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Use the SVT Initialize Swept Sine (DAQmx) VI to create a new swept-sine task for a designated device, source channel settings, and acquisition channel settings. Swept-sine measurements in the NI Sound and Vibration Measurement Suite supports only measurements on a single device with output and input capabilities.

Use the Configure Swept Sine VIs to configure scaling, test frequencies, averaging, delays, and other measurement settings. The Configure Swept Sine VIs allow control over basic and advanced measurement parameters. The order in which you place the Configure Swept Sine VIs enables you to customize a swept-sine measurement. For example, you can generate 100 logarithmically spaced test frequencies in the audio range, then apply inverse A-weighted scaling to the excitation level by adding code similar to that in the following block diagram into the swept-sine application.

You can use the Configure Swept Sine VIs to customize your swept-sine application. For example, to speed up a swept-sine measurement, reduce the settling or integration time specified by the SVT Set Swept Sine Averaging VI. You also can configure the device integrated electronic piezoelectric (IEPE) excitation with the SVT Set Swept Sine Coupling and IEPE Excitation (DAQmx) VI. Furthermore, you can reduce the block duration input to SVT Set Swept Sine Block Duration VI.

Note  The minimum block duration is limited by the capabilities of the computer processing the measurement. A very small block duration can result in a loss of continuous processing, causing the swept-sine measurement to stop and return an error.

Use the SVT Start Swept Sine (DAQmx) VI to begin the data generation and acquisition. Initially, this VI fills the device output buffer with zeros before writing the first test frequency excitation.

The SVT Swept Sine Engine (DAQmx) VI continually acquires data and processes it to remove samples acquired during delays, transitions, and settling periods. The SVT Swept Sine Engine (DAQmx) VI performs measurement analysis on samples acquired during integration periods. This VI updates the excitation to excite the DUT at the next test frequency after integrating sufficient data at the current test frequency.

Note  The transition to the next excitation tone, both frequency and amplitude, always occurs at a zero crossing to minimize transients introduced to the DUT.

Use the Read Swept Sine Measurements (DAQmx) VIs to read the raw measurements, scale the measurements, and perform additional conversions to display and report the data in the desired format.

Use the SVT Close Swept Sine (DAQmx) VI to stop the generation and acquisition, and clear the swept-sine task.