Terminology for the representation of a rational number using a tuple {integer,scaling-factor}

Question

In a system with no floating-point (fraction) support, I am using the following operation in order to emulate with good accuracy a multiplication by $\pi$:

$$f(x) = \frac{{N}\times{x}}{2^{D}}$$

Of course, I choose $D$ and calculate $N$ once, in advance.

For example, I choose $D=30$ and calculate $N=\lfloor2^{30}\times{\pi}\rfloor=3373259426$.

I would like to know what is the terminology for $N$ and $D$.

Thank you.

Answer 1

$N$ is known as the mantissa, while $D$ (or more accurately, $-D$) is the exponent.