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:
- 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?
- I see the SFDR is -54dBc @400MHz. I need the absolute best possible SFDR. Is there a way to improve this number?
- 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?