文档介绍：RF Calibration Introduction
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Agenda
What is RF calibration.
Why calibration.
NV items of RF calibration.
Rx Calibration.
Tx Calibration.
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What is RF calibration
• RF calibration is the process of measuring data to be used in the
system for the purpose of compensation of non-linear
characteristics and frequency variations, and to provide absolute
power reference and temperature compensation to ensure
performance of the Tx and Rx paths of a subscriber unit.
• Output from the calibration process is stored in non-volatile (NV)
memory items in AMSS.
• AMSS uses calibration values during normal operation to ensure
system performance is met.
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Setup:
What is RF calibration
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Why calibration
Subscriber units have differing RF characteristics
Differences in design
Part-to-part variations of components of the same design
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Individual phones also change their own RF characteristics:
over frequency channel
over temperature
Why calibration
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Why calibration
The subscriber unit must estimate the Rx power properly to
maximize signal-to-noise ratios and to provide a basis for Tx
power output.
The subscriber unit must transmit at correct Tx power level over
its large dynamic range.
The Mobile Station Modem™ (MSM™) device and system software
combination must know the RF and analog characteristics of the
particular unit.
Failure to compensate for differing RF/analog characteristics may
cause the unit to fail minimum performance specifications
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The compensation values are classified:
Static RF NV items:
Measured once per design.
Calculated RF NV items:
RF NV items that are calculated based on other parameters of the design configurations.
Measured RF NV items:
Is determined by the RF calibration process.
NV items of RF calibration
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Rx calibration
Philosophy of Rx AGC(Automatic Gain control) loop.
DVGA(Digital VGA) offset calibration.
LNA(Low Noise Am