Nonlinear Distortion Detection via Signal Correlation
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Solution Overview
Problem
Existing technologies fail to effectively detect and measure nonlinear distortions in cable and wireless systems, leading to high modulation error rates and packet error ratios due to excessive nonlinear distortion in signal paths.
Innovation Solution
A method involving the transmission of two signal bursts with a known time difference, where one burst is inverted, to determine the presence and order of nonlinear distortion by processing signal samples in vacant bandwidths, allowing for the identification of even- and odd-order distortions through correlation analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional distortion measurement methods are used, then measurement simplicity is maintained, but measurement precision is insufficient to accurately detect and classify nonlinear distortions
Solution Approach 1:
The patent segments the distortion measurement process into distinct phases: transmitting separate signal bursts with different characteristics (e.g., different modulation schemes, frequencies, or time structures), capturing the composite signal, and then processing the captured signal to separately analyze distortion components. This segmentation allows for precise identification and classification of different types of nonlinear distortions while maintaining a systematic approach to measurement.
Solution Approach 2:
The patent employs parameter changes by varying signal characteristics such as modulation type, frequency, amplitude, or time structure between different transmitted bursts. By changing these parameters and observing how distortion manifests differently under each condition, the system can precisely characterize and classify nonlinear distortion components, achieving high measurement precision through controlled parameter variation.
2Measurement precision
If signal processing is performed to accurately measure distortion, then measurement precision improves, but loss of time increases due to multiple signal transmissions and processing steps
Solution Approach 1:
The patent applies preliminary action by pre-planning and pre-transmitting multiple signal bursts with different characteristics before performing the actual distortion analysis. The system prepares the test signal sequence in advance, knowing exactly what to transmit and how to process each component. This preliminary preparation allows for efficient, systematic processing that achieves high measurement precision without unnecessary time loss during the actual measurement phase.
Data Source
AI summary
A method to test a signal path with vacant bandwidth by sending a test signal twice and processing two resulting nonlinear distortion signals captured in the vacant bands to determine presence of nonlinear distortion. If the signals correlate, the energy in the vacant bands is nonlinear distortion. If the test signal is sent followed by an inverse (in time-domain) of itself, and a resulting correlation peak is negative, the nonlinear distortion is determined to have been created by odd-order nonlinear distortion.