Honeywell G.m.b.h.

Texscan Corporation

Peter David Bailey

Paul W Schwerman

Kirk A Snodgrass

Peter James Bobrowitz

A novel bias circuit provides precise base emitter voltage(V.sub.BE) which tracks the temperature coefficient of an RF transistor using low cost devices. The bias circuit includes a precision current source which injects current through a P-N junction device to derive a temperature compensating reference voltage thereacross. The P-N junction device is isolated from current fluctuations using a current isolation circuit coupled between the P-N junction device and the base of the RF transistor. The diode is thereby isolated from and unaffected by changes in the base current of the RF transistor. Multiple RF transistors are biased from the single P-N junction device by replicating only a trimming potentiometer and the current isolation circuitry for each additional RF transistor to be biased.

Precision bias circuit for a class AB amplifier

A step attenuator comprises two branchline couplers with two coupling transmission lines therebetween. Attenuation is accomplished through switchable resistors, in series with switching diodes, shunted across the transmission lines. These resistors reflect and absorb incident power. Switching signals are provided to the diodes through the branchline couplers and the coupling transmission lines. The reflected power is absorbed by a matched termination at the port of the input branchline coupler that is isolated from the port at which the signal to be attenuated is coupled. Phase shift and insertion loss are minimized by tuning the series inductance inherent in the diode resistor combination with tuning capacitors in series therewith. These capacitors are by passed by low-susceptance inductors which provide a dc path to ground for the diodes.

Discrete step microwave attenuator

Radio frequency chokes for use in combining and separating radio frequency signals and single phase AC power in the equipment used in cable transmission and distribution systems. The radio frequency chokes include a conductor wound on a magnetic core to form a primary winding upon which first and second swamping circuits are mounted. Each of the swamping circuits include a secondary winding with a resistor connected across the ends thereof with the swamping circuits effectively dampening parasitic resonances in the primary winding which occur in the frequeny range of from about 5 MHz to at least 800 MHz.

Growing community of inventors

Phoenix, AZ, United States of America

Peter David Bailey