Ground Line Detection in Video Cables via High-Frequency Signal Testing

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Solution Overview

Problem

Mobile devices face challenges in correctly identifying the ground line in video cables, which is crucial for signal transmission, as there is no certainty which of the two possible lines represents the ground, leading to potential failure in video operation.

Innovation Solution

A method and system utilizing a signal generator, preamplifier, and threshold detector, along with a switch matrix, to automatically detect the ground line by transmitting a high frequency signal and measuring outputs, allowing any video cable to be compatible with a mobile device without requiring specific compatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a video cable is connected to a mobile device, then video transmission is enabled, but the ground line may be incorrectly selected resulting in signal transmission failure

Engineering Contradiction:
Improveground line selection accuracyVSAvoidcable detection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary detection of the ground line by transmitting test signals through the cable before actual video transmission begins. The signal generator sends high-frequency signals and the threshold detector预先 determines which line is the ground line, ensuring correct configuration before operational use.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces manual ground line identification with an automated electrical detection system. Instead of relying on physical inspection or user judgment, the system uses signal transmission and threshold detection to automatically identify the ground line, substituting mechanical/manual processes with electrical measurement.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If the device supports multiple cable types, then versatility is improved, but the ability to correctly identify the ground line deteriorates due to varying cable configurations

Engineering Contradiction:
Improvecable type compatibilityVSAvoidground line detection accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The detection system is designed with universal applicability to work with multiple cable types including LEFT/RIGHT/GND/VIDEO and LEFT/RIGHT/VIDEO/GND configurations. The signal generator and threshold detector can adapt to different cable configurations by systematically testing each line to identify the ground line regardless of cable-specific wiring arrangements.

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

Solution Approach 2:

The system handles different cable configurations by changing detection parameters and signal transmission patterns. By adjusting the detection methodology based on the specific cable type detected, the system maintains high accuracy across varying cable configurations while preserving versatility.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If no ground line detection system is used, then device complexity is reduced, but video operation fails due to incorrect ground line selection

Engineering Contradiction:
Improvecable connection simplicityVSAvoidvideo transmission reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs self-configuration by automatically detecting and identifying the ground line without requiring user intervention. The signal generator and threshold detector work autonomously to determine the correct ground line, allowing the device to self-adapt to different cable configurations and ensuring reliable video transmission.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2492699B1Automatic detection of ground line in a video cable
Publication Date: 2013.07.31 BLACKBERRY LTD
  • EP2492699B1 patent drawingFigure 1
  • EP2492699B1 patent drawingFigure 2
  • EP2492699B1 patent drawingFigure 3

AI summary

The present disclosure provides a method of determining a ground line within a video cable, the video cable including a left audio line, a right audio line, a third line and a fourth line, the method comprising connecting one of the third or fourth line to ground; transmitting a high frequency signal over the other of third and fourth line; measuring outputs of the left audio line or the right audio line; and determining the ground line based on the measured outputs.