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,
• Click the Signal button on the toolbar and select "Show signal".
• Press enter key.
• Right-click and select "Show signal" from the context menu.

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

• Panning
  Right mouse button drag (can be changed in Graph Preferences)
• Scaling
  Mouse wheel
• Zoom in around the cursor position
  Double click
• Rectangle zoom
  Left mouse button drag（can be changed in Graph Preferences）
• Resetting the range
  Click the Reset button on the toolbar or right-click and select "Reset Range" from the context menu.

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.

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

• Show/Hide Signals: Clicking on a legend toggles between showing and hiding the corresponding signal.
• Change legend: By right-clicking on a legend, you can select a property to be displayed as a legend from "Measurement date", "Tag", and "Original file name".

  

• Reorder legend: When multiple signals are displayed, you can reorder the legend by drag and dropping the legends.

Chart view setting

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

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.
   • Automatic (default)
   The signal with the largest vertical width is drawn first.
   • Legend order
   The signals are drawn in legend order.
   • Manual
   When selected, the "Order" item appears in the list. Click a cell and enter a value to change it.

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

• Copying and pasting the view range

  The operation is the same as copying and pasting the view range, but in the case of individual chart, the chart where the cursor is currently placed will be the target of copy and paste of the range.

• Replacing the chart position

  By drag and dropping the legend to another chart area, you can change the order of the charts.

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.

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.

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.

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.

• Tag

  An arbitrary string to be saved as a tag for the record to be saved.

• Save folder

  Select from "Same as original record" or "Loaded data"

• Physical Quantity

  Use to change the physical quantity

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.

• Split scheme

  You can select from the following three split schemes.

  1. Constant time interval
     Split at a specified time interval.
  2. Constant number of samples
     Split at a specified number of samples.
  3. Specify time
     Set split points to multiple arbitrary times. In the example above, split points are set at the 1, 3, and 4 seconds of the original record, and the record is split into four records (0 to 1 second, 1 to 3 seconds, 3 to 4 seconds, and 4 seconds to the end of the signal). 　 　

• Advanced Settings
  • If you check the "Not save records less than specified samples" checkbox and enter the number of samples, records with less than the specified number of samples after splitting will not be saved.
  • Filtering the target records
    　If you set up a filter condition, only the records that match the condition will be split.

Execute record splitting

There are two ways to execute record splitting.

1. Batch split of records in folders
   • Press the Calc button on the toolbar, and select the split setting you want to use from "Split Records". You can select "Simple Split" or user-defined setting.
   • In the dialog box that appears, specify the target folder and the save folder, and click the Execute button to execute the split.
   • Target Folder
     Selected folder : All records stored in the currently selected folder will be split.
     Selected folder and subfolders：All records stored in the currently selected folder and all folders under the selected folder will be split.

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.

• Click the Signal button on the toolbar and select "Show Spectrogram"
• Right-click on the record and select "Show Spectrogram" from the context menu.

• Resolution Slider

  This slider is used to change the frequency and time resolution. The higher the frequency resolution, the lower the time resolution, and vice versa. To specify the resolution in numerical values, right-click on the spectrogram view and select "Chart View Setting".

• Copying and pasting of spectrogram settings

  If you have multiple spectrogram views open, you can apply the settings of one view (contour level, frequency resolution) to another view.

  • Copying spectrogram settings

  Right-click on the spectrogram view you want to copy, and select "Copy Spectrogram Setting" from the context menu (or press Alt + C).

  • Pasting spectrogram settings

  Right-click on the spectrogram view to be pasted, and select "Paste Spectrogram Setting" from the context menu. (or press Alt + V)

• Other operations

  Mouse operations such as scaling, panning, operations on the legend, copying and pasting the view range, and saving images are all common to the signal view.

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.

• Legend

  Selects the legend type

• Resolution

  Change the resolution by moving the slider or entering a numerical value for the frequency resolution. The range that can be changed is limited by the sampling rate and sampling duration of the record.

• Contour level

  Enter the minimum and maximum values. (By default, the value is calculated automatically.)

Scatter plot view

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

• 2-D plot

  Plots the raw waveform values of two records on the XY plane, with the value of the first record as X and the value of the second record as Y. The difference in sampling rate between the two records is not taken into account, and the n-th point of each raw waveform becomes a pair and a point on the plane. If the number of samples in the two records is different, it can still be displayed, but in that case, the samples will be plotted up to the point that a pair can be created.

• 3-D plot

  Plots the raw waveform values of the three records in XYZ space, with the value of the first record as X, the value of the second record as Y, and the value of the third record as Z. Sampling rate and number of samples are handled in the same way as for 2D plots.

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

• Click the Signal button on the toolbar and select "Scatter".
• Right-click on the record list and select "Scatter".

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

• Unify the range of all axes

  To unify the view range of X-axis and Y-axis, right-click on the scatter plot view and select "Unify all axes range" from the context menu.

• Other operations

  Mouse operations such as scaling, panning, operations on the legend, copying and pasting the view range, and saving images are all common to the signal view.

3-D scatter plot

Mouse operation

• Rotate viewpoint : Left button drag
• Scaling：Mouse wheel
• Zoom in：Double-click

Pannign and rectangel zoom are not supported.