About usrp_standard::tune


#1

Hi All,

In dxc_control::set_dxc_freq is the following line:

set_dxc_freq(double dxc_freq){ return d_u->set_rx_freq(d_chan,
dxc_freq);

If we go to usrp_standard.h we see that channel is between 0 and 3. I
think
for the standard “.rbf” it is 0 or 1 depending on the side (A or B) as I
recall. However, the value of d_chan is passed from the first parameter
of
the function usrp_standard::tune. The documentation in usrp_standard.h
says
“which DDC channel we’re controlling (almost always 0)”. If we set this
to
zero we will always control the A side and never the B side dxc
frequency.

?

BR/
Per


#2

On Tue, Mar 31, 2009 at 05:22:32PM +0200, Per Z. wrote:

the function usrp_standard::tune. The documentation in usrp_standard.h says
“which DDC channel we’re controlling (almost always 0)”. If we set this to
zero we will always control the A side and never the B side dxc frequency.

The Rx mux controls which ADCs are connected to which DDC.
The channel refers to which DDC. As indicated above channel is almost
always zero, independent of which side you are talking to.

There are nice diagrams and explanation of this in the USRP FAQ.
Please take a look at the wiki.

Eric