Line system for reducing interference to front VGA cable

Abstract

The invention discloses a line system for reducing the interference to a front VGA cable, which relates to an electromagnetic compatibility technology. The line system includes a motherboard arranged inside a case, a front small board at the front panel of the case, and a display outside the case. An integrated circuit IC and a VGA connector are arranged on the motherboard. A filter line is arranged on the front small board. The connector is connected to the filter line through an internal cable. The filter line is connected to the display through an external cable. The VGA signal on the motherboard goes out of the integrated circuit IC and arrives at the VGA connector, arrives at the filter line on the front small board through the internal cable, passes through the filter file, and arrives at the display through the external cable. The risk of over-radiation of an external VGA cable due to interference is reduced greatly, and the risk that external interference enters the motherboard from the external VGA cable and affects normal work of the motherboard is reduced. The quality of VGA signal transmission is improved, and the stability of normal work of the motherboard is maintained.

Description

technical field [0001] The invention relates to electromagnetic compatibility technology, in particular to a line system for reducing the interference of a front VGA cable. Background technique [0002] Electromagnetic Interference (EMI for short) refers to the interference phenomenon caused by the interaction between electromagnetic waves and electronic components, including conduction interference and radiation interference. Conducted interference is the coupling of a signal on one electrical network to another electrical network through a conductive medium. Radiation interference is the interference source coupling its signal to another electrical network through space. In high-speed PCB and system design, high-frequency signal lines, pins of integrated circuits, and various connectors may have radiation interference with antenna characteristics, emit electromagnetic waves and affect the normal operation of other systems or other subsystems in the system. [0003] Elect...

AI Technical Summary

Problems solved by technology

[0005] In the existing transmission lines of VGA signals, the protection signals of the VGA lines are all placed on the motherboard side. After the VGA signal is filtered, it is easy to crosstalk into the interference signal during the process of entering the connector; It is also easy to crosstalk into interference signals during transmission

In addition, the interference signal flows into the external cable through the front small board, and is received by the antenna of the radiation test site, causing the radiation interference test to fail

Moreover, in the radiation anti-jamming project, the interference signal from the crosstalk on the external cable is "inverted" into the main board, which may easily cause abnormal performance of the main board

[0006] At present, the shell of the front small board of the chassis is usually made of plastic material. Although some interiors are sprayed with conductive paint, compared with metal materials, the conductivity of the front small board shell is very weak.

In this way, even if the VGA line is effectively filtered, there is no place to release the interference filtered to the ground plane of the front small board

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