Lucent Technologies Inc.

Jenshan Lin

Young-Kai Chen

Sanjay Kasturia

Fan Ren

Huan-Shang Tsai

James Robert Lothian

Joel L Dawson

An active balun circuit is provided for single-ended to differential RF signal conversion with enhanced common-mode rejection which suppresses common mode signal and which achieves phase and amplitude balance without sophisticated tuning or compensation methods. The circuit has a single-ended input and balanced output with phase and amplitude balance error less than 2&#xb0; and 1.2 dB, respectively, measured from 1.5 GHz to 1.8 GHz at 5V supply. When supply voltage drops down to 1.5V, its phase and amplitude balance error remains within 5&#xb0; and 2 dB, respectively. The circuit achieves a balanced output via an output network which behaves as an impedance matching network for differential mode signal and is grounded for common mode signal. As a result, common mode signal is suppressed and 180-degree phase balance at output is achieved. The circuit has high-linearity (P1 dB=5 dBm, IIP3=16.6 dBm) and low residual phase noise (&#x3c;&#x2212;155 dBc/Hz at 100 kHz and above) which make it suitable as an active balun/buffer amplifier between LO and balanced mixer for base station receiver applications.

Active balun circuit for single-ended to differential RF signal conversion with enhanced common-mode rejection

A circuit that increases the efficiency of a radio frequency mobile telephone unit is disclosed. When the signal strength between the base station and the mobile unit is below a predetermined signal strength level, the power amplifier is turned on and the transmitter circuit of the mobile unit fully amplifies the RF signal. However, when the signal strength between the mobile telephone unit and the base station is above a predetermined signal strength level, the power amplifier is deactivated and bypassed from the transmitter circuitry, thereby conserving the battery power of the mobile unit.

Method and apparatus for enhancing transmitter circuit efficiency of mobile radio units by selectable switching of power amplifier

In accordance with one embodiment of the present intention, an adaptive feedback controller is configured to substantially reduce an error control signal defined by the difference between a command signal and the output signal of a controlled device. The adaptive controller comprises a step generator circuit configured to provide a control signal which is employed to vary the input signal received by the controlled device, The control signal is substantially in the shape of a ramp signal having a given slew rate. An adaptive slew rate computation circuit is coupled to the step generator so as to provide a slew rate compensation signal to the step generator to increase the slew rate of the control signal, when the controlled device is responding to a substantially fast varying input signal. The slew rate compensation circuit decreases the slew rate of the control signal, when the controlled device is responding to a slow varying input signal.

Low-complexity adaptive controller

An indoor wireless communications system using two-way active-antenna repeaters to distribute signals received from external signal sources within an office, and to extend the range of cordless phone units in use there, is disclosed. The repeaters provide menu-selectable phase-shifting, selectable receiver sensitivity and transmitter power, and selectable signal format conversion to provide added privacy and to prevent interference with communication links in use by third parties within the building. Pattern selection is done by empirical adjustment of an antenna pattern suited to the general floor plan of the area served.

Communication system comprising an active-antenna repeater

A dynamic power amplifier advantageously employed in a wireless terminal for transferring and receiving signals from a base terminal includes an input amplifier adapted to receive an input signal having a given power signal level corresponding to the distance of said wireless terminal to the terminal and adapted to provide an amplifier output signal having a given power output signal level. The dynamic amplifier further includes a power sensor configured to receive the power output signal and to generate a power indication signal corresponding to the power output signal, and a converter adapted to receive the power indication signal in order to generate a biasing signal corresponding to the power indication signal. The biasing signal is applied to the input amplifier so that the operating bias point of the power amplifier varies as a function of the power indication signal.

Linear power amplifier with automatic gate/base bias control for optimum

A thin conformal passivating dielectric film is deposited by ECR-CVD on an IC chip comprising semiconductor devices each of which includes a sub-micron-width irregularly shaped gate electrode. A protective layer of patterned resist is formed overlying each passivated device. Additional dielectric material is then deposited by ECP-CVD, at a temperature below the glass transition temperature of the resist, on the surface of the chip. Subsequently, in a lift-off step, the patterned resist together with the additional dielectric material overlying the resist is removed from the chip.

Growing community of inventors

Pine Brook, NJ, United States of America

Jenshan Lin