[evlatests] [evla-sw-discuss] Terminology

[Sonja Vrcic]

WIDAR correlator uses the following identifiers:
Station ID: 1-255
Base band ID : 0-7
Subband ID : 0-17
(Specified ranges are  inclusive. Station ID=0 is not used)

These IDs are embedded in the sampled data streams within the correlator 
and appear in the output data of the correlator and the correlator backend.

I wander if it is possible to use the same numbering scheme for the 
antennas.
If not, it seems to me that it is better to use a  completely different 
set of identifiers (i.e. letters), to avoid confusion. For example: 
Antenna output A could be assigned Baseband ID 0, and so on: B = 1, C = 
2,...

In the "normal" WIDAR configuration, consecutive  IDs (e.g. 0 and 1) are 
assigned to basebands that represent a pair; but this is not enforced, 
and different configurations are possible (that is the plan).

WIDAR identifiers are defined in the following document:
EVLA Correlator System Numbering Plan
http://www.drao-ofr.hia-iha.nrc-cnrc.gc.ca/science/widar/private/System.html

Sonja


Barry Clark wrote:

>I'm starting to think about code to drive the 4 GHz samplers.  In order 
>that the comments in my code bear some relation to what we eventually
>end up calling things, I'd like to talk about terminology now.
>
>My suggestion is that the first output from the T304s, be called
>basebands A, B, C, D, as they are now, ignoring the fact that they
>have different filters and samplers selected.
>
>Let's call the second outputs from the T304s basebands E, F, G, H.
>
>So the baseband pairs are AC, BD, EG, FH.
>
>Another alternative is to assign nunbers to the baseband pairs, a la
>AIPS, so the basebands become 1R, 1L, 2R, 2L, 3R, 3L, 4R, 4L.  (Which
>T304 baseband 2R comes from TBD.)  I think this is more confusing 
>because we seem to have settled on numbering the subbands, so subbands
>would be things like 101R, 101L, 102R, 201R, etc. which I find less
>euphonious than A01, C01, A02, B01, etc.
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