Signal Processing Blockset™

Check Signal Attributes - Generate error when input signal does or does not match selected attributes exactly

Library

Signal Management / Signal Attributes

dspsigattribs

Description

The Check Signal Attributes block terminates the simulation with an error when the input characteristics differ from those specified by the block parameters.

When the Error when input parameter is set to Does not match attributes exactly, the block generates an error if the input fails to match any of the attributes specified by the other parameters. Only signals that possess all of the specified attributes are propagated to the output unaltered, and do not cause the block to generate an error.

When the Error when input parameter is set to Matches attributes exactly, the block generates an error only when the input possesses all attributes specified by the other parameters. Signals that do not possess all of the specified attributes are propagated to the output unaltered, and do not cause the block to generate an error.

Signal Attributes

The Check Signal Attributes block can test for up to five different signal attributes, as specified by the following parameters. When you select the Ignore in any parameter, the block does not check the signal for the corresponding attribute. For example, when Complexity is set to Ignore, neither real nor complex inputs cause the block to generate an error. The attributes are:

• Complexity

  Checks whether the signal is real or complex. (Note that this information can be displayed in a model by attaching a Probe block with Probe complex signal selected. Alternatively, in the model window, from the Format menu, point to Port/Signal Displays and select Port Data Types.)

• Frame status

  Checks whether the signal is frame based or sample based. (Note that the Simulink environment displays sample-based signals using a single line and displays frame-based signals using a double line.)

• Dimensionality

  Checks the dimension of signal for compliance (Is...) or noncompliance (Is not...) with the attributes in the subordinate Dimension menu, which are shown in the following table. M and N are positive integers unless otherwise indicated.

  Dimensions	Is...	Is not...
  1-D	1-D vector, 1-D scalar	M-by-N matrix, 1-by-N matrix (row vector), M-by-1 matrix (column vector), 1-by-1 matrix (2-D scalar)
  2-D	M-by-N matrix, 1-by-N matrix (row vector), M-by-1 matrix (column vector), 1-by-1 matrix (2-D scalar)	1-D vector, 1-D scalar
  Scalar (1-D or 2-D)	1-D scalar, 1-by-1 matrix (2-D scalar)	1-D vector with length>1, M-by-N matrix with M>1 and/or N>1
  Vector (1-D or 2-D)	1-D vector, 1-D scalar, 1-by-N matrix (row vector), M-by-1 matrix (column vector), 1-by-1 matrix (2-D scalar) Vector (1-D or 2-D) or scalar	M-by-N matrix with M>1 and N>1
  Row Vector (2-D)	1-by-N matrix (row vector), 1-by-1 matrix (2-D scalar) Row vector (2-D) or scalar	1-D vector, 1-D scalar, M-by-N matrix with M>1
  Column Vector (2-D)	M-by-1 matrix (column vector), 1-by-1 matrix (2-D scalar) Column vector (2-D) or scalar	1-D vector, 1-D scalar, M-by-N matrix with N>1
  Full matrix	M-by-N matrix with M>1 and N>1	1-D vector, 1-D scalar, 1-by-N matrix (row vector), M-by-1 matrix (column vector), 1-by-1 matrix (2-D scalar)
  Square matrix	M-by-N matrix with M=N, 1-D scalar, 1-by-1 matrix (2-D scalar	M-by-N matrix with M≠N, 1-D vector, 1-by-N matrix (row vector), M-by-1 matrix (column vector)

  If, in the model window, from the Format menu, you point to Port/Signal Displays and select Signal Dimensions, Simulink displays the size of a 1-D vector signal as an unbracketed integer, and displays the dimension of a 2-D signal as a pair of bracketed integers, [MxN]. Simulink does not display any size information for a 1-D or 2-D scalar signal. Dimension information for a signal can also be displayed in a model by attaching a Probe block with Probe signal dimensions selected.

• Data type

  Checks the signal data type for compliance (Is...) or noncompliance (Is not...) with the attributes in the subordinate General data type menu, which are listed in the following table. Any of the specific data types listed in the Is... column can be individually selected from the subordinate Specific data type menu.

To display data type information, in your model window, from the Format menu, point to Port/Signal Displays and select Port Data Types.

• Sample time

  Checks whether the signal is discrete time or continuous time. (If, from the Format menu, you point to Sample Time Display and select Colors, Simulink displays continuous-time signal lines in black or grey and discrete-time signal lines in colors corresponding to the relative rate.)

  When a Probe block with Probe sample time enabled is attached to a continuous-time signal, the block icon displays the string Ts:[0 To], where To is the sample time offset. Valid values of To for continuous-time signals are 0 and 1. If To is 0, updates occur at every major and minor time step; if To is 1, updates occur only at major time steps, and the sample time is said to be fixed in minor time step.

  When a Probe block with Probe sample time enabled is attached to a discrete-time signal, the block icon displays the string Ts:[Ts To] for sample-based signals, and displays Tf:[Tf To] for frame-based signals. Ts and Tf are the positive sample period and frame period, respectively. To is the offset, such that 0 ≤ offset < period. Frame-based signals are almost always discrete time. For more information on the Simulink Probe block, see the Probe reference page.

Dialog Box

Error when input

Specifies whether the block generates an error when the input does not possess all of the required attributes (Does not match attributes exactly), or when the input does possess all of the required attributes (Matches attributes exactly).

Complexity

The complexity for which the input should be checked, Real or Complex. When you select Ignore from the list, the block does not check the input's complexity.

Frame status

The frame status for which the input should be checked, Sample-based or Frame-based. When you select Ignore from the list, the block does not check the input's frame status.

Dimensionality

Specifies whether the input should be checked for compliance (Is...) or noncompliance (Is not...) with the attributes in the subordinate Dimensions menu. When you select Ignore from the list, the block does not check the input's dimensionality.

Data type

Specifies whether the input should be checked for compliance (Is...) or noncompliance (Is not...) with the attributes in the subordinate General data type menu. When you select Ignore from the list, the block does not check the input's data type.

Sample time

The sample time for which the input should be checked, Discrete or Continuous. When you select Ignore from the list, the block does not check the input's sample time.

Supported Data Types

See Also

Burg Method

Chirp