http://www.lowrance.in/Products/Marine/Broadband-Radar/The-Technology/

Traditional "pulse" radars use high-powered magnetrons to generate microwave signals with very short pulses of applied voltage. Navico has developed the first solid-state X-band radar technology, which utilizes FMCW techniques.

Lowrance Broadband Radar™ sends a continuous transmission wave with linear increasing frequency (hence the term Broadband). The wave retains its frequency as it travels out and reflects back from any objects. Meanwhile, the transmitter continues to output an increasing frequency. The difference between the currently transmitted and received frequencies, coupled with the known rate of frequency increase, is the basis for precisely calculating a "time of flight" and target distance. Since FMCW constantly builds up radar return energy (vs. a single pulse), this system provides target detection superior to pulse radars while transmitting at far lower energy levels.

Hey, I really don't know anything about it, so I looked it up.