[daip] amplitude in AIPS

[Amy Mioduszewski]

Dear Zhi-Qiang,

> What are those amplitudes immediately after the data is loaded into 
> AIPS using FITLD (probably plus ACCOR)? Are they exactly the same as 
> the outputs from the correlator, i.e. the correlation coefficients?

The quick answer is "probably not".  If you are using data from
the VLBA correlator, there is a correction that is applied automatically
in FITLD (the second order delay corrections).  Also there is a
correction you can turn on with FITLD (DIGICOR, applies digital
correction) and then ACCOR will also add another layer of corrections,
making what you get out not what you get out of the correlator.

If you want to know if after all these corrections the correlation
coefficients are basically preserved (with just small tweeks to fix
up what the correlator does not do perfectly), I will investigate
that further and get back to next week.

Cheers,

Amy