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AD9957 modulation questions

Question asked by CoachNabo on Sep 29, 2010
Latest reply on May 16, 2013 by Karami

I'm a microwave guy trying to figure out if I it makes more sense to use the AD9957 instead of a traditional Direct I/Q modulator.  I already plan a dual conversion solution so your app not AN-0996 makes sense to me.  The critical parameters that I must satisfy are dynamic range, modulation speed, low phase noise and spurious and channet to channel synchronization.  The applicatoin involves amplitude and phase modulating a mircowave signal essentially providing specific and varied envelope shapes and phases of a microwave carrier in the time domain. These shapes could be gaussian pulses, multilevel steps, etc.  The application is to excite Qbits used by researchers studying quantum computing.  My questions follow:

  1. Is the I/Q modulation bandwidth 250MHz?  I ask this because I have a requirement to create 4nsec amplitude modulated pulse widths as a minimum.  If not, what is the minimum time resolution for amplitude changes?
  2. I see the SFDR is -54dBc @400MHz.  I need the absolute best possible SFDR.  Is there a way to improve this number?
  3. As I understand this the app note I can get an IF output of up to about 400-450MHz (limited by DAC) and then upconvert to my desired final output frequency from there.  Is that correct?

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