Density-Modulated Feedback Control for Higher SNDR

The patent segments the control signal into multiple quantization levels over time using density modulation. Instead of using a high-resolution ADC, the system uses a low-resolution ADC that samples at a higher rate, with each sample representing a coarser quantization level. Multiple such samples are combined to achieve the equivalent precision of a high-resolution ADC, thereby improving SNDR performance without requiring a complex high-resolution converter.

The system employs periodic high-frequency sampling at the up-sampling frequency, where the ADC operates at a rate much higher than the Nyquist rate. This periodic oversampling allows the quantization noise to be spread across a wider frequency range, enabling noise shaping techniques to push quantization noise out of the band of interest, thus improving effective SNDR performance.

The patent divides the measurement task into multiple low-resolution measurements taken over time, rather than requiring a single high-resolution measurement. By using a low-resolution ADC that operates at high speed and combining multiple samples through density modulation and noise shaping, the system achieves high effective precision while keeping the power consumption of individual ADC operations low.

The system changes the sampling frequency parameter significantly, operating the ADC at an up-sampling frequency much higher than the Nyquist rate. This parameter change allows the use of lower-resolution quantization at each sample while achieving high effective precision through the combination of oversampling and noise shaping, thereby reducing the power consumption associated with high-resolution conversion.

The patent segments the precision requirement into temporal domains rather than spatial domains. Instead of using a large high-resolution ADC, the system uses a smaller low-resolution ADC that operates continuously at high speed, with precision achieved through the combination of multiple samples over time rather than through a large number of bits in a single sample.

The system uses periodic high-frequency sampling to achieve high effective precision. The ADC operates continuously at an up-sampling frequency much higher than the signal bandwidth, allowing the use of a compact low-resolution converter whose small size is compensated by its high operating rate and the subsequent processing of multiple samples.

The patent merges the functions of upsampling, delta modulation, sigma modulation, and noise shaping into an integrated density modulation architecture. The up-sampling circuit, delta circuit, and sigma circuit work together as a unified system where the delta-sigma modulation inherently performs both upsampling and noise shaping, reducing the need for separate complex components and optimizing the overall circuit implementation.

The system employs feedback through the delta-sigma modulation architecture, where the quantization error is fed back and filtered by the sigma (integrator) circuit. This feedback mechanism shapes the quantization noise spectrum, pushing noise out of the band of interest, and achieves high SNDR performance through the closed-loop control inherent in delta-sigma modulators.