Receiver Nonlinearity Calibration With Memory-Based Distortion Correction
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Solution Overview
Problem
Nonlinearities in signal chains, such as harmonic distortion and intermodulation distortion, compromise the integrity and accuracy of signals in high-precision applications, necessitating improved techniques for distortion correction.
Innovation Solution
A system that stores concatenated distortion correction terms in a memory, uses fewer replica memories for efficient updating, and incorporates a dither system to correct distortions in analog input signals processed through multiple parallel paths, enhancing signal integrity and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple replica memories are used to store distortion correction terms for updating primary memories, then the accuracy and integrity of processed signals are improved, but the hardware resources and device complexity increase
Solution Approach 1:
The patent divides the memory system into primary memories ( storing operational data) and replica memories (storing distortion correction terms). This segmentation allows the system to maintain high signal accuracy through distortion correction while using a limited number of replica memories to update multiple primary memories, thereby reducing hardware resources compared to using full copies for each memory.
Solution Approach 2:
The patent creates replica memories as copies that contain distortion correction terms used to update primary memories. Instead of duplicating full memory contents across multiple units, the system uses these replicated correction terms to improve signal accuracy while minimizing the number of replica memories needed, thus reducing device complexity.
2Reliability
If distortion correction terms are stored and applied to correct nonlinearities, then the signal integrity is improved, but the processing time and loss of time increase
Solution Approach 1:
The patent pre-calculates and stores distortion correction terms in replica memories before they are needed for signal processing. When processing occurs, the system simply retrieves and applies these pre-computed correction terms to correct nonlinearities in real-time, maintaining signal integrity without adding significant processing delay.
3Measurement precision
If a dither system with two memories is used to reduce noise, then the measurement precision is improved, but the device complexity and power consumption increase
Solution Approach 1:
The patent combines the dither system functionality with the existing replica memory structure. The two memories in the dither system are integrated into the overall memory architecture, allowing noise reduction through dithering while sharing hardware resources with the distortion correction function, thereby reducing overall power consumption compared to implementing separate systems.
Data Source
AI summary
Various techniques are described for correcting distortion in an analog input signal after digitization in a receiver signal chain. The techniques include a system that stores concatenated distortion correction terms, allowing for efficient data handling and processing. The techniques further include a system that has a smaller number of replica memories compared to primary memories, which store operational data. The replica memories are updated with new data and may be swapped with primary memories to update them without interrupting system operations. The techniques further include a dither system that uses two memories to store and process the dithered signals, which are then combined to produce a noise-corrected digital output. The techniques further include a system to correct distortions in analog input signals processed through multiple parallel paths.