[evlatests] Ant. 13, IFs BD: ~60d phase jumps every 20 seconds at C, X, L bands

[Jim Jackson]

Matt,

I guess we need to look at implementing ALMA's solution to this problem.  I 
believe it essentially involved selecting which edge of the 128MHz clock 
they are using.  I believe it was implemented in the FPGA on the DDS 
board.  If it requires MIB intervention, I guess the commands will have to 
be passed back and forth on the SPI bus.

Jim

At 09:58 AM 7/20/2006, Matt Luce wrote:
>The modules have the same MIB firmware and FPGA firmware.  They are
>missing the latest logical points XML
>which lists the available monitors/commands.  Those XML files will be
>updated shortly but they won't load until
>the MIBs are reset.
>
>Matt
>
>Jim Jackson wrote:
>
> >This is curious. We noticed earlier this afternoon that the two L302's in
> >Antenna 13 seem to have different firmware (or something else) in the
> >MIB.  Even though both claim to be MIBVERSION 0.99 and MODULEVERSION 0.20,
> >there are two missing monitor points on the L302-2 in antenna 13 and the
> >L302-1 in Antenna 24  The monitor points are  M_LOCKH and C_LOCKH.
> >
> >Pete and Matt - Are we sure these modules all have the same MIB and FPGA
> >firmware?
> >
> >Adding length to the LVDS heartbeat cable to these modules is a
> >problem.  The project's worth of twinax cables were purchased from
> >Tensolite as an expensive special order with custom connectors.  They are
> >all the same length.  We could vary the length of the 128MHz coax cable
> >feeding the clock to the FPGA.
> >
> >Jim
> >
> >
> >
> >At 09:54 AM 7/19/2006, Rick Perley wrote:
> >
> >
> >>    But why would this non-subtle behavior be absent before July 7th?
> >>And why only
> >>with antenna 13, IFs B and D?
> >>
> >>Barry Clark wrote:
> >>
> >>
> >>
> >>>This is almost certainly the heartbeat capture uncertaintly glitch we
> >>>saw in the lab.  I am happy that things are now working well enough in
> >>>the field that we notice it.  It could probably be cured by adding a foot
> >>>of cable to the LVDS heartbeat cable.  Only worth doing if this L302 is
> >>>in final form.
> >>>
> >>>I've lost track of what the revision state of this L302 is.  The vaunted
> >>>spreadsheets in techdocs contain no useful information for L302s.
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>>AR603 data taken between July 12th and July 15th show an odd behavior
> >>>>for ant. 13, IFs BD (AIPS IF 2 RR & LL): frequent ~60 degree phase jumps
> >>>>within a scan.
> >>>>
> >>>>
> >>>>
> >>>>
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> >>>
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> >
> >
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