Many waveform generators are based on the Direct Digital Synthesis (DDS) technique.
This design has become common primarily because it features great stability and
flexibility. But, not all DDS based generators have the same output performance.
In some situations, the output waveform will not smoothly transition from one setting to
another. This is typically observed when changing the output frequency while the output is enabled. These sharp transitions can be especially tricky if you are manually testing frequency sensitive circuits such as an audio amplifier.
In this note, we are going to describe a method of ensuring smooth transitions
during changes in frequency by using the Independent Phase Mode of the
Both the SDG1000X and SDG 2000X models have two independent outputs. In some
applications, it is critical to lock the phase deviation between the channels. In this way,
the programmed phase difference between the two remains fixed, regardless of any
changes to any channel frequency. With the SDG1000X and SDG2000X, this is called
the Phase Locked mode.