How does direct digital synthesis (DDS) work?
There are at least three elements to DDS: a numerically controlled oscillator (NCO) with a phase modulator, a block that converts the phase information to amplitude values, and a digital-to-analog converter (DAC). An inphase/quadrature (I and Q) modulator may be added ahead of the DAC?
What are the advantages of DDS?
The digital nature of DDS technology provides flexibility, repeatability, and precision. The output is digitally calculated, so it does not deviate over time as long as the reference clock is stable. With careful attention to frequency planning, it also can enhance spurious-free dynamic range (SFDR).