Table Of Contents

Histogram (Continuous) (G Dataflow)

Version:
    Last Modified: March 31, 2017

    Finds the continuous histogram of a signal.

    connector_pane_image
    datatype_icon

    output representation

    Representation for the output.

    Name Description
    sample count

    Represents the value of each bin as the number of samples in that bin.

    percent of total

    Represents the value of each bin as a percentage of the total.

    Default: sample count

    datatype_icon

    reset

    A Boolean to determine initialization of the internal state of the node.

    True Initializes the internal states to zero.
    False Initializes the internal states to the final states from the previous call of this node.

    This node automatically initializes the internal state to zero on the first call and runs continuously until this input is True. For a large data sequence consisting of smaller blocks, when this input is True, this node calculates the histogram of the current block only and ignores previous blocks.

    Default: False

    datatype_icon

    signal

    Input signal.

    This input accepts the following data types:

    • Waveform
    • 1D array of waveforms
    • Double-precision, floating-point number
    • 1D array of double-precision, floating-point numbers
    • 2D array of double-precision, floating-point numbers
    datatype_icon

    number of bins

    Number of bins in the histogram.

    Default: 10

    datatype_icon

    maximum

    Maximum value to include in the histogram.

    Default: 0

    datatype_icon

    minimum

    Minimum value to include in the histogram.

    Default: 0

    datatype_icon

    error in

    Error conditions that occur before this node runs.

    The node responds to this input according to standard error behavior.

    Standard Error Behavior

    Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

    error in does not contain an error error in contains an error
    If no error occurred before the node runs, the node begins execution normally.

    If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

    If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

    Default: No error

    datatype_icon

    inclusion

    The boundary of each bin to handle.

    If bin specifications are provided in bins, this node uses the inclusion in bins instead.

    Name Description
    lower

    Includes the lower boundary.

    upper

    Includes the upper boundary.

    Determining the Bin Widths When inclusion Is lower

    If inclusion is set to lower, the bin widths are determined according to the following equations.

    Δ 0 = [ min , min + Δ x )
    Δ 1 = [ min + Δ x , min + 2 Δ x )
    Δ i = [ min + i Δ x , min + ( i + 1 ) Δ x )
    Δ k 1 = [ min + ( k 1 ) Δ x , max ]

    where

    • Δ x = max min m
    • max is the maximum
    • min is the minimum
    • m is the number of bins

    Determining the Bin Widths When inclusion Is upper

    If inclusion is set to upper, the bin widths are determined according to the following equations.

    Δ 0 = [ min , min + Δ x ]
    Δ 1 = ( min + Δ x , min + 2 Δ x ]
    Δ i = ( min + i Δ x , min + ( i + 1 ) Δ x ]
    Δ k 1 = ( min + ( k 1 ) Δ x , max ]

    where

    • Δ x = max min m
    • max is the maximum
    • min is the minimum
    • m is the number of bins

    Default: lower

    datatype_icon

    histogram

    The histogram of the input signal.

    This input accepts a cluster or a 1D array of clusters.

    datatype_icon

    x values

    An array of the center values of the bins of the histogram.

    datatype_icon

    histogram h(x)

    Discrete histogram of the input signal.

    datatype_icon

    actual number of bins

    Actual number of bins in the histogram.

    This output can return a 32-bit signed integer number or a 1D array of 32-bit signed integer numbers.

    This output is available only if you wire one of the following data types to signal:

    • Waveform
    • Array of waveforms
    • 1D array of double-precision, floating-point numbers
    • 2D array of double-precision, floating-point numbers
    datatype_icon

    actual maximum

    Actual maximum value in the histogram.

    This output can return a double-precision, floating-point number or a 1D array of double-precision, floating-point numbers.

    This output is available only if you wire one of the following data types to signal:

    • Waveform
    • Array of waveforms
    • 1D array of double-precision, floating-point numbers
    • 2D array of double-precision, floating-point numbers
    datatype_icon

    actual minimum

    Actual minimum value to include in the histogram.

    This output can return a double-precision, floating-point number or a 1D array of double-precision, floating-point numbers.

    This output is available only if you wire one of the following data types to signal:

    • Waveform
    • Array of waveforms
    • 1D array of double-precision, floating-point numbers
    • 2D array of double-precision, floating-point numbers
    datatype_icon

    error out

    Error information.

    The node produces this output according to standard error behavior.

    Standard Error Behavior

    Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

    error in does not contain an error error in contains an error
    If no error occurred before the node runs, the node begins execution normally.

    If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

    If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.
    datatype_icon

    samples outside

    Information about points that do not fall in any bin upon successful execution of the node.

    datatype_icon

    total

    Total number of values in signal that do not fall in any bin upon successful execution.

    datatype_icon

    below

    Number of values in signal below the first bin on the lower boundary.

    datatype_icon

    above

    Number of values in signal above the last bin on the upper boundary.

    Algorithm for Constructing histogram

    The histogram is a frequency count of the number of times that a specified frequency bin occurs in the input sequence. The node constructs histogram as follows.

    The following equation calculates the width of the frequency bin Δx.

    Δ x = max min m

    where max is the maximum, min is the minimum, and m is the number of bins.

    The node calculates the center of each frequency bin according to the following equation.

    center [ i ] = min + 0.5 Δ x + i Δ x

    The node defines the range of the ith frequency bin according to the following definition.

    Δ i ( center [ i ] 0.5 Δ x , center [ i ] + 0.5 Δ x )

    for i = 0, 1, 2, ..., m - 1

    The node scans the input sequence, calculates the number of samples in each frequency bin from 0 to m - 1, and returns the histogram.

    The following illustration shows the waveform of an input signal.

    This example configures the node using the following input values:

    • maximum = 6
    • minimum = 0
    • number of bins = 3
    For the previous input values, the following illustration shows the output histogram for the input signal.

    Where This Node Can Run:

    Desktop OS: Windows

    FPGA: This product does not support FPGA devices


    Recently Viewed Topics