Before starting spectral analysis, prepare background data using
the following command:
IDL> bkgd = mk_hxtdata(index,data,ssss,infil,channel=0)
In the above example, the time profile in the L band (channel=0) is displayed on
the screen. Choose the background data interval in the same way as described in
3.3.3 (4). Note that BGD data in all the four energy bands, which have the same
start and end times specified from the L band time profile, are stored in the
structure variable bkgd. The variable bkgd has the same structure as the
one in 3.3.3 (4); if you have already have the BGD data in your IDL memory, you
need not run the above MK_HXTDATA.