Adaptive Tone Prediction Circuit for Real-Time EMI Cancellation
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Solution Overview
Problem
Existing methods for removing electromagnetic interference (EMI) from signals in local area networks are inefficient, often requiring extensive data collection and resulting in link drops due to the time-consuming nature of generating reliable EMI estimates.
Innovation Solution
An adaptive circuit that spectrally enhances the input signal, filters out EMI, and uses tone predictors to generate predicted tone signals, which are then subtracted from the received signal to cancel out the interference, implemented as a feed-forward or feedback noise-predictive narrowband interference canceller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spectral analysis is applied directly to the received signal to remove EMI, then EMI removal capability is improved, but the time required to generate reliable EMI estimates increases causing link drops
Solution Approach 1:
The patent segments the EMI removal process into distinct functional blocks: adaptive spectral enhancement circuit for signal processing, tone detection circuit for interference identification, tone predictor for future EMI estimation, and arithmetic unit for signal reconstruction. This segmentation allows parallel processing and reduces the time required to generate reliable EMI estimates while maintaining effectiveness.
Solution Approach 2:
The tone predictor generates predicted tone signals based on previously detected interference patterns before they fully corrupt the received signal. This preliminary action allows the system to proactively cancel EMI rather than reactively processing it, significantly reducing the time required for EMI removal and preventing link drops.
2Productivity
If adaptive spectral enhancement and tone prediction are implemented, then real-time EMI reduction is achieved, but device complexity increases
Solution Approach 1:
The adaptive spectral enhancement circuit performs multiple functions: it enhances desired signal tones, detects interference patterns, and provides input to the tone predictor. This multi-functionality reduces the need for separate dedicated circuits for each processing stage, thereby reducing overall device complexity while maintaining real-time EMI reduction capability.
Solution Approach 2:
The patent introduces an adaptive spectral enhancement circuit as an intermediary between the received signal and the tone detection circuit. This intermediary pre-processes the signal by enhancing spectral components of interest, making subsequent tone detection and prediction more efficient and accurate, thereby reducing the complexity of downstream circuits.
3Reliability
If feed-forward or feedback noise-predictive cancellation is used, then signal integrity is maintained, but the amount of data collection required increases
Solution Approach 1:
The feedback noise-predictive cancellation path uses the original received signal as feedback input to continuously refine EMI estimates. This feedback mechanism allows the system to maintain signal integrity by continuously adapting to changing interference patterns without requiring extensive additional data collection, as the feedback loop efficiently utilizes already-available signal information.
Solution Approach 2:
The adaptive spectral enhancement circuit dynamically changes spectral parameters (gain, frequency response) based on detected interference characteristics. This parameter adaptation allows the system to maintain signal integrity under varying EMI conditions without requiring large volumes of training data, as the parameters are adjusted in real-time based on current signal conditions.
Data Source
AI summary
An input signal that includes narrowband interference is spectrally enhanced by an adaptive circuit that supplies as output signal(s), portion(s) of NBI at one or more frequencies that change adaptively. The output signal(s) are used in one or more tone predictor(s) to generate, based on prior values of the NBI portion, one or more predicted tone signals that are subtracted from a received signal containing the NBI, and the result is used in the normal manner, e.g. decoded. The adaptive circuit and the one or more tone predictor(s), form a feed-forward NBI predictor wherein the received signal is supplied as the input signal of the adaptive circuit. The result of subtraction may be supplied to a slicer that slices the result, yielding a sliced signal which is subtracted from the received signal to generate a signal can be used as the input signal, to implement a feedback NBI predictor.