| Electromagnetic compatibility (EMC) is an important criterion to measure the normal function and performance of device. It is an issue that must be considered in automotive electronics design for its important impact on improving the safety and reliability of electronic devices. Solving signal integrity problems in the design phase is the key to control EMC problems. This paper tried to improve a device’s electromagnetic compatibility from the perspective of signal integrity, through signal integrity simulations and analysis of the printed circuit board (PCB) to provide reasonable constraints for the optimal design of a designed combination switch based on controller area network (CAN).This article first overviewed a variety of signal integrity issues of electronic equipment in classification and introduced signal integrity simulation tools, device models and simulation processes used in the hardware design. By researching on the basic theory of the transmission line, using distributed parameter model, the transmission characteristics of the transmission line and their impacts on signal transmission was analyzed.Then, the two main issues of signal integrity about the problems of reflection and crosstalk were analyzed respectively based on the transmission line theory. After studying the formation mechanism of reflection and crosstalk, several factors’influence on reflection and crosstalk was discussed by simulation and comparative analysis, such as the different types of impedance mutations in the signal transmission line, the transmission line delay time and the signal rising time. Based on the results of simulation analysis, some methods in hardware design were presented to reduce reflection and crosstalk.On the basis of these studies, this paper simulated the signal integrity of critical signals on CAN bus network in designed vehicle combination switch to make design optimization. By simulating the reflection of single-ended and differential signals on critical network for communication, the presence of overshoot and jitter of the receiver signals when using different matching methods termination were studied to select the appropriate match programs and matching parameters. Finally the system analyzed the crosstalk between parallel lines in the maximum operating frequency, according to the simulation results to determine the crosstalk saturation line length, the maximum coupling of parallel lines and minimum line length spacing to control the crosstalk noise in the range of10%. According to the simulation results of the analysis, to make appropriate routing constraint rules.Solving signal integrity issues of hardware at the design stage is necessary. It not only help to improve signal transmission quality and reduce the signal radiation intensity, but also can increase the veneer signal noise margin to improve anti-jamming capability of the system, so as to reduce the impact of external electromagnetic interference on device performance. Dealing with electromagnetic compatibility problem in the hardware design phase with high-precision analysis of professional simulation tool is the most effective and the lowest cost approach to make electronic devices to achieve the EMC test standards. |
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