Electromagnetic Pulse Waves

Very very broad bandwidth.

A theoretical impulse spike has an infinite bandwidth. Now whatever in real life produced your EMP will have limitations that will prevent it from being a true theoretical impulse spike. But for nearly all practical applications, it can be considered an infinite bandwidth signal.

EMP is nowhere near a delta function. See reference cited in my first response. Rise-time greater than 2 ns. That computes to around 150 MHz, hardly infinite bandwidth.

emc_c

Yes, EMP is not a delta function. But a rise-time greater than 2 ns does approach a delta function, particularly since one normally pictures an EMP as a single pulse. So I am guilty of using hyperbole to explain the bandwidth as infinite to somebody that presumably does not know the definition of a delta function, the fundamentals of a Fourier transform or how to translate the values generated by this method into useful parameters. Piffle.

Everything you need to know, and nothing you need a clearance for:

You can download MIL-STD-461F from the DoD site for unlimited distribution military standards:

http://www.assistdocs.com/search/search_basic.cfm

Just type MIL-STD-461 into the Document ID field and click on submit. Then download MIL-STD-461F as a pdf. Look at requirement RS105, Figure RS105-1; it shows the unclassified free-field waveform, which is 50 kV/m, with a sub-10 ns risetime, and a long exponential decay.

That is the forcing function. The bandwidth of the signal that might cause damage or upset to a circuit depends on the parameters of the pickup mechanism, whether it's a cable, an antenna, or a printed circuit board trace. In the same way that how far and how fast your child travels after given a push on a swing depends on his/her mass and the length of the swing rope. Same phenomenon: the response of a physical or electrical system to an impulsive force.

emc_c