RF Signal Processing via Single Cable Circulators
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Solution Overview
Problem
RF transmission systems face challenges with costly and unreliable high-power RF circuitry elements at antenna mastheads, leading to system downtime and increased cabling that can result in catastrophic failures due to environmental factors and logistical concerns.
Innovation Solution
A method and apparatus that process multiple signals at a common frequency through a single RF cable, using high power amplifiers at the base for forward link transmissions and low power preamplifiers at the masthead for reverse link transmissions, reducing the need for multiple RF cabling and high power RF circuitry elements by combining and de-combining signals using Walsh code and Serrodyne modulation/demodulation schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high power amplifiers are placed at the antenna masthead, then signal transmission quality is improved, but system reliability deteriorates due to environmental exposure and logistical access difficulties
Solution Approach 1:
The system divides the signal processing function into two segments: high power amplification at the base station and low power signal combination at the masthead. This segmentation allows the unreliable high power amplifier to be located in a protected environment while still achieving the desired signal transmission quality through the use of a single high power amplifier serving multiple sectors.
Solution Approach 2:
A signal combiner device is introduced as an intermediary component at the masthead. This intermediary combines multiple sector signals and transmits them through a single cable to the base station, eliminating the need for high power amplifiers at the masthead while maintaining signal transmission quality.
2Adaptability or versatility
If multiple high power amplifiers are used for multi-sectored systems, then signal coverage is improved, but device complexity and cabling requirements increase
Solution Approach 1:
The system merges multiple sector signals into a single combined signal stream using a signal combiner at the masthead. This combining approach maintains comprehensive signal coverage for all sectors while reducing the number of amplifiers needed at the base station to just one high power amplifier, thereby reducing device complexity.
Solution Approach 2:
The single high power amplifier at the base station serves multiple sectors simultaneously through the signal combination approach. This universal amplifier handles signals from all sectors, eliminating the need for separate dedicated amplifiers for each sector and reducing overall system complexity.
3Productivity
If multiple RF cables are run to antenna ports, then signal transmission capability is improved, but wind load and structural stability worsen
Solution Approach 1:
Multiple sector signals are merged into a single combined signal stream that travels through one RF cable from the masthead to the base station. This combining approach maintains full signal transmission capability for all sectors while reducing the cable infrastructure from multiple cables to a single cable, thereby significantly reducing wind load and improving structural stability.
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 approach reduces system losses, minimizes costly high power RF circuitry, and enhances reliability by eliminating the need for multiple RF cables and high power amplifiers at the masthead, while maintaining efficient signal propagation and reducing wind load on antenna structures.
Implementation Method 1
a first circulator having a first input, a first output, and a first isolated port; a second circulator having a second input, a second output, and a second isolated port
Data Source
AI summary
A method and apparatus for processing multiple signals at a common frequency combined into a single radio frequency cable and subsequently recovering the signals without significant losses, distortion, or cross-talk. The method and apparatus includes processing multiple signals at a common frequency fed through a single radio frequency (RF) cable with or without one or more amplifiers and utilized for either forward or reverse link transmissions. The invention enables a single power amplifier to amplify multiple RF signals that occupy a common frequency channel and after amplification splitting these signals into amplified copies of the originals. The amplified signals may be sent to different antenna ports to illuminate different base station sectors if required. The signal splitting function is performed at the antenna masthead such that this method reduces the number of feeder cables running up the antenna tower by a factor of N, where N is the number of common frequency signals (e.g., the number of sectors) amplified by the single power amplifier. This invention enables a single power amplifier to simultaneously provide all the radio frequency signals necessary to feed a general N input phased array antenna system and form multiple antenna beams uniquely for several individual users simultaneously.