Distributed Antenna Remote Unit for Swept PIM Distortion Measurement
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Solution Overview
Problem
Current measurement apparatuses for passive intermodulation distortion (PIMD) in communication systems are expensive and inefficient, limiting their ability to effectively measure PIMD, which degrades communication quality.
Innovation Solution
A remote apparatus for a distributed antenna system that uses swept conversion signals to convert intermodulation signals, allowing for the determination of intermodulation distortion without frequency correction, incorporating sub-amplification units, test signal generation, conversion units, and control units to assess distortion levels across sub-amplification units connected in a cascade structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement apparatuses are used to measure passive intermodulation distortion, then measurement accuracy can be achieved, but the apparatus becomes expensive and inefficient
Solution Approach 1:
The measurement system is segmented into functional modules: a signal generation unit that creates test signals, a conversion unit that converts IM signals using frequency sweeping, and a control unit that analyzes distortion levels. This segmentation allows each module to perform its specific function efficiently, reducing overall system complexity and cost while maintaining measurement accuracy.
Solution Approach 2:
The system changes the frequency parameter of conversion signals dynamically through frequency sweeping. By varying the frequency parameter across different IM signals, the system can identify and measure distortion levels without requiring complex frequency correction apparatuses, thereby reducing device complexity while maintaining measurement precision.
2Measurement precision
If frequency correction is applied to IM signals for measurement, then measurement accuracy improves, but measurement time and system complexity increase
Solution Approach 1:
The system performs preliminary frequency sweeping of conversion signals before actual measurement. By pre-establishing the frequency sweep pattern and conversion characteristics, the system eliminates the need for time-consuming frequency correction during measurement, thereby reducing measurement time while maintaining accuracy through the pre-characterized frequency-response relationship.
Solution Approach 2:
Instead of directly measuring IM signals at their original frequencies requiring complex correction, the system creates a simplified copy of the measurement process using frequency-swept conversion signals. This copying approach transforms the complex frequency-correction problem into a simpler time-domain analysis problem, reducing both measurement time and system complexity.
3Measurement precision
If multiple sub amplification units are measured individually, then distortion levels can be determined for each unit, but measurement time increases
Solution Approach 1:
The system merges the measurement of multiple sub amplification units into a single integrated measurement process. By injecting test signals that traverse multiple cascade-connected sub amplification units simultaneously and using the frequency-swept conversion to capture IM signals from all units, the system determines distortion levels for each unit without requiring separate measurements, thereby significantly improving measurement efficiency while maintaining precise distortion determination.
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
Enables efficient and cost-effective measurement of PIMD, allowing for selective determination of distortion levels across sub-amplification units, thereby improving communication quality and reducing measurement time and costs.
Implementation Method 1
a conversion unit converting intermodulation (IM) signals generated in response to the test signals into a plurality of conversion IM signals by using a conversion signal of which a frequency is swept
Implementation Method 2
Intermodulation represents a phenomenon in which an output frequency component harmonized by the sum and the difference between harmonic frequencies of two different input frequency signals is output during processing a radio frequency (RF) signal through a non-linear element
Data Source
AI summary
A remote apparatus includes: a plurality of sub amplification units amplifying radio frequency (RF) signals of different frequency bands, respectively; a test signal generation unit generating test signals of a frequency band for any one sub amplification unit among the plurality of sub amplification units; a conversion unit converting intermodulation (IM) signals generated in response to the test signals into a plurality of conversion IM signals by using a conversion signal of which a frequency is swept; and a control unit determining a degree of an intermodulation distortion by the any one sub amplification unit based on signal levels of the plurality of the conversion IM signals.