Keysight E8663D, Руководство пользователя

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Keysight E8357D/67D & E8663D PSG User’s Guide 141
Basic Digital Operation
Using Waveform Scaling
Figure 3-18 Waveform Overshoot
How Scaling Eliminates DAC Over–Range Errors
Scaling reduces or shrinks a baseband waveform’s amplitude while
maintaining its basic shape and characteristics, such as peak–to–average
power ratio. If the fast–rising baseband waveform is scaled enough to allow an
adequate margin for the overshoot, the interpolator filter is then able to
calculate sample points that include the ripple effect, thereby eliminating the
over–range error
(see Figure 3-19 ).
Figure 3-19 Waveform Scaling
Although scaling maintains the basic shape of the waveform, too much scaling
can compromise its integrity because the bit resolution can be so low that the
waveform becomes corrupted with quantization noise. Maximum accuracy and
optimum dynamic range are achieved by scaling the waveform just enough to
remove the DAC over–range error. Optimum scaling varies with waveform
content.