I'm new to using DDS devices, and I'm considering using the AD9833 to produce a PWM signal. I need a square wave output with frequency up to 500 kHz and 0.1Hz resolution, but with duty cycle between 10% and 90%. Firstly, are there any DDS that don't include the ROM and DAC since I don't need that? But more importantly, can anyone suggest how I would go about producing the variable duty cycle? Are there DDS devices that allow that adjustment, or can you suggest an external component that would accomplish it? I imagine a PLL would be needed but I haven't seen any yet with adustable duty cycle.