INSTRUMENT_MODE_DESC gives an overview of the different operational 
modes of SOIR
Written by Eddy NEEFS

SOIR spectra contained within one observation may be taken in either 
of 3 modes:

(1) AOTF frequency hopping :

During each observation up to 4 random AOTF frequencies (hopping) and
hence non-contiguous small wavelength domains are recorded.

(2) Single parameter stepping :

During each observation a series of up to 4 wavelength domains is 
recorded. The parameters defining each of the domains are identical, 
except one which is incremented by a fixed amount from domain to 
domain. Can be executed either continuous from one observation to the
next or reset to a value specified by TC at each observation.

A special case of single parameter stepping is AOTF frequency 
stepping: the AOTF frequency is incremented by a fixed frequency step
for each sequential spectral domain, while all other parameters remain
unchanged.

(3) Automatic window stepping :

The detector is read-out completely by reading sequentially windows of
8 lines. Observations start with the detector window positioned at
line 1 and for subsequent observations the window is shifted by 8 
lines. In total 32 observations are required to read out the complete
detector array.