Motorola Corporation

John E Eberhardt

Oscar M Garay

Ronald L Bane

Yew S Tay

Enrico Bellotti

A transceiver (100) includes a radio frequency power amplifier (116) which is biased by an active bias circuit (110). Active bias circuit (110) provides a low cost bias circuit for amplifier (116) which adjusts the bias over changes in temperature and supply voltage levels to provide a constant output power. A set of control inputs (122-126) coming from controller (108) provide for power output level adjustment for the amplifier (116) in a frequency modulated (FM) environment and for both power and modulation level adjustments in an amplitude modulated (AM) environment.

Active bias for radio frequency power amplifier

In order to program the output frequency of a synthesizer such as that of a two-way radio, first the reference oscillator is warped or tuned substantially to one limit of its tuning range. The 'N' divisor of the synthesizer dividor is then selected to produce a loop output close to the desired loop output frequency. The reference oscillator is then tuned to provide the desired loop output frequency.

Method of programming a frequency synthesizer

A multilayer printed circuit board (100) includes a plurality of layers (101, 102, 104, 106, 108 and 110). Located within intermediate layer (106) is an inductor (200) which is shielded by top layer ground plane (202) and bottom layer ground plane (204). In another embodiment of the present invention, the inductor (200) can have its inductance adjusted by way of a inductance adjustment runner (316, 318) or by an electronic inductance adjustment device (408).

Printed circuit board inductor

An antenna (100) includes a quarter-wave monopole radiating element (110, 110') having a signal feed point end (110A). The antenna (100) further includes a reactive element (150) in the form of a conductive sleeve. The sleeve (150) includes a grounding end (150A) and is coaxially positioned around a portion of the monopole radiating element (110, 110'). A spacer (140) is coaxially situated between the monopole radiating element (110, 110') and the reactive element (150), for electrically insulating the monopole radiating element (110, 110') from the reactive element (150). The spacer (140) is sufficiently dimensioned such that the monopole radiating element is tightly coupled to the reactive element (150) at substantially around the feed point end (150A).

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Alpharetta, GA, United States of America

John E Eberhardt