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Fetch IQ Data (More » 2D I16) (G Dataflow)

Version:
    Last Modified: December 19, 2018

    Fetches binary I/Q data from multiple records in an acquisition.

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    session in

    Instrument session obtained from Initialize With Options .

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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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    samples to read

    Number of samples to fetch.

    A value of -1 specifies that NI-RFSA fetches all samples.

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    Note

    If you set this input to -1, NI-RFSA fetches all remaining samples currently available depending on your settings for the Fetch Relative To property and the Fetch Offset property.

    Number of Samples Not Available

    If the number of samples specified in this input is not available after the time duration specified in the timeout input, Fetch IQ returns no data with a timeout error.

    Default: -1

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    timeout

    Time, in seconds, allotted for the node to complete before returning a timeout error. For the PXIe-5644/5645/5646, PXIe-5668, and the PXIe-5820/5840, this input specifies the time allotted to receive the reference trigger.

    Timeout Value Behaviors

    A value of -1 specifies that the node waits until all data is available. A value of 0 specifies that the node immediately returns available data.

    Default: 10

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    starting record

    First record to retrieve.

    Record numbers are zero-based.

    Default: 0

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    number of records

    Number of records to fetch.

    A value of -1 specifies that NI-RFSA fetches all records in an acquisition. Record numbers are zero-based.

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    If you set this input to 0, this node returns an error.

    Input Value Behaviors

    If starting record is set to a value greater than 0, setting this input to -1 returns an error. If you set starting record to a value greater than 0, set this input to the exact number of records to fetch.

    Default: -1

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    session out

    Reference to your instrument session passed to the next node.

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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.
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    data

    Array of the acquired unscaled, complex waveform for each record.

    Order of the Array

    Each record occupies a row of the two-dimensional array. A record is composed of interleaved I and Q samples, where the order of the array is as follows:

    • Array[0] = I(0)
    • Array[1] = Q(0)
    • Array[2] = I(1)
    • Array[3] = Q(1)
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    wfm info

    Absolute and relative timestamps for the operation, the time interval, and the actual number of samples read.

    Each element of this array corresponds to a record.

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    absolute timestamp

    Timestamp, in seconds, of the first fetched sample that is comparable between records and acquisitions.

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    Note

    The value of the absolute timestamp returned is always 0 for the PXIe-5644/5645/5646, PXIe-5668, and PXIe-5820/5840.

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    relative timestamp

    Timestamp that corresponds to the difference, in seconds, between the first sample returned and the Reference Trigger location.

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    Note

    The value of the relative timestamp returned is always 0 for the PXIe-5644/5645/5646.

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    dt

    Time interval between data points in the acquired signal.

    The I/Q data sample rate is the reciprocal of this value.

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    actual samples read

    Integer representing the number of samples in the waveform.

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    Note

    The actual number of samples for each record can vary if the Number of Samples property changes per step during RF list mode.

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    offset

    Offset to scale data, (b), in mx + b form.

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    gain

    Gain to scale data, (m), in mx + b form.

    Where This Node Can Run:

    Desktop OS: Windows

    FPGA: Not supported

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

    Hardware Support:

    This node supports the following hardware:

    • PXIe-5644/5645/5646
    • PXIe-5663E/5665/5667/5668
    • PXIe-5820/5840


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