Delta-Sigma Modulator Coefficient Scaling for Extended Stable Range
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Solution Overview
Problem
Conventional delta-sigma modulators face limitations in achieving high signal-to-noise ratio (SNR) at both low and high signal amplitudes, with higher-order modulators suitable for small amplitudes but unstable at larger amplitudes, and vice versa, leading to abrupt SNR changes when switching between orders.
Innovation Solution
The delta-sigma modulator dynamically alters its noise transfer function by scaling coupling and feedback resonator coefficients, allowing it to maintain high SNR at low amplitudes and extend the range of stable output amplitudes by switching to a different noise transfer function at higher amplitudes, without changing the modulator's order.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the order of the delta-sigma modulator is increased to improve signal-to-noise ratio at low amplitudes, then the maximum stable output amplitude range is reduced
Solution Approach 1:
The patent implements dynamic switching between different modulator orders based on the input signal amplitude. The system transitions from a fixed-order architecture to a dynamically reconfigurable one, where the modulator order is adjusted in real-time to match the signal conditions, thereby achieving high SNR at low amplitudes while maintaining stability at high amplitudes
Solution Approach 2:
The patent changes the operational parameters of the modulator by switching between different orders (e.g., 3rd order, 4th order, 5th order) depending on the signal amplitude level. This parameter change allows the system to optimize SNR performance for small signals while preventing instability for large signals, effectively resolving the contradiction between precision and stability range
2Adaptability or versatility
If the order of the delta-sigma modulator is switched between higher and lower orders to adapt to different signal amplitudes, then the signal-to-noise ratio changes abruptly
Solution Approach 1:
The patent employs transition regions and intermediate states when switching between modulator orders. Instead of abrupt transitions, the system uses overlapping operational ranges and gradual parameter changes to cushion the transition, preventing sudden SNR drops and maintaining continuous performance across amplitude boundaries
Solution Approach 2:
The dynamic switching mechanism includes hysteresis and transition management to prevent abrupt SNR changes. The system dynamically adjusts the switching thresholds and uses intermediate transition states to ensure smooth, continuous SNR performance when adapting to different signal amplitude levels
Data Source
AI summary
Devices, systems, and methods for providing delta-sigma modulation in conjunction with analog-to-digital or digital-to-analog signal conversion are disclosed. The delta-sigma modulator and delta-sigma converter include dynamically-scalable coefficients, which, at relatively low signal amplitudes, allow the delta-sigma modulator and delta-sigma converter to modulate the signals using a first noise transfer function and, at relatively greater signal amplitudes, allow the delta-sigma modulator and delta-sigma converter to modulate the signals using a second noise transfer function.