an interrupted ring. The film has conductive coatings on both sides for the application of an electrical signal voltage. In the figure, 20.6 is a carrier ring made of a plastic such as polyoxymethylene (Delrin). The piezoelectric PVDF material 1.6 is carefully cemented to the carrier ring and folded back on itself for greater sensitivity. The open shape allows the transducer to be easily slipped on and off a finger. One arrangement shown is to have a transducer on each finger, each activated by a processed signal derived from one band of the voice frequency spectrum.--SFL

(PARCOR) coefficients are supplied by a microprocessor, along with an excitation signal representing either a glottal pulse or a noise signal. In the all-zero mode, the filter performs adaptive LPC analysis and the coefficients are collected into buffers and averaged over a block of samples to produce successive frames of speech spectral data.--DLR

4,791,672

43.66.Ts WEARABLE DIGITAL HEARING AID AND

METHOD FOR IMPROVING HEARING ABILITY

James A. Nunley, John W. Steadman, and Perry J. Wechsler, assign- ors to Audiotone, Incorporated

13 December 1988 {Class 381/68.2); filed 5 October 1984

The objective is to produce analog output signals of improved intelligi- bility. The hearing aid includes a wearable, programmable digital signal processor for processing in real time digital samples of input analog signals

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and delivering output analog signals having the processed characteristics. The hearing aid program stored in the processor is continuously executed and modifies the analog signals reaching it by digital filtering in real time, in accordance with the varying noise levels in the received signals. The signal processing program is designed to suppress interfering noise.--SFL

4,520,499

43.72.Ne COMBINATION SPEECH SYNTHESIS AND

RECOGNITION APPARATUS

Terry Montlick et al., assignors to Milton Bradley Company 28 May 1985 (Class 381/36); filed 25 June 1982

The central element of the synthesis/recognition device described here is a lattice filter circuit that can be configured as either an all-pole or an all- zero filter suitable for speech synthesis or analysis, respectively. In the all- pole mode, synthesis coefficients in the form of linear prediction reflection

4,520,500

43.72.Ne SPEECH RECOGNITION SYSTEM

Kaneyoshi Mizuno et al., assignors to Oki Electric Industry Company 28 May 1985 (Class 381/43); filed in Japan 7 May 1981

This speech recognition device is described as having improved perfor- mance due to a weighting factor applied to each point in the time/frequency matrix when unknown and reference items are compared. Along with each matrix point for each reference item is stored a bit which determines whether to use a more severe distance criterion for that matrix point in computing the overall distance between unknown and reference items. It was not dear, at least to this reviewer, how these penalty bits arc to bc assigned to the reference items.--DLR

4,796,504

43.75.Gh MUSICAL INSTRUMENT

Harlan McWillis, Los Angeles, CA 10 January 1989 (Class 84/265); filed 30 July 1986

The musical instrument here is a harp. Several different modifications of normal harp design are intended to improve the tonal output of the instrument. The soundboard is held in place on the case by retaining rails but is movable in the sense that it is not rigidly attached (screwed and glued). "The result is a sound which is both louder and mellower." Another

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change that is intended to be "an improvement in the sympathetic reso- nance system" is a "focus board" glued to the under side of the soundboard from which "the sound waves are returned to the middle of the board where

they can best activate the sympathetic resonance system." In order to im- prove tone production for the longest strings near post 15, the manner in which the lower end of the post 15 connects to the end of the soundboard and case is modified.--DWM

2693 J. Acoust. Soc. Am. 85(6), June 1989; 0001-4966/89/062693-01500.80; @ 1989 Acoust. Soc. Am.; Patent Reviews 2693

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