BINARY CODED DECIMALS
Consider a B-bit digital to analog converter with full-scale range R:
The mapping of digital values to voltage levels depends on the nature of the converter. There are three types of commonly used converters: unipolar natural binary, bipolar offset binary, and bipolar two's complement converters.

The unipolar natural binary converter computes the output as follows:
The bipolar offset binary converter shifts the output down by half the scale: