High-frequency signal sources based on digital techniques include arbitrary waveform generators (AWGs) and direct digital synthesizers (DDSs). Both types of signal sources have gained in frequency and bandwidth over the years, thanks to the enhanced performance of digital components such as digital-to-analog converters (DACs).
AWG- and DDS-based signal sources are both able to create complex output waveforms with high switching speeds, although DDS sources running at high clock frequencies are typically capable of higher-resolution frequency tuning than AWG sources. For that reason, DDS-based sources are often included in AWG designs to provide the benefits of both technologies within a single package.