Configurable Load Impedance for PA Predistortion Calibration
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Solution Overview
Problem
Existing wireless communication systems face challenges with phase and amplitude distortion in the analog transmit path, leading to spectral regrowth and anomalies, which are not optimally compensated by pre-distortion techniques.
Innovation Solution
The implementation of a configurable load impedance and pre-distortion compensation method that adjusts gain and filter settings based on specific power spectral density masks and modulation schemes to reduce spectral regrowth, using a combination of digital and analog gain control and filtering to optimize signal shaping and pre-distortion curves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If pre-distortion compensation is applied to compensate for phase and amplitude distortion in the analog transmit path, then spectral regrowth is reduced, but the compensation is not optimal resulting in residual anomalies
Solution Approach 1:
The patent changes the load impedance parameter from a fixed value to a configurable value that can be set to match different antenna impedances. This allows the pre-distortion compensation to be optimized for each specific antenna configuration, thereby improving compensation accuracy and reducing residual spectral regrowth anomalies that persisted with fixed impedance designs.
Solution Approach 2:
The patent introduces dynamic configurability of the load impedance, allowing the system to adapt to different antenna conditions. This dynamic adjustment capability enables optimal pre-distortion compensation settings to be applied for various antenna impedances, improving the overall effectiveness of spectral regrowth reduction.
2Device complexity
If fixed load impedance is used in power amplifier design, then device complexity is reduced, but adaptability to different antenna impedances is limited
Solution Approach 1:
The patent transforms the static load impedance into a dynamic, configurable parameter. By introducing switching circuitry that can connect different impedance values based on control signals, the system achieves adaptability to various antenna impedances while maintaining relatively simple device architecture through selective activation of impedance options.
Solution Approach 2:
The patent makes the power amplifier universally applicable to different antenna types by providing multiple configurable load impedance options. This multi-functionality allows the same amplifier design to work optimally with various antenna impedances (e.g., 50 ohms, 75 ohms, or other values) without requiring separate amplifier designs for each antenna type.
Data Source
AI summary
An integrated circuit radio transceiver and method therefor includes an integrated circuit radio transceiver operable to provide specified gain levels and transmit path filter responses to correspond with a selected power spectral density mask. Changes in gain may be provided solely digital gain changes or may include analog gain module gain changes. A transmitter selects from one of at least three masks to reduce or eliminate spectral regrowth out of band to satisfy EVM requirements. Circuitry is provided to allow a transceiver to determine in advance what pre-distortion compensation settings are required for the various gain settings.