Cross-Correlator Time Measurement with Flat Trigger Slopes
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Solution Overview
Problem
Current time measurement systems face challenges in achieving high-resolution time measurements due to limited bandwidth and steep trigger slopes, which are difficult to realize with existing semiconductor technologies, especially at high signal frequencies like 10 GHz, where the required bandwidth exceeds the capabilities of current semiconductor technology.
Innovation Solution
The method employs a cross-correlation function between the trigger signal and the system clock to achieve accurate time measurements using relatively flat trigger-signal slopes, similar in form and length to the system clock, thereby reducing the necessary bandwidth and improving signal-noise ratio, allowing for time resolution below 1 ps with a system clock pulse of 10 GHz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional time measurement methods using steep trigger slopes are employed, then time resolution can be improved, but the required bandwidth exceeds the capabilities of current semiconductor technology
Solution Approach 1:
The patent changes the fundamental parameter of trigger slope steepness from very steep (conventional) to relatively flat (innovative). By using flat trigger slopes that match the system clock's bandwidth capabilities, the measurement system can achieve high time resolution without requiring bandwidth beyond semiconductor technology limits. The trigger signal's rise time is intentionally made comparable to or slower than the system clock period.
Solution Approach 2:
The patent introduces a correlation-based measurement mechanism as an intermediary between the trigger signal and time measurement. Instead of directly measuring time based on steep slope intersections, the system uses correlation processing to determine time differences, allowing accurate measurements even with flat slopes that match available bandwidth.
2Measurement precision
If the bandwidth of the measuring system is increased to achieve higher time resolution, then time resolution improves, but the complexity and cost of the system increases
Solution Approach 1:
The patent fundamentally changes the bandwidth requirement parameter from very high (conventional) to moderate (innovative). By accepting flat trigger slopes and using correlation-based measurement, the system achieves sub-clock-period time resolution without requiring bandwidth multiples beyond what's already available in the system clock, thereby avoiding increased device complexity.
3Measurement precision
If steep trigger slopes are used for accurate time measurement, then measurement precision improves, but the signal-noise ratio deteriorates
Solution Approach 1:
The patent introduces correlation processing as an intermediary that enhances the signal-noise ratio. By correlating the trigger signal with reference waveforms over multiple cycles, the system achieves accurate time measurement while simultaneously improving the signal-noise ratio, as the correlation process inherently filters out random noise.
Solution Approach 2:
The patent uses continuous correlation processing across multiple signal cycles rather than single-shot measurements. This continuous action allows the system to accumulate signal information while averaging out noise, thereby improving the signal-noise ratio while maintaining measurement precision.
Data Source
AI summary
The invention relates to a device for determining the temporal position of an analogue trigger signal with relation to an analogue clock signal, comprising an analogue cross-correlator (30), which carries out an analogue cross-correlation between the trigger signal and clock signal to provide a fine resolution.