The 11400 series oscilloscopes have a 20 MS sampling rate for a single channel. If more than one channel is turned on the sample rate is reduced. It also makes a difference which channels are turned on. If the channels that are being acquired are in the same plug-in, one set of rules apply. If the channels are in separate plug-ins, another set of rules applies. With one channel in the left compartment and one channel in the center compartment selected, the sampling rate is reduced to 5 MS/s. With three channels selected, each in separate compartments, the sample rate is 2.5 MS/s. If the selected channels are in the same plug-in, the sample rate is limited by the chop rate of the plug-in. The plug-ins chop between channels at a 1 MHz rate. Up to eight channels can be selected, or more precisely, eight traces can be defined, with up to twelve channels used in those definitions. The bottom line is that the maximum sampling rate for capturing those eight traces is 200 kS/s.