Level 2 Help for SIGNAL

 STRING--OPTIONAL
	INP=(D1,D2,D3,...,Dn)
 Inputs are flat-field images which may have been PICSUM'd.

 STRING--REQUIRED
 The output ASCII text file which contains the exposure and signal of the
 specified pixel.

 STRING--OPTIONAL
 Specifies the name of the SRCH-format text file containing the names of
 the input files to be processed.  This is an alternative to listing the 
 filenames with the INP parameter.  

 STRING--REQUIRED
 The line and sample of the pixel whose exposure and signal is output.