Resources Contact Us Home
Method and apparatus for amplifying a signal

Image Number 11 for United States Patent #5673001.

A unique method and apparatus modifies the load impedance at the output of a power amplifier by varying a voltage variable capacitor (VVC) (310) to maximize the efficiency of the power amplifier (304). A comparator (509) generates amplifier control signal (211) based upon a detected power output signal (216) and a reference signal. In addition to providing power control, the control signal is also coupled to a VVC circuit (506) to control the output impedance of the power amplifier. In an alternate embodiment, a separate VVC control signal (527) based upon a comparison of the power control signal and the battery voltage is coupled to a VVC. In another alternate embodiment, a second VVC can be coupled in parallel to the first VVC. The second VVC is preferably controlled by a signal (805) based upon the current in the power amplifier. Finally, an alternate embodiment incorporates a VVC circuit (506) at the input of the power amplifier to compensate for variations in input impedance to improve other power amplifier parameters such as IM, gain, output power and noise level.

  Recently Added Patents
Methods and apparatus for address translation functions
Portable electronic device housing including hinge
RFID device using single antenna for multiple resonant frequency ranges
Cucumber plants with a compact growing habit
Resin composition and molded article
Method and system for advertisement using internet browser to insert advertisements
Treatment devices with deliver-activated inflatable members, and associated systems and methods for treating the spinal cord and other tissues
  Randomly Featured Patents
Adjustable routing device for routing fiber optic jumpers from fiber optic jumper raceways
Making a stabilized superconductor
Liquid applicator
Fuel injection control apparatus for in-cylinder injection type internal combustion engine and fuel injection control method
Water- and oil-repellent treatment of textile
Radio pager or similar article
Gamma camera system
Specific antibodies against activated platelets, the preparation thereof and the use thereof in diagnosis and therapy
Mop head
Phase demodulation method for minimizing phase error in communication signals