Hi, really don't know what you mean. One can only assume you are refering to a destructive 'EM pulse', similar to that created after an atomic explosion. Which is a short, intense (really, really intense) burst of wide-band EM radiation, that can apparently disable electronics, from various appliances at a distance. What do you want to know?
If you meant EM pulse in a different context, then I'm sorry, ignore this. But I can't think of any other situation where the phrase 'Electromagnetic pulse' would be used.
Confused,
BuriedCode