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MT Generate System Parameters (MT Generate PSK System Parameters (M)) (G Dataflow)

Version:
    Last Modified: February 7, 2018

    Calculates parameters for use with either MT Modulate PSK or MT Demodulate PSK. This node generates the symbol map for PSK-modulated systems. This node accepts an M-ary value that specifies a predefined symbol map with the number of distinct symbol map values to use as symbols.

    Example Symbol Map for PSK

    This symbol map corresponds to input symbol values {0, 1, 3, 2} for a quadrature-phase-shift-keying (QPSK) modulation system.

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    samples per symbol

    An even number of samples dedicated to each symbol. Multiply this value by the symbol rate to determine the sample rate.

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    Note  

    The demodulation and detector nodes use timing recovery, which is optimized for four or more samples per symbol.

    Default: 16

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    M-PSK

    The M-ary number, which is the number of distinct states that represent symbols in the complex baseband modulated waveform. This value must be a positive power of 2.

    Default: 4

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    differential PSK

    A value that indicates how the PSK modulation represents symbols.

    Differential operation is used to implement PSK formats such as differential quadrature PSK (DQPSK) and π /4-DQPSK.

    Name Description
    disable

    Symbols are represented as constellation points.

    enable

    Symbols are represented as the transitions between constellation points.

    Default: disable

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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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    PSK type

    Type of PSK modulation.

    Name Description
    normal

    Sets the modulation type to regular PSK.

    shifted

    Rotates the constellation by π /M each symbol.

    offset

    Sets the modulation type to offset quadrature phase-shift keying (OQPSK). This modulation scheme is a form of phase-shift keying in which four different phase angles are used. This scheme is sometimes referred to as staggered quadrature phase-shift keying (SQPSK). For offset PSK, the ideal symbol timing for Q is offset by 1/2 of a symbol period from the ideal symbol timing for I. offset is currently only supported for M= 4.

    Default: normal

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    PSK system parameters

    Parameter values defining the PSK system. Wire this cluster to the corresponding system parameters clusters of MT Modulate PSK or MT Demodulate PSK.

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    samples per symbol

    Number of samples per symbol in the modulated output complex waveform. For error-free operation, the samples per symbol must be an even number.

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    symbol map

    An ordered array that maps each Boolean symbol to its desired coordinates in the complex plane. The number of PSK states in the array must be 2 N , where N is the number of bits per symbol.

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    differential PSK

    A value that indicates how the PSK modulation represents symbols.

    Differential operation is used to implement PSK formats such as differential quadrature PSK (DQPSK) and π /4-DQPSK.

    Name Description
    disable

    Symbols are represented as constellation points.

    enable

    Symbols are represented as the transitions between constellation points.

    Default: disable

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    PSK type

    Type of PSK modulation.

    Name Description
    normal

    Sets the modulation type to regular PSK.

    shifted

    Rotates the constellation by π /M each symbol.

    offset

    Sets the modulation type to offset quadrature phase-shift keying (OQPSK). This modulation scheme is a form of phase-shift keying in which four different phase angles are used. This scheme is sometimes referred to as staggered quadrature phase-shift keying (SQPSK). For offset PSK, the ideal symbol timing for Q is offset by 1/2 of a symbol period from the ideal symbol timing for I. offset is currently only supported for M= 4.

    Default: normal

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    bits per symbol

    Number of bits represented by each symbol. This value is equal to Log 2 (M), where M is the order of the modulation (for example, for 16-PSK, M = 16).

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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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