A Photoelectric Decimal-Coded Shaft Digitizer

This aper describes a non-counting decimal-coded shaft digitizer. Phototubes are used to read the posi-of masks, permitting static as well as dynamic readout with minimum loading of the measured shaft. Reading is done with several units, each reading a digit of the decimal number representing the shaft position. A special decimal code enmploying 5 phototubes per decade is used to avoid intra-decade ambiguities. Inter-decade ambiguities are prevented by using two masks on all but the first decade. An experimental digitizer, using standard components, is described.