Drop, Droop and Roll-Off

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New for June 2007! No, we're not talking about fire safety (stop, drop and roll!) This page seems almost unnecessary. Unless you've been to a design review with technical presentations by managers, marketing types or other idiots.

Drop, droop and roll-off are words used to describe phenomena such as voltage or power, with respect to something else. Usually when that phenomenon is falling below a lower specification limit. Many engineers don't analyze the combined effects of drop, droop and roll-off when they look at design margin.

Droop is used when you are referring to a slope with respect to time. Let's put this in a practice sentence...

The charge storage capacitor is too small and we're getting excessive voltage droop over the 20 mirosecond pulse.

Drop is used when you are referring to a slope against distance. Let's put this in a practice sentence...

The voltage drop along that drain bias line is killing the output power of our transmitter.

Roll-off is used when you are referring to a slope with respect to frequency. Let's put this in a practice sentence...

That damn TriQuint amplifier has a gain roll-off right at the edge of our frequency band.

OK, now does everyone get it?

 

Author : Unknown Editor