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FTS                         ! Fourier Transform Spectrometer

The FTS supports two modes: 
 -  wide bandwidth, up to ~ 4000 MHz on EMIR (~ 1000 MHz on HERA), 
    with a resolution of ~ 0.195 [MHz], or
 -  fine resolution, ~ 0.049 MHz, 
    with a bandwidth up to 1820 MHz on EMIR (~ 500 MHz on HERA)

All parts of the FTS must use the same resolution.

.so nroffSoSubtopics/subbandIFcables.nroff


NOTE: bandwidth selection with EMIR

The pako command already allows some flexibility that is not yet fully
supported by the data handling, e.g., to select only part of the full
bandwidth.


NOTE: FTS on HERA

With HERA, the FTS can be connected to HERA1 and/or HERA2. 

On HERA, the FTS provides some extra bandwidth, which is not
symmetrical to the point where the line (the commanded frequency) gets
centered.  

With HERA /width wide, the line gets centered at the center of WILMA
and 4MHz.  Relative to this point, the FTS in wide mode covers IF
offset frequencies from < -512 to > +512. In pako the nominal value of
the bandwidth is 1024, symmetric around the line.

With HERA /width narrow, the line gets centered at the center of
VESPA.  Relative to this point, the FTS in fine mode covers IF offset
frequencies from < -256 to > +360. In pako the nominal value of the
bandwidth is 512, symmetric around the line.

It is also possible to connect FTS in fine mode on HERA /width wide or
FTS in wide mode on HERA /width narrow.  However, in these cases the
FTS band coverages are very asymmetric to the line. (See HERA and FTS
documentation for the exact details of the IF ranges).


