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MT Pulse Shaping Filter (MT Apply Pulse Shaping Filter (Generic)) (G Dataflow)

Version:
    Last Modified: February 7, 2018

    Applies a pulse-shaping filter to an input stream comprised of PAM, ASK, QAM, and nonoffset PSK-modulated symbols. Separate nodes are available for offset PSK, FSK, and MSK.

    This node first upsamples (zero-insertion) the symbols array by a factor equal to the samples per symbol value, then filters the symbols stream with the pulse-shaping filter that you specify.

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    symbols

    Array of symbols (comprised of frequency deviations) corresponding to information bits. Wire the symbols parameter of MT Map Bits to Symbols to this parameter.

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    pulse shaping filter coefficients

    An ordered array containing sample-spaced coefficients for the desired pulse-shaping filter. Wire the pulse shaping filter coefficients parameter of MT Generate Filter Coefficients to this parameter. Ensure that the value of the samples per symbol parameter passed to this node matches the pulse shaping samples per symbol value used to generate the filter coefficients.

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    Note  

    When reset? is set to TRUE, there is a transient response of ½ the filter length at the start of the modulated signal, and the returned data is shortened by approximately ½ the filter length. When reset? is set to FALSE, the node uses data from the previous iteration to eliminate the transient.

    You can also specify custom pulse-shaping filter coefficients.
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    Note  

    This node does not verify absence of intersymbol interference in custom filter coefficients before applying the pulse-shaping filter.

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    samples per symbol

    Number of samples per information symbol in the output complex waveform. Multiply this value by the symbol rate to determine the system sample rate.

    Default: 16

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    symbol rate

    The symbol rate in symbols per second.

    Default: 1.0

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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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    reset?

    A Boolean that determines whether the node continues pulse-shape filtering using the previous iteration states.

    TRUE Resets the pulse-shape filtering.
    FALSE Continues pulse shaping at the previous iteration state on subsequent calls.

    Default: TRUE

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    output complex waveform

    The output pulse-shaped continuous-time I/Q baseband waveform.

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    t0

    Trigger (start) time of the Y array.

    Default: 0

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    dt

    Time interval between data points in the Y array. The reciprocal of this value is equal to the system sample rate.

    Default: 1.0

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    Y

    The complex-valued signal-only baseband modulated waveform. The real and imaginary parts of this complex data array correspond to the in-phase (I) and quadrature-phase (Q) data, respectively.

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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.

    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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