Threshold Crossing Detection With Sub-Clock Time Interpolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for detecting the threshold crossing instant of an electrical signal suffer from limited temporal accuracy due to digital discretization, which is constrained by the system clock period, leading to unsatisfactory detection errors in applications like radar and GPS systems.
Innovation Solution
A method and device that utilize an analogue-to-digital conversion module to sample the signal, followed by a detection module to identify the sampling instants where the signal crosses a threshold, and a calculation module to determine a fractional time interval between these instants, allowing for a more accurate detection of the threshold crossing instant with a known delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital sampling is used to detect threshold crossing instant, then the method is compatible with digital electronics and eliminates noise/thermal drift issues, but the temporal accuracy is limited by the clock period
Solution Approach 1:
The method segments the clock period into multiple finer time intervals by dividing the clock period by a division factor. This allows the temporal measurement resolution to be improved beyond the original clock period, effectively resolving the contradiction between digital compatibility and temporal accuracy.
Solution Approach 2:
The patent introduces a new dimension of time measurement by creating a finer time grid through clock period division. This additional temporal dimension enables sub-clock-period resolution, allowing the system to achieve high temporal accuracy while maintaining digital electronics compatibility.
2Measurement precision
If a very high frequency clock is used, then the temporal resolution of threshold crossing detection is improved, but the circuit complexity, signal integrity problems, and energy consumption increase
Solution Approach 1:
The system dynamically adjusts the clock period division factor based on the required measurement precision. This dynamic adaptation allows the system to achieve high temporal resolution only when necessary, reducing overall circuit complexity and energy consumption while maintaining the capability for high-precision measurements when needed.
Solution Approach 2:
The patent changes the effective time resolution parameter by dividing the clock period rather than increasing the clock frequency. This parameter transformation achieves the same temporal resolution improvement without the negative side effects of high-frequency operation, such as increased circuit complexity and energy consumption.
3Measurement precision
If the clock period is reduced to improve temporal resolution, then the detection error margin is reduced, but the system becomes more complex and costly
Solution Approach 1:
The patent replaces the mechanical approach of using a higher frequency clock with a computational approach of dividing the existing clock period. This substitution achieves the same effect of reduced detection error margin without the increased system complexity and cost associated with higher frequency clock operation.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for detecting, through an electronic detection device (1), a threshold crossing instant (TOA) at which an electrical signal (V) crosses a threshold S is described. Such method comprises the steps of: defining, by a clock signal (CL), a sequence of discrete clock instants (Tn) such that two consecutive clock instants of the sequence are time spaced from one another by a clock period (T); then, sampling the electrical signal (V) with a sampling period (T) equal to the clock period (T), at a plurality of sampling instants (Ts) belonging to the sequence of clock instants (Tn); then detecting a first sampling instant (Ts1) and a subsequent consecutive second (Ts2) sampling instant, such that at one of said first (Ts1) and second sampling instant (Ts2) the sampled signal value has a first signal value (V1) lower than or equal to threshold (S), and at the other one of said first (Ts1) and second (Ts2) sampling instant the sampled signal value has a second signal value (V2) higher than threshold (S); moreover, calculating, on the basis of the first signal value (V1), the second signal value (V2) and threshold (S), a first time interval (Δt), fractional with respect to the clock period (T), indicative of a temporal distance between the threshold crossing instant (TOA) and the first sampling instant (Ts1); then, setting a reference electrical signal (VR) having a reference amplitude (VR) representative of the first time interval (Δt) relative to a reference scale; subsequently, providing the reference signal (VR) as an input signal of a comparison module (500), configured for generating a signal with a controlled delay depending on said input signal; then, generating a threshold crossing detection signal (VTOA) through the comparison module (500), at a threshold crossing detection instant (TTOA) delayed by a second time interval (Δt') relative to a reference instant (Tr) belonging to the sequence of clock instants (Tn), said second time interval (Δt') depending on the reference amplitude (VR); finally, calibrating the reference scale of the reference amplitude (VR) so that said second time interval (Δt') is substantially equal in length to said first time interval (Δt).