Wave Generator (Arbitrary) (G Dataflow)

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Last Modified: June 25, 2019

Generates a signal containing an arbitrary wave.

wave table

One cycle of the waveform used in creating the output arbitrary wave.

reset phase

The initial phase of the arbitrary wave.

True	Sets the initial phase to phase in and sets the initial time to t0 if you configure this node to return a waveform. Sets the initial phase to phase in if you configure this node to return a double-precision, floating-point number or an array of double-precision, floating-point numbers.
False	Uses the values of phase out and t0 from when the node last executed as the initial phase and time of the wave if you configure this node to return a waveform. Uses the values of phase out from when the node last executed as the initial phase of the wave if you configure this node to return a double-precision, floating-point number or an array of double-precision, floating-point numbers.

True

Sets the initial phase to phase in and sets the initial time to t0 if you configure this node to return a waveform.

Sets the initial phase to phase in if you configure this node to return a double-precision, floating-point number or an array of double-precision, floating-point numbers.

False

Uses the values of phase out and t0 from when the node last executed as the initial phase and time of the wave if you configure this node to return a waveform.

Uses the values of phase out from when the node last executed as the initial phase of the wave if you configure this node to return a double-precision, floating-point number or an array of double-precision, floating-point numbers.

Default: False

amplitude

Amplitude of the arbitrary wave.

Default: 1

frequency

Frequency of the arbitrary wave in normalized units of cycles/sample.

Default: 10

phase in

The initial phase, in degrees, of the arbitrary wave.

phase in is valid only when you set reset phase to True.

Default: 0

interpolation

The type of interpolation this node uses to generate the arbitrary wave.

Name	Value	Description
None	0	No interpolation.
Linear	1	Linear interpolation.

Default: None

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

sample rate

Sample rate in samples per second.

Default: 1000

samples

Number of samples in the signal.

samples must be greater than 0. Otherwise, this node returns an error.

This input is available when you configure this node to return a waveform or an array of double-precision, floating-point numbers.

Default: 1000

t0

Timestamp of the output signal. If this input is unwired, this node uses the current time as the timestamp of the output signal.

This input is available only if you configure this node to return a waveform.

arbitrary wave

Output arbitrary wave.

This output can return the following data types:

Waveform
Double-precision, floating-point number
1D array of double-precision, floating-point numbers

phase out

Phase of the signal in degrees.

error out

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

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.

Algorithm for Generating an Arbitrary Wave

If the sequence Y represents arbitrary wave, this node generates the sequence according to the following equation:

y_{i} = a * arb ({phase}_{i})

for i = 0, 1, 2, …, n - 1

where a is amplitude and n is samples.

This node calculates $arb ({phase}_{i})$ using the following equation:

arb ({phase}_{i}) = W T (\frac{({phase}_{i} modulo 360) \times m}{360})

where

m is the size of wave table
$W T (x) = wave table [int (x)]$ if interpolation = 0 (no interpolation)
WT(x) is the linearly interpolated value of $wave table [int (x)]$ and $wave table [(int (x) + 1) modulo m]$ if interpolation = 1 (linear interpolation)
phase_i = initial_phase + frequency
initial_phase is phase in if reset phase is True
initial_phase is the phase out from the previous execution of this instance of the node if reset phase is False

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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