The superposition technique is a new analysis method to obtain average
properties of certain kinds of aperiodic time variations. Real averag
e profiles of X-ray shots in Cyg X-l, GS 339-4, GS 2023+338 and GS 112
4-68 in the hard state are obtained in detail by applying the techniqu
e to rapid time Variations of these sources observed by Ginga. The sho
t profiles obtained are consistent with structures of power spectral d
ensities and phase (time) lags below a few Hz. Soft energy spectra of
the S-ray shots are thought to be the origin of soft excess components
in time-averaged energy spectra. The shot profiles imply that the X-r
ay shots arise from aperiodic mass accretion in the advection dominate
d disk. These results are briefly described.