This slide shows the ideal transfer function of three converters with different digital code representations of an analog signal. The unipolar transfer function (left-most plot) represents a converter which has an analog range from 0 to +FS (Full Scale). The digital input code goes from all 0’s for an analog voltage of 0V to all 1’s for an analog voltage of FS–1 LSB. This code format is oftentimes called straight (or natural) binary. The number of discrete values along the way depends on the resolution of the converter. The middle plot shows the transfer function for a converter, which handles an analog bipolar range from –FS to +FS. In this case, the digital code is called offset binary where a digital input code of all 0’s corresponds to –FS, a code of 1 and all 0’s (i.e. MSB is 1 and all other bits are 0) corresponds to an analog value of 0V and a code of all 1’s corresponds to an analog value of FS-1LSB. Finally, the right-hand plot represents a converter similar to the left-hand one, but with an additional bit representing the sign (positive or negative) of the analog signal.