Abstract: A directional acoustic transducer includes a plurality of acoustic paths each having first and second ends. The second end of each path terminates in the atmosphere. An electroacoustic device is attached to an acoustic cavity and the acoustic path first ends are coupled to the said acoustic cavity through an acoustic arrangement adapted to produce a predetermined transducer directional response pattern.

Abstract: This disclosure relates to the instant method and system for controlling the interconnecting of a plurality of local communications networks. A source station and a destination station may respectively be adapted to be coupled to at least one communications channel of a communications path, which path includes a plurality of channels, each channel being assignable to at least one of a plurality of local data networks. The respective stations are adapted to determine the home network of the other respective stations with which the respective stations may communicate. Broadly, a source station, which has a message to transmit to a destination station, determines the home network of the destination and couples a first source receiver and a source transmitter to the home network of the destination for transmitting a packet from the source to the destination. A first packet may be transmitted when the source station acquires access to an idle channel of the destination home network.

Abstract: Subband signals are formed each corresponding to a portion of an input signal frequency spectrum. The subband signals are partitioned into subband time segments. The subband time segment signals are permuted. The permuted signals are combined to form a scrambled signal.

Abstract: The instant communications system and method for controlling both digital voice traffic and digital data traffic includes a communications path, a source station and a destination station. The source and destination stations are respectively adapted to be coupled to a source station home network and to a destination station home network. The source station is further adapted to transmit a signaling packet on a first transmit control channel. The signaling packet is for signaling a destination station that the source station has an information packet intended for the destination station. The destination station is adapted to detect the signaling packet on a second receive control channel. The signaling packet includes a field for identifying the source station which has the information packet intended for the destination station. In response to the signaling packet, the destination station is coupled to the source home network.

Abstract: A force sensor includes an elastic dielectric, a first plurality of conductive elements on one side of the dielectric and a second plurality of conductive elements on the opposite side of the dielectric. First signals are applied to one plurality of conductive elements through nonconductive coupling. Second signals representative of the forces on said elastic dielectric are generated responsive to the applied first signals coupled to the other plurality of conductive elements.

Abstract: In a speech recognition arrangement, a speech pattern is recognized as one of a plurality of reference patterns for which acoustic feature signal templates are stored. Each template includes a time frame (e.g., 10 millisecond) sequence of spectral features e.g., LPC and nonspectral e.g., acoustic energy (E) normalized to the peak energy over an utterance interval. LPC and normalized energy feature signal sequences are produced for an unknown speech pattern. For each time frame, the correspondence between the LPC features of the speech pattern and each reference is measured as well as the correspodence between the energy (E) features. In comparing the unknown speech features to those of the reference templates, the dynamic time warp distance DT=D.sub.LPC +.alpha.D.sub.E is used where .alpha. is a weighting factor selected to minimize the probability of erroneous recognition.

Abstract: A microphone arrangement focuses on a prescribed volume in a large room such as an auditorium. The arrangement includes a plurality of directable beam microphone structures. Each beam is directed to a prescribed location. The signals produced in the microphone structures are selectively adjusted to accept sounds from a predetermined volume surrounding the location and to reject sounds outside the prescribed volume.

Abstract: An improved speech analysis and synthesis system wherein LPC parameters and a modified residual signal for excitation is transmitted: the excitation signal is the cross correlation of the residual signal and the LPC-recreated original signal.

Abstract: A system for generating speech pattern templates for use with either speech recognition or speech synthesis. Reference demisyllable templates are first generated from a reference first speaker using both manual and automatic analysis. The analysis for a second speaker is simplified and automated by comparing with the first speaker's templates. The second speaker speaks the same words at a rate time-warped to match the first speakers rate and template. We define a demisyllable as each of the two halves of a syllable, assuming a syllable starts and ends with a noisy consonant, and the syllable is split at its vowel center, thereby simplifying concatenation and comparison. Key features of the invention include generating a set of signals representative of the time alignment between the first and second speaker's templates, and the time-of-occurence boundaries of each syllable in a word.

Abstract: In an ADPCM system, improved detection of silence intervals in a speech signal is attained by detecting the level of the logarithm step-size signal (d.sub.n), which is representative of the energy of the speech samples. A speech pattern is converted into a sequence of adaptive digital codes. Intervals of silence in the pattern are detected and a digital code representative of each silence interval is generated. The adaptive digital codes and the silence interval codes are combined to form a digitally coded signal representative of the pattern. The conversion of the pattern to adaptive digital codes includes forming a signal corresponding to the adaptation step-size for each digital code. The silence interval detection includes producing first and second threshold signals.

Abstract: An electret transducer for producing a directional response, electret foil (92) and a backplate (94) with the actual air gap thickness therebetween varying in accordance with a predetermined relationship. The sensitivity of the electret transducer varies inversely as the actual air gap thickness. In one embodiment the actual air gap thickness is realized by a plurality of posts (90) having heights varying according to the aforesaid relationship. In another embodiment, the actual air gap thickness is realized by varying the thickness of the aforesaid backplate.

Abstract: An electret transducer comprises an electrostatically charged electret foil (10) superimposed directly over a selectively metalized rough surface (16) of a backplate (18). Selective metalization is realized by depositing a thin metal layer (20), the contour of which is defined by a predetermined relationship, over the rough surface (16). The sensitivity of the electret transducer at any point thereon is directly proportional to the width of the metal layer on the backplate. The response characteristic of the electret transducer comprises a main lobe and a plurality of sidelobes below a preselected threshold.

Abstract: An acoustic transducer for producing highly directional characteristics comprises a metalized backplate (130) facing the flat surface (134) of an electrostatically charged electret foil (132). The thickness of the electret foil varies along the length thereof according to a predetermined relationship. The sensitivity of the electret transducer varies directly with the thickness of the electret foil.

Abstract: A rough surfaced backplate has deposited thereon a metallic electrode having a plurality of large areas interconnected by thin strips. The large areas are symmetrically located on opposite sides of the center of the metallic electrode. Furthermore, the distances between the areas is nonlinear. Superimposed on the metallic electrode is an electret foil having a uniform electrostatic charge deposited on the polymer surface thereof.

Abstract: An electret transducer for producting a highly directional response characteristic comprises a backplate (18) and, superimposed thereon, an electrostatically charged electret foil (10). The electrostatic charge varies according to a predetermined relationship. The sensitivity of the electret transducer, at any point thereon, is directly proportional to the electrostatic charge on the electret foil at that point.

Abstract: A directional electret transducer comprises an electret foil and a metalized backplate the effective air gap thickness therebetween varying according to a predetermined relationship. The sensitivity of the electret transducer is directly proportional to the effective air gap thickness. The effective air gap thickness is realized in three ways: first, a plurality of equal diameter holes are drilled to varying depths in the aforesaid backplate; second, a plurality of holes of varying diameters are drilled through the aforesaid backplate; third, a plurality of equal diameter holes are drilled through the aforesaid backplate, the density of the holes varying. In each of the aforesaid three ways, the variation is according to the predetermined relationship.

Abstract: An arrangement for generating x-ray microbeams includes an electron source for generating an electron beam. The electron beam is directed toward a target comprising discrete x-ray emissive spots. X-rays from the spots are formed into microbeams and directed through an examination field.

Abstract: Highly directional response patterns can be obtained by connecting microphones or loudspeakers with tubular coupling path structures. The coupling paths comprise a plurality of elements (110,111 . . . 157) arranged in pairs (110,111; 112,113; . . . 156,157) so that for every element (110) below a center line (102) there is an element (111) above the line. Furthermore, the relationship between the element pairs is nonlinear. The desired directional response comprises one main lobe and a plurality of substantially smaller lobes below a determinable threshold value. The elements may be a bundle of tubes (90) or a plurality of apertures (110,111, . . . 157) in a single tube (100).

Abstract: Improved digital encoding of an input speech signal for transmission uses an adaptive low-pass filter and adaptive coder responsive to the total spectral energy of the input signal, thereby providing reduced coder bit rate at constant coder noise, or conversely reduced coder noise at constant bit rate.

Abstract: A speech controlled dialing circuit identifies input utterances which may be a command word (mode select), repertory word (dialing name or number), or nonrecognized ("Other"). Responsive to the identification of each occurring input utterance, a set of predetermined templates are selected to identify the next occuring utterance. A programmed microprocessor system is described to implement the main controller function.