The Signature series allows the possibility to operate in both narrowband and broadband in the same deployment when using concurrent or alternating plans. Let us refer to the modes as broadband and long range mode. To remove any confusion we use the term long range mode instead of narrowband since single ping standard deviation is still lower than our classic narrowband instrumens (f.ex AquaPro or AWAC).
In the Deployment software there is a field called "Long Range Mode" which can be seen in the Effect tab on the right of the Deployment Wizard. Long range mode ON means that the bandwidth is reduced to get increased range, whereas OFF means that broadband is used. The two modes differ mainly in terms of power consumption, accuracy and range. Burst mode will always use broadband. Current profile/Average mode will turn on Long range mode when it detects that the desired max range will not be reached using broadband with the selected configuration (dependent on power level, range and cell size). For example, the Signature500 at max power level = 0dB and cell size = 1m will turn on Long range mode between 49m and 50m.
The Signature55 is slightly different since it can operate in Coarse (Long range mode) or Fine profile (full bandwidth). In Coarse mode it will use a narrower bandwidth with center frequency of 55kHz which gives the longest range, sacrificing some resolution. In the Fine profile a broadband ping centered around 75kHz will be used which gives high resolution, but sacrificing some range.