from:	 Young, Ken 
to:	 Mark Gurwell ,
         Chunhua Qi ,
         Jun-Hui Zhao ,
         Jonathan Weintroub ,
         Rurik Primiani 
date:	 Fri, Apr 25, 2014 at 4:59 PM
subject: Yesterday's SWARM test data file.

We got a very nice SWARM data file yesterday; the first to have both 
sidebands recovered.  Unfortunately there is a frequency error of almost 
exactly 72 MHz in the SWARM chunk s49. I will produce a version of the 
data file that has the frequency error corrected, and I'll send you 
a pointer to it when it's done.

Taco

from:	 Jonathan Weintroub 
to:	 "Young, Ken" 
cc:	 Mark Gurwell ,
         Chunhua Qi ,
         Jun-Hui Zhao ,
         Rurik Primiani 
date:	 Fri, Apr 25, 2014 at 11:34 PM
subject: Re: Yesterday's SWARM test data file

Thanks for the update. What is the root cause of the 72 MHz error?


Jonathan



from:	 Young, Ken 
to:	 Jonathan Weintroub 
cc:	 Mark Gurwell ,
         Chunhua Qi ,
         Jun-Hui Zhao ,
         Rurik Primiani 
date:	 Mon, Apr 28, 2014 at 10:30 AM
subject: Re: Yesterday's SWARM test data file.

Dear SWARM Science Verification Aficionados,

   I have produced a version of last week's SWARM test data that has the 
frequency scale corrected. It lives in

/sma/SMAusers/taco/SWARMTest24apr14/140424_12:18:22

(on the CF linux boxes)
Note that only the sp_read file differs from that of the original data set, 
so if you have your own copy of the test data, you can just copy over 
the sp_read file from the above location, and you'll be fine. I've verified 
that the ASIC and SWARM frequency scales now agree in both sidebands.The 
USB needed to have 72 MHz added, and the LSB needed 72 MHz subtracted from 
it (the actual value I used was 72.0185 MHz, which I got from line fits 
to the MWC 349 data, but I'll bet the real value will turn out to be 
72 MHz exactly).   I have also verified that the LSB SWARM phase has 
not been conjugated, as we automatically do with the SWARM correlator, 
so the phase differs in sign in the LSB.

Taco


from:	 Mark Gurwell 
to:	 "Young, Ken" 
cc:	 Jonathan Weintroub ,
         Chunhua Qi ,
         Jun-Hui Zhao ,
         Rurik Primiani 
date:	 Mon, Apr 28, 2014 at 10:38 AM
subject: Re: Yesterday's SWARM test data file.

Just an FYI for MIR users, that to 'correct' the SWARM phase 
(in the sense that it will match the sense of the Legacy 
correlator data) you can do the following (I assume s50 will 
be thrown out, so it is not included here):

select,/re, band='s49',sideband='l'
phase_conjugate,/force

Now the SWARM s49 lsb will have the same sense as the Legacy 
correlator data for the lsb (which also matches the sense of phase in the usb).


from:	 Young, Ken 
to:	 Mark Gurwell 
cc:	 Jonathan Weintroub ,
         Chunhua Qi ,
         Jun-Hui Zhao ,
         Rurik Primiani 
date:	 Mon, Apr 28, 2014 at 10:43 AM
subject: Re: Yesterday's SWARM test data file.

Also, the fix I did to the frequency scale had the side effect of forcing 
S49 and s50 to have the same frequency scale. I didn't bother to fix that 
because there is no useful data in s50.