Questions about the DAC of USRP2

GNU Radio
1

Hi, i have encounted with the questions about the DAC of USRP2 for some
time, and havn’t solved it yet. I listed the questions as follows:

  1. The DAC of is 400MSPS, and the ADC is 100MSPS. Is that means when i
    design a communication system(one tramsmitted signal and the other
    received signal), i must set the interp rate (on the transmitted side) 4
    times of the decim rate(on the receive side)? This question is based on
    the suppose that the other settings on both side are the same.

  2. baseband_frequency
    dxc_frequency
    residential_freqency
    what are these respectively indicate?

  3. On the transmit side, the DUC interp the digital signal, and then the
    DUC transferred the digital signal to the IF. Is the number of IF
    certein, or it can be setted by the PYTHON?
    And what’s the real process of transferring the digital signal to the IF
    ?
    Does it use the COSwt adn SINwt to mutiply the digital signal? Am i
    right?

I’m sincerely anticipating for the reply. And thanks wery much.