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Meeting Bandwidth requirements with AD916X/AD917X


We are evaluating AD916X and AD917X for our application, here following are the requirements of our application

  1. To have an Instantaneous Baseband Bandwidth of 1200 MHz (centered at 0)
  2. Use DAC Sampling rate (FDAC) of about 8000 MSPS
  3. Use 2x or 4x interpolation in order to have easier onboard analogs, effective DAC Data rate (FDATA) will be 4000 MSPS or 2000 MSPS respectively
  4. DAC LO frequency needs to be around 2500 MHz

Following are our doubts

  1. As per AD916X and AD917X datasheets, using any Interpolator limits the Usable Bandwidth, suppose if we are interpolating by 4x, then Usable BW = 80% of FDATA/2 = 800 MHz. Is it correct? Is there any way to use it for 1200 MHz Bandwidth?
  2. In the case of AD916X, with FDAC = 8000 MSPS interpolation by 2x cannot be used as this will make the FDATA = 4000 MSPS, this FDATA is not supported for Complex data as per Note 2 under Table 35, is it correct?
  3. If we use 2x FIR85 in AD916X and send the 1200 MHz Bandwidth Baseband samples centered @ 0 Hz @ FDATA = 2000 MSPS, and if we mix it with a LO; then at the output of the DAC, LO to LO+600 MHz will contain (DC to +600MHz) baseband spectrum and its mirror image on LO-600MHz to LO, is it correct? An EZ gives a GIST on it:
  4. Do you suggest any DACs among AD916X, AD917X, or any other DACs to meet our requirements?