Abstract: A system, device, and method for time-domain equalizer training uses a two-pass auto-regressive moving average model. A communication channel is first modeled using p1 poles and q1 zeros to form a first shortened channel impulse response having a first approximation H1(z)=B1(z)/1+A1(z), wherein q1, is greater than a predetermined cyclic prefix length. A time-mirrored image of the first shortened channel impulse response is then formed, and the resulting time-mirrored image of the first shortened channel impulse response is modeled using p2 poles and q2 zeros to form a second shortened channel impulse response having a second approximation H2(z)=B2(z)/1+A2(z), wherein q2 is less than or equal to the predetermined cyclic prefix length. The time-domain equalizer coefficients are determined by combining A1(z) and A2(1/z) with an appropriate amount of delay.

Abstract: A method and system are provided for sending location dependent and personal identification information to a public safety answering point. Base stations for receiving a transmission packet signal having a transmitter identification number are located throughout an area where personal security coverage is desired. Whenever a personal security transmitter is activated, it is received by one or more base stations. Each base station has a signal receiving unit for receiving a transmission packet signal and a signal processing unit for processing a transmission packet signal and generating a base station packet. Base station packets contain both a transmitter identification number and location information about the activated transmitter. After a base station packet is generated, it is sent to a command center for processing.

Abstract: A precoding scheme for noise whitening on ISI channels is presented where the scheme permits any type of shaping and is compatible with trellis coding. Its implementation complexity is significantly less than that of trellis precoding. The resulting reduction in shaping gain is small and becomes negligible as the rate per 2D of the constellation increases. This technique uses a structured vector quantization (SVQ) technique for optimal shaping of the constellation. Optimal (N-sphere) SVQ shaping results in higher shaping gains than those of Voronoi constellations based on known N-dimensional lattices. For a given CER.sub.2 (or PAR.sub.2) SVQ shaping results in optimal shaping. This is useful for implementation over QAM modems as significant shaping gains can be achieved even for a small constellation expansion. The SVQ-shaped constellations have a very reasonable implementation complexity.

Abstract: Repetitive phenomena cancelling controller arrangement for cancelling unwanted repetitive phenomena comprising known fundamental frequencies. The known frequencies are determined and an electrical known frequency signal corresponding to the known fundamental frequencies of the unwanted repetition phenomena is generated. A plurality of sensors are employed in which each sensor senses residual phenomena and generates an electrical residual phenomena signal representative of the residual phenomena. A plurality of actuators are provided for cancelling phenomena signals at a plurality of locations, and a controller is utilized for automatically controlling each of the actuators as a predetermined function of the known fundamental frequencies of the unwanted repetitive phenomena and of the residual phenomena signals from the plurality of sensors.

Abstract: A modem and method for modulation-demodulation of a received analog signal. The modem receives sixteen bits at four bits per baud. The 8 D Block Encoder encodes nine of the sixteen bits into 12 Z-bits which are used to specify a sequence of four 2 D constellation points. These 2 D constellation points correspond to a sequence of four 2 D subsets of a 8 D subtype selected. The differential encoder differentially encodes two of the sixteen bits to make the code transparent to a 90 degree rotation. The rate 3/4 convolutional encoder generates a check bit and a bit converter converts the check bit, the differential encoded bits and the remaining five bits into 8 Z-bits. The result is an 8 D trellis with a 20-point 2 D constellation.

Abstract: A 14.4 kilobit/second modem uses an encoding scheme in which groups of five bits are encoded as one of thirty-two (2.sup.5) possible code groups. This is done by using quadrature amplitude modulation and a 6 by 6 space-state constellation which allows a maximum of thirty-six different points to be encoded. Since only thirty-two points are needed the four outer corner points of the constellation are not used. In order to achieve the desired 14.4 KBPS data rate the baud clock must run at 2880 Hz. However, this bandwidth is very close to the maximum bandwidth available on voice-grade telephone lines. Accordingly, data encoding and data recovery techniques must be used which maximize the probabilities of correctly receiving the encoded data signals.