Keysight E4428C ESG RF Programming Manual page 235

Creating and Downloading Waveform Files
Waveform Phase Continuity
Sampled Sinewave with No Discontinuity
Added sample
Waveform length
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 signal. The measurement on the right shows the same waveform using all 100 samples to
maintain periodicity and avoid a phase discontinuity. Maintaining periodicity removes the distortion
products.
Phase Continuity
Phase Discontinuity
3–tone – 20 MHz Bandwidth
3–tone – 20 MHz Bandwidth
Measured distortion = 86 dBc
Measured distortion = 35 dBc
Keysight Signal Generators Programming Guide 227