An oscilloscope includes a probe and an analog to digital converter. The probe detects a varying electronic signal and produces an analog signal. The analog to digital converter converts the analog signal to a digital signal. The oscilloscope detects vertical movement of the digital signal as a first digital trigger triggered at a trigger time. A segment of the digital signal is compared with predetermined parameters for the varying electronic signal received from a user to confirm whether a pattern of the varying electronic signal in the segment matches the predetermined parameters. When the pattern of the varying electronic signal in the segment matches the predetermined parameters, the process includes generating a display showing the varying electronic signal in the segment based on the trigger time.