Intercept Point Measurement System with Dual Operating Modes
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Solution Overview
Problem
Characterizing the nonlinear transmission properties of RF devices is challenging due to the measurement instruments themselves exhibiting nonlinear properties, which affects the reliability of intercept point measurements.
Innovation Solution
A measurement system that includes an input port connected to a device-under-test and a measurement unit capable of receiving continuous wave signals and intermodulation signals, operating in two modes: one for quick IPx calculations using stored system information and another for multiple measurements with varying system characteristics to derive IPx values, thereby isolating the device's nonlinear effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional measurement instruments are used to measure IPx values, then the measurement process is simple, but the measurement reliability deteriorates due to nonlinear properties of the measurement instruments
Solution Approach 1:
The measurement process is segmented into two distinct operating modes: a first operating mode for quick measurements using stored IPx information, and a second operating mode for accurate determination of IPx values by varying system characteristics. This segmentation allows the system to balance between speed and accuracy based on measurement requirements.
Solution Approach 2:
The system performs preliminary characterization of its own nonlinear properties and stores IPx information about the measurement system components (amplifier, attenuator, mixer, ADC) in advance. This preliminary action enables the system to compensate for its nonlinear effects during subsequent measurements, improving reliability without adding complexity to the measurement process.
2Measurement precision
If multiple IPx measurements with varying system characteristics are performed, then the IPx value determination accuracy is improved, but the measurement time increases
Solution Approach 1:
The measurement system dynamically switches between two operating modes based on measurement needs. The first operating mode provides quick measurements using pre-stored IPx information, while the second operating mode performs multiple measurements with varying characteristics for accurate IPx determination. This dynamic approach optimizes the trade-off between measurement speed and accuracy.
Solution Approach 2:
In the second operating mode, the system changes characteristics of measurement system components (such as amplifier gain, attenuator attenuation, or mixer conversion loss) during multiple IPx measurements. By varying these parameters in a controlled manner, the system can accurately determine the DUT's IPx value while accounting for the measurement system's nonlinear properties.
Data Source
AI summary
The invention relates to a measurement system for measuring an intercept point, IPx, value of a device-under-test, DUT. The system includes: an input port arranged for being directly or indirectly connected to the DUT; and a measurement unit which is connected to the input port. The input port is configured to receive a first CW signal, a second CW signal, and at least one intermodulation signal of the first and the second CW signal from the DUT, and to forward the signals to the measurement unit. The measurement unit is configured to perform an IPx measurement. The IPx measurement includes measuring a signal level of at least one or both of the first and the second CW signal, and measuring a signal level of the at least one intermodulation signal. The measurement unit is operable in a first operating mode and/or in a second operating mode.