AMiBA Engineering Telecon Minutes
20, Jun, 2002
| Participants: | Australia: M. Kesteven, W.
Wilson |
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| USA: | B. Martin, P. Ho, J. Peterson, D. Kubo | |
| Taiwan: |
H. Wang, P. Wu, C.T. Li, Y.J. Hwang, H.M. Jiang, W. Ho, |
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| T. Huang, C.C. Han, C.J. Ma, K.Y. Lin, P. Shaw | ||
Summary
MMIC:
1. Maggie Sarkuni will be handling the RCUH contract instead of Stacy. She asked for a authorization letter from JPL, it should spell out the exact specific chip name that authorizing RCUH to use. Sandy Weinreb agreed to write that letter, he will talk to Todd Gaier to sort out what are the best designs to spell out. Huei will follow up on this with Sandy and Todd.
2. Huei got the test report of silicon germanium multiplier from Warwick, its band width is not as wide as we want, however its noise is looks good. Both Warwick and Huei thought this is a possible back-up option for mixer. Huei will forward this report to Paul Shaw.
Reviver:
CT. got phase switch last night and put on receiver as well, he will do some tests on signal noise today.
IF/LO:
We got one LO box new back yesterday, and will put it on the system and test together.
Correlator:
1. We tentatively agreed to provide 2 correlation products per baseline. These products can be switched from L*R and R*L to L*L and R*R using a wideband mechanical switch. The switch is tentatively an HP 8762B ($702 USD ea.) and is specified to provide a repeatability of < 0.03 dB for under 1,000,000 cycles.
2. Derek made an feasibility study on the expansion from 7 to 13, and 13 to 19 elements. In summary:
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7-element
(initial config): |
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19-element: |
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comments: |
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| 1) | existing 2nd section 4-way power dividers need to be converted to 5-way (included in cost estimate) | |||
| 2) | correlator box needs to grow in size beyond our allocated space within the platform | |||
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More details on web site, please click
the link below to access: http://www.asiaa.sinica.edu.tw/amiba/New/correlator/image/corr_expansion.pdf As for the needs of above expansion, we need to think harder about how to keep the size and weight of modules small and light ,and make components as conversable as possible. |
3.
Derek has revised the correlator schedule according the reduction
approach. According this schedule, the optimistic delivery for correlator
assembly is in the end of April, 2003.
4. All agreed to start ordering parts for the 1st & 2nd section of correlator according the approach of 2 correlation products per baseline.
5. Derek and C.T. suggest to put the amplifier in front of the 4 way power divider and connect to the correlator module, in doing that we may able to use the same amplifier for the 2nd section and 4th section. It is $1625 for each and total we need 42 amplifiers(38 plus 4 spare). Derek will send its block diagram and planning to Warwick to review.
6. C.T. is working on the SNR measurement on Marki, Mica mixers and Meridian correlator as well as the square term rejection measurement. C.T. and Homing are still working on the checking and testing on the on-board demodulation of correlator. C.T. will discuss more details with Warwich by offline.
7. Rapadas has been testing the biased mixer, and he has to make a small modification on the circuit layout and replace a leakage capacitor, Jeff updated.
Platform:
Philippe had some discussion with Vertex on the interface between platform and mount last week, he will update the specs and the drawings together with Ted shortly. Philippe should send the specs and the drawings to Vertex for quote ASAP.
Action items:
1. Mingtang/C.T./ Since both LO and IF are pretty done in the lab, so the next step is to put them together and test the whole system. Mingtang should take care of the following work and sort out the schedule when he get back here by next Tuesday.
2. Bob/ Bob will inform Vertex about Fred is going to take over the directorship of NRAO effectively in Sep.1, in order to motivate their interesting in Alma so that they could do good job, cheap and faster for AMiBA.
3. Bob/ As for the pointing telescope, Bob will collect the data of software interface and pre-interface with prototype mount and forward to Mike, Homing, C.J., Philippe and Ted ASAP.
4. C.J./ We need some spare feed horn to carry on the far field measurement on 30cm prototype dish, C.J. will sort it out with Mingtang.
5. Bob/Philippe Regarding the FEA analysis on the Mileflect 60cm dish, Bob will follow up on this with Philippe to work it out ASAP. Bob will also talk to CMA further to see if they can simplify dish design, low down its cost and shorten its delivery time.
Next
telecon: Thursday, June
27, 8:30AM Taipei time (10:30AM Sydney time, 10:30PM EST, 2:30PM Hawaii)