Cable Amplifier Downstream Frequency Management

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Solution Overview

Problem

The existing cable system architecture is inadequate to meet the growing demand for narrowcast services due to limitations in the number of narrowcast channels and fiber capacity, leading to costly signal level management and fiber expansion challenges.

Innovation Solution

The proposed solution involves digitizing analog-modulated RF narrowcast signals, re-modulating them as digital QAM signals, and transmitting them over a multi-wavelength optical fiber, allowing for increased bandwidth and channel capacity without requiring extensive fiber upgrades, using digitizers and digital optical transmitters to enhance downstream capacity and support more users with reduced noise and power requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If analog narrowcast signals are transmitted over existing fiber infrastructure, then the system can support narrowcast services, but the number of available narrowcast channels is limited and fiber capacity is insufficient

Engineering Contradiction:

Improvenumber of narrowcast channelsVSAvoidfiber capacity

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent replaces analog signal transmission with digital QAM modulation over optical fiber. By converting narrowcast signals to digital format and using QAM modulation, the system can transmit multiple channels simultaneously over the same fiber infrastructure, dramatically increasing channel capacity without requiring additional fiber deployment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the signal transmission parameters from analog to digital domain, using QAM modulation schemes that allow multiple channels to share the same physical medium. This parameter transformation enables the existing fiber capacity to support many more narrowcast channels than the analog system could provide.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If fiber capacity is expanded to support more narrowcast channels, then channel capacity increases, but the cost and complexity of fiber expansion increases

Engineering Contradiction:

Improvechannel capacityVSAvoidfiber expansion complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes the existing fiber infrastructure multi-functional by enabling it to carry both broadcast and narrowcast services simultaneously using digital QAM modulation. The same fiber that carries traditional broadcast signals can also carry multiple narrowcast channels, eliminating the need for separate fiber infrastructure for narrowcast services.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges broadcast and narrowcast signal transmission into a single digital QAM-modulated optical signal. By combining multiple narrowcast channels with broadcast services over the same fiber infrastructure using digital modulation, the system achieves high channel capacity without requiring separate fiber expansions.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If analog signal levels are managed in the existing system, then signal transmission is maintained, but signal level management becomes costly and complex

Engineering Contradiction:

Improvesignal transmission reliabilityVSAvoidsignal level management complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces analog signal level management with digital signal processing. By converting signals to digital QAM format, the system eliminates the need for complex analog signal level balancing and management, as digital signals are more robust to attenuation and noise, simplifying the overall signal management architecture.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical 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

This approach increases the number of narrowcast channels and bandwidth, improving system performance while reducing costs and complexity by leveraging existing infrastructure, enabling efficient delivery of high-demand narrowcast services without the need for extensive fiber expansions.

Implementation Method 1

One or more optical transmitters convert the RF signals to RF optically modulated signals for transmission to a fiber node

Methodology Applied

Scientific EffectOptical modulation: Phase Modulation

Implementation Method 2

Each of the fiber nodes includes an optical receiver that converts the received optically modulated signals representing broadcast and narrowcast services to electrical RF signals

Methodology Applied

Scientific EffectOptical detection: Photoelectric Effect

Data Source

PatentUS11553244B2Downstream plant capacity

Publication Date: 2023.01.10 ARRIS ENTERPRISES LLC

AI summary

An amplification system for amplifying a service of a cable television network that includes a first amplifier receiving the service and providing a first output signal having a first frequency band with a first maximum downstream frequency to a first customer and a second amplifier. The amplification system includes the second amplifier receiving the first output signal and providing a second output signal having a second frequency band with a second maximum downstream frequency to a second customer, wherein the second maximum downstream frequency is less than the first maximum downstream frequency.