Summary
Receiver:
Mingtang said that now we have one working receiver integrated completely
and ready for integration test. As for the second receiver, one missing LO
box should be delivered here today. He thinks everything will get ready before
May . Although, the gain variation is around 10 to 15 dB cross the band, and
we don't know where this problem come from so far. Mingtang and Eugene are
still trying very hard to work out this problem.
Correlator:
1.
We are still figuring on giving the proper mixer for the
correlator, Derek is working on this with J. Rapadas, Marki and other venders.
According the test result on the Rapadas's module, we can get good signal
for noise without too much gain to compress. Andy Harris is one really recommended
that we drive harder .and not to be concerned about going to soft the compression.
J. Rapadas needs some time to improve the existing biased mixer version in
order to give a better match, to gain the variation of responsivity with frequency
and phase variation, since both are affect the efficiency of correlator. In
addition, we shall try to use the zero biased Schottky version mixer of detector
diodes to see if we can solve the dynamic problem.
2.
Derek will bring all five detectors and couplers with him
to Taipei.
3.
Derek will order 5 low pass filters directly through RCUH
in order to save the cost which over charged by local agent.
4.
Derek found another source of biased mixer from Miteq, he
will talk to the designer to see if he can shorten its delivery time. He also
talked with Rapadas to see if he can use the existing diodes to produce the
responsivity can give us slight DC bias to turn them on, basically to lower
the noise. That's part of development to get want J. Rapadas to do. And Marki
is very nice to do part of the development work for us for free basically
and sending us sample. J. Rapadas agrees to use a better mixer we could found
than what he did, he will integrate it into the module if he supply the module
in the end.
5.
Warwick has sent off the prototype on Tuesday to Taipei by
DHL, he will forward the tracking number to Jackie to track on that.
MMIC:
1.
TRW is still checking on the new design form Huei, and there
are some systematic questions raised by TRW. Huei is going to answer TRW within
this week.
2.
As for sending people to JPL to work on the packaging and
cold test for 28 LNA, we decide nominate C.C. Han and two Huei's students
to JPL for approval.
Read-out
chips:
As for the 4 lags correlator, T.D. will design a new version of read-out
chips.
60cm dish:
Ted has finished the drawings and reviewed by Philippe and Bob, he
send off the drawings to Dr. Ong for quote as well.
Far field
range measurement:
C.J. Ma and K.Y. Lin has made their first try on the FFR measurement
and came up with a report. The far field limit of the 30cm dish is 60m. Due
to field setup limitation, the receiver is about 150 to 200m away from the
transmitter. This results in an extra loss of 10dB, and the resulting dynamical
range is 30dB. In this range we can detect the first sidelobe at 1.25±0.17°,
loss 19.67dBc. This result is preliminary and they are planning a second test
to improve it. Mingtang will follow up to look into the report and to see
how to get improvement.
Hexapod
mount:
Bob and Philippe had a kick off meeting with Vertex this week in Germany,
discussing the schedule, design review and so on, trying to get things going
properly. One mission Fred asked them to try to accomplish is to shorten the
delivery time, we will see what happen.
Platform:
Ted has modified the drawings and sent off to Bob and Philippe to review.
Ted will follow up on this with Bob and Philippe until all details settled.
IF amplifier specification:
C.T. has generated a work package and sent around for comment. Huei
will follow up to look into the details and feed back his comment C.T.
Budget plan:
as for the 7 elements array, Paul got essentially all the package and
added all dollar amount , we basically bankrupt. Fred asked everybody to go
back to look what you have done and put together, and see how you can do things
simpler and cheaper.
Action items:
1.
Derek/ Derek will get a quote from J. Rapadas
for providing 1 single-balanced biased mixer, and 1 signal-balanced mixer
composed of detector diodes. These two mixers will be packaged and connectorized.
2.
Mingtang/ To understand
what we have on the receiver measurement. Mingtang will forward the noise
and gain date Jeff Peterson to look at.
3.
All/
In order to save the purchasing
cost for import components which may be over charged by local agent here,
we decide to purchase these components through RCUH as possible as we can.
4.
Ted/ Ted will follow up to ask Dr. Ong when
he can get the quote back to us for the 60cm dish.
5.
All/
We will show the prototype
operation at lab here to the site visitors of MoE in May 28, it's very important
for us, everybody should keep this in mind.
6.
Ted/ Ted will follow up to talk with Bob and
Philippe to finalize the drawings and specs for platform ASAP.
7.
Derek/ Derek will follow up to get a quote from Rapadas for mixer development.
8.
Huei/ Huei will send over some SiGe chips to
Warwick to test.
Next meeting:
Thursday, May 2, 8:30AM Taipei time.