Intermodulation Interference Attenuation via Signal Copying
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Solution Overview
Problem
Existing methods for reducing intermodulation interference in cable television distribution networks are limited as they require knowledge of the non-linearity and access to the original undistorted signal, which are often not readily available.
Innovation Solution
The proposed solution involves using modern analog-to-digital technology to model and approximate the channel effects in the cable network, allowing for the attenuation of intermodulation interference through inverse methods and subtractive techniques, specifically targeting narrow bands of interest within the aggregate signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional methods are used to remove intermodulation interference, then interference attenuation is achieved, but the system requires knowledge of non-linearity and access to original undistorted signal which are not readily available
Solution Approach 1:
The patent creates a copy of the transmitted signal and processes it through a modeled version of the channel non-linearity to generate an estimate of the intermodulation interference. This copied and processed signal is then subtracted from the received signal to remove the interference, eliminating the need for direct access to the original undistorted signal or knowledge of the actual non-linearity characteristics.
Solution Approach 2:
The patent introduces an intermediary model of the channel non-linearity that mediates between the received signal and the interference removal process. This model acts as a surrogate that generates interference estimates without requiring direct measurement or knowledge of the actual channel non-linearity, simplifying the system requirements.
2Measurement precision
If methods requiring original undistorted signal are used, then interference removal accuracy is improved, but accessibility and ease of operation deteriorate
Solution Approach 1:
The system performs self-service by using the received signal itself and a modeled version of the channel characteristics to generate the interference estimate. The received signal is copied, processed through the model, and the resulting interference estimate is subtracted from the original received signal, making the system self-sufficient without external access to undistorted signals.
Solution Approach 2:
By creating and processing a copy of the received signal through the channel model, the system achieves accurate interference estimation without needing to access the original undistorted signal. The copy is sufficient for generating the interference estimate that will be subtracted from the received signal.
3Object-affected harmful factors
If channel effects are precisely modeled, then interference attenuation performance is improved, but computational complexity increases
Solution Approach 1:
The patent models the channel non-linearity using parameterized functions that can be adjusted to match the actual channel characteristics. By changing the parameters of the model to fit the channel, the system achieves accurate interference attenuation without requiring complex computational models, balancing performance and computational complexity.
Data Source
AI summary
The present invention is directed to systems and method for attenuating intermodulation interference. In particular, methods and systems to attenuate intermodulation interference contained within an aggregate signal having a transmitted signal that was transmitted over a communications channel having channel effects that produce the intermodulation interference are provided. The communications channel may be a cable television distribution network and the signal may be a cable television signal. A method is provided to predict when intermodulation interference will be large, so that actions within a receiver can be taken to reduce the impact of the interference and improve overall receiver performance.