218 Keysight CXG, EXG, and MXG X-Series Signal Generators Programming Guide
Creating and Downloading Waveform Files
Waveform Phase Continuity
Avoiding Phase Discontinuities
You can easily avoid phase discontinuities for periodic waveforms by
simulating an integer number of cycles when you create your waveform
segment.
By adding off time at the beginning of the waveform and subtracting an
equivalent amount of off time from the end of the waveform, you can address
phase discontinuity for pulsed periodic waveforms. Consequently, when the
waveform repeats, the lack of signal present avoids the issue of phase
discontinuity.
However, if the period of the waveform exceeds the waveform playback
memory available in the arbitrary waveform generator, a periodic phase
discontinuity could be unavoidable.
The following figures illustrate the influence a single sample can have. The
generated 3–tone test signal requires 100 samples in the waveform to maintain
periodicity for all three tones. The measurement on the left shows the effect of
using the first 99 samples rather than all 100 samples. Notice all the distortion
products (at levels up to –35 dBc) introduced in addition to the wanted 3–tone
If there are N samples in a complete cycle, only the first N–1 samples are
stored in the waveform segment. Therefore, when continuously playing
back the segment, the first and Nth waveform samples are always the
same, preserving the periodicity of the waveform.
Sampled Sinewave with No Discontinuity
Waveform length
Added sample
Summary of Contents for X-Series
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