Feature: Interface design
Figure 1: The use of differential signal interfaces across a wide range of smartphones, personal computers and TV/monitors
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Investigating and reducing noise from high-speed digital interfaces By Shingo Uda, Manager in
Field Application Engineering, EMI Suppression Filters and Inductors, Murata
24 July/August 2025
www.electronicsworld.co.uk
ur need for ever faster data transfer rates continues unabated. At the leading edge of this demand, the electronics industry continues to advance the limits of data communication of wired and wireless communication. Most wired communication
interfaces have adopted a differential signalling approach, from Ethernet to HDMI, a widely used method. USB also employs differential signalling, and this popular communication interface shows no signs of reaching its limit. The latest version of the USB standard is USB 4, which has a maximum transfer rate of 40Gbps and incorporates the Thunderbolt protocol. Other differential interfaces include PCI Express and the high-speed digital video protocols DisplayPort and HDMI. Figure 1 highlights the extent to which smartphones, laptops and computer monitors use all these wired differential interfaces. 2.4GHz-based wireless interfaces such as Wi-Fi and
Bluetooth are also prevalent, with most consumer devices featuring both methods. Wi-Fi standards have advanced significantly over the last decade, with Wi-Fi 6-based devices starting to appear on the market and using the 5GHz frequency spectrum. Wi-Fi 6 has a maximum transfer rate of 9.6Gbps, but development and testing work is already progressing for Wi-Fi 7, raising the theoretical maximum transfer rate to 40Gbps.
Noise affecting performance However, as wired interface transfer rates climb ever higher, electromagnetic interference (EMI) from differential signalling is becoming an increasingly significant challenge. Not only has such interference have the potential to cause intra-system electromagnetic compatibility issues, but it also can de-sensitise the wireless receiver’s front-end, reducing wireless link performance.
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