How the PRF 16M/64M is calculated

In the user manual, section 10.3, for 16M PRF, I saw the preamble symbol is around 1us, and the code is 31 with 15 zeros inserted. So I think for the 0, there will be no pulse at all, while for the 31 codes, there will be pulse transmitted. So the PRF should be 31M, instead of 16M.
The same problem exists with the 64MPRF, where the PRF should be around 127M.

I think there is some mis-understanding. I just want to know the physical meaning of the 16M PRF. Thanks.

Please see IEEE Standard 802.15.4 - section 16.2.4 Preamble timing parameters - this section describes the timings of preamble symbols and their rate/PRF

Hi, Thank you for your quick reply. It seems the standard is not free. Can you post the equations here? Thanks.