The SWS grating sections can be used at wavelengths between 2.38 
m
and 45.2 m. This section links instrument units to units applicable to
astronomical sources with a high precision on a single detector element basis,
and provides the strategy for planning of observations.
The SWS instrumental signal-level unit is
Vs 
, the average rise of the voltage of the ramp during one second
of time. It is found that the signal response of the
instrument is a linear function of the illumination over a very large range of
input signals (0.5 - 100,000 Jy), when hysteresis effects are ignored.
Therefore this unit is fully qualified for simple linear calculations backwards
and forwards relating source flux density, instrument signal level, instrument
noise level and noise equivalent flux density (NEFD , i.e., the input flux density which
gives an output signal with a signal-to-noise ratio SNR = 1). The SWS
grating sections produce a 
2 Vs signal on a single detector
element for a source flux density of 1 Jy. As the SWS grating detectors
produce a minimum noise in a 2 sec integration in the range
0.7-3.0 Vs , independent of wavelength, this statement provides the
full specification of the SWS grating maximum sensitivity on a single detector
element basis with an accuracy of about a factor 2.