N5161A/62A/81A/82A/83A MXG Signal Generators User's Guide

Basic Digital Operation (Option 651/652/654)Scaling a WaveformHow Scaling Eliminates DAC Over–Range ErrorsScaling reduces the amplitude of the basebandwaveform while maintaining its basic shape andcharacteristics, such as peak–to–average powerratio. If the fast–rising baseband waveform isscaled enough to allow an adequate margin forthe interpolator filter overshoot, the interpolatorfilter can calculate sample points that includethe ripple effect and eliminate the over–rangeerror (see the figure at the right).Although scaling maintains the basic shape ofthe waveform, excessive scaling can compromisewaveform integrity. For example, if the bitresolution becomes too low the waveformbecomes corrupted with quantization noise. Toachieve maximum accuracy and optimizedynamic range, scale the waveform no morethan is required to remove the DAC over–rangeerror. Optimum scaling varies with waveformcontent.190 Agilent N5161A/62A/81A/82A/83A MXG Signal Generators User’s Guide