Re: [Discuss-gnuradio] Re: problem with USRP/FFT sink in GRC

[Eric Blossom]

On Mon, Apr 30, 2007 at 08:28:54PM -0400, Josh Blum wrote:
> Or in other words...
> 
> To tune the transmitter on sideA : u.tune(0, subdev, freq)
> To tune the transmitter on sideB : u.tune(1, subdev, freq)
> 
> But to tune the receiver for either side :  u.tune(0, subdev, freq)
> 
> Is this correct? Is this they way all boards work?

Yes.  Yes.

FWIW, the asymmetry is a result of the use of the upconverter in the
AD9862.  In the receive case, the first argument specifies which DDC
you want to mess with.  Because of how the the RX mux works, the DDC
assignment is completely orthogonal to the selection of ADCs.
However, on the Tx path, the DUC is actually in the AD9862 that is
wired to the specific daughterboard slot.

Yes, I know it's ugly.  There's probably a better way to handle this.
If anyone wants to sort it out, please go ahead.  We could implement
the change without breaking any existing code by creating a new
interface, say u.tune2.  If anyone does look at this, be sure to
consider the behavior of the multichannel case.

Eric