Re: [Discuss-gnuradio] tx output level

[Eric Blossom]

On Mon, Aug 22, 2005 at 01:53:55PM -0400, cswiger wrote:
> Just another stab - set_pga() seems to be screwy. With a
> usrp_siggen.py looped back to usrp_oscope.py, not using
> set_pga and amplitude 16e3 there's a signal peaking at 500.
> However, use set_pga(0,n) (n=any value from 0 to 20)
> and the signal drops to about 300.  Checking with

On the Tx side set_pga accepts values from -20.0 to 0.0 by 0.1.  
See usrp_basic.cc: usrp_basic_tx for docs. 

Try stepping it from -20.0 to 0.0 by 0.1.  I'm pretty sure it works.

> Also looks like broken information in the Register 16 docs, as
> they only show 6 bits with max gain scaling as 63.

Yes, I think it's really an 8 bit value.

> Bottom line, set_pga() seems to be broken on the tx side - but
> it's stuck at max gain anyway.

If you get a chance, can you check it again?

Thanks,
Eric