USRP gain in Tx e Rx


I would like to understand which gains are applied to the signal during
transmission and reception.

Inside the document “Tutorial 4: The USRP Board” provided on the
gnuradio website, I found that:

“The DACs can supply 1V peak to a 50ohm differential load, or 10mW
(10dBm)”. There is also a PGA used after the DAC, providing up to 20dB
gain. Note that the PGAs on both RX and TX paths are programmable."
(something equivalent is written also about the reception path)

At this point I would like to understand if the --tx-gain option and the
–rx-gain options, which we set in the benchmark_tx and benchmark_rx,
respectively, are manipulating the gain of this PGA or if they refer to
another amplifier.

Thanks in advance