Help with filter design

Discussion in 'Wireless & RF Design' started by vijaybala85, Apr 11, 2011.

  1. vijaybala85

    Thread Starter Member

    Jan 7, 2010
    Hi everyone.

    I am in need of help designing a filter to filter RF waves that enter into an MRI room. I have this cable that enters into an MRI room to connect to an ECG acquisition module. The module is powered by 12Vdc through this cable and this cable also sends back recorded ECG tracings back to computer outside the MRI room. Now, for our research, when imaging, this cable is DISCONNECTED and removed from the room. If the cable were disconnected and kept in the room, the open connector with ends acts as an antenna and transmits noise. I suspect, it is the power pin 12Vdc that is causing unwanted interference.

    What I am trying to do is add a filter in the cable to filter our frequencies that cause a problem with the MRI. MRI and it's RF pulses work around 63MHz. I would assume a bandwidth suppression of between 60Mhz and 70Mhz. I don't really care about the rest of the frequencies because they don't affect the MRI.

    Any help with resources, examples is greatly appreciated. Thanks!

  2. beenthere

    Retired Moderator

    Apr 20, 2004
    What kind of cable is it? Does anything prevent you from making a shorting connector for it?
  3. vijaybala85

    Thread Starter Member

    Jan 7, 2010
    This ECG device I am talking about is a manufactured device from GE. The cable that connects to the acquisition module has a plug made from D01 series connector 9 pin from hypertronics corporation.

    I am thinking about ordering a male end and a female end connector similar to the one that they use, create an adapter (only that it would be a filter).

    Attached jpeg shows idea in mind.
  4. bertus


    Apr 5, 2008
  5. ronv

    AAC Fanatic!

    Nov 12, 2008
    Might try one of those clip on ferrite beads that you see on monitors and such. Simple if it works.