The 802.15.4 standard says:

"In the 2450 MHz, 915 MHz, and 868 MHz bands, the half-sine pulse shape is used to represent each baseband chip and is given by:

p(t) = sin ( π t / (2 Tc) ) , 0 ≤ t ≤ 2 Tc"

According to the figures in that document, Tc is the duration of a chip, which is 0.5 microseconds for the 2.4 GHz frequency band; that is, there are 2 million chips per second.

To my understanding, that gives 2 MHz sine wave as the value of p(t). How exactly is this sine wave related to the 2.4 GHz RF signal?