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MT Compensate Sample Clock Frequency Error (MT Compensate Sample Clock Frequency Error (QAM)) (G Dataflow)

Version:
    Last Modified: February 7, 2018

    Estimates and corrects sample clock frequency offset, which is the difference between the sample clocks at the D/A converter of the transmitting DUT and digitizer. Use this node before MT Demodulate QAM. You might need to call this node multiple times for high values of sample clock offsets.

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    input complex waveform

    The modulated complex baseband waveform data.

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    t0

    Trigger (start) time of the Y array.

    Default: 0.0

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    dt

    Time interval between data points in the Y array.

    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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    samples per symbol

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

    Default: 16

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    matched filter coefficients

    An ordered array containing the desired matched filter coefficients. Wire the matched filter coefficients parameter of MT Generate Filter Coefficients to this parameter. When generating the filter coefficients, ensure that the value of the matched samples per symbol parameter of MT Generate Filter Coefficients is equal to the value of the samples per symbol input.

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    clock phase computation window (symbols)

    Length of the symbol window to use in computation of the symbol timing offset in each iteration. Use a higher value to improve the accuracy of the estimated clock phase and sample clock frequency. Use a smaller value if the expected sample clock offset is large.

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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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    output complex waveform

    The baseband complex waveform corrected for the estimated sample clock frequency offset.

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    t0

    Trigger (start) time of the Y array.

    Default: 0

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    dt

    Time interval between data values in the Y array.

    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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    sample clock frequency error

    The estimated offset, in parts per million (ppm), as the difference between the sample clock frequencies at the generator and analyzer. For example, if the symbol rate set at the analyzer is 30 ppm more than the corresponding symbol rate set at the generator, the parameter returns a value of -30 ppm.

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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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