Vintomie Networks B.v., LLC

Motorola Corporation

Other

Intel Corporation

Keyeye Communications

Key Eye

Mark Joseph Callicotte

Hiroshi Takatori

Lawrence Edwin Connell

Kenneth Colin Dyer

Brian David Storm

William J Roeckner

Stephen V Cahill

John K Grosspietsch

Kenneth R Haddad

Stephen C Thilenius

Susuma Hara

A method of optimizing filter performance through monitoring channel characteristics is provided. A signal enters a channel and a receiver receives the signal. The receiver includes a FIR filter to remove near-end transmitted interference and recover a far-end desired signal. The filter has storage elements configured as a shift registers to move the signal, multipliers to multiply the signal by a filter coefficient, an intermittent summer to combine the multiplied results into a replica of an interfering signal, a final summer to remove the replica from the receiver signal to provide direct and indirect monitoring of the signal, where direct monitoring includes time or frequency monitoring, and indirect monitoring includes monitoring signal to noise ratio, error magnitude or bit error rate. The filter is optimized according to monitoring and includes reducing a dynamic range, reducing bits of precision, reducing linearity, the filter, and reallocating the filter.

Use of line characterization to configure physical layered devices

The present invention effectively cancels echo, near-end crosstalk and far-end crosstalk. A FEXT canceller is placed at the transmitter rather than at the receiver according to an aspect of the invention. In some embodiment, a FEXT canceller can be placed at the receiver only or the combination of both ends. The FEXT canceller is continuously adapted with information sent back from a remote receiver and with data from a neighbor transmitter that causes the crosstalk at the remote receiver. This allows the FEXT canceller to quickly adapt to a change in crosstalk function or conditions with the surrounding environment, for example, aging, temperature, humidity, physical pressure, etc. In some embodiments, an adaptation control signal is sent back from the receiver to the transmitter by using an overhead bit in the frame format. In some embodiments, part of the FEXT canceller is built-in at the remote receiver.

System, method and apparatus for crosstalk cancellation

An adaptive transversal filter having tap weights Wj which are products of corresponding tap coefficients Cand tap gains Mis provided. A filter control loop controls all of the tap coefficients Csuch that an error signal derived from the filter output is minimized. One or more tap control loops controls a tap gain Msuch that the corresponding tap coefficient Csatisfies a predetermined control condition. For example, |C| can be maximized subject to a constraint |C| C, where Cis a predetermined maximum coefficient value. In this manner, the effect of quantization noise on the coefficients Ccan be reduced. Multiple tap control loops can be employed, one for each tap. Alternatively, a single tap control loop can be used to control multiple taps by time interleaving.

Scaled signal processing elements for reduced filter tap noise

An adaptive transversal filter having tap weights Wwhich are products of corresponding tap coefficients Cand tap gains Mis provided. A filter control loop controls all of the tap coefficients Csuch that an error signal derived from the filter output is minimized. One or more tap control loops controls a tap gain Msuch that the corresponding tap coefficient Csatisfies a predetermined control condition. For example, |C| can be maximized subject to a constraint |C|&#x2266;C, where Cis a predetermined maximum coefficient value. In this manner, the effect of quantization noise on the coefficients Ccan be reduced. Multiple tap control loops can be employed, one for each tap. Alternatively, a single tap control loop can be used to control multiple taps by time interleaving.

Interference reduction with a current-mode transversal filter having taps including binary current sources is provided. Each binary current source provides an output current having either of two distinct values, depending on a binary input. The product of a tap coefficient and an interference data signal value is obtained by independently generating the contribution from each interference data bit using a binary current source and providing these contributions to a current summing junction. Binary current sources can be implemented in analog, digital, or mixed-mode circuitry. Echo, near end cross talk, and far end cross talk are examples of interference that can be reduced in this manner. The use of binary current sources provides significant flexibility, especially in connection with multilevel modulation schemes such as pulse amplitude modulation (PAM).

Interference cancellation receiver for high-speed communication systems

According to one aspect of the invention, an apparatus is provided which includes a first amplifier and a common mode feedback circuit. The first amplifier includes a first input, a second input, a first output, and a second output. The first input and the second input are coupled to receive a first input voltage and a second input voltage, respectively. The first and second outputs provide a first output voltage and a second output voltage, respectively. The common mode feedback circuit has first and second switched capacitors coupled to provide a common mode feedback signal based on the first and second output voltages to the first and second inputs of first amplifier.

Method, apparatus, and system for common mode feedback circuit using switched capacitors

A level detector detects an input signal level. A rectifier (210) receives the input signal and provides a rectified signal. A prefilter (220) receives the rectified signal and attenuates high frequency components at frequencies near multiples of a decimation sample rate. The prefiltered signal is decimated (230) and low pass filtered by a lowpass filter (240) having a passband below the input frequency of the input signal. The level detector can be provided to control a variable gain stage circuit (935, 1010) which applies a gain to the input signal based on the level to form a dynamic range compressor or expander.

Method and apparatus for detecting an input signal

A radiotelephone (104) in a radiotelephone system (100) enters a low power sleep mode and times the duration of the sleep mode using a sleep clock generator (205) having a coarse resolution. The radiotelephone synchronizes timing of the radiotelephone to system timing using an oscillator (116) having a fine resolution. The radiotelephone then exits the low power sleep mode synchronized with system timing.

Radiotelephone and method for clock calibration for slotted paging mode

Prior to entry into a low-power sleep mode, a radiotelephone (104) in a radiotelephone system (100) calculates in advance the timing required to wake up selected portions of the radiotelephone and stores the calculated wakeup times in registers (216). Also prior to entry into sleep mode, local timing of the radiotelephone is synchronized to received PN roll boundaries from the radiotelephone system. In the sleep mode, the radiotelephone uses a sleep timer (210) to simulate system timing. When the sleep timer (210) matches the stored wakeup times, the radiotelephone re-activates the selected portions of the radiotelephone, such as an oscillator (116) and a radio frequency portion (109) of an analog front end (108), to exit the sleep mode and reacquire communication with the system. This also permits an early exit from sleep mode, for example to service an interrupt, while maintaining system timing.

Radio telephone and method for operating a radiotelephone in slotted

A transconductance filter (200) comprises multiple stages of a transconductor (110,120,130) having an input and an output, and a switch (260,265,270) coupled between the output and the voltage source. The switch is operatively responsive to the control signal for coupling and decoupling the voltage source directly to the output of the transconductor at least prior to the time the filter is required to filter the input voltage signal. The voltage source is within a predetermined input voltage range of the transconductor defined by a region in which a transconductance of the transconductor is substantially constant and positive.

Filter

A method and apparatus for integrating a plurality of analog input signals. A first integrator(725) having a first pole frequency integrates a first of the input signals and a second integrator(730) having a second pole frequency different than the first pole frequency integrates a second of the input signals. A summer(735) is connected to the first and second integrators to then sum the integrated first and second signals and provide a composite integrated signal prior to transmitting a communications signal.

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Sacramento, CA, United States of America

Mark Joseph Callicotte