Multi-Ring Oscillator ADC Modes for Lower Phase Noise

The single ring oscillator is segmented into multiple coupled ring oscillators (first, second, and third ring oscillators with different numbers of stages). Each ring oscillator processes a portion of the input signal with different phase shifts, and their outputs are combined through a summer. This segmentation reduces the phase noise contribution to the noise floor while maintaining manageable device complexity through modular architecture.

The ADC employs dynamic configuration where the number of active ring oscillators and their coupling can be adjusted based on the required bandwidth and dynamic range. The system can selectively enable or disable specific ring oscillators (e.g., using only one ring for low bandwidth applications or multiple coupled rings for high bandwidth applications), allowing power consumption to scale efficiently with the actual processing requirements rather than operating at maximum capacity continuously.

Multiple ring oscillators are merged through a summer that combines their outputs. The first, second, and third ring oscillators each produce signals with different phase characteristics, and the summer merges these signals to produce an output with reduced phase noise. This merging approach achieves phase noise reduction while maintaining a relatively simple overall structure compared to other multi-oscillator configurations.

The system changes operational parameters (number of active ring oscillators, coupling configuration, sampling frequency) to achieve different dynamic range requirements. For high dynamic range applications, multiple ring oscillators are activated with appropriate coupling to provide fine phase resolution. For lower dynamic range requirements, fewer ring oscillators are used, reducing power consumption while maintaining adequate performance. This parameter adjustment allows the ADC to adapt its power consumption to the actual measurement precision requirements.