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
Grip for a racket
Motion estimation for a video transcoder
Accessing a base station
Nucleic acid sequences encoding secE/sec61-gamma subunits of protein translocation complexes
Bootstrap gate driver
Communication system, authentication device, control server, communication method, and program
Systems and methods for processing supplemental information associated with media programming
  Randomly Featured Patents
Modular forend system for tactical firearms
High performance ultracapacitors with carbon nanomaterials and ionic liquids
Liquid crystalline 3,4:9,10-perylenetetacarbocylic acid diimides
Compact mobile reconnaissance system
Flight for apron feeder
Pendant amusement device
Table for a conferencing environment
Device for axially preloading a machine element
Ignition system for internal combustion engines