numerictype of Fixed-Point Objects

Valid Values for numerictype Object Properties

The numerictype object contains all the data type and scaling attributes of a fixed-point object. The numerictype object behaves like any MATLAB® object, except that it only lets you set valid values for defined fields. The following table shows the possible settings of each field of the object.

    Note   When you create a fi object, any unspecified field of the numerictype object reverts to its default value. Thus, if the DataTypeMode is set to unspecified scaling, it defaults to binary point scaling when the fi object is created. If the Signedness property of the numerictype object is set to Auto, it defaults to Signed when the fi object is created.

DataTypeModeDataTypeScalingSignednessWord-
Length
Fraction-
Length
SlopeBias

Fixed-point data types

Fixed-point: binary point scaling

Fixed

BinaryPoint

Signed
Unsigned
Auto

Positive integer from 1 to 65,536

Positive or negative integer

2^(-fraction length)

0

Fixed-point: slope and bias scaling

Fixed

SlopeBias

Signed
Unsigned
Auto

Positive integer from 1 to 65,536

N/A

Any floating- point number

Any floating- point number

Fixed-point: unspecified scaling

Fixed

Unspecified

Signed
Unsigned
Auto

Positive integer from 1 to 65,536

N/A

N/A

N/A

Scaled double data types

Scaled double: binary point scaling

ScaledDouble

BinaryPoint

Signed
Unsigned
Auto

Positive integer from 1 to 65,536

Positive or negative integer

2^(-fraction length)

0

Scaled double: slope and bias scaling

ScaledDouble

SlopeBias

Signed
Unsigned
Auto

Positive integer from 1 to 65,536

N/A

Any floating- point number

Any floating- point number

Scaled double: unspecified scaling

ScaledDouble

Unspecified

Signed
Unsigned
Auto

Positive integer from 1 to 65,536

N/A

N/A

N/A

Built-in data types

Double

double

N/A

1
true

64

0

1

0

Single

single

N/A

1
true

32

0

1

0

Boolean

boolean

N/A

0
false

1

0

1

0

You cannot change the numerictype properties of a fi object after fi object creation.

Properties That Affect the Slope

The Slope field of the numerictype object is related to the SlopeAdjustmentFactor and FixedExponent properties by

slope=slope adjustment factor×2fixed exponent

The FixedExponent and FractionLength properties are related by

fixed exponent=fraction length

If you set the SlopeAdjustmentFactor, FixedExponent, or FractionLength property, the Slope field is modified.

Stored Integer Value and Real World Value

In binary point scaling the numerictype StoredIntegerValue and RealWorldValue properties are related according to

real-world value=stored integer value×2-fraction length

In [Slope Bias] scaling the RealWorldValue can be represented by

real-world value=            stored integer value×(slope adjustment factor×2fixed exponent)+bias

which is equivalent to

If any of these properties are updated, the others are modified accordingly.

For more detail on these properties see numerictype Object Properties.

For more information on scaling see Data Types and Scaling

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