SAW Filter Diplexer for LTE Interference Suppression
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Solution Overview
Problem
Existing MATV/SMATV systems face significant interference issues from high-frequency signals like GSM and LTE, which affect television channels, particularly in the UHF band, leading to signal degradation and errors.
Innovation Solution
A device comprising an input diplexer, output diplexer, two frequency converters, and a SAW filter, connected in parallel and series configurations, effectively eliminates interfering high-frequency signals above a predetermined television channel, using automatic gain control and remote-controlled switching to adapt to varying interference levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-frequency signals (GSM, LTE) are allowed to pass through the antenna and amplifier elements, then the signal level is maintained, but interference problems occur in television channels
Solution Approach 1:
The invention extracts and removes high-frequency interfering signals (GSM, LTE) from the combined signal stream using a filter device positioned in the signal path between the amplifier and the distribution network. This extraction allows the desired television signals to pass while eliminating the harmful high-frequency components that cause interference in adjacent channels.
Solution Approach 2:
The filter device acts as an intermediary element in the signal path, mediating between the amplifier output and the distribution network input. It selectively passes desired television frequency ranges while blocking harmful high-frequency signals, thus resolving the conflict between maintaining signal level and preventing interference.
2Object-affected harmful factors
If complex filtering circuits are used to suppress high-frequency interference, then interference is reduced, but device complexity increases
Solution Approach 1:
The filtering function is segmented into a dedicated, standalone filter device that can be independently designed and optimized. This segmentation allows the filter to be positioned at a specific location in the signal path (between amplifier and distribution network), simplifying the overall system architecture compared to integrating complex filtering into the amplifier or receiver circuits.
Solution Approach 2:
The invention employs a relatively simple, cost-effective filter design that can be easily installed and replaced if needed. The filter device uses standard electronic filtering components rather than complex active circuitry, making it a economical solution that can be deployed without significant system redesign or high cost.
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
This solution provides a simpler, less error-prone method to suppress interfering signals, allowing for selective channel elimination and improved signal quality by eliminating LTE interference in the UHF band, thereby enhancing the reliability of television and radio signals in MATV/SMATV systems.
Implementation Method 1
The first frequency converter, the SAW filter and the second frequency converter are connected in series
Implementation Method 2
a first frequency converter, a SAW filter and a second frequency converter, connected in series
Data Source
Figure 1
Figure 2~4
AI summary
The device has an input diplexer, a switch i.e. remote control device, a frequency shift block, two frequency transducers, a surface acoustic wave (SAW) filter and an output diplexer including TV signals with TV channels (21-60) applied at an inlet, and eliminating unwanted high frequency signals (LTE) whose frequency lies above one of the TV channels (60). The two frequency transducers and the filter are connected in parallel to a connecting line between the input diplexer and the output diplexer. The two frequency transducers and the filter are connected in series.