Title:
【発明の名称】増幅器の自己バイアス・システムおよび方法
Document Type and Number:
Japanese Patent JP2003516689
Kind Code:
A
Abstract:
The present invention provides a method and apparatus for auto-biasing an amplifier. The invention is particularly useful in biasing non-linear amplifiers and amplifiers whose input signal may be amplitude modulated (AM). The auto-bias system of the present invention has an active bias feedback loop that continuously adjusts the bias condition of an amplifier to a wanted state during amplifier operation by monitoring a physical quantity indicative of the operating state of the amplifier and controlling the amplifier bias so as to control the amplifier operating point sufficiently to compensate for variations in amplifier electrical characteristics, amplifier load, amplifier temperature, and input signals. In the case of an AM input signal, the auto-bias system of the present invention may provide sample and hold function so that the amplifier bias is the same during high power periods and low power periods, even though during high power periods the amplifier may be operating in a non-linear region. In one variation of the invention the amplifier may be an RF transistor, for example, a bipolar transistor, and may be used in a mobile cellular communications system. Further, the present amplifier auto-bias system eliminates the need for manually setting the amplifier bias during production and enables use of any transistor type in the amplifier.
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Inventors:
Kukukari Ero
Application Number:
JP2001543849A
Publication Date:
May 13, 2003
Filing Date:
December 04, 2000
Export Citation:
Assignee:
Nokia corporation
International Classes:
H03F1/30; H03F1/34; (IPC1-7): H03F1/34
Domestic Patent References:
| JPH06177658A | 1994-06-24 |
Attorney, Agent or Firm:
Shimizu Hatsushi (1 person outside)