TDC Time Measurement Using Multi-Delay Signals for Accuracy
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Solution Overview
Problem
Time measurement devices using the TDC scheme face challenges in setting a regular quantization interval, leading to variations that affect the accuracy of time measurement, as the real time and quantization interval often fail to correspond properly, resulting in inaccurate digital signals.
Innovation Solution
A time measurement device that includes a first and second signal generation unit, a digital conversion unit, a time delay unit, and a time calculation unit, where at least one signal is delayed by multiple preset delay times to smooth the variation in the quantization interval, allowing for accurate time calculation from multiple digital signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a TDC scheme is used for time measurement, then the measurement range is long and the cost is low, but the quantization interval varies and measurement accuracy is insufficient
Solution Approach 1:
The patent applies periodic action by using a ring oscillator that generates periodic clock signals. The ring oscillator continuously oscillates, providing a stable periodic signal that serves as the basis for time measurement. This periodic signal allows the TDC to consistently measure time intervals across its entire measurement range, reducing quantization interval variation while maintaining long measurement range and low cost.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the operating parameters of the ring oscillator and TDC circuit. By changing the oscillation frequency and timing parameters based on the measured time interval, the system optimizes the quantization interval for different measurement ranges. This allows the device to maintain high measurement accuracy across the entire measurement range while keeping the device complexity manageable.
2Measurement precision
If the quantization interval is set to a regular interval, then the digital signal corresponds properly to real time, but it is difficult to achieve complete correspondence
Solution Approach 1:
The patent implements feedback by using the output of the ring oscillator to continuously monitor and adjust the timing signals. The feedback mechanism ensures that any deviations in the quantization interval are detected and corrected, maintaining regular intervals despite variations in the measurement process. This feedback loop guarantees that the digital signal accurately corresponds to real time intervals, improving both measurement precision and reliability.
Solution Approach 2:
The patent applies equipotentiality by designing the TDC circuit to maintain equal time intervals across all measurement ranges. The circuit is configured so that each quantization level represents an equal time duration, ensuring that the digital output uniformly corresponds to real time regardless of the specific measurement value. This equipotential design approach ensures consistent accuracy across the entire measurement range.
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AI summary
A time measurement device for calculating a time from an input of a first trigger signal to an input of a second trigger signal as a measured time includes a start gate configured to generate a start signal, a stop gate configured to generate a stop signal, a TDC circuit configured to generate a digital code corresponding to the time from an input of a start signal to an input of a stop signal, a delay circuit configured to delay an input of at least one of the start signal and the stop signal to the TDC circuit by a predetermined delay time, and a control unit configured to calculate a measured time on the basis of a plurality of digital codes generated by the TDC circuit, wherein the time delay unit selects at least two delay times.