Communication Bus Start-Signal Timing for EMI Noise Reduction
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Solution Overview
Problem
High-intensity electromagnetic disturbance noise generated by communication buses in vehicles interferes with signal transmission, leading to improper reading of signals.
Innovation Solution
A communication device and system that control the transmission interval of start signals by adjusting the voltage of the communication bus, using methods like PLCA and CSMA/CD to prevent collision and synchronize data transmission, thereby reducing disturbance noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If data transmission is performed by adjusting voltage of the communication bus frequently, then data transmission speed is improved, but electromagnetic disturbance noise intensity increases
Solution Approach 1:
The patent implements periodic action by introducing a beacon signal transmission mechanism where the transmission interval is adjusted based on the number of active communication devices. The beacon signal is transmitted at regular intervals to synchronize data transmission timing, and the interval is extended when fewer devices are active, thereby reducing electromagnetic disturbance noise while maintaining efficient data transmission.
2Reliability
If the transmission interval of start signals is reduced, then data transmission synchronization is improved, but disturbance noise intensity increases
Solution Approach 1:
The patent applies dynamics by making the beacon signal transmission interval variable rather than fixed. The processing unit dynamically adjusts the interval based on the number of communication devices currently transmitting data. When fewer devices are active, the interval is extended to reduce noise; when more devices are active, the interval is shortened to maintain synchronization, thus balancing reliability and noise reduction.
3Productivity
If multiple communication devices transmit data simultaneously, then communication efficiency is improved, but signal disturbance noise increases
Solution Approach 1:
The patent implements preliminary action by having the master device transmit a beacon signal before actual data transmission begins. This beacon signal预先 announces the upcoming data transmission phase and allows slave devices to prepare accordingly. The beacon signal transmission interval is adjusted based on the number of devices, ensuring that all devices are synchronized before data transmission starts, thereby enabling efficient simultaneous transmission without excessive noise.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents the generation of high-intensity disturbance noise, ensuring reliable signal transmission and synchronization among multiple communication devices connected to a bus.
Implementation Method 1
When the voltage of the communication bus changes, the current value of the current flowing through the communication bus changes, and electromagnetic waves are generated from the communication bus
Data Source
AI summary
A communication device includes: a data transmission unit that is connected to a communication bus to which a plurality of communication equipments are connected and transmits data; and a processing unit that performs processing. The order in which the plurality of pieces of communication equipment and the data transmission unit transmit data through the communication bus is determined in advance. A start signal indicating the start of data transmission is repeatedly transmitted through the communication bus. The data transmission unit transmits data according to the order when the start signal is transmitted. The processing unit changes the transmission interval of the start signal.