Direct digital synthesizer as a reference source of a millimeter-wave frequency synthesizer

Application of a direct digital synthesizer (DDS) gives a number of advantages in comparison with other methods of frequency synthesis. Here we point out only advantages of DDS that are important for spectroscopic application. They are the following: micro-Hertz tuning resolution of output frequency under complete digital control; extremely fast hopping speed in tuning of output frequency, phase-continuous frequency hop; the digital control interface of the DDS architecture facilitates an environment where systems can be remotely controlled; possibility of frequency modulation with digital control.