Abstract: A method of implementing troposcatter communications is provided. Transmittal of signals between receive and transmit antennas is performed in the time domain. After reception of a transmitted signal, the signal is converted to the frequency domain for signal processing. After signal processing, the signal is converted back into the time domain.

Abstract: A system for the removing of interference (ingress) in cable modems without reducing the data rate or changing the frequency of the signal. The invention comprises both, a variable band stop filter bank, and a non-linear equalization system. The band stop filter bank removes ingress while the equalization system, comprising of an inner and an outer equalizer, removes the distortion created by the band stop filtering. A spectrum monitor detects both the presence of ingress and its frequency, then feeds the data to a digital signal processor which calculates the distortion removal settings for the equalizers. No additional hardware of software is required in the users homes, but rather the invention is designed to be used solely at the head end and in addition to the basic Cable Modem Termination System.

Abstract: This invention relates generally to signal processing techniques for removing or reducing the effects of instabilities in pulsed signal sources, as in phase echo systems using a pulsed signal transmitter source, and, more particularly, to a technique for compensating for the varying amplitude, frequency and/or phase characteristics of the signal source pulses during operation.

Abstract: A signal processing system for measuring the amplitude and time delay responses of a network over the bandwidth allocated to the network wherein a plurality of subburst signals each in the form of a suppressed-carrier, amplitude-modulated signal, is applied to the network. The signals received from the network are provided in complex form having in-phase and quadrature components. Matched filters respond to such components and the matched filter outputs are processed so as to determine the estimated amplitude and time delay responses of the network at the carrier frequency of the subburst signals over the operating bandwidth of the network.

Abstract: Signal processing circuitry, preferably for use in multiplying two input signals, one at RF frequency and one at baseband frequency, which includes at least a basic four branch bridge circuit having a diode connected in each branch in a generally symmetrical four branch circuit configuration using a single bias supply and including a trimming resistor in at least one branch for controlling the current through the diodes in such branch so that the characteristics of the diodes in all branches can be matched over substantially the complete range of control current values therefor.

Abstract: Signal processing circuitry, preferably for use in multiplying two input signals, one at RF frequency and one at base-band frequency, which includes a pair of PIN diodes connected in a generally symmetrical circuit configuration using a single bias supply and including a trimming resistor for controlling the current through a selected one of the diodes so that the characteristics of both diodes can be matched over substantially the complete range of control current values therefor. Further, the circuit configuration permits the use of an easy and effective technique for compensating for temperature changes of the circuit during operation.

Abstract: An improved high speed digital communications diversity receiver using a forward adaptive transversal filter equalizer, having a plurality of weighting sections in each diversity channel to provide a combined weighting signal, wherein the required complex multiplications and correlations needed for weighting purposes are performed at IF frequencies, while the time-delayed combining operations for providing the desired combined weighted output signal are performed at baseband frequencies. Such an arrangement reduces the number of tapped delay lines normally needed for such transversal filter equalizer operation and further reduces the signal losses incurred in operating delay line devices at intermediate frequencies so that fewer large gain-bandwidth product amplifiers are required in the system than the number required in previously available systems using such forward transversal filter equalizers.