Observation ADC Sampling Control for Low-Noise Transceiver Calibration
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Solution Overview
Problem
In multi-GHz transceivers, non-linear distortions and memory effects in ADCs and DACs lead to spurious tones, spectral regrowth, and degradation in spurious-free dynamic range (SFDR) and error vector magnitude (EVM), particularly severe at high signal levels and critical for wideband operation.
Innovation Solution
Implementing a combined uniform and non-uniform sampling scheme in the observation path of the transceiver, where the observation ADC is activated at both regular and irregularly spaced sampling instants, with only valid samples from uniform sampling used for calibration, reducing noise and power dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If non-uniform sampling is used in the observation path, then power dissipation is reduced and noise is lowered, but random transients are generated at the buffer output
Solution Approach 1:
The patent applies periodic action by implementing uniform sampling at regular intervals in the observation path. This periodic sampling approach ensures that the buffer operates with a constant load, eliminating random transients while maintaining reduced power dissipation compared to continuous sampling. The regular sampling pattern creates predictable, periodic operation that avoids the harmful random transients generated by irregular sampling.
Solution Approach 2:
The patent applies local quality by using different sampling strategies in different parts of the system. Specifically, uniform sampling is applied in the observation path where constant load is beneficial, while the main signal processing path can use other sampling methods. This localized application of uniform sampling optimizes the buffer operation without affecting the overall system performance.
2Measurement precision
If the observation ADC is activated continuously, then measurement precision is maintained, but power dissipation increases
Solution Approach 1:
The patent implements periodic action by activating the observation ADC at regular, uniform intervals rather than continuously. This periodic activation maintains sufficient measurement precision for calibration purposes while significantly reducing power dissipation compared to continuous operation. The uniform sampling rate ensures that the observation path captures necessary signal characteristics without wasting energy on redundant samples.
Solution Approach 2:
The patent applies partial action by using a reduced sampling rate in the observation path compared to the main signal processing path. This partial sampling provides sufficient measurement precision for calibration and monitoring functions without the full power consumption of continuous high-rate sampling, achieving an optimal balance between precision and energy efficiency.
3Stability of the object's composition
If uniform sampling is used in the observation path, then random transients are minimized and buffer load is constant, but sampling flexibility is reduced
Solution Approach 1:
The patent applies local quality by implementing uniform sampling specifically in the observation path where stability is critical, while allowing flexibility in the main signal processing path. This localized approach ensures buffer load stability without compromising the overall system's adaptability. The observation path's uniform sampling provides a stable reference for calibration while the rest of the system maintains sampling flexibility.
Solution Approach 2:
The patent applies segmentation by separating the sampling functions into different paths with different characteristics. The observation path uses uniform sampling for stability, while the main processing path can use flexible, adaptive sampling. This segmentation allows each path to be optimized for its specific function without compromising the other, achieving both stability and flexibility in the overall system.
Data Source
AI summary
A method and system for controlling an analog-to-digital converter (ADC) in an observation path in a transceiver. The transceiver includes a transmit path, a receive path, and an observation path. The observation path includes an analog buffer and an observation ADC. A controller generates a control signal to control sampling events at the observation ADC to activate the observation ADC at combined uniform and non-uniform sampling instants. The controller may also generate a second control signal indicating whether digital data obtained by the observation ADC is valid or not. The digital data generated by the observation ADC at non-uniform sampling instants is indicated as invalid and digital data generated by the observation ADC at uniform sampling instants is indicated as valid. The digital data indicated as invalid may be discarded and the digital data indicated as valid is used for calibration of the transmit path or the receive path.