Create Analog Signal
Creates an analog signal. You can create various periodic waveform signals as well as noise, multi-tone, or DC signals. You also can use a formula to define a signal. Use Create Analog Signal to create arbitrary signals. For example, you can use Create Analog Signal to create a signal to use as a stimulus for a hardware device. Create Analog Signal can run in continuous signal mode or repeated signal mode, depending on whether you place a checkmark in the Repeated signal checkbox. The default is continuous signal mode.
| Parameter | Description |
|---|---|
| Output Signal | Displays the signal the step creates. |
| Configuration | Contains the following options:
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| Execution Control | Contains the following option:
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Create Analog Signal Details
In continuous signal mode, the signal that Create Analog Signal creates at each iteration is contiguous to the previous iteration. The result is a signal with a continuously increasing time stamp and phase continuity. You can use the continuous signal mode to continuously generate a signal with arbitrary frequency or a non-repetitive noise signal with an analog output device if the device supports updating the output buffer while running.
In repeated signal mode, this step calculates the signal only during the first iteration of the step after you click the Run button or, in LabVIEW SignalExpress, the Reset Signal button and each time you change a configuration parameter. The signal then repeats with the same time stamp and start phase. National Instruments recommends that you use repeated signal mode if you generate the signal with an analog output device that does not support updating the output buffer while running, such as the devices that NI-FGEN Arbitrary Waveform supports.
Signal Frequency Coercion
If you select a standard periodic signal type, you can place a checkmark in the N periods checkbox to coerce the signal frequency you specify so that Create Analog Signal creates a signal with an integer number of periods. The periods repeat without phase discontinuities. If you place a checkmark in the N periods checkbox, the actual coerced values overwrite the input value you type. When you select a multi-tone signal type, Create Analog Signal coerces the Start freq. (Hz), Stop freq. (Hz), and Step freq. (Hz) values to create a repeatable signal. Place a checkmark in the Export coerced values checkbox to export coerced frequency values as an output of Create Analog Signal.