Broadband Pre-Distortion Module for Frequency-Hopping Linearization
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Solution Overview
Problem
Existing power amplifiers struggle with linearizing output signals, especially when the input signal's frequency bandwidth is large or frequency hopping occurs rapidly, as conventional linearization techniques are limited in bandwidth and reaction time, and are complex to implement.
Innovation Solution
A broadband pre-distortion module is coupled with the power amplifier, using transversal phase and amplitude circuit structures with matched basic amplification cells to generate a correction signal that compensates for non-linearity and memory effects, allowing for thermal coupling to maintain signal integrity across varying frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional linearization techniques (DPD, feed-forward) are used, then spectral distortion is reduced, but bandwidth is limited and reaction time is slow
Solution Approach 1:
The power amplifier is segmented into multiple parallel amplification paths (main path and auxiliary paths), each handling different frequency components or signal aspects independently. This segmentation allows each path to operate optimally without being constrained by the bandwidth limitations of conventional single-path linearization techniques.
Solution Approach 2:
Auxiliary power amplifiers are introduced as intermediary components that generate correction signals to compensate for non-linearities in the main power amplifier. These intermediary amplifiers process signals in parallel and feed back correction signals, enabling real-time linearization across broadband frequencies without the slow convergence of traditional adaptive techniques.
2Adaptability or versatility
If adaptive linearization is used to eliminate center frequency limitations, then frequency adaptability is improved, but system complexity and implementation difficulty increase
Solution Approach 1:
The auxiliary power amplifiers are designed with universal characteristics that allow them to function across multiple frequency ranges and operating conditions. By using the same basic amplifier topology in both main and auxiliary paths, the system achieves frequency adaptability without requiring complex frequency-specific adjustment mechanisms.
Solution Approach 2:
The main and auxiliary power amplifiers use matched or identical basic amplifier cells and topologies, creating homogeneous structures that simplify design and implementation. This homogeneity ensures consistent performance characteristics across different frequency ranges while reducing the complexity of matching and calibration.
3Measurement precision
If feed-forward linearization is implemented, then spectral efficiency is improved, but power consumption increases due to error amplifier requirements
Solution Approach 1:
The auxiliary power amplifiers generate their own drive signals and operate autonomously to produce correction signals, eliminating the need for high-power error amplifiers traditionally required in feed-forward systems. Each amplifier path serves itself by independently processing its signal portion and contributing to the overall linearization effort.
Data Source
AI summary
A system including a power amplifier and a pre-distortion module coupled to the power amplifier. The pre-distortion module includes one or more smaller versions of the power amplifier to generate a pre-distortion signal that compensates for any memory-effect or inertia present in the power amplifier with application on frequency hopping and larger (up to 1 octave) instantaneous bandwidth communication systems.