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
Dual protocol input device
Automated synchronization of design features in disparate code components using type differencing
Magnetic resonance imaging apparatus for use with radiotherapy
Horizontal cable manager
System and methods for obstacle mapping and navigation
Collaborative system for capture and reuse of software application knowledge and a method of realizing same
Vehicle running control system
  Randomly Featured Patents
Fire-retardant filter medium and air filter unit
Using an acoustic ping and sonic velocity to control an artificial lift device
Self-sealing fastening assembly
Structural health monitoring using active members and neural networks
Combination sink
Signal combiner, a signal splitter and a circuit using a combiner and a splitter
Dual sided image printing device and method
Interactive quiz machine with cartridge
System and method for mapping functions to and from network devices using configuration compatible with an adapter by remapping plurality of logical ports of adapter
Open top tank having a removable and sealable lid with a flow rate control device supported therein