Time-to-Digital Converter Range Extension With Coarse-Fine Phase Sensing
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Solution Overview
Problem
Time to Digital Converters (TDCs) face challenges in achieving a wide input range with high resolution and sensitivity, particularly in low power, high performance RF systems, where existing solutions struggle to accurately measure time differences with sufficient precision and range.
Innovation Solution
The implementation of a TDC system that combines coarse and fine measurements using a ring oscillator for coarse estimation and a two-dimensional Vernier structure for fine resolution, allowing for a wide input range of 2.5 ns to 5 ns with a resolution of 5 ps, by integrating coarse and fine TDC components within a low power RF receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a simple counter-based TDC is used, then the device complexity is low, but the measurement precision and sensitivity are insufficient
Solution Approach 1:
The TDC is segmented into multiple independent measurement channels, each capable of measuring time differences autonomously. This segmentation allows parallel operation of multiple channels, improving overall measurement precision without proportionally increasing complexity of individual channels.
Solution Approach 2:
The patent introduces a third dimension to the traditional TDC architecture by adding temporal multiplexing across multiple channels. Instead of improving precision within a single channel, the solution extends the measurement capability to multiple channels operating in parallel, effectively increasing precision through dimensional expansion.
2Adaptability or versatility
If the TDC input range is extended to cover wider frequency ranges, then the adaptability improves, but the measurement precision deteriorates
Solution Approach 1:
The TDC incorporates dynamic range adjustment capability through multiple measurement channels with different scaling factors. The system can dynamically select or switch between channels based on the input signal frequency, maintaining optimal measurement precision across a wide frequency range by adapting to different input conditions.
Solution Approach 2:
Different measurement channels are designed with different time scaling parameters to accommodate various input frequency ranges. By changing the effective measurement parameter (time scale) based on input frequency, the system maintains high precision across wide frequency ranges without being limited to a single operating point.
3Productivity
If multiple measurement channels are added to increase measurement capacity, then the productivity improves, but the device complexity increases
Solution Approach 1:
Multiple measurement channels share common functional blocks and resources, such as delay lines and decoding logic. This universal design allows the system to achieve high measurement throughput through parallel channels while minimizing the increase in overall device complexity by avoiding complete duplication of all components.
Solution Approach 2:
The multi-channel TDC structure nests multiple measurement functions within a unified architecture. Channels are organized in a hierarchical manner where common resources are shared at lower levels and channel-specific functions are layered above, reducing complexity through structured nesting rather than flat duplication.
Data Source
AI summary
Systems and methods are described for determining a phase measurement difference between a received modulated signal and a local clock signal. An adjusted local clock phase measurement may be determined by subtracting, from the phase measurement difference, a phase correction that is based on the frequency difference between the modulator signal's carrier frequency and the local clock's frequency. A phase modulation value may be generated by scaling the adjusted local clock phase measurement. The scaling may be based on a ratio of the modulated signal's carrier frequency and the local clock's frequency. The phase correction may be based on (i) a count of periods of the modulated signal occurring between each corrected phase measurement and (ii) a difference between the carrier frequency and the local clock frequency.