Complex sentence: Tektronix's time base trigger and time sweep generator design would become the standard in the 1950's and into the 21st century and would replace DuMont Oscillographs as the leading selling oscilloscope brand.
Split into simpler sentences: Tektronix's time base trigger and time sweep generator design would become the standard in the 1950's and into the 21st century. Tektronix would replace DuMont Oscillographs as the leading selling oscilloscope brand.