Table Of Contents

Threshold Detector (G Dataflow)

Version:
    Last Modified: January 9, 2017

    Analyzes an input sequence for valid peaks and tracks the number of peaks encountered and a record of indices, which locates the points that exceed the threshold in a valid peak.

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    signal

    The input sequence. If the input sequence is less than or equal to the minimum width, this node sets the number of valid peaks to zero and returns an error.

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    threshold

    The level that all valid peaks must equal or exceed for the duration of the minimum width.

    Default: 0

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    width

    The minimum width, in number of samples, that the input sequence must remain at or above the threshold for the candidate peak to be considered a valid peak. This input must be greater than zero. If this input is less than or equal to zero, this node sets the number of valid peaks to zero and returns an error.

    Default: 1

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    error in

    Error conditions that occur before this node runs. The node responds to this input according to standard error behavior.

    Default: No error

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    indices

    The beginning index of all valid peaks.

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    count

    The number of valid peaks.

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    error out

    Error information. The node produces this output according to standard error behavior.

    Algorithm for Detecting Valid Peaks

    A peak is valid where the consecutive elements of the input sequence exceed the threshold, and the number of elements that exceed the threshold is equal to at least width. This node detects the peak when the number of consecutive elements that exceed the threshold is greater than or equal to width.

    The following figure shows the threshold detector result of a sinusoid waveform, where the threshold is 0.1 and width is 4. The green cross represents the beginning index of a detected peak.

    The following figure also shows a valid peak. Here the input waveform is a step signal. The threshold is 0.5 and width is 5. Because thirteen consecutive elements exceed the threshold, the beginning index of the peak is 8.

    Where This Node Can Run:

    Desktop OS: Windows

    FPGA: Not supported


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