We visualize the binary word containing these bits as
The most-significant bit in the word, , can be interpreted as the ``sign bit''. If is ``on'', the number is negative. If it is ``off'', the number is either zero or positive.
The least-significant bit is . ``Turning on'' that bit adds 1 to the number, and there are no fractions allowed.
The largest positive number is when all bits are on except , in which case . The largest (in magnitude) negative number is , i.e., and for all . Table G.4 shows some of the most common cases.
Signal Energy and Power
Two's Complement Fixed-Point Format