Basically, there are three possibilities depending on which model of oscilloscope is being referred to. Most Gould DSO's have exactly 30 digitizer levels per division (on the graticule). This means for example that a digitized level of 135, correspond to exactly 4.5 divisions. If the ground line was to be placed on digitizer level zero and the voltage range set to 2 Volts/Div, then 4.5 divisions corresponds to exactly 9 Volts. This has the result that each digitizer level corresponds to 1/30th of a division, i.e. 0.033333... divisions, and there is a total of exactly 240 digitizer levels across the eight vertical graticules shown on the screen.
High-resolution DSO's, like the Classic 6100, DataSYS 7200 and DataSYS 840 have 480 levels per division offering remarkable dynamic range.
The older 1600 family of instruments was designed so that each digitizer level corresponds to exactly 0.035 divisions. This means for example that a digitized level of 135 on a 1600 instrument corresponds to exactly 4.725 divisions. If the ground line were to be placed on digitizer level zero the voltage range set to 2 Volts/Div, then 4.725 divisions would be exactly 9.45 Volts. In this case there is a total of 1/0.035 digitizer levels per division, i.e. 28.571429... levels and a total of 228.571429.... digitizer levels across the eight vertical graticules shown on the screen.