Abstract: Network elements in a telecommunications network, such as toll switches, databases and the like, are provided with redundant SS7 signaling interfaces based on different software designs. At least one of the interfaces, referred to as a network endpoint signaling transfer point, or NESTP, is loosely coupled to its host and has signaling transfer point (STP) capabilities. In a routing table within the NESTP, a plurality of prioritized route lists are provided for at least some destinations, the list that is used to route a particular message to such a destination being a function of the route by which that message arrived at the NESTP.
October 9, 1992
Date of Patent:
January 24, 1995
Jo Ann Blatchford, Pamela L. DeFazio, Joel K. Young
Abstract: A signal processing arrangement uses a codebook of first vector quantized speech feature signals formed responsive to a large collection of speech feature signals. The codebook is altered by combining the first speech feature signals of the codebook with second speech feature signals generated responsive to later input speech patterns during normal speech processing. A speaker recognition template can be updated in this fashion to take account of change which may occur in the voice and speaking characteristics of a known speaker.
Abstract: A subband adaptive filter is disclosed that retains the computational and convergence speed advantages of subband processing while eliminating delay in the signal path. The technique has applications in active noise control where delay seriously limits cancellation performance and in acoustic echo cancellation where transmission delay specifications may limit the use of conventional subband designs. A reference signal and a residual error signal are each decomposed into a plurality of subband signals, and a set of adaptive weighting coefficients is generated for each of these subbands by a conventional complex LMS (least-mean-squared) technique. These sets of subband weighting coefficients are then transformed into the frequency domain, appropriately stacked and inverse transformed back into the time domain to obtain wideband filter coefficients for a programmable filter.
Abstract: The present invention provides a method of coding a set of multi-level signals, such as video signals. The method comprises filtering the set of multi-level signals into one or more sets of multi-level sub-band signals; allocating a first quantity of bits for use in coding a first set of sub-band signals; coding the first set of multi-level sub-band signals using zero or more of the first quantity of allocated bits; allocating a second quantity of bits for use in coding a second set of sub-band signals, the second quantity of bits comprising zero or more of the first quantity of bits not used in coding the first set of multi-level sub-band signals; and coding the second set of multi-level sub-band signals using zero or more of the second quantity of allocated bits. Three examples of the method are provided. A hardware implementation involving the use of digital signal processors operating in parallel is also provided.
July 16, 1993
Date of Patent:
May 3, 1994
AT&T Bell Laboratories
John Hartung, Arnaud E. Jacquin, Thomas A. Michel, Christine I. Podilchuk