If you're looking for a scope and plan to use the gradient displays, be sure to get a demo scope to try with your application. You'll find that the scope manufacturers make various claims as to how well their scope emulates an analog scope. One company might claim that its scope can display more acquisitions in closer to real time than other scopes can. Another company might argue that its scopes can acquire more triggers or that its longer memory compensates for fewer acquisitions placed on the screen. Keep in mind that no matter how well a digital scope emulates an analog scope, you're still using a digitizer.
All digitizers are subject to artifacts from aliasing.
These scopes are fast, but not fast enough just yet. Figure B. Color-grade persistence displays every written pixel until the scope's accumulator clears. Display persistence doesn't need the accumulators that gradient displays require. You can set the display persistence through the scope's controls. With no display persistence, the scope simply writes a new pixel map to the display each time it updates the screen.