[mmaimcal] forwarded message on subarrays from Jacob Baars

[Al Wootten]

Imcalers:  Comments on this note from Jaap?  I think it looks workable.

Al

I have finally found the time to work on a possible wording of the 
"sub array" issue.
We, or at least some of us, discussed that a short note might be 
appended to the ALMA System Preliminary Design Recommendations, as 
well as to the ASAC minutes. Using mainly a proposed version by 
Stephane, here is a draft proposal of such a note.

Any comments and improvements, as well as alternatives to its 
dissemination are are welcome.

regards,

Jaap
=====================================
DRAFT

There exists confusion, and possibly differences of opinion, among 
the scientists and engineers of the ALMA Project as to the final 
decision regarding the number of sub-arrays, which would be supported 
in ALMA. After discussions in the ASAC and among the Project 
Scientists and System Engineers, we have agreed that the following 
definition is appropriate.

We distinguish three types of sub-array levels:

     1) Number of different frequencies the LO system can drive simultaneously
         Specification: up to 4.
     2) Number of antenna sets the correlator can treat independently:
         Specification: up to 6
     3) Number of antenna sets the software can handle independently:
         Specification: up to 8
     4) Independent control of any antenna will be possible (for 
maintenance and repair).