electromagnetic DevicesALMA SIS mixers for Bands 3 & 6ALMA SIS mixers for Bands 3 & 6ALMA Front End LO for All BandsALMA Front End LO for All BandsALMA CorrelatorALMA CorrelatorOther Digital ProjectsOther Digital ProjectsL-band Array Receiver (with Green Bank)L-band Array Receiver (with Green Bank)
IEEE CDL Tour April 2003 4
Amplifier GoalsAmplifier Goals
Keep up with receiver buildsKeep up with receiver builds Improve production efficiencyImprove production efficiencyDevelop InP amplifiers for Develop InP amplifiers for
bands down to 1 GHzbands down to 1 GHzStart replacement of Start replacement of
antiquated test equipmentantiquated test equipment
IEEE CDL Tour April 2003 5
Production AmplifiersProduction Amplifiers
Band (GHz) Noise (K) Comment Band (GHz) Noise (K) CommentBand (GHz) Noise (K) Comment Band (GHz) Noise (K) Comment
0.3-0.40.3-0.4 2.0 balanced 2.0 balanced C 4-6 C 4-6 9 9
0.4-0.50.4-0.5 2.0 balanced2.0 balanced C/X 3-13 C/X 3-13 5 5 InPInP
0.5-0.70.5-0.7 2.0 balanced2.0 balanced X/Ku 8-18 X/Ku 8-18 6 6 InPInP
0.7-0.90.7-0.9 3.0 balanced3.0 balanced K 18-26 K 18-26 9 9 InPInP
0.9-1.20.9-1.2 3.0 balanced3.0 balanced Ka 26-40 Ka 26-40 14 14 InPInP
1.2-1.71.2-1.7 3.0 3.0 Q 40-50 Q 40-50 18 18 InP InP
1.7-2.61.7-2.6 4.5 4.5 V 65-90 V 65-90 45 45 InP InP
2.6-42.6-4 5.2 5.2 W 68-116 W 68-116 60 60 InP InP
IEEE CDL Tour April 2003 6
ElectromagneticsElectromagnetics
Feeds for GBT: 26-40 and 68-92 GHzFeeds for GBT: 26-40 and 68-92 GHzFeed for EVLA: 1.2-2.0 GHzFeed for EVLA: 1.2-2.0 GHz
G/T slightly worse at zenithG/T slightly worse at zenithG/T much improved integrated over skyG/T much improved integrated over skyScaled versions for 2-4 and 4-8 GHzScaled versions for 2-4 and 4-8 GHz
Optics for ALMA Band 6 (211-275 GHz)Optics for ALMA Band 6 (211-275 GHz)
IEEE CDL Tour April 2003 7
GBT 68-92 GHz Feed DesignGBT 68-92 GHz Feed Design
IEEE CDL Tour April 2003 8
SIS Mixer ObjectivesSIS Mixer ObjectivesALMA Band 6 (211-275) GHz ALMA Band 6 (211-275) GHz
sideband-separating, balanced mixersideband-separating, balanced mixerALMA Band 3 (84-116 GHz) elemental ALMA Band 3 (84-116 GHz) elemental
mixer for use by Herzberg Institutemixer for use by Herzberg Institute Internal IF amp for 8 GHz bandwidthInternal IF amp for 8 GHz bandwidthBand 6 cartridge developmentBand 6 cartridge developmentAutomated mixer testingAutomated mixer testing
IEEE CDL Tour April 2003 9
Band 6 Waveguide-HybridBand 6 Waveguide-HybridSIS Mixer BlockSIS Mixer Block
IEEE CDL Tour April 2003 10
Band 6 Waveguide-HybridBand 6 Waveguide-HybridSIS Mixer Block DetailSIS Mixer Block Detail
IEEE CDL Tour April 2003 11
New Band 3 ElementalNew Band 3 ElementalSIS Mixer WaferSIS Mixer Wafer
IEEE CDL Tour April 2003 12
New Band 3 ElementalNew Band 3 ElementalSIS Mixer Wafer DetailSIS Mixer Wafer Detail
IEEE CDL Tour April 2003 13
New Band 3 ElementalNew Band 3 ElementalSIS Mixer Wafer DetailSIS Mixer Wafer Detail
IEEE CDL Tour April 2003 14
Band 6 BalancedBand 6 BalancedMixer-preamp AssemblyMixer-preamp Assembly
IEEE CDL Tour April 2003 15
SIS Mixer Test FacilitySIS Mixer Test FacilityWith Two 4K DewarsWith Two 4K Dewars
IEEE CDL Tour April 2003 16
ALMA Front End LO TasksALMA Front End LO Tasks
YIG-Tuned-Oscillator-based driversYIG-Tuned-Oscillator-based driversLow phase noise lock loopsLow phase noise lock loopsFinal power amplifiersFinal power amplifiersHigh-frequency multipliersHigh-frequency multipliers
IEEE CDL Tour April 2003 17
96-104 GHz Power-combining96-104 GHz Power-combiningBalanced Power AmplifierBalanced Power Amplifier
IEEE CDL Tour April 2003 18
ALMA Band 6 LO PrototypeALMA Band 6 LO Prototypefor SIS Mixer Test Facilityfor SIS Mixer Test Facility
IEEE CDL Tour April 2003 19
Prototype Warm Multiplier Prototype Warm Multiplier AssemblyAssembly
IEEE CDL Tour April 2003 20
Band 6 CartridgeBand 6 CartridgeLO componentsLO components
IEEE CDL Tour April 2003 21
ALMA CorrelatorALMA Correlator• 64 antennas• 8 IF bands per antenna• 4 Gsamples/sec per IF band, 2 bits/sample
correlated• 1024 lead + 1024 lag correlations per baseline• 30 km maximum baseline delay range• Full polarization capability plus autocorrelation• Digital filter for bandwidths <2 GHz• Switch modes in less than 1.5 seconds
• This requires 4,194,304 multiply-and-add correlators at 4 GHz rate
• Total computation rate is 1.7 X 1016 multiply-and-add operations/sec
IEEE CDL Tour April 2003 22
FIR Filter Card & Station CardFIR Filter Card & Station Card
FIR Filter Card Station Card
IEEE CDL Tour April 2003 23
Station Card in Test FixtureStation Card in Test Fixture
IEEE CDL Tour April 2003 24
Correlator Card BackCorrelator Card Back
IEEE CDL Tour April 2003 25
Front
and
Rear
Views
IEEE CDL Tour April 2003 26
Station Bin
IEEE CDL Tour April 2003 27
Beam-Forming Array Beam-Forming Array ReceiverReceiver
Objective: synthesize multiple beams for Objective: synthesize multiple beams for 1300-1750 GHz, where conventional 1300-1750 GHz, where conventional feed arrays are impractical on the GBTfeed arrays are impractical on the GBT
Approach: oversample e-m field at focal Approach: oversample e-m field at focal plane with closely spaced feedsplane with closely spaced feeds
Challenges:Challenges: Achieve system noise temperature close to that of a Achieve system noise temperature close to that of a
conventional receiverconventional receiver Achieve mechanical and electronic stability sufficient Achieve mechanical and electronic stability sufficient
for reliable calibrationfor reliable calibration
IEEE CDL Tour April 2003 28
Beam Forming ArrayBeam Forming Array
IEEE CDL Tour April 2003 29
Beam-Forming Array FeedsBeam-Forming Array Feeds
Array of dipoles Array of dipoles samples focal planesamples focal plane
Tuned for 1300-Tuned for 1300-1750 MHz1750 MHz
37-element 37-element prototype provides prototype provides 7 beams on the sky7 beams on the sky
IEEE CDL Tour April 2003 30
Prototype DipolePrototype Dipole