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IviSpecAn Fetch Y Trace (G Dataflow)

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    Last Modified: October 24, 2017

    Returns the trace the spectrum analyzer acquires. The trace is from a previously initiated acquisition. Call IviSpecAn Initiate to start an acquisition. Call IviSpecAn Acquisition Status to determine when the acquisition is complete. Once the acquisition is complete, call the Fetch Y Trace node to return the trace. You may call IviSpecAn Read Y Trace instead of IviSpecAn Initiate. IviSpecAn Read Y Trace starts an acquisition, waits for the acquisition to complete, and returns the trace in one node call. Use IviSpecAn Fetch Y Trace when acquiring multiple traces. Use a different trace name for each IviSpecAn Fetch Y Trace call. You may also call IviSpecAn Fetch Y Trace after calling IviSpecAn Read Y Trace to acquire subsequent traces. The array returns data that represents the amplitude of the signals of the sweep from the start frequency to the stop frequency (in frequency domain, in time domain the amplitude array is ordered from beginning of sweep to end). The IviSpecAn>>Basic Operation>>Amplitude Units property determines the units of the points in the amplitude array. The array returns data that represents the amplitude of the signals of the sweep from the start frequency to the stop frequency (in frequency domain, in time domain the amplitude array is ordered from beginning of sweep to end). The IviSpecAn>>Basic Operation>>Amplitude Units property determines the units of the points in the amplitude array. This node does not check the instrument status. Typically, you call this node only in a sequence of calls to other low-level driver nodes. The sequence performs one operation. You use the low-level nodes to optimize one or more aspects of interaction with the instrument. If you want to check the instrument status, call IviSpecAn Error-Query at the conclusion of the sequence.

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    instrument handle

    The instrument handle you obtain from the IviCounter Initialize node or IviCounter Initialize With Options node. The handle identifies a particular instrument session.

    Default: None

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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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    trace name ("")

    Pass the name of the trace for the desired amplitude array. This control accepts either a virtual repeated capability name or an instrument-specific trace name. Users who want to achieve interchangeability should use a virtual repeated capability name. The virtual repeated capability name should be sufficiently specific to the test system such that it is unlikely to conflict with a physical repeated capability name. Virtual repeated capability names are aliases for instrument-specific trace strings. The instrument-specific trace strings can differ from one instrument to another. Virtual repeated capability names allow you to use and swap instruments without having to change the trace names in your source code. You specify virtual repeated capability names in MAX. Default Value: ""

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    array length (2048)

    Pass the number of Amplitude array points requested. Default Value: None

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    instrument handle out

    The instrument handle that you obtain from the IviSpecAn Initialize Node or IviSpecAn Initialize With Options Node. The handle identifies a particular instrument session.

    Default: None

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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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    amplitude

    Returns the amplitude waveform that the spectrum analyzer acquires. Units: The units are determined by setting the Amplitude Units parameter of the IviSpecAn Configure Level.vi or by setting IviSpecAn>>Basic Operation>>Amplitude Units property. Note: The IviSpecAn Query Trace Size.vi returns the number of points the spectrum analyzer acquires. Pass a ViReal64 array with at least this many elements.

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    actual points

    Indicates the number of points the VI places in the Amplitude array.

    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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