It starts from values on a coarse sequence of sampling points and produces values for successively more densely spaced sequences of sampling points.
Because it applies the same operation over and over to the output of the previous application, it is known as the cascade algorithm.
The iterative algorithm generates successive approximations to ψ(t) or φ(t) from {h} and {g} filter coefficients.
The frequency domain estimates of the basic scaling function is given by and the limit can be viewed as an infinite product in the form If such a limit exists, the spectrum of the scaling function is The limit does not depends on the initial shape assume for φ(0)(t).
From this scaling function, the wavelet can be generated from Successive approximation can also be derived in the frequency domain.