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USB EMI Problem - Losing communication with webcam - How do I suppress noise in USB?

Discussion in 'Electronic Basics' started by [email protected], Jan 9, 2006.

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  1. Guest

    Here's my problem. I've got a USB webcam which keeps losing
    communication with my PC. The USB cable is running alongside an AC
    power cable which is turning on and off repeatedly to turn a pump on
    and off. Each time the pump is turned on and off, the PC drops the
    webcam, and then reconnects. I am fairly certain that the USB cable is
    picking up electrical noise generated by the sudden rushes of current
    in the power cable. When the cables are seperated from eachother, the
    problem goes away. But I have no option but to keep the cables

    What is the best way for me to suppress the noise in the USB signal? I
    have observed the USB signal on an oscilloscope, and it appers that
    every time the pump is turned on and off, there is a spike in the

    So far I have tried installing a snubber across the live and neutral
    lines of the power cable, and I have also placed a toroid on the USB
    cable, but with no luck.

    Any help is much appreciated. Thanks
  2. dholsop


    Apr 14, 2010
    Try applying a number of ferrite beads. You can get ones to apply to existing cable or built-in by the mfg. If you have any Hubs between your USB devices and the PC, try running them directly to the PC, bypassing the hub. The hubs appear to be sensitive to noise.
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