OFDM Short Training Field clarification I want to clarify my understanding of OFDM training fields. Please correct me if I am wrong as I am getting 2 different information from online resources.

For 802.11a standard the preamble contains 10 short training Field (STF) and 2 Long Traning Field (LTF). Each of the STF (A1,...A10) contains 52 subcarriers that contain symbols as shown in the picture.

And In some other document, I am seeing that there is 2 short training field instead of 10, the 2 LTF is there as same. Which one is true, or both are true in a different perspective? I have also seen in many implementation 2 STF are used.


In addition:

a) Is the same packet detection method used for both 802.11a and 802.11n? (i.e with STF)?

b) The standard says each of the STF symbols has 16 samples. Can anyone explain this? How this 16 sample is achieved or comes from?
Typically both are used, coming from an 802.11p perspective. The short preamble (STF) is used for packet detection and coarse frequency offset. The long training preamble (LTF) is used for timing synchronization and fine frequency offset. The LTF can also be used for channel equalization. Both are used from my understanding to accomplish total synchronization.