I've been using AD9910 to generate high fidelity 50-200MHz sine waves. I need to change their amplitudes and frequencies. Update speed of new amplitude and frequency should be above 10MHz. Until now we have used ad9910 to generate frequency ramps and play back amplitude profiles from the RAM. Now we need more complicated frequency profiles. We have tried using the parallel input of the DDS to feed freq AND amplitude to the core directly. Without success. The documentation of AD9910 is not clear here how often it is allowed to change between data destination.
Is it really impossible to use the parallel input to feed AD9910 with freq AND amplitude alternatingly (at >33MHz each)? What could we do wrong?
Is there any other AD DDS chip/circuit with which we can do the thing: updating with high speed the freq and amplitude of a DDS core which synthesise output with >1GHz clock and 10bit resolution?