Wired Communications Device Bit Scrambling for Common Mode Signal Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wired communications networks, an outgoing frame preamble with a repeating bit sequence can cause an undesired common mode signal due to unscrambled signals, leading to interference issues when transmitted over differential signals.
Innovation Solution
The method involves performing bit mapping and scrambling operations on the input bit stream to generate a mapped and scrambled bit stream, which includes a frame boundary bit sequence and a random data sequence as a preamble, reducing the need for a predefined repeating bit sequence and thereby minimizing common mode signals at the receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a repeating bit sequence is used in the frame preamble for clock synchronization, then receiver clock synchronization is achieved, but an undesired common mode signal is generated due to finite mode conversion value
Solution Approach 1:
The patent applies preliminary action by performing bit scrambling on the data portion of the frame before transmission, while deliberately leaving the preamble unscrambled. This preliminary processing ensures that the repeating bit sequence in the preamble remains intact for clock synchronization, while the scrambled data portion prevents common mode signal generation. The scrambling is performed in advance of transmission, resolving the contradiction between synchronization requirements and electromagnetic interference reduction.
2Object-generated harmful factors
If bit scrambling is applied to the frame preamble, then common mode signals are reduced, but clock synchronization capability is degraded
Solution Approach 1:
The patent applies local quality by differentiating the processing applied to different portions of the transmitted frame. The preamble portion is left unscrambled with a repeating bit sequence to maintain clock synchronization capability, while the data portion is scrambled to reduce common mode signals. This localized differentiation of signal processing quality resolves the contradiction by optimizing each portion for its specific function.
3Ease of operation
If a predefined repeating bit sequence is used in the preamble, then transmission simplicity is maintained, but power spectral density management is compromised
Solution Approach 1:
The patent applies preliminary action by performing bit scrambling on the data portion of the frame before transmission, while deliberately leaving the preamble unscrambled. This preliminary processing ensures that the repeating bit sequence in the preamble remains intact for clock synchronization, while the scrambled data portion prevents common mode signal generation. The scrambling is performed in advance of transmission, resolving the contradiction between synchronization requirements and electromagnetic interference reduction.
Data Source
AI summary
Embodiments of a method and a device are disclosed. In an embodiment, a method for operating a wired communications device involves performing a bit mapping operation on an input bit stream to generate a mapped bit stream, performing a bit scrambling operation in response to the mapped bit stream to generate a scrambled bit stream, generating an encoded bit stream in response to the scrambled bit stream, and transmitting the encoded bit stream using the wired communications device.