A low probability of intercept signal detection receiver using quadrature mirror filter bank trees

This paper describes a new type of spread spectrum intercept receiver. The receiver uses orthogonal wavelet techniques and a Quadrature Mirror Filter (QMF) bank tree to decompose a waveform into components representing the energy in rectangular “tiles” in the time frequency plane. By simultaneously examining multiple layers of the tree, the dimensions of concentrations of energy can be estimated with a higher resolution than is normally associated with linear transform techniques. This allows detection and feature extraction even when the interceptor has little knowledge of specific parameters of the signal being detected. For example, no prior knowledge of channelization or time segmentation is assumed. In addition, the receiver can intercept and distinguish between multiple signals