In the Results module, the spectral functions are plotted and written to files or the MATLAB workspace. Information about the time response dataset, the references and responses in the channels sieve, and the frequency range and resolution is displayed in the Data Info panel. Hovering the mouse pointer over ATI Name will show some additional information about the data file or workspace imat_fn. Information about the signal processing parameters defined in the Setup module that were used to generate the spectral functions is displayed in the Setup Info panel. The STOP button will stop a file write in progress.
Selecting a plotted line with the mouse pointer and holding down the middle button will highlight that line and its corresponding entry in the plot legend. Selecting a line in the plot legend with the mouse pointer and holding down the middle button will highlight that line and the corresponding line in the plot axes (this feature is not available in Matlab R2014b). The associated line in the other plot axes will also be highlighted, if applicable, and the name from the legend will be displayed in the message line at the bottom of the window.
Spectra : Clear Lower & Clear Upper – Enter numeric values in Hertz for the Clear Lower and Clear Upper frequencies. The x-limits of the upper and lower plot axes are set to the Clear Lower and Clear Upper frequencies. The spectral functions are truncated to the Clear Lower and Clear Upper frequency range when written to a file or a workspace imat_fn, or sent to other IMAT applications or plots. There is a context menu on the edit boxes to set the Clear Lower and Clear Upper frequencies to the full Nyquist bandwidth (0 - Nyquist), the customary alias-protected bandwidth (0 – Span), or the plot axes X limits..
Plot Function – Select the spectral function type to plot. The available selections are dependent on which measurements (FRF, coherence, auto-spectra, cross-spectra, etc.) were computed during the signal processing.
When a complex-valued function is plotted, and the complex format is magnitude and phase, there is a context menu on the upper axes y-label ("Phase (deg)") that contains a selection for the "clean phase" option. If "clean phase" is enabled, points where the phase differs by more than 270 degrees from the previous point are not displayed. The "clean phase" option can also be accessed from the Display menu for the Results module.
References – Select the reference channels to plot. Use the context menu to select the attributes listed or displayed in the legend, or to plot drive points or reciprocals.
Responses – Select the response channels to plot. Use the context menu to select the attributes listed or displayed in the legend, choose an FRF sorting option, find a channel, or open the Channels dialog.
Selecting Find Channel from the context menu presents an input dialog into which a response coordinate (e.g., 1234X+ or 1234X) or node (e.g., 1234) is entered. Any channel with the specified coordinate or node will be found and plotted. The direction sense (i.e., +/−) is not required and if omitted, any response coordinate with the positive or negative sense of the specified direction will be found.
FRF sorting is intended to rank the channels listed in the Responses listbox from "worst" to "best." The Sort by options are either None, Coherence, or Summary Coherence. Sorting by coherence is based on the average coherence for each response over the plotted frequency range. Sorting by summary coherence is based on the integral of the coherence multiplied by the power spectrum mode indicator function and dividing it by the integral of the power spectrum mode indicator function over the plotted frequency range. Refer to [3] for more information on summary coherence. An FRF sorting value between zero and one is assigned to each response, which is displayed in the plot legend. Sorting by coherence or summary coherence from lowest to highest places channels that are most likely to be nonfunctional at the top of the list. Other reasons for low coherence or summary coherence could be locations with little or no measured response, such as accelerometers on a fixed base. Therefore, it is recommended that the user view these channels manually to determine whether or not the responses are nonfunctional.
Slide Show – The slide show is an automated means to sequentially plot spectral functions by incrementing one response channel. All of the selected references are plotted, if applicable (e.g., FRF and cross-spectra). The slide show controls on the toolbar are meant to have similar functionality to the buttons on a DVD player remote control. The slide show can step one response forward or reverse, or play the responses forward or reverse sequentially. In the slide show play mode, the response channel is automatically incremented on a timed interval. The Slide Show Pause Interval is set in the Preferences dialog.
Tools > Results > Send Plot Channels to UIPLOT – Sends the plotted spectral functions, truncated to the Clear Lower and Clear Upper frequency range, to UIPLOT.
Tools > Results > Send Plot Channels to IMAT Plot – Sends the plotted spectral functions, truncated to the Clear Lower and Clear Upper frequency range, to an IMAT plot figure.
Tools > Results > Send Plot Channels to spVIEW Spectra – Sends the plotted spectral functions, truncated to the Clear Lower and Clear Upper frequency range, to the spVIEW Spectra module. If spVIEW is already running, the functions are sent to this instance of spVIEW, otherwise a new spVIEW is started.
Tools > Results > Send Mode Indicators to spVIEW MIFs – Computes the selected mode indicator functions from the FRFs (if available) and sends them, truncated to the Clear Lower and Clear Upper frequency range, to the spVIEW MIFs module. A list dialog is presented from which to select the MIFs to send. The available MIFs are listed below. If spVIEW is already running, the functions are sent to this instance of spVIEW, otherwise a new spVIEW is started.
PSMIF |
Power Spectra Mode Indicator Function |
CMIF |
Complex Mode Indicator Function |
QMIF |
Quadrature Mode Indicator Function, which is the CMIF of the imaginary part of the FRF |
MMIF |
Multivariate Mode Indicator Function |
NMIF |
Normal Mode Indicator Function |
Tools > Results > Send Auto Spectra to spVIEW SPL – Sends the auto spectra functions (if available), truncated to the Clear Lower and Clear Upper frequency range, to the spVIEW SPL module. If spVIEW is already running, the functions are sent to this instance of spVIEW, otherwise a new spVIEW is started.
Tools > Results > Write Results Info Structure to CSV File – When the spectral functions are written to an imat_fn in the MATLAB workspace, an accompanying info structure is also created. The imat_fn can be written from the workspace to an AFU or universal file using writeadf or writeunv, respectively. Use this tool to write an info structure to a CSV file. Select the info structure from the variable selection dialog, then select the corresponding AFU file. The CSV file written has same filename, but .info.csv is appended to the extension.