What is DDS on the AFG3000?

Direct digital synthesis (DDS) is a common technique for generating signals. The desired waveform is stored digitally in waveform memory as a series of amplitude points. A digital-to-analog converter (DAC) converts the data into a series of voltage output steps. The DAC is clocked at the function generator’s fixed sampling rate.

Because the sample rate is fixed then the function generator must either add or subtract points to gain the desired frequency dialed in by the user. If you require signal generation with complete fidelity to your original data, then using a function generator with DDS is not the appropriate solution.