Measuring Device Cable Calibration via Internal Reference Path
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Solution Overview
Problem
Current calibration methods for wireless electronic devices fail to accurately account for path loss in radio-frequency cables and test fixtures, leading to inconsistent measurement data across different test stations.
Innovation Solution
A method involving alternating measurements of a signal through a calibration element (short or open) and a reference path within the measuring device, combined with phase and magnitude averaging, to accurately calculate cable loss without requiring external equipment like a vector network analyzer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a VNA is used to calibrate path loss, then cable path loss can be determined, but test fixture path loss and variations among different test instruments are ignored
Solution Approach 1:
The patent combines cable path loss calibration with test fixture path loss calibration into a single integrated process. By measuring through both the cable and test fixture together, the method determines total path loss including both components, eliminating the need for separate calibration steps and ensuring that all path loss elements are accounted for in the measurement system.
Solution Approach 2:
The measurement system calibrates itself by using its own test instruments and fixtures to determine the path loss characteristics. The system measures the actual path loss through its own cable and test fixture combination, automatically compensating for variations among different test instruments without requiring external reference equipment.
2Productivity
If a special control test setup with calibration plate is used, then calibration can be performed, but measurement accuracy is limited and calibration procedure is slow
Solution Approach 1:
The patent extracts the calibration function from external equipment (VNA, calibration plates) and implements it within the measurement system itself. By removing the need for separate calibration equipment and procedures, the system achieves both faster calibration (no external equipment setup) and higher accuracy (using the actual measurement instruments in their operational state).
Solution Approach 2:
The system performs path loss calibration as a preliminary step before actual measurements are taken. By determining and storing the path loss values for each test station in advance, the system enables rapid subsequent measurements without repeating the calibration process, thereby improving both calibration speed and overall measurement efficiency.
3Ease of operation
If test stations are not calibrated for path loss and variations, then measurement process is simple, but performance parameters show offsets across different test stations
Solution Approach 1:
Each test station automatically determines its own path loss characteristics and variations through self-calibration. The system uses its own test instruments and fixtures to measure and compensate for its specific path loss and variations, making the calibration process as simple as initiating a self-test routine while achieving high measurement consistency across all stations.
Solution Approach 2:
The system changes the operational parameters of the test stations by determining specific path loss values and variation characteristics for each station. These calibrated parameters are then used to compensate measurements, transforming the raw inconsistent data into consistent, comparable results across different test stations without complicating the overall measurement process.
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 approach significantly increases calibration accuracy, allowing for precise measurement of cable damping and reducing errors, while enabling calibration without disconnection from the measuring device.
Implementation Method 1
a measurement signal is measured as a return signal reflected by the first calibration element
Data Source
AI summary
A measuring device comprises at least one port, an external cable connected to the at least one port, a transmitter connected to the at least one port through a switch, a receiver connected to the at least one port through the switch and a reference path connecting the transmitter with the receiver through the switch. The cable is connected to calibration elements, e.g., short and open. The switch alternately switch in a manner that in a first state the transmitter and the receiver are connected to the at least one port and that in a second state the transmitter and the receiver are connected via the reference path.