| 摘要 |
An amplifier system (120) for radio frequency signals comprises a combination of a phase and gain adjuster (122) and a first amplifier (123) which receives an input signal and generates a first amplified signal having a gain adjusted in accordance with a gain of the phase and gain adjuster. A main amplifier (126) receives the first amplified signal and generates a second amplified signal. A first controller (134) uses a signal derived from the second amplified signal to generate a first control signal. The first control signal is applied to the phase and gain adjuster to control the gain of the phase and gain adjuster. A second controller (170) is connected to receive the first control signal and to generate a second control signal which is applied to the first amplifier. The second control signal is generated to control the first control signal and thereby control noise of the amplifier system. With the second control signal being used to control the first control signal, the phase and gain adjuster (122) can adjust the adjusted signal to make adjustments for a first type of gain variation of the amplifier system. The second control signal is used to enable the first amplifier (123) to change its first amplified signal to make adjustments for a second type of gain variation of the amplifier system. For example, the first type of gain variation handled by the phase and gain adjuster can be a fast gain variation, and the second type of gain variation handled by the second amplifier can be a slow gain variation. The second type of gain variation can be, for example, a gain variation attributable to one of amplifier system production differences, aging, and temperature variations. The first amplifier is preferably a variable gain auxiliary amplifier.
|
