Hi Wes, that is a difficult one as the pulses are mixed with different lengths over one transmission cycle. The sd2000 had 4 X 60us followed by 1 at 240us for memory, as the models were slowly made more sensitive to smaller gold the pulse lengths became shorter and the receiver off time was reduced. Different modes like enhance, shart and fine gold can se pulses as short as 6us combined with 35us and 120us in the pulse cycle. The detectors do not technically run at a constant frequency but more as a collection of different on and off times in a repititious cycle.