Tektronix was founded in 1946 and has been producing excellent oscilloscopes ever since. The first Tek oscilloscope was the Model 511. Although described as "portable", it weighed in at about 23 kg. More recent offerings are a bit more compact!
Tektronix still manufactures a range of test equipment but the name is probably still mostly associated with oscilloscopes and similar equipment. Please select an item from the sidebar for further details.