Controlled Isolation Splitter for Low-Loss RF Port Communication
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Solution Overview
Problem
Existing coaxial cable network splitter devices cause high isolation loss, preventing communication between terminal devices and restricting the use of available bandwidth for revenue-producing programming by blocking forward-bound video signals.
Innovation Solution
A controlled isolation splitter apparatus and method that reduces isolation loss in specific frequency bands, allowing communication between terminal devices while maintaining impedance matching to prevent signal reflections, and using a band-pass filter to enable unattenuated signal propagation within specified frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional splitter device is used to divide signal paths in a coaxial cable network, then the output ports are isolated from each other to prevent signal interference, but this isolation causes high isolation loss that prevents communication between terminal devices connected to different output ports
Solution Approach 1:
A bypass circuit is introduced as an intermediary path between output ports. This bypass circuit includes a band-pass filter that allows signals within specific frequency bands to pass through with low attenuation, enabling communication between terminal devices while maintaining isolation for other frequencies. The bypass circuit acts as a mediator that selectively connects output ports only when needed for specific frequency bands.
Solution Approach 2:
The isolation characteristic is made frequency-dependent rather than uniform across all frequencies. The bypass circuit is designed to provide low isolation loss only within specific frequency bands where communication is desired, while maintaining high isolation for other frequencies. This local quality approach allows the splitter to simultaneously provide both isolation and communication paths depending on the frequency of the signal.
2Reliability
If high isolation is maintained between output ports to prevent signal reflections and interference, then signal quality is improved, but forward-bound video signals are blocked and bandwidth utilization is reduced
Solution Approach 1:
The splitter provides different isolation characteristics for different frequency bands. Within specific frequency bands where communication is desired, the isolation is reduced to allow signal passage. For other frequencies, high isolation is maintained to prevent interference and reflections. This frequency-selective approach optimizes both signal quality and bandwidth utilization simultaneously.
Solution Approach 2:
The band-pass filter in the bypass circuit acts as a frequency-selective intermediary that allows desired video signals to pass through while blocking unwanted signals. This intermediary component enables the system to achieve both high signal quality for authorized frequencies and high bandwidth utilization by allowing multiple frequency bands to be used effectively.
3Loss of energy
If a bypass circuit with band-pass filter is added to reduce isolation loss, then communication between terminal devices is enabled, but device complexity increases
Solution Approach 1:
The bypass circuit is designed as a modular addition to the conventional splitter. The band-pass filter and associated components are segmented as a separate functional unit that can be integrated into the existing splitter structure. This segmentation allows the complexity to be managed as a distinct module rather than requiring complete redesign of the entire splitter system.
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
Enables low-isolation communication between terminal devices, allowing desired forward-bound video signals to reach subscriber sites while blocking unwanted signals, thus optimizing bandwidth usage and reducing installation costs.
Implementation Method 1
using a band-pass filter to enable unattenuated signal propagation within specified frequency bands
Implementation Method 2
maintaining impedance matching to prevent signal reflections
Data Source
AI summary
Apparatus and methods for controlled splitting and isolation of signals in a radio frequency network. In one embodiment, the network comprises a cable television network, and the apparatus comprises a signal splitter having controlled isolation loss at its output ports in at least one frequency band, thereby enabling communications between terminal devices at the subscriber premises that would otherwise be isolated by high losses typical of prior art splitters. The splitter apparatus can also be utilized with a filter/reflector circuit that advantageously provides maximal downstream frequency spectrum bandwidth while suitably reflecting the aforementioned communications to maintain them within the subscriber-side network without interference.