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, systems, and products for providing communications services
ASICs having programmable bypass of design faults
Regenerative power storage system mounted on DC electric railway car
System and method for providing private demand-driven pricing
Auto-provisioning of network services over an Ethernet access link
Cell proliferation inhibitor
Disk drive to enable defect margining
  Randomly Featured Patents
Method of coating substrates with polydiorganosiloxanes having lower alkyl substituents to provide release coatings
Method for producing a monocrystalline or polycrystalline semiconductor material
Bipolar transistor with self-aligned retrograde extrinsic base implant profile and self-aligned silicide
Electromagnetic rail gun
Solder removal devices
Inert composite electrode, in particular an anode for molten salt electrolysis
Lens shutter camera
Raster scanning display system
Mapping data from multiple data sources into a single software component
Color image communication apparatus capable of transmitting or receiving a color expression form