niRFSA_FetchIQSingleRecordComplexF64

NI RF Vector Signal Analyzers

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niRFSA_FetchIQSingleRecordComplexF64

ViStatus = niRFSA_FetchIQSingleRecordComplexF64( ViSession vi, ViConstString channelList, ViInt64 recordNumber, ViInt64 numberOfSamples, ViReal64 timeout, NIComplexNumber* data, niRFSA_wfmInfo* wfmInfo);

Purpose

Fetches IQ data from a single record in an acquisition. The fetch transfers acquired waveform data from device memory to PC memory. The data was acquired to onboard memory previously by the hardware after it was initiated.

This function is not necessary if you use the niRFSA_ReadIQSingleRecordComplexF64 function, as the fetch is performed as part of that function.

Parameters

Input
Name Type Description
vi ViSession Identifies your instrument session. vi is obtained from the niRFSA_init or the niRFSA_initWithOptions functions and identifies a particular instrument session.
channelList ViConstString Specifies channels from which to fetch data.
recordNumber ViInt64 Specifies the record to fetch. Record numbers are zero-indexed.
numberOfSamples ViInt64 Specifies the number of samples to fetch.
timeout ViReal64 Specifies in seconds the time allotted for the function to complete before returning a timeout error. A value of -1 specifies the function waits until all data is available. A value of 0 specifies the function returns available data immediately.
Output
Name Type Description
data NIComplexNumber* Returns the acquired waveform.
wfmInfo niRFSA_wfmInfo* Returns the absolute and relative timestamp for the operation, the dt, and the actual number of samples read.

The following list provides more information about each of these properties:
  • absolute timestamp—specifies the timestamp in seconds of the first fetched sample that is comparable between records and acquisitions.
  • relative timestamp—returns a timestamp that corresponds to the difference in seconds between the first sample returned and the Reference trigger location.
  • dt—returns the time interval between data points in the acquired signal. The IQ data sampling rate is the reciprocal of this value.
  • actual samples read—returns an integer representing the number of samples in the waveform.
  • offset—specifies the offset to scale data in mx+b form.
  • gain—specifies the gain to scale data in mx+b form.

Return Value

Name Type Description
status ViStatus Returns the status code of this operation. The status code either indicates success or describes an error or warning condition. You examine the status code from each call to an instrument driver function to determine if an error occurred.

To obtain a text description of the status code, call the niRFSA_error_message function. To obtain additional information about the error condition, call the niRFSA_GetError function. To clear the error information from the driver, call the niRFSA_ClearError function.

The general meaning of the status code is as follows:

Value
 Meaning
0 Success
Positive Values Warnings
Negative Values Errors
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