Q Number Notation

A Q number is written in the form Qm.n where n is the power of 2 used to multiply the number by and m is the unsigned integer size of the integer portion

Q1.1

\[ \underbrace{1}_{\text{integer portion}} \quad \underbrace{0}_{\text{fractional portion}} \]

Q8.4

\[ \underbrace{00000001}_{\text{whole number portion}} \quad \underbrace{0000}_{\text{fractional portion}} \]

Q4.8

\[ \underbrace{0001}_{\text{whole number portion}} \quad \underbrace{00000000}_{\text{fractional portion}} \]

bits to the right of the decimal represent fractional powers of two:

\[ \begin{array}{ccccccccc} \cdots & 1 & 1 & 1 & 1 & . & 1 & 1 & 1 & 1 & \cdots \\ \cdots & 8 & 4 & 2 & 1 & . & \frac{1}{2} & \frac{1}{4} & \frac{1}{8} & \frac{1}{16} & \cdots \end{array} \]

Fixed-Point Demo