A scaling function is the solution to a dilation equation PHI(t) = SIG
MAc(k)PHI(2t-k), in which the coefficients come from a low-pass filter
. The coefficients in the wavelet W(t) = SIGMAd(k)PHI(2t-k) come from
a high-pass filter. When these coefficients are matrices, PHI and W ar
e vectors: there are two or more scaling functions and an equal number
of wavelets. By dilation and translation of the wavelets, we have an
orthogonal basis W(ijk) = W(i)(2(j)t - k) for all functions of finite
energy. These ''multiwavelets'' open new possibilities. They can be sh
orter, with more vanishing moments, than single wavelets. They can be
symmetric, which is impossible for scalar wavelets (except for Haar's)
. We determine the conditions to impose on the matrix coefficients c(k
) in the design of multiwavelets, and we construct a new pair of piece
wise linear orthogonal wavelets with two vanishing moments.