Signal Delay Measurement via Cable Reflections
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Solution Overview
Problem
Existing test systems face challenges in accurately determining signal transmission delays in wired transmission media, such as cables, which affect the accuracy of device under test (DUT) measurements, particularly in ultra-wide band and over-the-air measurements, due to the labor-intensive nature of current methods requiring specialized equipment.
Innovation Solution
A system utilizing a signal generator and analyzer that outputs signals on multiple carrier frequencies over an open-ended wired transmission medium to produce reflections, allowing for a coarse and fine search process to determine the transmission time, which is insensitive to magnitude and phase offsets in the coarse search but sensitive in the fine search, enabling precise delay calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If specialized equipment and manual setup methods are used to determine transmission delay, then measurement precision can be achieved, but device complexity and labor intensity increase significantly
Solution Approach 1:
The test system performs self-calibration by automatically generating test signals, measuring reflections, and calculating transmission delay without requiring external specialized equipment. The system uses its own built-in signal generator and analyzer to determine the delay, eliminating the need for separate calibration devices and manual setup procedures.
Solution Approach 2:
The patent introduces signal reflections as an intermediary mechanism to indirectly measure transmission delay. Instead of directly measuring delay with complex equipment, the system uses the reflected signals from the open-ended cable to infer the transmission time, simplifying the measurement process while maintaining accuracy.
2Measurement precision
If manual setup and specialized equipment are used for delay measurement, then accurate transmission time can be determined, but productivity decreases due to labor-intensive processes
Solution Approach 1:
The test system automatically performs delay measurement without requiring manual intervention or specialized equipment setup. The system self-calibrates by generating test signals, capturing reflections, and computing transmission delay, thereby eliminating labor-intensive procedures and significantly improving testing productivity.
Solution Approach 2:
The system performs preliminary self-calibration before actual testing by automatically determining the transmission delay and storing the calibration data. This preliminary action eliminates the need for repeated manual setup and equipment configuration during subsequent testing operations, improving overall productivity.
3Productivity
If coarse search with large step size is used, then device complexity is reduced and measurement speed increases, but measurement precision decreases
Solution Approach 1:
The measurement process is segmented into two distinct phases: a coarse search phase with large step size for rapid initial estimation, and a fine search phase with small step size for precise refinement. This segmentation allows the system to achieve both high productivity in the coarse phase and high precision in the fine phase, balancing speed and accuracy.
Solution Approach 2:
The coarse search performs partial measurement with excessive step size to quickly narrow down the transmission time range, then the fine search completes the precise measurement within this narrowed range. This approach uses partial action (coarse search) to achieve productivity goals while reserving full precision for the fine search phase.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for efficient and accurate determination of signal transmission delays, reducing labor and equipment requirements, and improving the accuracy of DUT measurements by refining the transmission time within a precise range, thereby enhancing measurement precision.
Implementation Method 1
a wired transmission medium for carrying the signals, where the wired transmission medium is configured as open ended to produce reflections on the wired transmission medium of the signals
Data Source
AI summary
An example system includes a signal generator to output signals based on multiple carrier frequencies; a wired transmission medium for carrying the signals, where the wired transmission medium is configured as open ended to produce reflections on the wired transmission medium of the signals; and a signal analyzer to receive the reflections and to determine a transmission time of a signal along the wired transmission medium based on the reflections. The signal analyzer is configured to perform operations that include performing a search based on an estimated transmission time of the signal along the wired transmission medium and the reflections to determine the transmission time. The search is to determine which of multiple candidate transmission times to select for the transmission time.