Wireless Communication Device Adaptive S/N Improvement
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Solution Overview
Problem
Existing wireless communication devices face challenges in maintaining accurate tuning and sound quality when the signal-to-noise ratio (S/N) of continuous wave (CW) signals is degraded, leading to unnatural demodulated sound and reduced precision in tuning operations.
Innovation Solution
A wireless communication device incorporating a demodulation unit, an S/N improvement processing unit, an adaptive notch filter, a frequency determination processing unit, and a peak filter that performs adaptive operations to improve S/N, update filter coefficients, and adjust reception frequencies to match the pitch frequency, while limiting the frequency bandwidth of demodulated signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If noise reduction is performed on degraded CW signals, then S/N ratio is improved, but demodulated sound becomes degraded and unnatural
Solution Approach 1:
The patent segments the signal processing into distinct stages: first performing product detection to obtain demodulated sound, then separately performing noise reduction only on the carrier wave component. This segmentation allows noise reduction to be applied selectively to the carrier without degrading the demodulated sound quality, resolving the contradiction between improving S/N ratio and maintaining natural sound quality.
Solution Approach 2:
The patent introduces an intermediary approach by using the demodulated sound signal itself as a reference to identify and preserve the carrier wave components during noise reduction. The carrier wave is extracted as an intermediary element that can be processed independently for noise reduction while maintaining the integrity of the final demodulated output.
2Ease of operation
If automatic tuning is performed without considering S/N degradation, then tuning operation is simplified, but tuning accuracy is lowered when S/N is degraded
Solution Approach 1:
The patent implements feedback by continuously monitoring the S/N ratio of the received CW signal and adjusting the automatic tuning process accordingly. When S/N degradation is detected, the system modifies its tuning behavior to compensate for the degraded conditions, thereby maintaining tuning accuracy while preserving the simplicity of automatic operation.
Solution Approach 2:
The patent applies dynamics by making the automatic tuning process adaptive to changing signal conditions. The tuning parameters and processing methods are dynamically adjusted based on the detected S/N ratio, allowing the system to maintain high accuracy in good conditions while remaining simple and robust in degraded conditions.
3Device complexity
If frequency bandwidth of demodulated signal is not limited, then signal processing is simplified, but noise and interference increase
Solution Approach 1:
The patent applies local quality by implementing frequency band filtering specifically for the carrier wave component rather than applying it to the entire demodulated signal. This localized filtering approach reduces noise and interference in the carrier processing while maintaining the simplicity of the overall signal processing and preserving the quality of the demodulated sound.
Data Source
AI summary
A wireless communication device includes a demodulation unit which demodulates a predetermined reception frequency, an S/N improvement processing unit which performs an S/N improvement process on a demodulated signal output from the demodulation unit, a first filter which performs an adaptive operation with respect to a frequency having a largest amplitude in a signal output from the S/N improvement processing unit, and outputs a filter coefficient updated by the adaptive operation, a controller which calculates the frequency of the largest amplitude defined by the filter coefficient output from the first filter, and controls the demodulation unit to update the reception frequency so as to reduce a difference between the frequency having the largest amplitude and a predetermined frequency, and a second filter which limits a range of a frequency bandwidth of the demodulated signal based on the frequency having the largest amplitude.