[Hackrf-dev] Gain stages/settings

[Karsten von Hornbostel]

Hi,

I am doing some research on HackRF gain stages and settings. There is
a FAQ entry about that, where one can read:

"The three RX gain controls are at the RF ("amp", 0 or 14 dB), IF
("lna", 0 to 40 dB in 8 dB steps), and baseband ("vga", 0 to 62 dB in
2 dB steps) stages."
(https://github.com/mossmann/hackrf/wiki/FAQ)

I have no doubt that this is the trueth, but i would like to
understand where these values are coming from :).

The RF "amp" stage is formed by the MGA81563, that is clear to me so
far, since it does 14 dB when enabled and 0 dB wen bypassed.

The other two stages can be found inside the MAX2837 i guess. So,
how do you calculate the max 40 dB (0 to 40 dB in 8 dB Steps) gain 
for the lna and the 62 dB (0 to 62 dB in 2 dB steps) for the vga?

I have found the 62 dB mentioned under "Baseband Gain Range" and the 8
dB steps under "RF Gain Steps", but i dont see how the lna has max 40
dB gain and where the VGA can be changed in 2 dB steps from 0 to 62
dB. Can you point out the places in the datasheet where this is
mentioned?

Also, is there a more detailed version of the datasheet than the one
linked from the wiki?

Thanks in advance,
Karsten



mentioned in the
Datasheet?