Phase-Shifted Sampling with Equalization for ADC Path Mismatch
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Solution Overview
Problem
High-cost large-bandwidth analog-to-digital converters (ADCs) are required for phase-shifted sampling modules to digitize signals with large bandwidths, necessitating a cost-effective solution while maintaining signal quality.
Innovation Solution
A phase-shifted sampling module with a primary sampler module, ADC module, and equalization module that uses lower bandwidth ADCs and compensates for low-frequency mismatches between signal paths through a primary sampler equalizer sub-module and ADC equalizer sub-module, employing multi-rate filter circuits and time-variant filtering to reduce unwanted disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large-bandwidth ADCs are used to digitize signals with large bandwidths in phase-shifted sampling modules, then signal quality is maintained, but production costs increase
Solution Approach 1:
The patent divides the bandwidth requirement into segments handled by different components. Instead of requiring each ADC to handle the full large bandwidth, the system uses multiple ADCs with smaller individual bandwidths that collectively cover the required signal bandwidth through phase-shifted sampling. This segmentation allows using cheaper, lower-bandwidth ADCs while maintaining overall system performance.
Solution Approach 2:
The patent changes the bandwidth parameter of the ADCs from large to smaller values, compensating for this reduction through the phase-shifted sampling architecture and equalization. By adjusting the sampling phase and applying digital signal processing, the system achieves the required signal quality without needing expensive high-bandwidth ADCs.
2Ease of manufacture
If multiple ADCs with smaller bandwidths are used instead of single large-bandwidth ADCs, then production costs are reduced, but low-frequency mismatches between signal paths occur
Solution Approach 1:
The patent implements an equalization module that uses feedback mechanisms to detect and correct low-frequency mismatches between the parallel signal paths. By continuously monitoring the signal paths and applying compensatory adjustments, the system maintains high signal path matching precision despite using multiple separate ADCs with potentially different characteristics.
Solution Approach 2:
The equalization module acts as an intermediary between the parallel signal paths from multiple ADCs. It processes the digital output signals from each ADC, compensating for phase and amplitude differences, and combines them into a unified output. This intermediary processing resolves the mismatches that arise from using multiple separate conversion paths.
3Productivity
If phase-shifted sampling is implemented to achieve higher sampling rates, then sampling rate increases, but device complexity increases due to multiple ADCs and equalization modules
Solution Approach 1:
The patent designs the equalization module to perform multiple functions simultaneously: it compensates for low-frequency mismatches, adjusts phase relationships between signals, and combines outputs from multiple ADCs. This multi-functionality reduces the need for separate dedicated components for each task, thereby managing device complexity while achieving high sampling rates.
Data Source
AI summary
A phase-shifted sampling module for sampling a signal is described. The phase-shifted sampling module includes a primary sampler module, an ADC module, and an equalization module. The primary sampler module includes an analog signal input, a first signal path, and a second signal path. The equalization module includes a primary sampler equalizer sub-module. The primary sampler equalizer sub-module is configured to compensate low-frequency mismatches between the first signal path and the second signal path. Further, a method for determining filter coefficients of an equalization module of a phase-shifted sampling module is described.