Re: [Discuss-gnuradio] DBSRx set gain code

[Matt Ettus]

Lee Patton wrote:
> 
> After looking at the data sheets for all components on the DBSRX, I
> gather that the RF LNA and IF low-pass filter gain control, both of
> which are in the MAX2118, are the two variable gain amps to which you
> are referring. Is that correct?

Yes

> daughterboard gain (79dB) + PGA gain (20dB) = 99dB. The DBSRX returns
> 104dB. Where does the extra 5dB of programmable gain come from? (It
> looks like it is the "dl" variable in your code, but I don't know what
> that corresponds to. Please see below)

Yes, it comes from dl.  dl turns on a 5dB gain amp in the chip.
> 
> To minimize noise, I would assume that when setting the gain it is
> preferable to fist max out the RF LNA, then the IF gain control, and
> finally the PGA.  Is that correct?

Yes

Matt