An analytical expression has been obtained that describes the time Variatio
n of time-resolved signals transmitted through or reflected by a homogeneou
s scattering slab as measured with a detection system having a square-impul
se response. This expression can be used to improve the match between theor
etical and experimental time-resolved signals measured with a system having
a finite response time. It can also be used to assess the effect of a fini
te detection response time on the time-domain characterization of a turbid
medium. The expression can be adapted to detection systems that are not tim
e invariant. (C) 1999 Optical Society of America.