In order to determine a system's
behaviour experimentally test input
signals are required that suffice the
conditions of Duhamel's
convolution integral. As the
convolution integral describes the
response to infinitely short signals
the d or
Diracfunction is suitable as test
signal. The Dirac pulse can be realized
only approximately. Instead of it the
heaviside function that corresponds to
the integral of the Diracfunction may
be used.
Harmonic oscillations are to be used to
obtain the system's response to
harmonic input signals that can be
obtained from arbitrary shapes by means
of Fourier or
Laplacetransformation.
