Control-loop analysis studies the variation in the parameters of the switched-mode power feedback loop. Teledyne LeCroy’s Power Analysis software facilitates this analysis by plotting variations in pulse width, duty cycle, period, or frequency. An important aspect of this type of analysis is the length of the oscilloscope’s memory.  Consider that most power supply variations take a long time to manifest themselves. For example, startup may take several seconds. The HDO family of oscilloscopes supports up to 50 Megasamples of acquisition memory, lending itself to this application.