[daip] Issue with task PCAL

[Eric Greisen]

Matthew Mallory wrote:
> To whomever can help,
> 
> I am failing to see a connection between the amplitude and phase numbers 
> from the pcal output and the real and imaginary parts input in the AN 
> table after pcal is run.  Here is the info from both the AN table and 
> pcal output.
> 
> AN Table:
> The only numbers of real import (or not 0) were in columns 2, 9, and 12. 
> I assume that the columns 9 (POLCALA) and 12 (POLCALB) hold the real and 
> imaginary values.  I also assume the values in POLCALA are Right IF1 
> Real, Right IF1 Imaginary, Right IF2 Real, Right IF2 Imaginary, and the 
> same for POLCALB except Left feeds.
> 
> POLCALA          POLCALB
> -5.662E-03        1.758E-02
> 2.567E-02        2.475E-02
> -2.169E-03        1.062E-02
> 2.761E-02        2.276E-02
> 
> If other numbers are important I have attached a .txt file with the full 
> AN table.  All values in POLAA and POLAB are 0, and POLTYA and POLTYB 
> just tell whether it is the right or left feed.
> 
> 
> 
> 
> And this is an excerpt from the PCAL output:
> 
>   1    4   21-FEB-2009  00:39:21     PCAL      RMS residual =   
> 1.879E-04 DOF = 1747.30
>   1    4   21-FEB-2009  00:39:21     PCAL      Interferometer Element   1
>   1    4   21-FEB-2009  00:39:21     PCAL        R: Amp =   .02629+/-  
> .00184 Phase(deg) =   45.56+/-   2.83
>   1    4   21-FEB-2009  00:39:21     PCAL        L: Amp =   .03036+/-  
> .00586 Phase(deg) =  111.50+/-   7.82
> 
>   1    4   21-FEB-2009  00:39:22     PCAL      RMS residual =   
> 1.862E-04 DOF = 1749.17
>   1    4   21-FEB-2009  00:39:22     PCAL      Interferometer Element   1
>   1    4   21-FEB-2009  00:39:22     PCAL        R: Amp =   .02769+/-  
> .00180 Phase(deg) =  100.91+/-   2.63
>   1    4   21-FEB-2009  00:39:22     PCAL        L: Amp =   .02512+/-  
> .00577 Phase(deg) =   58.57+/-   9.31
> 
> I just gave you the printouts for Antenna 1 in both IFs.
> 
> If one adds the squares of the real and imaginary parts for antenna 1 
> IF1, right, (-.5662E-03 and 2.567E-02) we get back the square of the 
> amplitude printed in the pcal output for IF 1 antenna 1 R:Amp = .02629.  
> However, if I break down the real and imaginary parts into some phi 
> using phi = ArcCos(Real/Amp) for real and ArcSin for imaginary, it does 
> not match the phase given phase in the pcal output (45.56).  This holds 
> true for all antennas and all IFs.
> 
> Is there something I am missing or are the real and imaginary parts in 
> the AN table not wholly transparent?  Thank you in advance for your help.

Your results here are most confusing to me - looking at the code of PCAL 
I see that the numbers printed out are then passed around unchanged and 
put into the AN table in the way that you suggest.  Running it on some 
of my data, the printed numbers exactly match those in the AN file as 
they should.  (Note PRTAN is an easier way to see the numbers, but I 
also used PRTAB as you did.)  I do not know how you managed the correct 
amplitudes with confused phases...

Eric Greisen