[casper] soliciting your opinions

[Tom Kuiper]

Tomorrow some of us are meeting with Sandy Weinreb and Steve Smith to 
talk about a wideband, channelized down-converter.  Ultimately we want 
to be able to down-convert and digitize 14 - 26Ghz simultaneously.  
Sandy's GAVRT design was based on the 2 Gsamp/s CASPER iADCs.   Using 
that approach, with two polarizations, we would need twelve 
down-converter channels (both I and Q sampling). It looks like we could 
safely assume that 3 Gsamp/s ADCs can be used with the ROACH boards, 
which would reduce the number of channels to eight.  Chuck Naudet tells 
me that the next step in the VLBI world will go from the current 1 GHz 
bandwidth (at one or two bits/sample) to 4 GHz.  We need more dynamic 
range but even 4 Gsamp/s would be attractive, reducing the number of 
downconverter channels to six.  So what would you do if you expected to 
start building the downconverters in April?  in September? in December?

In advance, many thanks
Tom