The DS340 is a 15 MHz function and arbitrary waveform generator based on Direct Digital Synthesis (DDS). A combination of features, performance and low cost make the DS340 ideal for a variety of test and measurement applications. Sine waves and square waves can be generated at frequencies up to 15.1 MHz, and ramps and triangles up to 100 kHz. Frequency resolution is 1 µHz for all functions. The DS340 also includes a 10 MHz Gaussian white-noise generator. All functions can be swept logarithmically or linearly in a phase-continuous fashion over the entire frequency range of the instrument. A rear-panel SWEEP output provides a trigger signal at the start of a sweep to allow synchronization of external devices. Both unidirectional and bidirectional sweeps can be selected. Up to 16,300 arbitrary waveform points can be downloaded to the DS340's waveform memory via the optional GPIB or RS-232 interfaces. PC software is provided for for composing, editing and downloading arbitrary waveforms. The waveform memory can be played back at rates up to 40 Msamples/s. Both internal and external FSK modes allow the output frequency to be rapidly toggled between two preset values. FSK toggling can be done internally (at rates up to 50 kHz), or externally via a rear-panel input.