Resources Contact Us Home
Method and apparatus for amplifying a signal

Image Number 8 for United States Patent #6020787.

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
Prioritized random access method
Strict tenant isolation in multi-tenant enabled systems
Automated print shop service capability determination
Image display device and operation method thereof
Probabilistic estimation of location based on wireless signal strength and platform profiles
Electronic camera
Radiation detection apparatus, manufacturing method therefor, and radiation imaging system
  Randomly Featured Patents
System for selecting document recipients as determined by technical content of document and for electronically corroborating receipt of document
Floating wrist pin coupling for a piston assembly
Fuel dispensing and measuring device arranged on ground surface
Reusable diaper and construction method therefor
Spring assembly for floating seat ring
Data processing system having a storage controller for transferring an arbitrary amount of data at an arbitrary address boundary between storages
Encoding/decoding circuit, and digital video system comprising the circuit
Facial recognition
Combined combustion for in-situ retorting of oil shales