  The progress in nanofabrication, measurement technology, and mesoscopic
transport theory has been expanding the field of shot noise. Although a
wave-packet approach to DC shot noise of independent electrons at finite
temperature was offered as an intuitive alternative to the sophisticated
theories, actual shot noise data often behave more complicated than the derived
simple expression. For example, so-called effective charge can deviate from
elementary electronic charge due to correlated tunnelings. Also, there are
cases where one wishes to know the full spectrum of the shot noise. It will be
of great use if a handy method for the shot noise in various experimental
situations is available. In this article, a classical wave-packet approach to
the shot noise is presented. The classical formulation provides a rigorous yet
straightforward formalism to compute the full spectrum and, furthermore,
clarifies the structure of Fano factor and effective charge. Additionally, the
role of realistic detectors and an application to cross correlation
measurements are also discussed. The present method can serve as an intuitive
complement to the full quantum mechanical and field theoretical approaches.
