Help regarding Filtering vs shielding

Discussion in 'General Electronics Chat' started by vijaybala85, May 12, 2010.

  1. vijaybala85

    Thread Starter Member

    Jan 7, 2010
    Hi Guys,

    I was wondering if someone would direct me toward resources regarding filtering high frequencies vs shielding a cable so that it doesnt act as an antenna in a high magnetic field environment. I am trying to figure out a way to eliminate noisy signals to be transmitted through a cable either by filtering it or shielding it, so that our images from the MRI don't have noise spikes in them. Any leads would be greatly appreciated.

  2. beenthere

    Retired Moderator

    Apr 20, 2004
  3. studiot

    AAC Fanatic!

    Nov 9, 2007
    Ferrite beads or loop the cable a few times round a ferrite ring?

    Gate stopper resistors?

    Encode the signal to fibre optic and decode at the other end?
  4. vijaybala85

    Thread Starter Member

    Jan 7, 2010

    The issue we are facing is with a specific cable that is connected to a signal processing box and that is connected to the computer. It is an ECG cable to read the ECG of the patient on the computer. And with respect to grounding tthe outer shield, there is no shield. Even if we shield it until the end that connected to the ECG acquisition device on the patient, we disconnect it during imaging that makes it act as an antenna. Please see picture for more.


    there already is a ferrite bead on the cable just beneath the plug. And looping through a ferrite ring is not possible as we just have so much length of the cable for our purpose.

    Gate stopping resistors? what are those?

    Encoding would work but this is a commerically available product and until I would know what signals transfer through the cable, I wouldnt be able to encode and decode in the form of light.


  5. sashijoseph

    New Member

    Jun 29, 2006