US Patent 7802156 Identification circuit with repeatable output code

A comparator receives first differentials, compares the differentials to a positive offset, and sets bits dependent upon whether the differentials are greater than the positive offset. The comparator receives second differentials, compares the differentials to a negative offset, and sets bits dependent upon whether the differentials are greater than the negative offset. The comparator compares the first bits to the second bits, and sets a mask dependent upon whether the first bits and the second bits are identical. The comparator receives subsequent differentials, compares the differentials to a zero offset, and sets bits dependent upon whether the differentials are greater than the zero offset. The subsequent bits are compared to the mask and corrected.