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Compare To Zero

Determine how signal compares to zero

Library

Logic and Bit Operations

Description

The Compare To Zero block compares an input signal to zero. Specify how the input is compared to zero with the Operator parameter. The Operator parameter can have the following values:

  • == — Determine whether the input is equal to zero.

  • ~= — Determine whether the input is not equal to zero.

  • < — Determine whether the input is less than zero.

  • <= — Determine whether the input is less than or equal to zero.

  • > — Determine whether the input is greater than zero.

  • >= — Determine whether the input is greater than or equal to zero.

The output is 0 if the comparison is false, and 1 if it is true.

Data Type Support

The Compare To Zero block accepts inputs of the following data types:

  • Floating point

  • Built-in integer

  • Fixed point

  • Boolean

The block output is uint8 or boolean, depending on your selection for the Output data type parameter. For more information, see Data Types Supported by Simulink in the Simulink® documentation.

    Tip   If the input data type cannot represent zero, parameter overflow occurs. To detect this overflow, go to the Diagnostics > Data Validity pane of the Configuration Parameters dialog box and set Parameters > Detect overflow to warning or error.

    In this case, the block compares the input signal to the ground value of the input data type. For example, if you have an input signal of type fixdt(0,8,2^0,10), the input data type can represent unsigned 8-bit integers from 10 to 265 due to a bias of 10. The ground value is 10, instead of 0.

Parameters and Dialog Box

Operator

Specify how the input is compared to zero, as discussed in Description.

Output data type

Specify the data type of the output, boolean or uint8.

Enable zero-crossing detection

Select to enable zero-crossing detection. For more information, see Zero-Crossing Detection.

Characteristics

Direct Feedthrough

Yes

Scalar Expansion

Yes

Multidimensionalized

Yes

Zero-Crossing Detection

Yes, if enabled.

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