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).
