Raytheon Company

Brian P Helm

John G Heston

Scott Mitchel Heston

David D Heston

Gordon R Scott

Michael G Hawkins

David R Fletcher

William Sheridan Kopp

Brian L Dillaman

A low noise amplifying system with adjustable gain. The low noise amplifier includes a plurality of gain stages, including a first stage and a last stage each having fixed gain, and an intermediate stage having adjustable gain. The intermediate stage is an inverting gain stage that includes a field effect transistor connected from the output to the input, to provide negative feedback, reducing the gain as a control voltage (applied to the gate of the field effect transistor) is adjusted to decrease the channel resistance of the field effect transistor. A control circuit measures the input and output signal power of the amplifying system and adjusts the gain of one or more intermediate stages to trade off linearity against noise figure.

Amplifier with automatic gain control

In order to increase the switching speed of an RF FET in an RF shunt circuit, a second, smaller, FET, with respect to the size of the RF FET, is connected directly to the gate of the RF FET to shunt the gate to ground quickly when switched from the off-state to the on-state. The smaller FET switches faster, due to being smaller than the larger RF FET, but it is effectively open-circuited in terms of RF performance when off because it is so small.

Circuit for improved FET switching speed

In accordance with the teachings of the present invention, a method and apparatus for increasing the efficiency of electrical systems are provided. In a particular embodiment, the apparatus comprises a first electrical component including a self-biasing resistor and at least one input terminal coupled to a power supply, and a second electrical component including at least one input terminal coupled to an output terminal of the first electrical component, and an electrical short circuit connected across the self-biasing resistor in the first electrical component such that current from the power supply bypasses the self-biasing resistor.

Method and apparatus for increasing efficiency of electrical systems

According to one embodiment of the present invention a method for biasing a power amplifier having at least one transistor exhibiting kink anomaly includes providing a bias circuit coupled to a gate of at least one transistor of the power amplifier. The method also includes providing, by the bias circuit, a bias voltage to the gate. The bias circuit has a load characteristic that intersects a current versus gate voltage curve for the gate at a frequency of operation of the power amplifier only once and that exhibits a low impedance at the intersection of the load characteristic with the current versus gate curve of the gate.

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Sachse, TX, United States of America

Brian P Helm