Composite ADC Calibration for Imbalance and Distortion Cancellation
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Solution Overview
Problem
Existing communication systems face challenges in accurately processing signals with large dynamic ranges, leading to undesirably high signal-to-noise ratios and errors due to imbalance and distortion in analog-to-digital converters (ADCs), which prior technologies have not adequately addressed.
Innovation Solution
The implementation of adaptive calibration methods and architectures for ADCs to mitigate frequency-selective imbalance and distortion, including differential scaling, filtering, and error correction techniques to ensure identical response across multiple ADCs, thereby compensating for clipping and non-linear distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple ADCs are used to process signals with large dynamic ranges, then the extended dynamic input range is achieved, but frequency-selective imbalance and distortion between ADCs cause high bit error rates
Solution Approach 1:
The patent applies parameter changes by measuring the frequency response of each ADC and calculating compensation filters that modify the signal parameters (gain and phase) to equalize the ADC responses. This allows the system to maintain extended dynamic range while correcting imbalance and distortion through digital signal processing
Solution Approach 2:
The patent implements feedback by using a calibration signal to measure ADC performance characteristics, then using this information to generate compensation filters. The system continuously monitors and adjusts for ADC variations, creating a closed-loop correction mechanism that reduces bit error rates
2Productivity
If ADCs operate across wide dynamic ranges, then signal processing capability is improved, but clipping and non-linear distortions increase
Solution Approach 1:
The patent applies preliminary action by performing calibration measurements and calculating compensation filters before actual signal processing. The system pre-characterizes each ADC's frequency response and pre-computes the necessary correction filters, so that when wide dynamic range signals are processed, the distortions are already compensated for
Solution Approach 2:
The patent introduces compensation filters as intermediary elements between the ADCs and the signal processing pipeline. These filters act as mediators that correct the distorted signals from ADCs operating in wide dynamic range, removing clipping and non-linear effects before further processing
Data Source
AI summary
Imbalance and distortion cancellation for composite analog to digital converter (ADC). Such an ‘ADC’ is implemented using two or more ADCs may be employed for sampling (e.g., quantizing, digitizing, etc.) of an analog (e.g., continuous time) signal in accordance with generating a digital (e.g., discrete time) signal. Using at least two ADCs allows for the accommodation and sampling of various signals having a much broader dynamic range without suffering degradation in signal to noise ratio (SNR). Generally, the signal provided via at least one of the paths corresponding to at least one of the respective ADCs is scaled (e.g., attenuated), so that the various ADCs effectively sample signals of different magnitudes. The ADCs may respectively correspond to different magnitude and/or power levels (e.g., high power, lower power, any intermediary power level, etc.). Various implementations of compensation may be performed along the various paths corresponding to the respective ADCs.