Digital Radio Receiver Dynamic Threshold Peak Detection
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Solution Overview
Problem
Digital radio receivers face challenges in accurately identifying correlation peaks in noisy environments due to the presence of sidelobe peaks and noise peaks, which can lead to false detections and reduced sensitivity, especially when the signal-to-noise ratio is high.
Innovation Solution
A method that dynamically adjusts the selection threshold based on the amplitude of the first peak to distinguish correlation peaks from sidelobe peaks, using a dynamic sidelobe threshold that changes relative to the first peak's amplitude, and an additional time separation check to filter out false detections, allowing for improved sensitivity and robustness against noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed threshold is used to distinguish correlation peaks from sidelobe peaks, then false detections can be reduced, but receiver sensitivity is compromised and correlation peaks with lower amplitudes may be missed
Solution Approach 1:
The patent implements a dynamic thresholding mechanism where the selection threshold is adjusted based on the amplitude of the first detected peak in the correlation output. This allows the threshold to adapt to varying signal conditions, enabling the system to maintain high reliability in distinguishing true correlation peaks from sidelobe peaks while preserving receiver sensitivity to detect weaker correlation peaks that would be missed by a fixed threshold approach
Solution Approach 2:
The patent changes the threshold parameter dynamically based on the observed signal characteristics. Specifically, the selection threshold is set as a fraction of the first peak's amplitude, allowing the system to optimize its detection criteria for each received signal packet individually, thereby resolving the contradiction between maintaining strict detection criteria and preserving sensitivity
2Reliability
If a higher selection threshold is used to filter out sidelobe peaks, then false detections are reduced, but the ability to detect weak correlation peaks in noisy environments is diminished
Solution Approach 1:
The patent employs dynamic threshold adjustment that responds to the actual signal conditions. By setting the threshold as a proportion of the first peak's amplitude rather than using a fixed value, the system can adapt its robustness level to match the signal strength and noise conditions, maintaining reliability against false detections while preserving the ability to detect weak correlation peaks in noisy environments
Solution Approach 2:
The system uses feedback from the detected first peak to adjust the selection threshold for subsequent peaks. This feedback mechanism allows the system to learn from the initial detection and adapt its criteria accordingly, improving robustness against false detections caused by noise while maintaining sensitivity to genuine weak correlation peaks
3Measurement precision
If repeated correlation operations are performed to improve synchronization accuracy, then symbol timing recovery and frame synchronization are enhanced, but processing time and complexity increase
Solution Approach 1:
The patent performs preliminary correlation operations with a stored synchronization sequence to identify the first peak, which then informs the selection threshold for subsequent peak detection. This preliminary action enables the system to establish detection criteria before processing additional correlation results, improving synchronization accuracy while minimizing the need for extensive repeated operations and reducing overall processing time
Data Source
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AI summary
A method of operating a digital radio receiver comprising: receiving a radio signal; passing said radio signal to a correlator for correlating said radio signal with a predetermined pattern to provide an output signal comprising a plurality of peaks separated in time; determining an amplitude of a first peak in the plurality of peaks; calculating a selection threshold based on said first peak amplitude; determining an amplitude of a second peak in the plurality of peaks; comparing said second peak amplitude to the selection threshold; and identifying the second peak as a correlation peak if the second peak amplitude is greater than the selection threshold.