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Äàòà èçìåíåíèÿ: Tue Feb 15 22:24:41 2011
Äàòà èíäåêñèðîâàíèÿ: Sun Feb 3 19:59:17 2013
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dds synthesizers

DDS synthesizers

feb11

Intro
Documentation (includes pdf schematics)
Miscellaneous
Schematics
PalEquations

Intro:

The dds synthesizers are used for the doppler correction during radar experiments. There are two synthsizers that are drivenv by the dap1 computer in the da crate. The dap1 computer (mv162) has 4 industry pack interfaces (ip interfaces). One of these has bill sisk's custom ip board that drives the dds synthesizers (where are in an exteral chassis).

Names/locations of some software:

/home/phil/vw/diag/ipSynDg0[1-3].c

diagnostics for dds's. Access via rundiag (with cpu dap1) and selelction 11.

/home/phil/vw/devs/ipSyn/ipSynDrv.c

vxWorks driver that interfaces to ip card.

/home/phil/vw/datatk/dds/ddsProg.c

datatking program that runs on dap1. It does the doppler updates during a datataking run.

Documentation:

Bill Sisk's documentation:

Notes: this was copied from maestro server , bill sisk's disc on 15feb11.

Software documentation:

Software requirements (commands,status) (.pdf)

Schematics:

Wirewrap boards (in dds chip chassis)

DDS_IPACK (industry pack)

Chassis misc

Miscellaneous:

14feb11: ddsprog late for interrupt, stops doppler updates 12jul10 moon430 run

14feb11 - ddsProg stops doppler updates during moon430 run

    The 430 Mhz moon bistatic observing had trouble with the data on 12jul10. Looking at the datataking log file (/share/obs4/msgs/dtmsgs.2010) the ddsProg had some messages saying that it was late for interrupt. These errors occurred on:
10jul10, 11jul10,12jul10,29oct10, and 31oct10.
     When the error occurs, the ddsProg stops the doppler updates and waits for a command to start another look (or run). For asteroids this will occur every roundtrip time. For the moon 430 this is a bistatic run and it lasts for up to 2 hours.
    The dds update rate (dopipp) for most radar runs is 2000 usecs. For the moon430 runs it is set at 1000 usecs. On 15feb11 i ran the diagnostic program ipDgSyn02.c to check on how short an ipp would work:

ipp=1000 usecs. Usually missed an interrupt within a few minutes
ipp=1500 usecs. missed interrupts
ipp=1800 usecs. ran for an hour or more without missing an interrupt.
The test program has less to do between interrupts than the actual datataking routine.

the datataking routine must evalutate an Nth order polynomial at each ipp.
The test program uses a linear polynomial to compute the frequency step.

The solution to the problem is to change the ipp update rate of the moon datatking to 2000 usecs.

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