1. Central Development Laboratory (Adapted from John Webber’s Viewgraphs, April 2002 Presented tonight by Skip Thacker) IEEE Tour April 2003

2. IEEE CDL Tour April 20032 Block Diagram

3. IEEE CDL Tour April 20033 CDL Activities Low-noise Amplifiers Low-noise Amplifiers Passive Electromagnetic Devices Passive Electromagnetic Devices ALMA SIS mixers for Bands 3 & 6 ALMA SIS mixers for Bands 3 & 6 ALMA Front End LO for All Bands ALMA Front End LO for All Bands ALMA Correlator ALMA Correlator Other Digital Projects Other Digital Projects L-band Array Receiver (with Green Bank) L-band Array Receiver (with Green Bank)

4. IEEE CDL Tour April 20034 Amplifier Goals Keep up with receiver builds Keep up with receiver builds Improve production efficiency Improve production efficiency Develop InP amplifiers for bands down to 1 GHz Develop InP amplifiers for bands down to 1 GHz Start replacement of antiquated test equipment Start replacement of antiquated test equipment

5. IEEE CDL Tour April 20035 Production Amplifiers Band (GHz) Noise (K) Comment Band (GHz) Noise (K) Comment 0.3-0.42.0 balanced C 4-6 9 0.3-0.42.0 balanced C 4-6 9 0.4-0.52.0 balanced C/X 3-13 5 InP 0.4-0.52.0 balanced C/X 3-13 5 InP 0.5-0.72.0 balanced X/Ku 8-18 6 InP 0.5-0.72.0 balanced X/Ku 8-18 6 InP 0.7-0.93.0 balanced K 18-26 9 InP 0.7-0.93.0 balanced K 18-26 9 InP 0.9-1.23.0 balanced Ka 26-40 14 InP 0.9-1.23.0 balanced Ka 26-40 14 InP 1.2-1.73.0 Q 40-50 18 InP 1.2-1.73.0 Q 40-50 18 InP 1.7-2.64.5 V 65-90 45 InP 1.7-2.64.5 V 65-90 45 InP 2.6-45.2 W 68-116 60 InP 2.6-45.2 W 68-116 60 InP

6. IEEE CDL Tour April 20036 Electromagnetics Feeds for GBT: 26-40 and 68-92 GHz Feeds for GBT: 26-40 and 68-92 GHz Feed for EVLA: 1.2-2.0 GHz Feed for EVLA: 1.2-2.0 GHz G/T slightly worse at zenith G/T slightly worse at zenith G/T much improved integrated over sky G/T much improved integrated over sky Scaled versions for 2-4 and 4-8 GHz Scaled versions for 2-4 and 4-8 GHz Optics for ALMA Band 6 (211-275 GHz) Optics for ALMA Band 6 (211-275 GHz)

7. IEEE CDL Tour April 20037 GBT 68-92 GHz Feed Design

8. IEEE CDL Tour April 20038 SIS Mixer Objectives ALMA Band 6 (211-275) GHz sideband- separating, balanced mixer ALMA Band 6 (211-275) GHz sideband- separating, balanced mixer ALMA Band 3 (84-116 GHz) elemental mixer for use by Herzberg Institute ALMA Band 3 (84-116 GHz) elemental mixer for use by Herzberg Institute Internal IF amp for 8 GHz bandwidth Internal IF amp for 8 GHz bandwidth Band 6 cartridge development Band 6 cartridge development Automated mixer testing Automated mixer testing

9. IEEE CDL Tour April 20039 Band 6 Waveguide-Hybrid SIS Mixer Block

10. IEEE CDL Tour April 200310 Band 6 Waveguide-Hybrid SIS Mixer Block Detail

11. IEEE CDL Tour April 200311 New Band 3 Elemental SIS Mixer Wafer

12. IEEE CDL Tour April 200312 New Band 3 Elemental SIS Mixer Wafer Detail

13. IEEE CDL Tour April 200313 New Band 3 Elemental SIS Mixer Wafer Detail

14. IEEE CDL Tour April 200314 Band 6 Balanced Mixer-preamp Assembly

15. IEEE CDL Tour April 200315 SIS Mixer Test Facility With Two 4K Dewars

16. IEEE CDL Tour April 200316 ALMA Front End LO Tasks YIG-Tuned-Oscillator-based drivers YIG-Tuned-Oscillator-based drivers Low phase noise lock loops Low phase noise lock loops Final power amplifiers Final power amplifiers High-frequency multipliers High-frequency multipliers

17. IEEE CDL Tour April 200317 96-104 GHz Power-combining Balanced Power Amplifier

18. IEEE CDL Tour April 200318 ALMA Band 6 LO Prototype for SIS Mixer Test Facility

19. IEEE CDL Tour April 200319 Prototype Warm Multiplier Assembly

20. IEEE CDL Tour April 200320 Band 6 Cartridge LO components

21. IEEE CDL Tour April 200321 ALMA 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 10 16 multiply-and-add operations/sec

22. IEEE CDL Tour April 200322 FIR Filter Card & Station Card FIR Filter CardStation Card

23. IEEE CDL Tour April 200323 Station Card in Test Fixture

24. IEEE CDL Tour April 200324 Correlator Card Back

25. IEEE CDL Tour April 200325 Front and Rear Views

26. IEEE CDL Tour April 200326 Station Bin

27. IEEE CDL Tour April 200327 Beam-Forming Array Receiver Objective: synthesize multiple beams for 1300-1750 GHz, where conventional feed arrays are impractical on the GBT Objective: synthesize multiple beams for 1300-1750 GHz, where conventional feed arrays are impractical on the GBT Approach: oversample e-m field at focal plane with closely spaced feeds Approach: oversample e-m field at focal plane with closely spaced feeds Challenges: Challenges: Achieve system noise temperature close to that of a conventional receiver Achieve system noise temperature close to that of a conventional receiver Achieve mechanical and electronic stability sufficient for reliable calibration Achieve mechanical and electronic stability sufficient for reliable calibration

28. IEEE CDL Tour April 200328 Beam Forming Array

29. IEEE CDL Tour April 200329 Beam-Forming Array Feeds Array of dipoles samples focal plane Array of dipoles samples focal plane Tuned for 1300- 1750 MHz Tuned for 1300- 1750 MHz 37-element prototype provides 7 beams on the sky 37-element prototype provides 7 beams on the sky

30. IEEE CDL Tour April 200330 Prototype Dipole