Abstract: In a data transmission system including a transmission medium that is subject to fast fades of duration longer than individual data symbols to be transmitted, a chirp filter is provided for time-spread processing the data signals prior to transmission. The processing spreads the energy of each symbol over an interval longer than the length of expected individual fades. In a receiving terminal inverse processing is provided to remove the chirp effect.

Abstract: A multiband antenna mounting and feedline coupling arrangement includes a first transmission line segment secured in a mounting device for the antenna for coupling energy to and from the antenna. A second transmission line segment, extending, e.g., to grounded high band equipment, provides high band signal coupling with the first line and includes a direct current blocking capacitor in series in the ground return path of that second line segment, the capacitor having such a low impedance to high band energy that it presents negligible impedance to such energy. A third transmission line segment provides low band signal coupling with the first line by way of a part of the ground return path of the first line. A high band quarter wave, in the high band, filter stub transmission line is connected between the signal and ground return paths of the third transmission line adjacent to the point of coupling thereof to the first line.

Abstract: A signal processing arrangement is connected to a microphone array to form at least one directable beam sound receiver. The directable beam sound receivers are adapted to receive sounds from predetermined locations in a prescribed environment such as auditorium. Signals representative of prescribed sound features received from the plurality of predetermined locations are generated and one or more of the locations is selected responsive to the sound feature signals. A plurality of directable beam sound receivers may be used to concurrently analyze sound features from the predetermined locations. Alternatively, one directable beam sound receiver may be used to scan the predetermined locations so that the sound feature signals therefrom are compared to sound features from a currently selected location.

Abstract: A digital speech signal communication system includes a decoder that generates a predictively coded speech signal responsive to received digital codes and predicitve parameters corresponding thereto. A signal representative of the quality of said predictively coded speech signal is formed and the predictively coded speech signal is modified responsive to the quality representative signal and the predictive parameters, The quality representative signal may be generated by combining a signal corresponding to the step of each predictive code with the predictive parameters for the received code to form a signal representing an estimate of the noise in the predictive code.

Abstract: A compliant, synthetic material of predetermined thickness is inserted into the space between cables and the inner surface of a pedestal enclosure which houses the cables. The compliant material prevents moisture, rodents, and insects from entering the upper portion of the enclosure. Drainage slots are provided. A wire mesh pad or steel wool may be used instead of the compliant, synthetic material. A plurality of embodiments are disclosed.

Abstract: An adaptor terminates one or more modular protectors of the same size obviating the need for a telephone company to carry an inventory of many different sizes. Each modular unit, which protects a telephone line, has a hollow shell into which two terminals are received, each terminal communicating with a protector. The terminals are elevated above a landing on the housing so that the distance between the two terminals exceed a predetermined distance to reduce noise. The protectors are enclosed within the hollow shell by a base cover which is secured in place by a grounding clip which has many tines on one end for penetrating the side of the housing; the other end of the grounding clip is so formed as to secure the housing to the adaptor.

Abstract: Natural quality and bit-rate for LPC speech synthesis is improved by encoding the LPC residual signal in a prescribed multipulse format formed for each LPC frame. Voiced, unvoiced, and mixed (hiss plus periodic) excitation is inherent. The speaking-rate is changed by adding, deleting, or repeating pitch-periods, and the pitch (intonation) is changed by adding or deleting zeros in the multipulse excitation signal.

Abstract: A boot, or adapter, for an aerial cable or terminal housing is made from hard material in two halves. The two halves are fastened, or hinged, at one longitudinal edge by a eye-hook-like device and at the other longitudinal edge by a snap lock device. An end surface has a plurality of concentric plates which may be snapped out to allow a cable to pass through the boot. The space between the boot and the cable is filled with a compliant, synthetic material.

Abstract: A multipulse-code approximation of of one frame of a predictive residual signal may lose the frame-to-frame redundancy. Accordingly, pitch redundancy removal during the iterative process of forming the multipulse sequence, rather than frame-to-frame code comparison, provides reduction of excitation signal bit rate, substantially independent of voice pitch. A speech pattern predictive coding arrangement includes forming a prescribed format multipulse excitation signal for each successive time frame of the pattern. The multipulse excitation signal corresponds to the frame predictive residual. The redundancy in the multipulse excitation signal is reduced by forming a signal representative of the similarities between the current frame speech pattern and the speech pattern of preceding frames and removing such similarities from the multipulse excitation signal. Advantageously, the bit rate of the multipulse excitation signal is reduced and the excitation signal is rendered substantially independent of voice pitch.

Abstract: A speech pattern is partitioned into its syllabic subunits by generating signals representative of the speech energy and autocorrelation features of the time frames portions thereof. The peak energy time frames are identified from the frame energy signals and the minimum energy time frames between each pair of successive peak energy frames of the speech pattern are determined from the time frame energy and autocorrelation feature signals. Candidate syllabic subunits are formed responsive to the peak and minimum energy frame characteristics and the autocorrelation feature signals. Signals corresponding to the duration and the energy of each candidate syllabic subunit peak energy frame relative to the energy of the other peak energy frames and the maximum peak energy frame of the speech pattern are formed and these signals are combined to produce a figure of merit for each candidate syllabic subunit.

Abstract: An electroacoustic device comprises an array of electroacoustic transducer elements for producing a prescribed directional response pattern at a first frequency. Each element includes apparatus for restricting the frequency range of sound waves incident on said element so that the directional response pattern is invariant over a prescribed frequency band.

Abstract: A digital communication system includes a predictive decoder that is operative to convert received digital codes into a predictively decoded signal, e.g., speech signal, and to generate a set of predictive parameter signals and a signal representative of the communication system bit rate. A set of filter control signals is generated responsive to the communication bit rate signal. The predictively decoded signal is passed through a filter which modifies the output signal responsive to the filter control signals and the decoder predictive parameter signals to improve the output signal quality. The filter control signals selectively alter the predictive parameter signals to optimize the predictively decoded signal modification for the current transmission bit rate.

Abstract: A back electrode has a plurality of ridges on one surface. An electret foil is spaced from the ridged surface of the back electrode. In the absence of applied pressure, a gap remains between the foil and the surface of the back electrode between the ridges. Above one applied pressure, the foil collapses between the ridges. Below a second applied pressure, the foil returns to its original position.

Abstract: An acoustic transducer is connected to an electronically controllable time-dependent conductance so that energy may be rapidly applied to and extracted from the transducer and associated circuitry.

Abstract: A system, method and station interface arrangement which permits video games to be played over a telephone network is disclosed. Communications delay between the games can be mitigated by transmitting local player position data to a remote game, the position data being detected at a local game during a current "generation" but the position data not being used by the local and remote games until the next generation and the transmission occurring during the time interval in which the current generation is being run at the local game. The position data can be encoded so that errors, e.g. transmission errors, may be detected. Detected errors may be corrected by retransmitting the priorly transmitted local position data. In addition, the games may be synchronized or resynchronized by transmitting a frame count along with the position data. The frame count may identify by order of succession the respective local and remote position data so that the games obtain and remain synchronized.

Abstract: An analog-to-digital converter circuit is disclosed employing a plurality of comparators each having the same reference voltage input. At each comparator stage plus and minus binary "bit weights" are developed. Selection of either the positive or negative bit weights at a stage allows a binary fraction to be added or subtracted. The number of comparator stages need only equal the number of desired digit positions in the output instead of having one comparator for each quantizing level. The comparator stages operate in a "wave" or "pipeline" manner under the control of a plurality of high speed wave forms so that each stage decodes its respective binary digit for one analog sample while the other stages are decoding their respective binary digits of other analog samples.

Abstract: Speech signal pitch detection uses the residual signal output of an LPC (linear prediction coder) filter. The residual signal (or its Hilbert transform) is divided into frames of 20 milliseconds, and each frame searched for signal peak periodicity by first detecting the highest peak, then detecting a set of equally-spaced selected samples from which the pitch period is determined. If no periodicity is found over three frames, an unvoiced decision is made.

Abstract: In a communication system an input predictive type signal is analyzed in successive time intervals to generate a set of prediction signals for the interval. A predictive residual signal is produced jointly responsive to the input signal and the interval prediction signals. The predictive residual signal is quantized and encoded. The quantization includes dividing the predictive residual signal into a plurality of distinct portions and selectively quantizing the distinct portions to improve intelligibility.

Abstract: An arrangement for endpoint detection improves speech recognition accuracy and lowers rejection rates by developing an ordered list of endpoint candidates. A triple thresholding technique defines energy signal pulses. The energy pulses are combined according to predetermined criteria to form the endpoint candidates.

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.