Signal Extender Using Timing Memory Unit for Single CAT-5 Cable Transmission
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Solution Overview
Problem
Conventional signal extender systems for digital multimedia signals require multiple cables and repeaters for long-distance transmission, which is costly and complex, especially for high-bandwidth applications like HDMI, due to limitations in CAT-5 cable capacity and signal compatibility.
Innovation Solution
A signal extender system using a single CAT-5 cable with a timing memory unit to replicate the differential clock signal, allowing for the transmission of multiple differential data signals and bi-directional control signals, thereby simplifying the system and reducing cable requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two CAT-5 cables are used to transmit both differential data signals and control signals, then all signals can be transmitted, but the system complexity and cost increase
Solution Approach 1:
The patent combines the transmission of differential data signals and control signals into a single CAT-5 cable by using time-division multiplexing. The fourth pair of differential transmission lines is shared between data transmission and control signal transmission, eliminating the need for a second dedicated cable for control signals.
Solution Approach 2:
The patent implements periodic switching between data signal transmission and control signal transmission on the fourth cable pair. The system alternates between transmitting differential data signals and transmitting control signals (such as I2C, CEC, HPD) on the same physical medium, allowing single-cable operation for both functions.
2Length of stationary object
If CAT-5 cables are used for long-distance transmission, then transmission distance is extended, but signal reliability deteriorates due to bandwidth limitations
Solution Approach 1:
The patent segments the transmission path by introducing repeater devices at intermediate points along the CAT-5 cable. These repeaters divide the long transmission distance into multiple shorter segments, regenerating and retransmitting the differential data signals to maintain signal integrity over extended distances beyond the normal 120-foot limitation.
3Device complexity
If a single cable is used to share transmission lines for both data and control signals, then system complexity is reduced, but signal transmission reliability may be affected
Solution Approach 1:
The patent uses periodic time-division multiplexing where the fourth cable pair alternates between carrying differential data signals and control signals. This structured periodic switching ensures that each signal type receives dedicated transmission time slots, maintaining signal reliability while achieving single-cable operation.
Solution Approach 2:
The patent maintains continuous signal transmission by ensuring that the sharing of the fourth cable pair between data and control signals occurs without interruption to the overall transmission process. The switching between different signal types is seamless, preserving the continuity of useful action throughout the transmission medium.
Data Source
AI summary
A signal extender system including a first electronic apparatus, a second electronic apparatus, and a signal extender. The signal extender system includes a transmission module, a receiving module, and pairs of differential transmission lines. The receiving module includes a timing memory unit. The transmission module receives a digital image differential signal including differential data signals, a differential timing signal, and a two-way differential signal. A first pair of differential transmission lines, a second pair of differential transmission lines, and a third pair of differential transmission lines of the pairs of differential transmission lines transmit the differential data signals respectively. A fourth pair of differential transmission lines alternately transmits the two-way differential signal and a part of differential timing signal. The timing memory unit memories and continually replicates the part of differential timing signal to recover the differential timing signal and output it to the second electronic apparatus.