Time-to-Digital Converter Using Coarse-Fine Vernier Measurement
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Solution Overview
Problem
Existing Time to Digital Converters (TDCs) face challenges in achieving high resolution and wide input range while maintaining low power consumption, especially in low power, high performance RF systems on-chip using nanometer technology.
Innovation Solution
The proposed TDC system employs a combination of 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 and high resolution while optimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single TDC structure is used, then the device complexity is low, but it cannot achieve both high resolution and wide input range simultaneously
Solution Approach 1:
The TDC is divided into two independent measurement channels: a coarse TDC using a ring oscillator for wide range measurement, and a fine TDC using a Vernier delay structure for high resolution measurement. Each channel is optimized for its specific function, allowing the system to achieve both wide input range (2.5ns to 5ns) and high resolution (5ps) simultaneously without requiring a single complex structure.
2Measurement precision
If high resolution measurement is implemented, then the measurement precision improves, but the power consumption increases
Solution Approach 1:
The measurement function is segmented between two TDC channels with different power characteristics. The fine TDC provides high resolution (5ps) when needed, while the coarse TDC handles range measurement with lower power consumption. This segmentation allows the system to achieve high resolution without continuously consuming the power required for fine measurement across the entire operating range.
Solution Approach 2:
The system uses partial action by selectively employing the fine TDC measurement capability only when high resolution is required, rather than continuously operating at full resolution. The coarse TDC operates continuously for range measurement, and the fine TDC is engaged selectively to provide high resolution measurements, optimizing the balance between measurement precision and power consumption.
Data Source
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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.