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niUSRP Fetch Rx Data (niUSRP Fetch Rx Data (2D CDB)) (G Dataflow)

Last Modified: April 2, 2018

Fetches complex, double-precision floating-point data from the specified channels.

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session handle

Instrument session.

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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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number of samples

Number of samples to fetch from the acquisition channel. For finite acquisitions, if you specify a value of -1, NI-USRP returns all the remaining samples. NI-USRP returns the samples when the requested number of samples is retrieved from the device or when the timeout is exceeded, whichever happens first.

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timeout

Time to wait, in seconds, before returning an error if the requested number of samples have not been acquired.

Default: 10

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channel list

Channel(s) from which to fetch the data.

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session handle out

Reference to your instrument session to be 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

Received baseband samples as an array of complex, double-precision floating-point data. The real and imaginary parts of this complex data array correspond to the in-phase (I) and quadrature-phase (Q) data, respectively. The total number of elements returned in the array equals the value of the number of samples input x the number of channels. Each row of the 2D array corresponds to a separate channel.

The time between samples in the waveform (the sample period) equals 1 divided by the coerced I/Q rate. Determine the coerced I/Q rate by reading the IQ Rate property after you set it or by reading the coerced IQ rate output of Configure Signal.

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timestamp

Timestamp of the first receive (Rx) sample returned and the time associated with the first sample of the waveform, according to the onboard device timer.

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whole seconds

Integer number of seconds for the time associated with the first sample of the waveform, according to the onboard device timer.

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fractional seconds

Double-precision, floating-point value representing the remaining fraction of a second for the time associated with the first sample of the waveform, according to the onboard device timer.

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:

  • USRP-2900/2901
  • USRP-2920/2921/2922
  • USRP-2930/2932
  • USRP-2940/2942/2943/2944/2945
  • USRP-2950/2952/2953/2954/2955


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