Figure 4. A snapshot, in time, of two complex numbers whose exponents, and thus their phase angles, change with time. The notion of negative frequency is often troubling to engineers who've spent so ...

The seismic signals from volcanoes are complex waves that result from multiple single waves that occur simultaneously. To help students understand how a complex wave is formed, tell them that in this ...

Alain Bourdillon is a professor of Electrical Engineering at the University de Rennes. He is involved in research on Over The Horizon radar and on radio propagation. Direct frequency synthesizers have ...

Frequency Modulation (or FM) synthesis is a simple and powerful method for creating and controlling complex spectra, introduced by John Chowning of Stanford University around 1973. In its simplest ...

To identify the different patterns exhibited by volcano seismic waves by sketching the wave patterns. To describe how each wave pattern may be used to predict an eruption. To recognize that complex ...