Ring Oscillator State Capture for Linear Time-to-Digital Conversion
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Solution Overview
Problem
Existing time-to-digital converters require correction circuits to improve linearity due to varying internal state durations caused by differences in delay times and operation speeds among components, necessitating additional correction information and complex calculations.
Innovation Solution
A transition-state output device with a ring oscillator circuit, state machine, and transition-state acquisition section that calculates internal states based on state information, where the time until the internal state transitions back to the first state is longer than the state information update interval, allowing for simplified state acquisition and accurate time-digital value calculation without the need for correction calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correction circuits and correction information are used to improve linearity, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the problematic correction circuit from the system by redesigning the state transition section to inherently produce uniform state durations. Instead of adding a correction circuit to fix non-linearity, the invention removes the source of non-linearity by ensuring each internal state has substantially equal duration through careful design of the state transition timing, thereby achieving high linearity without correction circuits.
Solution Approach 2:
The state transition section is designed to self-correct for uniform state durations through its internal architecture. The state machine and tapped delay line are configured so that state transitions occur at timings that naturally create equal-duration states, eliminating the need for external correction mechanisms. The system serves its own linearity requirement through its inherent design rather than requiring additional correction components.
2Measurement precision
If correction calculations are performed to improve linearity, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the state transition section to produce uniform state durations from the outset. The state machine and delay elements are designed in advance to ensure equal timing intervals, so that when time-to-digital conversion occurs, the data is already linear and ready for immediate use without requiring subsequent correction calculations.
Solution Approach 2:
The invention converts the potential harm of variable state durations into a benefit by designing the state transition section to inherently produce uniform durations. The tapped delay line and state machine are configured so that what could have been sources of timing variation become the mechanism for ensuring timing uniformity, thereby eliminating the need for correction and saving time.
3Measurement precision
If correction information is prepared and stored, then measurement precision is improved, but loss of substance increases
Solution Approach 1:
The patent removes the need for correction information storage by extracting the linearity correction function from the data processing stage and embedding it directly into the state transition hardware. The state machine and tapped delay line are designed to produce uniformly timed states, eliminating the requirement for separate correction tables or stored correction data.
Solution Approach 2:
The state transition section serves its own linearity requirement through its inherent design. The state machine automatically generates uniformly distributed state transitions without requiring external correction information or storage resources. The system is self-sufficient for achieving linear time-to-digital conversion.
Data Source
AI summary
A transition-state output device includes: a ring oscillator circuit; a state machine changing in state according to a change in state of the ring oscillator circuit; a transition-state acquisition section acquiring and holding state information including a signal output from the ring oscillator circuit and a signal output from the state machine, synchronously with a reference signal; and an internal-state calculation section calculating an internal state corresponding to a number of changes in state of the ring oscillator circuit, based on the state information held by the transition-state acquisition section. A time until the internal state, after transitioning from a first internal state to a second internal state, transitions to the first internal state again is longer than a time interval of updating the state information held by the transition-state acquisition section.