Variable Clock Serial Transmission for Lower EMI Radiation
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Solution Overview
Problem
Conventional digital data transmission methods face challenges with increasing electromagnetic interference as data transmission rates rise, particularly in environments with complex line networks like motor vehicles, due to higher frequency radiation which requires more extensive suppression measures.
Innovation Solution
A method and system that transmit digital data using a variable clock signal, broadening the frequency band and reducing interference energy per frequency, allowing for simpler and cost-effective interference management, especially suitable for serial data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the data transmission rate is increased, then the productivity is improved, but the electromagnetic interference radiation increases
Solution Approach 1:
The patent applies parameter changes by varying the clock signal frequency over time instead of using a fixed frequency. The frequency is modulated according to a predetermined pattern, which changes the spectral distribution of the transmitted signal. This spreads the energy across a broader frequency range, reducing the peak interference at any single frequency while maintaining the same data transmission rate.
2Device complexity
If conventional fixed frequency transmission is used, then the device complexity is reduced, but the electromagnetic interference radiation increases
Solution Approach 1:
The patent implements dynamics by making the clock signal frequency variable over time rather than fixed. The frequency modulation follows a predetermined pattern that can be implemented through relatively simple circuitry. This dynamic frequency variation effectively reduces electromagnetic interference radiation while adding minimal complexity to the transmission system.
3Reliability
If differential transmission is used, then the interference immunity is improved, but the line requirement doubles
Solution Approach 1:
The patent applies parameter changes by modulating the frequency of the clock signal used for serial data transmission. This frequency variation spreads the spectral energy, reducing peak interference levels. The method achieves improved interference characteristics while maintaining single-ended transmission, thus avoiding the need for doubled line requirements associated with differential transmission.
Data Source
AI summary
A method for transmitting digital data via a line includes the steps of providing a clock signal and of transmitting the digital data in synchrony with the clock signal, the clock signal having a frequency that is variable over time.