INFORMATION-THEORETIC PERFORMANCE OF QUADRATURE MIRROR FILTERS

Most existing Quadrature Mirror Filters (QMF's) closely match the deri ved closed-form expression for an efficient class of QMF's. We use the closed-form expressions to derive the relationship between informatio n-theoretic loss and the Frequency selectivity of the QMF, by calculat ing first-order entropy as well as rate-distortion theoretic performan ce of a two band QMF system, me find that practical QMF's do not suffe r a significant information-theoretic loss with first-order autoregres sive Gaussian sources. With second-order autoregressive sources pie fi nd that practical QMF's suffer a notable information-theoretic loss wh en the bandwidth of the source is extremely narrow, but incur a small loss when the bandwidth is wider. We suggest that our results broadly apply to higher order autoregressive sources as well.