We are using AD9913 in our product. We want to use this DDS as polar modulator in our design. Kindly suggest how we can achieve this from AD9913.
Because polar modulation requires simultaneous control of both amplitude and phase, the AD9913 is not well suited for polar modulation.
Although the AD9913 provides digital control of the phase of the DDS output (via the POW register), it does not have a corresponding mechanism for controlling the amplitude of the DDS output. The only digital mechanism for amplitude control is the full scale current control of the DAC via register 0x02 (the 10 FSC bits).
It may be possible to implement polar modulation by using register 0x02 for amplitude control and the POW register for phase control. However, the amplitude and phase pathways are not matched for latency. As such, you would have to measure the latency offset between phase and amplitude experimentally and then compensate accordingly via the programmed phase/amplitude data.
Note the AD9910 is well suited for digital polar modulation, but it is much more power hungry than the AD9913. If power is not a limiting factor in your design, it would be worthwhile to take a look at the AD9910.
Retrieving data ...