A test and measurement instrument, comprising: an input configured to receive an analog signal; a sampler configured to produce digital sample data corresponding to the analog signal; a buffer configured to temporarily store a portion of the sample data corresponding to the analog signal; a memory configured to store sample data from the buffer; a plurality of comparators configurable to establish a vertical range; and a controller configured to: configure the plurality of comparators to establish a first vertical range based on a first sample data in the buffer; determine whether any of the sample data in the buffer transitions outside the first vertical range during a period of time; responsive to a determination that a second sample data in the buffer transitions outside the first vertical range during the period of time, cause the sample data in the buffer to be moved to the memory, reset the period of time, and further cause the plurality of comparators to be reconfigured to establish a second vertical range based on the second sample data in the buffer; and responsive to a determination that none of the sample data in the buffer transitions outside the first vertical range during the period of time, cause the sample data in the buffer to be discarded and reset the period of time. an input configured to receive an analog signal; a sampler configured to produce digital sample data corresponding to the analog signal; a buffer configured to temporarily store a portion of the sample data corresponding to the analog signal; a memory configured to store sample data from the buffer; a plurality of comparators configurable to establish a vertical range; and a controller configured to: configure the plurality of comparators to establish a first vertical range based on a first sample data in the buffer; determine whether any of the sample data in the buffer transitions outside the first vertical range during a period of time; responsive to a determination that a second sample data in the buffer transitions outside the first vertical range during the period of time, cause the sample data in the buffer to be moved to the memory, reset the period of time, and further cause the plurality of comparators to be reconfigured to establish a second vertical range based on the second sample data in the buffer; and responsive to a determination that none of the sample data in the buffer transitions outside the first vertical range during the period of time, cause the sample data in the buffer to be discarded and reset the period of time. configure the plurality of comparators to establish a first vertical range based on a first sample data in the buffer; determine whether any of the sample data in the buffer transitions outside the first vertical range during a period of time; responsive to a determination that a second sample data in the buffer transitions outside the first vertical range during the period of time, cause the sample data in the buffer to be moved to the memory, reset the period of time, and further cause the plurality of comparators to be reconfigured to establish a second vertical range based on the second sample data in the buffer; and responsive to a determination that none of the sample data in the buffer transitions outside the first vertical range during the period of time, cause the sample data in the buffer to be discarded and reset the period of time.