Phase Multiplexed Optical Sensor Signals on Single Carrier

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Solution Overview

Problem

Existing fiber optic sensor systems require a unique carrier for each sensor, leading to increased computing resources and complexity as the number of sensors increases, making it inefficient to handle multiple sensor data on a single carrier.

Innovation Solution

The system employs pseudo quadrature modulation of carriers, allowing multiple sensors to share a single carrier frequency with phase offsets, enabling the demodulation of sensor data from multiple sensors using a single carrier without a significant increase in processing throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a unique carrier is assigned to each sensor, then each sensor can be independently demodulated, but the computing resources and system complexity increase dramatically as the number of sensors increases

Engineering Contradiction:
Improvesensor data accuracyVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple sensors share a single carrier frequency by modulating their signals with different phase offsets. The sensor signals are combined into a single composite signal that is transmitted and demodulated using one carrier, eliminating the need for separate carriers for each sensor while maintaining signal integrity through phase diversity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

A single carrier frequency performs the function of multiple carriers by accommodating multiple sensor signals simultaneously through phase modulation. The carrier serves as a universal transport medium for all sensors in the array, reducing the number of carriers from N (one per sensor) to 1 (shared by all sensors).

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If multiple sensors share a single carrier, then the number of carriers is reduced, but the demodulation process becomes more complex due to signal interference

Engineering Contradiction:
Improvenumber of carriersVSAvoidsignal separation
Core Design Contradiction:
Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

Each sensor signal is assigned a unique phase offset relative to the common carrier frequency. This asymmetric phase assignment creates distinguishable signal components that can be separated during demodulation. The phase offsets break the symmetry of the combined signal, enabling individual sensor recovery through phase-sensitive detection.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The system transitions from frequency-domain separation (multiple carriers at different frequencies) to phase-domain separation (single carrier with multiple phase offsets). By exploiting the phase dimension rather than the frequency dimension, the system accommodates multiple sensors on a single carrier while maintaining signal distinguishability through phase differences.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 doubles the number of sensors per carrier that can be processed without increasing processing requirements, reducing the need for additional carriers and simplifying the demodulation process, thereby improving efficiency and reducing hardware demands.

Implementation Method 1

The system employs pseudo quadrature modulation of carriers, allowing multiple sensors to share a single carrier frequency with phase offsets

Methodology Applied
Scientific EffectPhase modulation: Phase Modulation

Implementation Method 2

Demodulation involves first converting the amplitude of the analog optical signal to an electrical signal

Methodology Applied
Scientific EffectPhotodetection: Photoelectric Effect

Data Source

PatentEP2759109B1Phase multiplexed optical sensor signals on a single carrier frequency
Publication Date: 2017.04.26 NORTHROP GRUMMAN GUIDANCE AND ELECTRONICS CO INC
  • EP2759109B1 patent drawingFigure 1
  • EP2759109B1 patent drawingFigure 2
  • EP2759109B1 patent drawingFigure 3

AI summary

An apparatus in one example configured to receive and demodulate a homodyne carrier signal, where the homodyne carrier signal comprises sensor data for at least two sensors.