**MSC:**- 41A10 Approximation by polynomials, {For approximation by trigonometric polynomials, See 42A10}
- 42A10 Trigonometric approximation

A good measure is provided by a periodic version of the Heisenberg

uncertainty principle. We consider multiresolution analyses generated

by de la Vallee Poussin means of the Dirichlet kernel. For the

resulting interpolatory and orthonormal scaling functions and wavelets,

the uncertainty product can be bounded from above by a constant.