Signal analysis

Signal view

To display the signal waveform, do one of the following operations.

  1. Double-click a record you want to display in the record list.
  2. With selecting records,

If you want to display multiple records in a window, use the method 2.

Signal view operations

Changing the view range

Changing the view range by mouse

The zoom mode switch button allows you to change the scaling direction to XY axis, X axis only, or Y axis only.

Specifying the range by numerical value

Right-click on the signal view and select "Range setting" from the context menu. Enter values in the range setting dialog and click OK to update the range.

You do not need to enter all fields. Blank fields will use the current state.

Copying and pasting the view range

When you have multiple signal views open, you can apply the view range of one window to another.

  1. Right-click on the signal view you want to copy from and select "Copy range" from the context menu (or press C key on the keyboard).
  2. Bring the destination signal window to the front. Right-click on the view and select "Paste range" from the context menu (or press V key on the keyboard).

Changing the view contents

Operation of legend area

Chart view setting

Right-click in the signal view area and select "Chart view setting" from the context menu.

The settings here apply to only a currently displayed chart. If you want to change the global color settings, please set it from Graph Preferences.

  1. Switches the property to be displayed as a legend between Time of measurement, Tag, and Original file name.
  2. Signal list :The order corresponds to the order of the legends.
  3. Color: Click to change the signal color.
    Note that the color can be selected from the eight basic colors, but if you want to change the basic colors itself, set it from Graph Preferences.
  4. Reset the signal colors to the default.
  5. Swaps the left and right axes when displaying two axes (when two physical quantities are displayed in a chart).
  6. Specifing the drawing order Since multiple signals are displayed on top of each other, one signal may be hidden by another signal, making it difficult to see. In such a case, you can change the drawing order algorithm.

Frequency marker

In the frequency spectrum view, CTRL+click adds a frequency marker to the peak near the cursor. To remove the marker, CTRL+click again.

Individual chart for multiple signals

When multiple signals displayed in one chart, right-click and select "Individula chart" from the context menu to display each signal in its own chart. If you resize the window, the layout will be automatically adjusted. To draw them in a single chart again, right-click and select "Gather Charts" from the context menu. If records contains more than three different physical quantities, only individual chart is possible.

Operations specific to individual display

Signal processing

Frequency spectrum

Click the FFT button to switch between the frequency spectrum and time waveform. Only when the frequency spectrum is being displayed, the logarithmic switch button appears on the toolbar, allowing you to switch the horizontal axis to logarithmic scale.

In Sigma, the FFT is performed using all the time region of waveform in one record. If you want to display the frequency spectrum of only a specific time region of one record, clip the signal (see Clipping signals) and press the FFT button.

Trimming signals

By right-clicking in the chart view and select "Trim record", you can trim the waveform into the currently displayed time range and display it in a separate window. This is used when you want to display the frequency spectrum of a specific time range, or when you want to save only a specific time range as a record.

Just trimming a signal does not save it as a separate record. To save it as a separate record, select Save as new record from the context menu.

Signal processing

The Processing button allow you to perform various types of signal processing. The signal processing is overlaid each time it is executed. If you want to return to the original signal, select "Restore" from the Processing button.

Signal processing type
Band pass filter Leaving only the specified frequency band.
Band stop filter Removing only the specified frequency band.
Envelope Simple envelope processing by low-pass filtering after taking absolute values.
Autocorrelation coefficient Correlation coefficient with own signal shifted in time

To save the processed signal, execute Save as new record.

Save as new record

To save the waveform as a separate record after trimming or signal processing, right-click in the chart view and select "Save as new record" from the context menu. Enter the information in the dialog box that appears and click OK to save the record.


Saving and copying signal images

Saving signal images

To save the currently displayed signal as an image, click the Save button or right-click on the signal view and select "Save Image" from the context menu. The first time you click on the Save button, a dialog box will appear asking you to select a folder to save the image. If you want to change the save folder, select "Save image at..." from the context menu.

Copying signal images

To copy the currently displayed signal image to the clipboard, press CTRL+C while the signal view is in the foreground, or right-click and select "Copy Image" from the context menu. The copied image can then be pasted into an application such as PowerPoint.

Splitting records

A raw waveform of single record can be divided into multiple sections, each of which can be saved as a separate record. There are two ways to split a record: using "Simple Split" or creating a "Record Split Setting" and use it.

Splitting a record does not change the original record. Deleting the original record after splitting will have no effect on the splitted record.

Simple split

The simple split allows you to split records at regular time intervals entered in the dialog. For details on how to execute this, see Execute record splitting.

Record split setting

The record split setting allows you to specify a more complex splitting scheme. It is also useful when the same splitting scheme is used many times.

To create or edit a record split setting, select "Record Split Setting" from the Setting button to open the record split setting list window.

To create a new record split setting, click the Add button to open the Split setting edit window.

Execute record splitting

There are two ways to execute record splitting.

  1. Batch split of records in folders

  2. Split selected records

    With one or more records selected in the record list, right-click and select "Split records" from the context menu, then select the split setting you want to use.

Spectrogram view

The spectrogram view shows the result of the short time Fourier transform of the signal as a contour graph with time as the horizontal axis and frequency as the vertical axis. In Sigma, the absolute value of the amplitude of each frequency component is used. To display the spectrogram, do one of the following with selecting records.

Concatenated view of multiple records

When showing the spectrogram with multple records selected, they will be concatenated in the time direction. To change the order, drag and drop the legend.

Advanced settings for spectrogram view

Right-click on the spectrogram view and select "Chart View Setting" to configure the detailed settings for the spectrogram view.


Scatter plot view

Plots the raw waveforms of multiple records on a two-dimensional plane or in three-dimensional space.

Display a scatter plot

To display a scatter plot view, select two records (or records in multiples of two) for a 2-D plot, or three records (or records in multiples of three) for a 3-D plot, and then do one of the following

The selected records will be paired in the order in which they are displayed in the record list. Example: If you have selected records A, B, C, and D, records A and B will be the first series, and records C and D will be the second series.

2-D scatter plot


3-D scatter plot

Mouse operation

Pannign and rectangel zoom are not supported.


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