numerictype of Fixed-Point Objects

Valid Values for`numerictype`Object Properties

Thenumerictypeobject contains all the data type and scaling attributes of a fixed-point object. Thenumerictypeobject 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 afiobject, any unspecified field of thenumerictypeobject reverts to its default value. Thus, if theDataTypeModeis set tounspecified scaling,它默认为binary point scalingwhen thefiobject is created. If theSignednessproperty of thenumerictypeobject is set toAuto,它默认为Signedwhen thefiobject is created.

DataTypeMode	DataType	Scaling	Signedness	Word- Length	Fraction- Length	Slope	Bias
Fixed-point data types
`Fixed-point: binary point scaling`	`Fixed`	`BinaryPoint`	`Signed` `Unsigned` `Auto`	Positive integer from 1 to 65,535	积极或否定ative integer	2^(-fraction length)	`0`
`Fixed-point: slope and bias scaling`	`Fixed`	`SlopeBias`	`Signed` `Unsigned` `Auto`	Positive integer from 1 to 65,535	`N/A`	Any floating- point number greater than zero	Any floating- point number
`Fixed-point: unspecified scaling`	`Fixed`	`Unspecified`	`Signed` `Unsigned` `Auto`	Positive integer from 1 to 65,535	`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 65,535	积极或否定ative integer	2^(-fraction length)	`0`
`Scaled double: slope and bias scaling`	`ScaledDouble`	`SlopeBias`	`Signed` `Unsigned` `Auto`	Positive integer from 1 to 65,535	`N/A`	Any floating- point number greater than zero	Any floating- point number
`Scaled double: unspecified scaling`	`ScaledDouble`	`Unspecified`	`Signed` `Unsigned` `Auto`	Positive integer from 1 to 65,535	`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 thenumerictypeproperties of afiobject afterfiobject creation.

Properties That Affect the Slope

TheSlopefield of thenumerictypeobject is related to theSlopeAdjustmentFactorandFixedExponentproperties by

$s l o p e = s l o p e a d j u s t m e n t f a c t o r \times 2^{f i x e d e x p o n e n t}$

TheFixedExponentandFractionLengthproperties are related by

$f i x e d e x p o n e n t = - f r a c t i o n l e n g t h$

If you set theSlopeAdjustmentFactor,FixedExponent, orFractionLengthproperty, theSlopefield is modified.

Stored Integer Value and Real World Value

In binary point scaling thenumerictypeStoredIntegerValueandRealWorldValueproperties are related according to

$r e a l - w o r l d v a l u e = s t o r e d i n t e g e r v a l u e \times 2^{- f r a c t i o n l e n g t h}$

In [Slope Bias] scaling theRealWorldValuecan be represented by

$\begin{array}{l} r e a l - w o r l d v a l u e = \\ s t o r e d i n t e g e r v a l u e \times (s l o p e a d j u s t m e n t f a c t o r \times 2^{f i x e d e x p o n e n t}) + b i a s \end{array}$

which is equivalent to

$r e a l - w o r l d v a l u e = (s l o p e \times s t o r e d i n t e g e r) + b i a s$

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