Dual-Channel ADC Mismatch Compensation for Timing Skew and IQ Error
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Solution Overview
Problem
Existing dual channel analog-to-digital converters (ADCs) in RF receivers face challenges in efficiently correcting for mismatches, particularly in timing skew and IQ mismatches, which require separate architectures and increased design complexity.
Innovation Solution
A dual channel ADC system with overlapping mismatch correction circuitry that can operate in both timing skew correction and IQ mismatch correction modes, utilizing adjustable delay elements and shared clock signals, allowing for efficient compensation of both types of mismatches using similar iterative calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate architectures are used for timing skew correction and IQ mismatch correction, then each type of mismatch can be corrected effectively, but the device complexity and design costs increase
Solution Approach 1:
The patent implements a unified mismatch correction architecture that can operate in multiple modes (timing skew correction mode and IQ mismatch correction mode) by configuring the same circuitry differently. The correction circuitry includes adjustable delay elements and coefficient adjustors that can be programmed to perform either timing skew correction or IQ mismatch correction, eliminating the need for separate dedicated circuits for each function.
Solution Approach 2:
The patent merges the timing skew correction circuitry and IQ mismatch correction circuitry into a single integrated correction block. Both correction functions share common components including the correction coefficients generator, adjustable delay elements, and coefficient adjustors, allowing both types of mismatch correction to be performed within one unified structure rather than requiring separate independent architectures.
2Reliability
If multiple separate correction circuits are implemented, then comprehensive mismatch correction is achieved, but production and design costs increase
Solution Approach 1:
The correction circuitry is designed as a universal block that can perform both timing skew correction and IQ mismatch correction by changing operational mode. The same hardware resources (adjustable delay elements, coefficient adjustors, correction coefficients generator) are reused for both functions, reducing the total component count and simplifying manufacturing processes while maintaining comprehensive mismatch correction capability.
3Measurement precision
If dedicated timing skew correction architecture is used, then timing skew is corrected accurately, but the design becomes less flexible for different receiver architectures
Solution Approach 1:
The correction architecture is designed to be dynamically reconfigurable between timing skew correction mode and IQ mismatch correction mode. The circuitry includes controllable switches and adjustable parameters that allow the same hardware to adapt its operation based on the required correction type, providing both accurate timing skew correction when needed and flexibility to support different receiver architectures (direct conversion or intermediate frequency).
Data Source
AI summary
Previously, when designing receivers for radio frequency (RF) or wireless communications, designers chose between time-interleaved (TI) analog-to-digital converters (ADCs) for intermediate frequency architectures and dual channel ADCs for direct conversion architectures. Here, similarities between TI ADCs and dual channel ADC were recognized, and an ADC that has the capability of operating as a TI ADCs and dual channel ADC is provided. This allows designer to have greatly increased flexibility during the design process which can greatly reduce design costs, while also allowing the manufacturer of the ADC to realize a reduction in its operating costs.