Re: [Discuss-gnuradio] rssi questions

[Johnathan Corgan]

Brian Padalino wrote:

> I haven't taken a look at the daughterboards, but do they all use 
> different amplifiers and different numbers of stages?

They are mostly different.  All the RFX boards are similar, but the RFX
uses a different front end from the TVRX, DBSRX and the new boards still
in development.

> Are the amplifiers setup in a linear or logarithmic mode?  Do they
> change significantly between the boards, or could a generic AGC
> module be created?

I think you could create a generic "rx power estimator" module on the
FPGA that used the ADC output and some configuration registers that were
poked at by the host code when the daughterboards are configured.  From
the host point of view this doesn't add much value, as you could more
easily just do the same calculations on the host.  If you need the value
as part of an AGC loop, though, obtaining it on the FPGA is needed for
tight control.

(I haven't looked into controlling the RFX board gain from the FPGA.
Matt is better to answer this one.)

-- 
Johnathan Corgan
Corgan Enterprises LLC
http://corganenterprises.com