Asynchronous CXPI Transceiver for Interference-Resistant Vehicle Data
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Solution Overview
Problem
In vehicle electronic systems, data transmission issues arise due to interference between on-vehicle Local Area Network (LAN) communication and other radio frequency systems, such as the smart key system, leading to inaccuracies in controlling electronic devices like engines and air conditioners, and existing solutions struggle to precisely control the duty width of reference clocks used in CXPI communication.
Innovation Solution
The implementation of an on-vehicle electronic device with a clock adjustment unit that generates and adjusts the duty width of reference clocks for CXPI communication, using methods like spread spectrum and precise clock generation to minimize interference, and includes transceivers that synchronize data signals with reference clocks to ensure accurate data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If spread spectrum method is applied to the reference clock, then radio wave interference is reduced, but circuit complexity increases
Solution Approach 1:
The patent applies spread spectrum technique by modulating the reference clock frequency to vary over a range of frequencies rather than operating at a single fixed frequency. This frequency modulation spreads the energy spectrum, reducing peak interference levels in the 134 kHz band while maintaining communication functionality. The parameter change approach transforms the clock signal characteristics to mitigate harmful radio wave interference without requiring complete system redesign.
2Measurement precision
If duty width of reference clock is precisely controlled, then communication accuracy is improved, but device complexity increases
Solution Approach 1:
The patent incorporates a feedback mechanism where the duty width of the reference clock is dynamically adjusted based on detection of communication quality metrics. The system monitors communication accuracy and automatically modifies the duty width parameter to optimize performance. This closed-loop control enables precise duty width control without requiring overly complex open-loop control systems, as the feedback provides self-correction capability.
Solution Approach 2:
The patent employs dynamic adjustment of the reference clock duty width rather than fixed static values. The duty width is made variable and adaptable to changing communication conditions, allowing the system to optimize communication accuracy in real-time. This dynamic approach replaces complex static control mechanisms with simpler adaptive control that responds to actual communication needs.
3Productivity
If CXPI communication is used for data transmission, then data transmission capability is improved, but susceptibility to interference from other radio frequency systems increases
Solution Approach 1:
The patent converts the potential harm of radio frequency interference into a benefit by deliberately using spread spectrum modulation on the CXPI reference clock. The interference-prone 134 kHz band is transformed from a harmful frequency into a managed parameter where the spread spectrum technique distributes energy across multiple frequencies, turning what would be concentrated interference into distributed, lower-level background noise that does not degrade communication performance.
Data Source
AI summary
An on-vehicle system comprises a Clock Extension Peripheral Interface (CXPI) bus and a device coupled to the CXPI bus. The device comprises a transceiver configured to: detect a baud rate clock signal and a phase difference between the baud rate clock signal and an input data signal that was generated asynchronously from the baud rate clock signal; obtain a timing from an edge of the baud rate clock signal based the phase difference; capture a value of the input data signal at the timing; and transmit the captured value as an output data signal over the CXPI bus.