Delay Circuit Measurement Using Feedback Pulse Periods
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Solution Overview
Problem
Conventional delay measurement techniques face limitations due to high-speed clock requirements for direct time measurement, measurement errors from input and output events, and resolution constraints in indirect time measurements, which affect accuracy and precision.
Innovation Solution
A method and circuit that utilize a feedback loop to generate consecutive output pulses, allowing for the calculation of delay by measuring periods at different delay values, thereby improving accuracy and reducing measurement errors through iterative adjustments and correction coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct time measurement is used with high-speed clocks, then measurement resolution is improved, but device complexity and clock speed requirements increase
Solution Approach 1:
The patent introduces a feedback circuit as an intermediary that converts the delay measurement problem into a frequency/period measurement problem. The feedback circuit generates oscillations where the delay manifests as a change in period, allowing measurement with lower-speed clocks while maintaining precision.
Solution Approach 2:
The patent changes the measurement parameter from direct time interval to period frequency. By measuring the period of oscillations at different delay settings and calculating the difference, the system achieves high precision without requiring high-speed clocks, thus resolving the contradiction between measurement precision and device complexity.
2Productivity
If direct time measurement is used, then measurement speed is improved, but measurement errors from input and output events increase
Solution Approach 1:
The patent employs feedback measurement where the output is fed back to the input through a feedback circuit. This creates a self-referential measurement system where the delay is determined by the change in oscillation period rather than absolute timing of input and output events, thereby eliminating errors from event timing while maintaining measurement speed.
3Device complexity
If indirect time measurement is used, then clock speed requirements are reduced, but measurement precision deteriorates due to voltage ramp and measurement errors
Solution Approach 1:
The patent replaces the voltage ramp mechanism (analog measurement) with a digital counting-based period measurement approach. By measuring the number of clock cycles in the oscillation period and calculating the difference, the system achieves high precision without the errors associated with voltage ramp linearity and analog measurement, while still using lower-speed clocks.
Data Source
AI summary
A circuit and corresponding method for determining a delay are presented. The circuit includes a delay circuit, a feedback circuit and a controller. The delay circuit receives an input signal having an input edge and provides an output signal having an output edge. The input edge and the output edge are separated by a delay. The feedback circuit causes the delay circuit to generate a series of consecutive output pulses. The controller sets the delay to a first delay value and measures a first period of output pulses; sets the delay to a second delay value and measure a second period of output pulses. The controller then calculates the delay based on a difference between the first period and the second period.