This tab is used to setup one or more output signals from the acquisition front end hardware to one or more shakers.
WARNING: This option only functions with connected to front end hardware that can receive source signals from the ME'scope Acquisition software.
Output signals are used to drive one or more shakers, and provide more controlled excitation of the test article.
Broad band random or chirp signals are used to excite structural resonances over the frequency Span of the acquired measurements.
Source Tab Showing Burst Random Output from Source Channel 1.
To setup a Source signal,
In the Signal Type section, choose a signal type
Select a Burst Width percentage
In the Active column, make one or more channels active
in the Range column, select a voltage range for the signal.
In the DOF column (optional), select a DOF on the test article to which the signal will be applied by a shaker.
Random & Chirp source signals are synthesized over the Frequency Span selected in the Sampling tab, and output to the front end hardware.
A random signal is synthesized with a constant magnitude and random phase
A chirp signal is a fast sine sweep signal, that is synthesized with a constant magnitude and random starting time
Defines the frequency range of all Source signals as percentages of the Minimum & Maximum percentages of the Frequency Span chosen on the Sampling tab.
Defines the percentage of the sampling window samples over which the synthesized random or chirp signals are non-zero. The remainder of the source samples are output as zeros. Outputting a source signal with zeros in it has the effect of removing all forces from the test article. Hence the acquired structural responses will decay to zero.
The Burst Width is chosen so that the acquired response waveforms will decay essentially to zero within the sampling window
A signal that decays within the sampling window is completely contained within the window. Therefore its spectrum is leakage-free and doesn't require special windowing to reduce leakage effects.
The amount of damping in the test article determines how quickly its structural responses will decay to zero within the sampling window
To determine the required burst width,
Choose a Burst Width percentage.
Execute Acquire | Front End Scope.(F2)
Scroll through the time waveforms in the upper graphics area to display the response channels of data
If the response signals decay essentially to zero within the window (as shown below), the signals are completely contained within the sampling window, and no special time domain windowed is required in order to reduce leakage in their spectra.
Correct Burst Random Output Showing Responses Contained In The Window.