Ground Coupling

Discussion in 'General Electronics Chat' started by chrisw1990, Oct 23, 2011.

  1. chrisw1990

    Thread Starter Active Member

    Oct 22, 2011
    543
    41
    Think this is the best place..
    currently working on hardware, uses GPS and analogue and digital parts.
    my question is, how best to decouple the grounds?
    the GPS antenna will have an RF GND, or should i just use one common ground and be super careful of the layout to protect it from circulating currents?
    hope this question makes sense.
     
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,395
    1,607
    It's never a simple answer. The grounds definitely WANT to be connected together, typically at one place, but finding that one idea place is always a challenge.

    The GPS module and the antenna should connect directly together, along with any associated parts. Call that ground mass "analog ground." Then connect all the digital and associated parts and call that "digital ground."

    Connect those two ground masses together at one point, closest to the main power regulator is usually. If you have other sensitive elements you can also connect them to that point in what is called a "star" connection
     
  3. Lundwall_Paul

    Member

    Oct 18, 2011
    220
    19
    Connecting a Digital Ground to an Analog Ground is seldom a good idea. They have two distinct names for a reason. Look at the schematic for such devices that may use two different grounds. Isolation is a common reason that there are two different grounds.
     
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