Adaptive Signal Tracking Circuit for Real-Time RF Predistortion
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Solution Overview
Problem
Conventional distortion correcting methods and devices for signal predistortion have slow adaptation times, making them ineffective in addressing short-term variations in environmental and operational parameters, such as temperature changes and power supply fluctuations, which affect the purity and stability of RF signals in communication systems.
Innovation Solution
A real-time adaptive distortion correcting device that includes a signal combiner, a delay unit, and an adaptive circuit, which combines input and delayed signals to generate an error signal and a supplemental correcting signal, allowing for rapid response to environmental changes by treating signals in both the digital and analog realms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional off-line software treatment is used for computing linearization parameters, then device complexity is reduced, but adaptation speed becomes too slow to address short-term variations in environmental parameters
Solution Approach 1:
The patent segments the adaptation function into two distinct parts: an off-line software component that computes linearization parameters slowly but accurately, and a new real-time hardware adaptive circuit that implements these parameters instantly. This segmentation allows each component to operate at its optimal speed without compromising the other, resolving the contradiction between adaptation speed and device complexity.
Solution Approach 2:
The patent introduces an intermediary adaptive circuit that acts as a bridge between the slow off-line software computation and the fast real-time signal processing. This intermediary hardware circuit receives pre-computed parameters from the software and applies them instantaneously to correct short-term variations, thereby achieving fast adaptation without requiring the entire system to be redesigned as high-speed hardware.
2Adaptability or versatility
If conventional predistortion devices are used, then they can compensate for slow-changing parameters like temperature, but they cannot address short-term variations in power supply parameters or other environmental changes
Solution Approach 1:
The patent transforms the static, slow-adapting predistortion device into a dynamic system by adding a real-time adaptive circuit that continuously adjusts correction parameters based on current environmental conditions. This dynamic component responds instantaneously to short-term variations in power supply, temperature, and other environmental factors, thereby enhancing adaptability without sacrificing response time.
Solution Approach 2:
The patent applies preliminary action by pre-computing linearization parameters through off-line software analysis of expected environmental variations. These pre-computed parameters are then stored and rapidly deployed by the adaptive circuit when environmental changes occur, allowing the system to respond quickly to short-term variations without performing complex real-time calculations.
3Measurement precision
If off-line software computation is used for signal treatment, then manufacturing precision is improved through accurate parameter calculation, but the adaptation time becomes longer than the signal period
Solution Approach 1:
The patent segments the parameter computation and application processes into two distinct stages: an off-line software stage that performs accurate but time-consuming parameter calculations, and a real-time hardware stage that instantly applies these parameters. This segmentation allows the system to benefit from both the high accuracy of software computation and the fast response of hardware implementation, resolving the contradiction between measurement precision and adaptation time.
Solution Approach 2:
The patent implements preliminary action by performing all complex parameter calculations in advance through off-line software analysis. The results are stored and ready for immediate deployment when environmental conditions change, eliminating the need for real-time computation and thereby achieving both high accuracy and fast adaptation response.
Data Source
AI summary
An apparatus providing additional response for a distortion correcting device that receives a first signal at a correcting input and provides a first delayed output signal at an output includes: (a) A first signal combiner coupled with an input and the correcting input. (b) A delay unit coupled with the input provides a second delayed signal to a delayed signal terminal. (c) A second signal combiner coupled with the delayed signal terminal and the output employs the output signal and the second delayed signal to present an error signal at a first error terminal. (d) An adaptive circuit coupled with the input locus, the first signal combiner and the second signal combiner employs provides a supplemental signal to the first signal combiner which employs the input signal and the supplemental signal to present the first signal to reduce the error signal.