Broadcom Corporation

Arnoldus Venes

Pieter Vorenkamp

Klaas Bult

Rudy J Van De Plassche

Thinh Cat Nguyen

Steven T Jaffe

Peter R Kinget

Kevin Lee Miller

Frank Carr

Myles H Wakayama

Daniel J Marz

Jiangfeng Wu

Tianwei Li

Yonghua Cong

Chung-Ying Chen

An integrated communications system. Comprising a substrate having a receiver disposed on the substrate for converting a received signal to an IF signal. Coupled to a VGA for low voltage applications and coupled to the receiver for processing the IF signal. The VGA includes a bank pair having a first bank of differential pairs of transistors and a second bank of differential pairs of transistors. The bank pair is cross-coupled in parallel, the IF signal is applied to the bank pair decoupled from a control signal used to control transconductance output gain of the bank pair over a range of input voltages. A digital IF demodulator is disposed on the substrate and coupled to the VGA for low voltage applications, for converting the IF signal to a demodulated baseband signal. And a transmitter is disposed on the substrate operating in cooperation with the receiver to establish a two way communications path.

Variable gain amplifier for low voltage applications

An integrated communications system. A substrate having a receiver disposed on the substrate for converting a received signal to an IF signal, a digital IF demodulator disposed on the substrate and coupled to the receiver for converting the IF signal to a demodulated baseband signal, and a transmitter disposed on the substrate operating in cooperation with the receiver to establish a two way communications path.

Digital IF demodulator for video applications

Provided are a method and system for a module for a cable modem termination system. The module includes a digital modulator configured to block up-convert a plurality of digital channels and a digital to analog converter coupled, at least indirectly, to an output of the digital modulator to convert the digital channels to an analog format.

Method and system for direct digital up-conversion in a cable modem

Provided is a transmitter in a communications system including a plurality of digital to analog converters. Also included is a plurality of clocks, each being communicably coupled to a corresponding one of the digital to analog converters.

Method and system for time interleaved digital to analog conversion for a cable modem

A line driver comprises a driving amplifier receiving an input of the line driver, a current sense resistor connected between the driving amplifier output and the line driver output, and a feedback amplifier sensing the voltage across the current sense resistor and providing a corresponding feedback voltage that is proportional to the output current to the driving amplifier, thereby determining an output impedance at the line driver output. Precise output impedance can be realized by using a high precision resistor as the current sense resistor, and using resistive feedback amplifiers with accurate gains as the driving and feedback amplifiers. The resistance of the current sense resistor can be substantially less than the line driver output impedance, and the driving amplifier output voltage swing can be substantially less than twice the line driver output voltage swing.

Line driver with active termination

A wide gain range current digital-to-analog converter (DAC) is presented that includes a unit current cell having a current source module biased by a current source voltage bias, a differential switch module, a main cascode module biased by a first bias voltage and an attenuation cascode module biased by a second bias voltage, configured such that a particular current gain range is obtained at the main cascode module output when a unit current cell current is at or above a current threshold. The output current at the attenuation cascode module output can be input into a current attenuator when the unit current cell current is below the current threshold to obtain additional current gain range. The current attenuator can include a plurality of attenuator cells that can be programmed to a desired level of current gain in linear decibels or linear step intervals. Smaller step sizes can be obtained by programming a current source within the step intervals.

Digital-to-analog converter with programmable current control

Continuously tuning a transconductance. Coupling a degeneration resistance from a first source of a first transistor in a differential pair of transistors to a second source of a second transistor in the differential pair of transistors. Applying a second variable degeneration resistance in parallel to the first degeneration resistance in response to the application of a first variable control voltage. And applying a third variable degeneration resistance in parallel to the first degeneration resistance and the second degeneration resistance in response to the application of a second variable control voltage having a fixed voltage offset from the first variable control voltage.

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Laguna Niguel, CA, United States of America

Arnoldus Venes