Pseudo Random Signal Mixing for EMC Improvement
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Solution Overview
Problem
Existing digital data transmission systems between movable units face challenges in electromagnetic compatibility (EMC) due to electromagnetic emissions, particularly in cable-bound and glass-fiber based systems, where standard encoding methods are costly or ineffective, and transmitters/receivers often lack encoding capabilities, leading to poor EMC properties.
Innovation Solution
A device and method that incorporates a pseudo random generator to combine digital signals with pseudo random values, reducing spectral line gaps and amplitudes without increasing bandwidth, using a combining unit and control unit to insert random data between information data intervals, and employing pseudo random generators in both transmitter and receiver units for synchronization and signal reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If standard encoding methods (4B/5B, 8B/10B) are used, then EMC properties are improved, but device complexity and manufacturing costs increase
Solution Approach 1:
The patent applies parameter changes by transitioning from deterministic encoding schemes (4B/5B, 8B/10B) to pseudo-random encoding. This changes the fundamental parameter of the encoding method from structured bit manipulation to statistical randomization, achieving superior EMC properties (up to 18 dB improvement) while maintaining implementation simplicity through linear feedback shift registers
Solution Approach 2:
The patent uses copying by implementing identical pseudo-random number generators at both transmitter and receiver ends. The receiver generates an exact copy of the transmitter's pseudo-random sequence, allowing simple XOR-based decoding without complex synchronization circuits, thus reducing device complexity while maintaining EMC benefits
2Object-affected harmful factors
If continuous scrambling is applied, then EMC properties are improved, but device complexity and synchronization requirements increase
Solution Approach 1:
The patent applies periodic action by using discrete pseudo-random sequences inserted at regular intervals (e.g., every 256 or 1024 data bits) rather than continuous scrambling. This periodic insertion reduces computational overhead and eliminates the need for complex continuous synchronization circuits, while still achieving effective spectral spreading and EMC improvement
Solution Approach 2:
The patent implements self-service by designing the pseudo-random sequence generator to be self-synchronizing. The sequence automatically regenerates at the receiver without requiring external synchronization signals or complex control circuits, eliminating the synchronization complexity associated with continuous scrambling methods
3Device complexity
If data are transmitted without encoding, then device complexity is reduced, but electromagnetic emissions and interference increase
Solution Approach 1:
The patent applies parameter changes by modifying the statistical properties of the transmitted signal through pseudo-random encoding. This changes the signal spectrum from concentrated discrete lines to a spread spectrum with uniform power distribution, dramatically reducing electromagnetic emissions and interference while keeping the encoding implementation simple
Data Source
AI summary
The invention relates to a device and a method for transmitting digital signals between at least two units disposed to move relative to each other. By combining information signals with random signals, the spectral power density of a signal is reduced for the same transmission power. The device can include a data transmitter, pseudo random generator or random generator, and a combining unit for combining the output from the transmitter with the output from the generator. The combined result is sent across a transmission path where it is received by a data receiver. The receiver has a combining unit for receiving the combined result compared to a second pseudo random or random generator output for recreating the original transmitter output.