Almost all EMC engineers these days are familiar with MIL-STD-461 and its various revisions because it has influenced the procedures in virtually all present day EMC standards. The original document and the A, B and C revisions all had requirements for measuring both broadband (BB) and narrowband (NB) emissions. When MIL-STD-461 was first released (July 31, 1967), the … [Read more...]
Random or Coherent Signals
In the previous post, I indicated that coupled Broadband energy levels are determined by whether the signals are random or coherent. Random/non-coherent signals originate from sources that are not time related. A couple of good examples would be receiver thermal noise and DC motor brush noise. Another would be the RF environment taken as a whole. Because the individual energy … [Read more...]
Narrowband and Broadband Signals
As I indicated in the previous post, this discussion begins examining signal characteristics from an electromagnetic compatibility (EMC) perspective. But first, a few words to describe EMC. This is a relationship issue. We want all the equipment items to get along in peace and in harmony, but if one of them is a big source and the other is a wimpy receiver, they may not play … [Read more...]
