Gnuradio controls the receiver side on the usrp inorder to receive data centered around certain center frequency.... and in doing that it sets 2 frequencies on the USRP one in the analog domain which is the center frequency of the VCO running on the daughterBoard, and the other one in the digital domain inside the fpga which is the NCO frequency which is NCO Frequency ..
We need to know how does gnuradio control or map these two frequency ? for example if we want to receive data around 913 Mhz ... what values will be loaded in the VCO frequency register and in NCO frequency register !!!!!
Objective : we need to make this desired frequency only dependant on the NCO frequency and independant on the the VCO frequency, so first we should know how gnuradio control these two values so that we could develop a method to make it only dependant on NCO frequency.
Thanks in advance.