Adaptive RF Front-Ends for Hand-held Applications (Analog Circuits and Signal Processing) (repost)
Andre van Bezooijen, Reza Mahmoudi, "Adaptive RF Front-Ends for Hand-held Applications (Analog Circuits and Signal Processing)"
1st Edition | English | 2010-11-05 | ISBN: 9048199344 | 170 pages | PDF | 3.5 mb
1st Edition | English | 2010-11-05 | ISBN: 9048199344 | 170 pages | PDF | 3.5 mb
The RF front-end – antenna combination is a vital part of a mobile phone because its performance is very relevant to the link quality between hand-set and cellular network base-stations. The RF front-end performance suffers from changes in operating environment, like hand-effects, that are often unpredictable.
Adaptive RF Front-Ends for Hand-Held Applications presents an analysis on the impact of fluctuating environmental parameters. In order to overcome undesired behavior two different adaptive control methods are treated that make RF frond-ends more resilient: adaptive impedance control, and adaptive power control.
Several adaptive impedance control techniques are discussed, using a priori knowledge on matching network properties, in order to simplify robust 2-dimensional control. A generic protection concept is presented, based on adaptive power control, which improves the ruggedness of a power amplifier or preserves its linearity under extremes. It comprises over-voltage, over-temperature, and under-voltage protection.