FFT (Fast Fourier Transform)

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The FFT chart shows the Fast-Fourier Transform for one or multiple components simultaneously. Similar to AVD Charts, users can plot the FFT chart for all components (H1, H2, V). Note that the users can only view the FFT plots if the records library database is available in their local disk.

Chart

Show/hide chart general features:

•Legend: show/hide the chart series legend

•Records: show/hide individual records (components & triplets)

•X Log: switch the X-axis scale between Linear and Logarithmic

•Y Log: switch the Y-axis scale between Linear and Logarithmic

•X Grid: show/hide grids on the X coordinates (parallel to Y-axis)

•Y Grid: show/hide grids on the Y coordinates (parallel to X-axis)

•Norm X-Axis: switch the X-axis normalization on/off (normalizes X-axis such that maximum value is 1.0)

•Norm Y-Axis: switch the Y-axis normalization on/off (normalizes Y-axis such that maximum value is 1.0)

•Freeze X-Axis: freeze X-axis scale to its current range (min,max)

•Freeze X-Axis: freeze Y-axis scale to its current range (min,max)

Components

Show/hide a specific record component in the chart:

•H1 Comp: show/hide 1st Horizontal Component

•H2 Comp: show/hide 2nd Horizontal Component

•V Comp: show/hide Vertical Component

Peaks

Show/hide the following chart annotations:

•Absolute maximum: display the absolute maximum value of the acceleration, velocity and displacement charts

•Maximum: display the maximum value of the acceleration, velocity and displacement charts

•Minimum: display the minimum value of the acceleration, velocity and displacement charts

Modification

For modified records, show/hide the following:

•Original: display the original record (before modification)

•Modified: display the modified record (after modification)

•Line Wt (Mod): display the modified chart with a heavier line thickness

Copy Data

Users may select the output chart of interest and have the ability to perform the following:

•Copy Metadata, copies the record view record data, including header and footers of the data, which makes it easy to create record tables in MS Excel or Word.

•Copy Chart Data, copies the chart series data which can be exported to create tables in MS Excel or Word.

•Copy Chart Image, take a screenshot of the selected chart

The figures below show the Fast Fourier Transform (FFT) charts for samples records.

Figure: FFT chart of the modified CMHS record.

Figure: FFT chart of the original and modified TCU050 record.