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KuskoSoft / FeitCSI

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What does "ftm_clock" mean? #4

Open yutailin1993 opened 1 month ago

yutailin1993 commented 1 month ago

Hi,

Thank you for providing such a good CSI measurement tool for WiFi. I'm not sure if this is the right place to ask general questions, but I am curious about the field "ftm_clock" in the header. Does it mean the timestamp when it received the packet?

Thank you.

KuskoSoft commented 1 month ago

Hello @yutailin1993 ,

Yes, it is the right place!

"ftm_clock" is a clock tick. Every tick is 3.125ns. The value is unsigned int (4294967295) so the maximum time is ~13.4s, then overflows and begins from 0 again. I hope that I clearly describe it.

If you have any questions please feel free to ask.

Thanks!

yutailin1993 commented 1 month ago

Hi @KuskoSoft,

Thank you for replying. I just want to clarify. From what I'm understand "ftm" stands for Fine Time Measurement, which used for WiFi ranging. If "ftm_clock" is a clock tick as you mentioned earlier, is it used for recording time of flight or is it used for something else. If former, how does it work to calculate time of flight?

Thank you!