I found this simplified explaination by Gil at THT ...(even I can understand this one)..

QUOTE...(in part):

The traditional sonar fires an single pulse at the specified unit kw per duty cycle.....that is just one single ping on your target.

Now..

The CHIRP fires a full band of pulses (from the "lower kHz" spec of the CHIRP band ...and up thru the "upper kHz" spec of the CHIRP band)...onto the target during one duty cycle.

Regardless of the wattage of each pulse..the total number of all these pulses puts a huge amount of energy onto the target...thus more energy onto the target the greater the return echo...per duty cycle.

Add to that ..the CHRIP system uses far superior processing to determine target information....called pattern matching...it memorizes the transmitted band and then compares it to the returned band echo... thus finding detailed target information.

All in all..CHIRP relies less on power of the unit and more on the overall CHIRP processing technology coupled with the higher quality transducers to achieve its results...

UNQUOTE...

(Some verbiage was intentionally changed by me because Gil was referring to a specific band xducer...with specific lower and upper frequency points..so I generalized it to fit any of the possible CHIRP band ranges)...

Rickie