USB Retimer Logic Circuit for Signal Regeneration
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Solution Overview
Problem
USB communication can be affected by signal deterioration due to noise and interference, and long USB cable lengths can exceed the latency threshold defined in the USB specification, leading to communication failures.
Innovation Solution
A USB retimer logic circuit that processes received data by searching for a predefined symbol, switching from outputting predefined data to recovered data when the symbol is found, and using a data processor to decode and encode USB data, thereby mitigating signal deterioration and reducing communication path latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If USB cable length is increased to extend communication distance, then coverage area is improved, but communication path latency exceeds the threshold defined in USB specification
Solution Approach 1:
A retimer device is introduced as an intermediary component in the USB communication path. The retimer receives deteriorated signals from the transmitter, regenerates them, and forwards them to the receiver. This mediator effectively resets the communication timing, allowing longer cable lengths without exceeding latency thresholds, as the retimer compensates for the time delay introduced by extended cable length.
Solution Approach 2:
The retimer performs preliminary signal regeneration and retiming actions before the signal reaches the receiver. By proactively restoring the signal integrity and timing characteristics in advance, the system prevents latency accumulation and signal deterioration that would otherwise occur over long transmission distances, ensuring the signal meets USB specification requirements before delivery.
2Length of stationary object
If USB cable length is increased, then communication distance is extended, but signal deterioration due to noise and interference increases
Solution Approach 1:
The retimer acts as a signal regeneration intermediary that receives deteriorated signals from the transmitter, cleans them from noise and interference, and forwards regenerated signals to the receiver. This mediator effectively removes the accumulation of harmful factors that occur over long transmission distances, maintaining signal quality despite extended cable length.
Solution Approach 2:
The retimer extracts and removes the deteriorated portions of the signal contaminated by noise and interference. By separating the useful signal components from the harmful distortions accumulated during long-distance transmission, the retimer restores signal integrity and allows extended USB cable lengths without compromising communication quality.
3Adaptability or versatility
If USB communication path latency exceeds the threshold, then communication reliability decreases, but extending cable length to improve coverage causes latency to exceed the threshold
Solution Approach 1:
The retimer serves as a timing reset intermediary that breaks the direct correlation between cable length and latency. By regenerating signals and resetting timing references at the retimer location, the system achieves extended coverage area without proportionally increasing end-to-end latency, thereby maintaining communication reliability even with longer cable lengths.
Data Source
AI summary
Embodiments of methods and devices for Universal Serial Bus (USB) communication are described. In an embodiment, a method for USB communication involves processing received USB data, including searching for a predefined symbol in a version of the received USB data, outputting predefined USB data during the processing of the received USB data and switching from outputting the predefined USB data to outputting recovered USB data in response to a finding of the predefined symbol in the version of the received USB data. The recovered USB data is derived from the received USB data. Other embodiments are also described.