Pulse Interference Detection Using Dual-Time Signal Statistics
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Solution Overview
Problem
Existing COFDM demodulators face challenges in effectively suppressing both high-power and medium-power pulse interferences due to the difficulty in selecting an appropriate detection threshold, leading to incorrect detection and suppression of pulse interferences.
Innovation Solution
A device and method that utilize a circuit to determine a short-term and long-term statistical coefficient of signal variation, comparing these coefficients to detect pulse interferences, and apply weighting constants to correct the signal, thereby improving interference suppression across various power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high detection threshold is used to suppress false alarms, then the false detection rate decreases, but the detection capability for medium-power pulse interferences is lost
Solution Approach 1:
The patent applies dynamics by making the detection threshold adaptive rather than fixed. The threshold automatically adjusts based on the estimated background noise level, allowing it to be low enough to detect medium-power pulse interferences while maintaining reliability by dynamically compensating for noise variations. This resolves the contradiction between fixed threshold reliability and detection sensitivity.
Solution Approach 2:
The patent changes the threshold parameter from a static value to a dynamic value that varies with the background noise estimate. By continuously updating the threshold based on measured noise characteristics, the system maintains optimal detection performance across different operating conditions, solving the trade-off between false alarm rate and detection capability.
2Measurement precision
If a low detection threshold is used to detect all pulse interferences, then the detection capability for medium-power pulse interferences is improved, but false detection of undisturbed signal increases
Solution Approach 1:
The system dynamically adjusts the detection threshold based on real-time background noise estimation. This allows the threshold to be low enough to detect medium-power pulse interferences while automatically adapting to noise conditions to prevent false detections of undisturbed signal, resolving the contradiction between detection sensitivity and reliability.
Solution Approach 2:
The patent implements feedback by continuously monitoring the background noise level and using this information to adjust the detection threshold. The noise estimate feeds back into the detection decision process, allowing the system to maintain optimal performance by adapting the threshold to current signal conditions, thereby reducing false detections while preserving detection capability.
3Device complexity
If conventional threshold detection is used, then the detection process is simple, but the ability to distinguish between interference and undisturbed signal is insufficient
Solution Approach 1:
The patent introduces an intermediary element - the background noise estimate - that mediates between the simple threshold comparison and the complex task of interference detection. By comparing the signal against an adaptively determined threshold based on noise characteristics, the system achieves better discrimination accuracy while maintaining relative simplicity in the detection process.
Data Source
AI summary
A device for suppressing pulse interferences contained in a signal, including a circuit for detecting pulse interferences contained in the signal, and a circuit for correcting the signal disturbed by the detected pulse interferences, in which the detection circuit comprises a circuit for determining a first coefficient representative of a statistical feature of the variation of the signal over a first time period; a circuit for determining a second coefficient representative of a statistical feature of the variation of the signal over a second time period longer than the first time period; and a comparison circuit comparing the first and second coefficients and providing a signal indicative of the presence of a pulse interference over the first time period when the first coefficient clearly differs from the second coefficient.