.IndustrialControlSystems.MathOperations.RealType.Expression

Information

Description

Model of a generic function of n real numbers.
The output ( y ) is the result of the generic function f(.) of the inputs ( u(:) ) signals.

    y = f(u[:])

Fixed Point numbers

When using fixed point real numbers, Nbit is the number of bits that can be represented. The range is

  Xfp in [-2^{Nbit - 1} + 1  ,...,  2^{Nbit - 1}]

Then it is possible to define a scaleFactor

  X = Xfp/scaleFactor

When the Fixed Point representation is selected (through the selection of the boolean flag FixedPoint), each input number u is converted into an integer Ufp

  Ufp = u*scaleFactor

then the result of the math operation Yfp is computed and converted into the output value y. The output conversion depends on the math operation performed.

Saturation

To note that the Fixed Point numbers have a maximum and minimum value. In order to avoid saturation when performing the computations, the number of bit as well the scale factor have to be choosen carefully.

Name	Description
f	generic real function
g	Output re-scaling function

Revisions