  This Letter proposes a controlled coupling process for information
processing. The net effect of conventional coupling is isolated from the
dynamical system and is analyzed in depth. The stability of the process is
studied. We show that the proposed process can locally minimize the smoothness
and the fidelity of dynamical data. A digital filter expression of the
controlled coupling process is derived and the connection is made to the
Hanning filter. The utility and robustness of proposed approach is demonstrated
by both the restoration of the contaminated solution of the nonlinear
Schr\"{o}dinger equation and the estimation of the trend of a time series.
