USB Transmission System Using Phantom Circuit Topology
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Solution Overview
Problem
The existing methods for transmitting USB3 signals require laying additional cables, which is labor-intensive and costly, as they need four-wire cables for differential data transmission, whereas conventional USB2 signals can be transmitted with two-wire cables, but upgrading to USB3 necessitates more complex cabling arrangements.
Innovation Solution
The method involves transmitting the third data signal as a common-mode component over one pair of conductors and its reference as a common-mode component over another pair, allowing differential transmission of three signals via only two pairs of conductors, leveraging the principle of phantom circuits to maintain data integrity without additional cabling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If USB3 signals are transmitted using conventional methods with separate four-wire cables for each differential data signal, then data transmission reliability is improved, but installation complexity and cost increase due to requiring three separate cable pairs
Solution Approach 1:
The patent combines three differential data signals into two cable pairs by merging the transmission paths. The first and second differential data signals are transmitted separately over the first and second cable pairs, while the third differential data signal is superimposed on both pairs simultaneously, allowing three signals to share only two physical cable pairs without compromising data integrity
Solution Approach 2:
Each cable pair is designed to serve multiple functions: the first cable pair carries both the first differential data signal and a portion of the third differential data signal, while the second cable pair carries both the second differential data signal and the remaining portion of the third differential data signal. This multi-functionality reduces the total number of cable pairs required
2Ease of manufacture
If USB3 signals are transmitted using existing two-wire cables without additional cabling, then installation effort is reduced, but signal interference and data integrity may deteriorate
Solution Approach 1:
The third differential data signal is segmented into two separate components: a first component is transmitted over the first cable pair combined with the first differential data signal, and a second component is transmitted over the second cable pair combined with the second differential data signal. This segmentation allows the signal to be distributed across existing infrastructure while maintaining signal integrity through differential transmission
Solution Approach 2:
The patent uses differential voltage transmission as an intermediary mechanism to protect against signal interference. By transmitting signals as differential voltages (V+ and V-) where the data is encoded in the voltage difference rather than absolute voltage levels, the system naturally rejects common-mode noise and interference that would affect both lines equally
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 the effort and cost associated with cabling by using existing two-wire cables for USB3 signal transmission, ensuring low interference and compatibility with existing infrastructure, such as in vehicles, while providing a compact and high-crosstalk-attenuation solution.
Implementation Method 1
Data is transmitted symmetrically and bidirectionally via the pair of signal conductors, with the data signal ('signal part') being transmitted through one line of the pair of signal conductors and the inverted data signal ('reference part') being transmitted through the other line. The signal receiver forms the differential voltage of the data signal transmitted differentially
Implementation Method 2
a signal part of the third data signal is transmitted as a common-mode component via the first pair of conductors and a reference part of the third data signal is transmitted as a common-mode component via the second pair of conductors
Data Source
Figure 1
AI summary
The invention relates to a method for transmitting three data signals from a USB signal in which the first data signal is transmitted differentially via a first conductor pair (32) and the second data signal is transmitted differentially via a second conductor pair (34). A signal portion of the third data signal is transmitted as a common mode component via the first conductor pair and a reference portion of the third data signal is transmitted as a common mode component via the second conductor pair. The invention additionally relates to a USB transmission system for carrying out this method and to an adapter for a USB transmission system.