Low-Pass Filter Segmentation for xDSL Upstream Interference
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Solution Overview
Problem
Existing xDSL technologies face interference issues from upstream signal transmission to downstream frequency bands due to device discreteness and cable impedance changes, which affect the suppression effect of hybrid circuits, leading to poor interference reduction.
Innovation Solution
Incorporating low-pass filters (LPFs) in the analog front end (AFE) and line driver (LD) modules of the sending apparatus, with adjustable filtering frequencies to filter out signals greater than the set frequency, thereby reducing interference from upstream signals to downstream frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the suppression ratio of the H circuit is increased to reduce upstream signal interference, then interference suppression is improved, but device discreteness and cable impedance changes greatly affect the suppression effect, leading to poor actual performance
Solution Approach 1:
The patent divides the interference suppression function into multiple independent low-pass filters placed at different locations (DFE output, AFE output, and hybrid circuit output). Each filter handles a specific stage of signal processing, making the overall suppression system more robust against device discreteness and impedance variations by distributing the suppression function across multiple segments rather than relying on a single H circuit.
Solution Approach 2:
The patent introduces low-pass filters as intermediary components between different signal processing stages. These filters act as mediators that selectively pass desired frequency components while blocking interfering upstream signals, providing stable suppression performance that is not affected by downstream impedance changes or device variations.
2Object-affected harmful factors
If low-pass filters are added to filter out high frequency signals, then interference from upstream signals is reduced, but device complexity increases
Solution Approach 1:
The patent segments the low-pass filtering function into multiple simple stages rather than using one complex filter. By placing simpler low-pass filters at different locations (DFE output, AFE output, hybrid circuit output), the system achieves better interference suppression with less complex individual filter designs, reducing overall device complexity while maintaining effectiveness.
Solution Approach 2:
The patent uses multiple copies of simple low-pass filter circuits at different stages rather than one complex filter design. This copying approach allows each filter to be a standardized, simple component that can be easily implemented and maintained, reducing device complexity while providing cumulative interference suppression benefits.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The implementation effectively reduces interference from upstream signal transmission to downstream frequency bands by filtering out unwanted frequencies, enhancing the suppression effect and improving signal quality.
Implementation Method 1
The AFE includes at least one low-pass filter LPF, and a filtering frequency is set for each LPF. The AFE is configured to obtain a first signal, and filter out, by using the LPF, a signal with a frequency greater than the filtering frequency from the first signal
Data Source
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AI summary
Embodiments of this application disclose a sending apparatus and a signal transmission method, to reduce interference from upstream signal transmission to a downstream frequency band. The sending apparatus in the embodiments of this application includes: an analog front end AFE and a line driver LD module. An output terminal of the AFE is connected to an input terminal of the LD module. The AFE includes at least one low-pass filter LPF, and a filtering frequency is set for each LPF. The AFE is configured to obtain a first signal, and filter out, by using the LPF, a signal with a frequency greater than the filtering frequency from the first signal, to obtain a second signal. The LD module is configured to receive the second signal. In addition, the signal transmission method is further provided, to reduce interference from upstream signal transmission to a downstream frequency band.