Abstract: Techniques for reducing the number of layers in a multilayer signal routing device are disclosed. In one particular exemplary embodiment, the techniques may be realized as a method wherein the multilayer signal routing device has a plurality of electrically conductive signal path layers for routing a plurality of electrical signals thereon. The method may comprise forming a plurality of electrically conductive vias in the multilayer signal routing device for electrically connecting at least two of the plurality of electrically conductive signal path layers, wherein the plurality of vias are arranged so as to form at least one channel in at least one other of the plurality of electrically conductive signal path layers. The method may also comprise grouping at least a portion of the plurality of electrical signals based at least in part upon their proximity to the at least one channel so that they may be efficiently routed therein.

Abstract: Techniques for reducing the number of layers in a multilayer signal routing device are disclosed. In one particular exemplary embodiment, the techniques may be realized as a method wherein the multilayer signal routing device has a plurality of electrically conductive signal path layers for routing a plurality of electrical signals thereon. The method may comprise forming a plurality of electrically conductive vias in the multilayer signal routing device for electrically connecting at least two of the plurality of electrically conductive signal path layers, wherein the plurality of vias are arranged so as to form at least one channel in at least one other of the plurality of electrically conductive signal path layers. The method may also comprise grouping at least a portion of the plurality of electrical signals based at least in part upon their proximity to the at least one channel so that they may be efficiently routed therein.

Abstract: The invention is a novel method and transmission system for mitigating the adverse effects of amateur (HAM) radio interference on digital signals transmitted across a twisted pair and reducing the interference caused by the digital signals to amateur radio communications. At the heart of the invention is strategical placement of the frequency spectrum of the transmitted signal relative to the center frequency of the HAM bands. In particular, the signal spectrum is permitted to straddle one or more HAM bands, which permits the transport of high data rates with a single carrier. At the transmitter, the signal is filtered with a real-valued symmetric baseband filter in order to remove signal content in the HAM bands. At the receiver, the signal undergoes adaptive interference cancellation, followed by processing through a decision feedback equalizer. In some cases, the signal is filtered at baseband with a real-valued filter to remove interference in the HAM bands.

Abstract: The invention is a novel method and transmission system for mitigating the adverse effects of amateur (HAM) radio interference on digital signals transmitted across a twisted pair and reducing the interference caused by the digital signals to amateur radio communications. At the heart of the invention is strategical placement of the frequency spectrum of the transmitted signal relative to the center frequency of the HAM bands. In particular, the signal spectrum is permitted to straddle one or more HAM bands, which permits the transport of high data rates with a single carrier. At the transmitter, the signal is filtered with a real-valued symmetric baseband filter in order to remove signal content in the HAM bands. At the receiver, the signal undergoes adaptive interference cancellation, followed by processing through a decision feedback equalizer. In some cases, the signal is filtered at baseband with a real-valued filter to remove interference in the HAM bands.

Abstract: The invention is a modem and associated method of data transmission which improve the protection afforded to data under conditions of occasional impulsive noise. The modem is ideally suited for use with another modem of similar type in a system whereby data is transmitted as a sequence of frames in either direction. Each modem applies forward error correction (FEC) to frames transmitted to the other modem. If a particular frame is corrupted on its way from a “first” modem to a “second” modem, the second modem attempts to correct these errors. If it is unable to do so, then the second modem will request a retransmission by placing a binary encoded message in the error field of a frame transmitted towards the first modem. The binary encoded message is itself protected from errors by a suitable combination of zeroes and ones. The second modem then sets a timer and subsequently ignores all frames received from the first modem until the timer expires.

Abstract: The invention discloses a novel equalization system for reducing the deleterious effects of crosstalk on signals received at a modem, with particular regard to QAM signals transmitted over copper twisted pairs. The equalization system employs the common combination of a linear equalizer followed by a decision-feedback equalizer (DFE). However, instead of aiming for perfect equalization of channel distortion, the overall frequency response of the channel plus the linear equalizer is skewed such that higher frequencies are attenuated relative to lower ones. More generally, the spectral regions where crosstalk is strongest are attenuated, which reduces the crosstalk noise present at the input to the DFE at the expense of introducing inter-symbol interference (ISI). Fortunately, most DFEs are capable of handling the added ISI, leading to data decisions that are relatively unaffected by crosstalk noise.