Table Of Contents

FIR Narrowband Filtering (G Dataflow)

Version:
    Last Modified: January 12, 2018

    Filters an input sequence using a specific interpolated FIR (IFIR) filter.

    Programming Patterns

    You can use the FIR Narrowband Filter Design node to generate the IFIR Filter for this node.

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    signal

    Input signal.

    This input accepts the following data types:

    • 1D array of double-precision, floating-point numbers
    • 1D array of complex double-precision, floating-point numbers
    • Waveform
    • Waveform in complex double-precision, floating-point numbers
    • 1D array of waveforms
    • 1D array of waveforms in complex double-precision, floating-point numbers
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    IFIR filter

    The IFIR filter.

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    filter type

    Passband of the filter.

    Name Description
    Lowpass

    Uses a lowpass filter.

    Highpass

    Uses a highpass filter.

    Bandpass

    Uses a bandpass filter.

    Bandstop

    Uses a bandstop filter.

    Default: Lowpass

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    interpolation

    Interpolation factor.

    The model filter is stretched by interpolation times.

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    model filter

    Coefficients of the model filter.

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    image suppressor

    Coefficients of the filter image suppressor.

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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.

    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

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    filtered signal

    Filtered signal.

    This output can return the following data types:

    • 1D array of double-precision, floating-point numbers
    • 1D array of complex double-precision, floating-point numbers
    • Waveform
    • Waveform in complex double-precision, floating-point numbers
    • 1D array of waveforms
    • 1D array of waveforms in complex double-precision, floating-point numbers
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    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.

    Algorithm for Calculating the Delay for the Filter

    The overall filter is a linear-phase FIR filter. This node calculates the delay for the filter using the following equation:

    delay = [ ( N G 1 ) M + N I ] 2

    where

    • NG is the number of elements in Model Filter
    • NI is the number of elements in Image Suppressor
    • M is the value of interpolation

    Where This Node Can Run:

    Desktop OS: Windows

    FPGA: Not supported

    Web Server: Not supported in VIs that run in a web application


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