Gennum Corporation

Huawei Technologies Co., Limited

Semtech Canada Corporation

Mohammad Hossein Shakiba

David L Lynch

John Hudson

Jack MacDougall

Martin Rofheart

Vasilis Papanikolaou

Eliyahu D Zamir

James Raymond Bailey

Tirdad Sowlati Hashjani

Jack Macdougall

A method and apparatus for signal equalization are provided. Multiple decision components are arranged in a sequence, beginning with a history portion and ending with a decode portion. Each decision component performs a decode decision on a symbol. Decode decisions are passed forward to other decision components where they can be used to compensate for intersymbol interference. Decode decision output by the history portion are otherwise discarded, while decode decisions output by the decode portion are output as a decoded signal. In the next decode cycle, input previously provided to the decode portion is again provided to the history portion, in a sliding, overlapping block manner.

Sliding block decision equalizer

Systems and methods are disclosed for detecting sequences of symbols in a received signal in the presence of inter-symbol interference. Maximum Likelihood Sequence Detection (MLSD) is a known method for optimum detection of such sequences. To reduce the complexity of the MLSD, a Reduced-State Sequence Detection (RSSD) technique has been considered based on partitioning the states of the MLSD. In this approach, a simplified sequence detector is placed within a global decision feedback loop. The disclosed architecture shortens the feedback loop by moving the sequence detector outside the loop and converting the interaction between the two to a feed-forward manner. This is achieved through slicing the signal and closing a nested loop around the sliced bins. A further variant simplifies the detector even more by reducing the number of bins.

Decision feed-forward reduced-state sequence detection

Systems and methods are provided herein for interfacing a first multi-media digital device with a second multi-media digital device. An exemplary method includes the steps of: (i) converting a plurality of differential digital content channels from the first multi-media digital device into a plurality of single-ended digital content channels; (ii) transmitting the plurality of single-ended digital content channels from the first multi-media digital device to the second multi-media digital device via one or more coaxial cables; and (iii) receiving the single-ended digital content channels from the one or more coaxial cables and converting the single-ended digital content channels back into a plurality of differential digital content channels that are supplied to the second multi-media digital device. Additional steps of the exemplary method may include: (i) transmitting one or more auxiliary channels between the first multi-media digital device and the second multi-media digital device; and (ii) combining the one or more auxiliary channels with at least one of the plurality of digital content channels to form a combined channel to be transmitted from the first multi-media digital device to the second multi-media digital device.

Multi-media digital interface systems and methods

Systems and methods are provided herein for interfacing a first digital device with a second digital device. An exemplary method includes the steps of combining one of a plurality of digital content channels and a back channel to form a composite channel, the back channel for transmitting information from the second multi-media digital device to the first multi-media digital device, converting a digital content channel and the composite channel from the first digital device into a plurality of single-ended digital content channels, transporting the plurality of single-ended digital content channels from the first digital device to the second digital device, and converting the single-ended digital content channels back into the digital content channel and the composite channel that are supplied to the second digital device. Cross-talk interference is reduced between the back channel and one of the plurality of digital content channels via a cross-talk cancellation filter.

Transmit, receive, and cross-talk cancellation filters for back channelling

An adaptive equalizer may include one or more equalizing gain stages coupled to an input signal. An automatic gain control circuit may be used to control the gain of the one or more equalizing gain stages, the automatic gain control circuit having an AGC reference input. A dual-output DC restoration circuit may be coupled to the output of the one or more equalizing gain stages for generating a first output signal using a first hysteresis slicer that DC restores the input signal and for generating a second output signal using a second hysteresis slicer that is coupled to the AGC reference input of the automatic gain control circuit, wherein the second hysteresis slicer introducing less hysteresis than the first hysteresis slicer.

Adaptive equalization system and method having a lock-up-free quantized feedback DC restoration circuit

In accordance with the teachings described herein, an extended equalizer circuit is provided for equalizing a digital communication signal transmitted over a transmission medium that causes a frequency-dependent attenuation of the digital communication signal. An equalizer may be used that includes a linear equalization circuit and a non-linear equalization circuit, the linear equalization circuit being configured to apply a linear filter to the digital communication signal to compensate for the frequency-dependent attenuation caused by a first portion of the transmission medium, and the non-linear equalization circuit being configured to apply one or more non-linear operations to the digital communication signal. A de-emphasizing equalizer circuit may be coupled in series between the transmission medium and the equalizer and configured to apply an additional linear filter to the digital communication signal in order to compensate for the frequency-dependent attenuation caused by a second portion of the transmission medium.

De-emphasizing cable equalizer

A method and apparatus for avoiding and or recovering from the latch-up condition in a quantized feedback DC restorer circuit for use in a digital data communication system receiver. An automatic gain control (AGC) circuit controls the level of the received data by comparing the AGC output with a quantized output signal from the DC restorer. A carrier detect circuit detects the presence of data transitions in the quantized output signal, and in the absence of such transitions continuously ramps up the gain of the AGC until such transitions are detected. The carrier detect circuit can be further used to disable, either entirely or partially, the positive feedback path of the DC restorer in the absence of transition in the quantized output signal. The present invention further provides an inherent muting function of the DC restorer output signal in the absence of valid data transitions.

Latch-up recovery in quantized feedback DC restorer circuits

A relaxation oscillator, such as a voltage controlled oscillator (VCO), with automatic swing control feedback which dynamically monitors the voltage swing across a capacitor and adjusts the oscillator threshold voltage, at which reversal of the polarity of the charging/discharging current occurs, to maintain the effective voltage swing at a constant level. The improved relaxation oscillator provides a very wide linear range of frequency variation versus control voltage (or current) and allows for the extendibility of linear operation to or near the maximum frequency that can be practically achieved by the oscillator circuitry.

Growing community of inventors

Richmond Hill, Canada

Mohammad Hossein Shakiba