Table Of Contents

MT Measure Quadrature Impairments (MT Measure PAM Quadrature Impairments) (G Dataflow)

Version:
    Last Modified: February 7, 2018

    Calculates and reports pulse-amplitude modulation (PAM) quadrature impairments on a symbol-by-symbol basis at the symbol timing.

    spd-note-note
    Note  

    Certain measurements like I/Q gain imbalance and quadrature skew are not applicable for the PAM modulation format because of the inherently one-dimensional nature of the PAM constellation.

    connector_pane_image
    datatype_icon

    recovered complex waveform

    The time-aligned and oversampled complex waveform data after matched filtering, frequency offset correction, and phase offset correction. Wire the recovered complex waveform parameter of MT Demodulate PAM to this parameter.

    datatype_icon

    t0

    Trigger (start) time of the Y array.

    Default: 0.0

    datatype_icon

    dt

    Time interval between data points in the Y array.

    Default: 1.0

    datatype_icon

    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.

    datatype_icon

    input bit stream

    The demodulated bit stream from the output bit stream parameter of MT Demodulate PAM.

    datatype_icon

    impairment measurement window

    The window over which impairments are measured.

    datatype_icon

    start index

    Index of the first sample of the measurement window.

    Default: 0

    datatype_icon

    width

    Number of symbols over which to measure impairments. A value of -1 (default) measures impairments over all symbols. Positive values must be two or greater.

    Default: -1

    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

    PAM system parameters

    Parameter values defining the PAM system. Wire the PAM system parameters cluster of MT Generate PAM System Parameters (M) or MT Generate PAM System Parameters (map) to this cluster. Do not alter the values.

    datatype_icon

    samples per symbol

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

    spd-note-note
    Note  

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

    Default: 16

    datatype_icon

    symbol map

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

    datatype_icon

    reset?

    A Boolean that determines how the node handles bits from partial symbols in the input bit stream.

    TRUE Discards bits making up incomplete symbols.
    FALSE Saves the leftover bits and starts with them on the next iteration.

    Default: TRUE

    datatype_icon

    magnitude error

    The measured magnitude error as a percentage. Magnitude error is the magnitude difference between the ideal and the actual measured symbol locations.

    datatype_icon

    RMS measurement

    The RMS impairment value calculated over the impairment measurement window.

    datatype_icon

    peak measurement

    The peak impairment value measured over the impairment measurement window.

    datatype_icon

    peak symbol index

    Index of the symbol having the peak magnitude of impairment.

    datatype_icon

    individual symbol measurements

    The impairment value for each individual symbol.

    datatype_icon

    DC offset measurements

    The measured DC offset of the I or Q waveforms as a percentage of the largest I and Q value in the symbol map of the recovered complex waveform.

    datatype_icon

    I

    The DC offset of the I waveform, expressed as a percentage of the largest I or Q value in the symbol map.

    datatype_icon

    Q

    The DC offset of the Q waveform, expressed as a percentage of the largest I or Q value in the symbol map.

    datatype_icon

    origin offset

    The offset, in dB, of the constellation origin from its ideal location.

    datatype_icon

    phase error

    The measured phase error in degrees. Notice that the phase offset is removed by the demodulator and is excluded from this measurement.

    datatype_icon

    RMS measurement

    The RMS impairment value calculated over the impairment measurement window.

    datatype_icon

    peak measurement

    The peak impairment value measured over the impairment measurement window.

    datatype_icon

    peak symbol index

    Index of the symbol having the peak magnitude of impairment.

    datatype_icon

    individual symbol measurements

    The impairment value for each individual symbol.

    datatype_icon

    EVM

    The measured error vector magnitude (EVM) expressed as a percentage.

    datatype_icon

    RMS measurement

    The RMS impairment value calculated over the impairment measurement window.

    datatype_icon

    peak measurement

    The peak impairment value measured over the impairment measurement window.

    datatype_icon

    peak symbol index

    Index of the symbol having the peak magnitude of impairment.

    datatype_icon

    individual symbol measurements

    The impairment value for each individual symbol.

    datatype_icon

    modulation error ratio

    The measured modulation error ratio in dB.

    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.

    Where This Node Can Run:

    Desktop OS: Windows

    FPGA: Not supported

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


    Recently Viewed Topics