Re: Questions on the GNU WiFi GUI with the USRP B210 box

[Marcus D. Leech]

On 06/27/2020 04:55 PM, Silvio Cardero wrote:

Thanks 

That goes with what I thought 

It seems to coincide with the ADC

 From my gain calculation and reading the transceiver specs the ADC should be a 1vp/p device hence 4 dBm FS + 3dB more for I&Q. 

Yet the GNU and Matlab views show the Received word seems to be 10 dBm FS or 1 v p/p

Gnu Radio doesn't give you numbers calibrated against powers or voltages seen at the antenna, only some approximation of dBFS in the
  digital domain.  If you want that calibrated in "real world, as seen at the antenna" units, you'll need to undertake a calibration exercise
  over the multi-dimension parameter space of:

   o Gain setting
   o Frequency
   o Analog bandwidth setting
   o Sample rate
   o Probably master clock rate
   o Whether you're using TX/RX or RX2 port for RX

Since Gnu Radio (and, by inference MatLab) do not *KNOW* anything about the analog behavior of the transceivers it's connected to, you
  cannot come to any conclusions about what the instantaneous samples *mean* in terms of real-world analog voltages other than that
  they're mostly linearly related, and that for a given situation, a larger sample magnitude means a larger output from the DAC (or, respectively
  from the ADC).