THRU WALL, SHIELDED FILTERED SIGNAL PROPAGATION ON TWO-SIDED CIRCUIT BOARDS
Original Publication Date: 1997-Mar-01
Included in the Prior Art Database: 2002-May-16
Electromagnetic compatibility (EMC) require- ments and standards for two way radios have con- tinued to become a greater concern and more strin- gent. Fulfilling these requirements usually demands the use of some type of shielded enclosure. An often overlooked aspect of the shielded enclosure is the method used to pass signals into and out from the enclosure. If these lines are not shielded or properly filtered, the shielding effectiveness of the enclosure is reduced. For example, signals within the enclo- sure will couple onto the lines exiting the enclosure. These signals will be conducted out of the enclosure and then be radiated. This radiation could cause the system to fail the EMC requirements. An effective means to reduce the level of the conducted energy is to use a feedthru capacitor or some other filter at the point where the signal lines leave or enter the enclo- sure.