i am trying to generate a train of pulses from 0 amplitude to full sin signal amplitude. I see that I have two possibilities to do this with this family of DDSs:
- To use the automatic OSK and the external pin. Here I have the problem that the time it takes the minimum ramp to reach the maximum value (around 17 us) is too big for my needs, which would be a couple hundred nanoseconds at most.
- Using the external power-down pin, at fast-recovery mode. This leads to satisfactory results in output but I am not very sure if it will be very healthy to operate the DDS this way. I would generate pulses at a maximum frequeny of around 100 kHz. Is there anything I have to fear about working this pulse mode through setting on and off the power of the DDS?
Previously I used an AD9959 which could deal with these with its amplitude modulation capacities... but unfortunately 10 output bits were too few for my application.
I though also about opening and closing the DAC feedback pin with a transistor to vary its gain from 0 to full amplitude... but I guess it will be more complicated and I am also not sure of the behavior of the DDS functioning this way.
Thank you in advance.