I have an ambiguity regarding pulses spreading in the UWB modulation (802.15.4-2011, 14.3.2 UWB PHY spreading). The LFSR is clocked Ncpb times for every UWB symbol. Sn+k*Ncpb sets the pulse polarity and h(k) sets the burst position between the Tbpm interval.

A. Based on Figure 91, page 208, the LFSR outputs are not buffered and the pulse position varies on every clock. In this case the pulse position h(k) changes on every clock, and the burst is spreading as shown in Fig_A.

B. Based on h(k) formula (page 209) the burst position value h(k) , between Tbpm interval, is buffered on the start of the LFSR clock, it does not change its value during Tbpm interval and the burst is continuous as shown in Fig_B.

Which is the right scenario, A or B?

http://www.ptc.com/product/mathcad