  We turn a given filter bank into a filtering scheme that provides perfect
reconstruction, synthesis is the adjoint of the analysis part (so-called
unitary filter banks), all filters have equal norm, and the essential features
of the original filter bank are preserved. Unitary filter banks providing
perfect reconstruction are induced by tight generalized frames, which enable
signal decomposition using a set of linear operators. If, in addition, frame
elements have equal norm, then the signal energy is spread through the various
filter bank channels in some uniform fashion, which is often more suitable for
further signal processing. We start with a given generalized frame whose
elements allow for fast matrix vector multiplication, as for instance,
convolution operators, and compute a normalized tight frame, for which signal
analysis and synthesis still preserve those fast algorithmic schemes.
