Time-Interleaved ADC Gain and Timing Mismatch Compensation
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Solution Overview
Problem
Time interleaved ADCs (TI-ADCs) suffer from gain mismatch and sampling timing offset issues, which degrade the signal-to-noise and distortion ratio (SNDR) of received signals.
Innovation Solution
A semiconductor device with a TI-ADC system that includes gain mismatch and timing offset compensation mechanisms, utilizing a gain mismatch estimator and timing offset estimator to calculate correction values, and compensators to adjust ADC outputs accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If time interleaved ADCs are used to process large amounts of data, then the sampling rate is improved, but gain mismatch and timing offset occur between ADC cores
Solution Approach 1:
The patent applies preliminary action by calculating average values of absolute values of output signals from multiple ADC cores before performing gain correction. The gain correction values are pre-calculated based on these average values, allowing the system to compensate for gain mismatch in advance before the actual signal processing occurs. This preliminary correction step ensures that subsequent signal processing benefits from already-balanced gain levels across all ADC cores.
Solution Approach 2:
The patent implements feedback by using the output signals from ADC cores to calculate gain correction values, which are then applied back to correct the output signals. The system continuously monitors the output signals, calculates the necessary corrections based on average absolute values, and applies these corrections to eliminate gain mismatch. This closed-loop feedback mechanism ensures that gain errors are automatically compensated without external intervention.
2Productivity
If time interleaved ADCs are used to process large amounts of data, then the sampling rate is improved, but timing offset occurs between ADC cores
Solution Approach 1:
The patent applies preliminary action by calculating average values of absolute values of differences between output signals from different ADC cores before determining timing offset. The timing offset value is pre-calculated based on these average differences, allowing the system to compensate for timing misalignment in advance. This preliminary timing correction ensures that subsequent signal processing operates with properly synchronized timing from all ADC cores.
Solution Approach 2:
The patent implements feedback by using the output signals from ADC cores to calculate timing offset values, which are then applied back to correct the timing alignment. The system continuously monitors the differences between output signals, calculates the necessary timing corrections based on average absolute differences, and applies these corrections to eliminate timing offset. This closed-loop feedback mechanism automatically compensates for timing errors without external intervention.
3Measurement precision
If gain mismatch and timing offset compensation is implemented, then signal quality is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the compensation mechanism into distinct functional blocks: a gain mismatch estimator that calculates gain correction values, a timing offset estimator that calculates timing correction values, and separate compensators that apply these corrections. This modular segmentation allows each component to perform a specific function independently, making the overall complex system more manageable and easier to implement while maintaining high signal quality through targeted corrections.
Data Source
AI summary
A semiconductor device includes a first ADC configured to sample an input signal based on a first clock signal, quantize the input signal with a first gain, and output a plurality of first output signals, and a second ADC configured to sample the input signal based on a second clock signal obtained by delaying the first clock signal, quantize the input signal with a second gain, and output a plurality of second output signals. The device includes a gain mismatch estimator configured to calculate first and second values which are averages of absolute values of the first output signals and the second output signals, and calculate first and second gain correction values using the first and second values. A gain mismatch compensator is configured to output a plurality of corrected first output signals and corrected second output signals, according to the first and second gain correction values.