Scope View provides a number of powerful visual tools to enhance analysis and display.

Transcription

1 Scope View Scope View: LabChart 7.1 or later Scope View in LabChart is an alternative way of displaying LabChart data. Together with PowerLab, Scope View in LabChart provides and expands upon the display and analysis capabilities of conventional digital storage oscilloscopes. Similar to a digital oscilloscope, Scope View provides a means to record and view consecutive intervals of data. Each data sweep is recorded and represented as a page. The resulting pages, or sweeps, can then be averaged and overlaid. New display features in Scope View Scope View provides a number of powerful visual tools to enhance analysis and display. The Scope Overlay options dialog allows the user to change the color saturation of the overlaid signals. The 3D Depth feature is used to modify the distance between each trace along the z-axis. This helps users distinguish the overlaid traces and easily identify any changes in signal amplitude or timing. To improve the contrast between the background and the signal trace, the default white background can be easily changed to black. Simply use the black background On/Off switch in Scope View. Using the Channel color drop-down list, a user can easily change the color of the selected and overlaid pages. Figure 1. The line color Saturation and 3D depth features in Scope View are easily adjusted using the Scope Overlay option. Page 1/8

2 Analysis features in Scope View Opening LabChart Scope View To open Scope View, select the Scope View icon in the Window icon on the LabChart Toolbar. Alternatively, open Scope View by clicking Window > Scope View icon. Page Generation in Scope View Figure 2. Opening Scope View in LabChart. With the introduction of LabChart, three sweep (page) analysis modes are now available in Scope View. In LabChart data can be recorded in and analysed using Block, Event and the new Comment Mode. These are selected in the drop-down menu as shown in Figure 2. The three modes are discussed in order. Figure 3. Scope View in LabChart provides three alternative analysis modes. Page 2/8

3 Block Mode In Block Mode the interval or width of a sweep is determined by the duration of each data block, as set by the user. Block Mode is ideal for a number of applications; for example, when displaying and analysing Evoked Potentials over fixed periods of repeated stimulus/response trials. To configure Block Mode open the Sampling dialog window (Fig. 4). In the Sampling panel a user can select to use, or not use, a Trigger to start recording. Triggering options include: The Trigger source (Channel, External Trigger, Stimulator Event) can be selected from a drop down menu. The threshold required used to trigger the start of recording can be adjusted using the slide bar. Triggering can be set to trigger above the threshold (i.e. contact closure) or below the threshold (contact opening) by choosing the Trigger slope icons. When the trigger option is used, data monitored before recording starts can be shown in Chart View. This is done by ticking the Show data while waiting for trigger box. The length of the Block period can be set in the Stop sampling panel located within the Sampling dialog panel. Note that the Block period, can also be set in the Scope View toolbar (see Figure 3). To set the Block length, tick the Fixed duration check box and enter the block width (the units range from ms to h:mm:ss). If the triggering option is enabled, the sampling can be set to begin either at the onset of the Trigger, or when the Trigger ends. Clicking the Fixed duration check box enables the options in the Multiple blocks panel to be configured. Scope View can be configured to average any number of Blocks and to any number of repeats. In the example shown in the Figure below, Scope View is averaging three pages and the process is repeated until sampling is manually stopped. Recording can be started by clicking Start in either the Scope View or Chart View panels. When in Block Mode, the data will appear as blocks in Chart View. Page 3/8

4 Figure 4. The Block Mode sampling parameters are configured in the Sampling dialog window. Event Mode When a signal is cyclical, LabChart is able to automatically mark peaks and other periodic parameters as events. The Event Mode in Scope View then uses these event markers to generate pages. Examples of cyclical event suited to analysis in Scope View include: ECG recording Pulse recording To use Event Mode in Scope View: Choose Event Mode from the Scope View menu. Event Mode in Scope View requires the Event Markers are present within the Chart View channel. Event markers can be generated by a number of different means including: Using Cyclic Measurements Using the Peak Analysis module The Spike Histogram module The Event Markers can be seen in Figure 4 in both the Scope View and Chart View panes. Page 4/8

5 Figure 5. The Event Mode sampling parameters are configured in the Event Mode Settings dialog window. Comment Mode Comments that are added to LabChart data during or after recording can also be used to generate pages using Comment Mode. This is a new feature introduced in LabChart. Example applications of using Comment Mode in Scope View include: EEG studies (Fig. 6) GSR studies The Comment Mode Settings window in Scope View allows the user to select the source and type of the comments, page settings and averaging. To use Comment Mode in Scope View: Select the Comment Mode for Scope View and open the Comment Mode Settings dialog panel. In the Comment channels panel select the channel for Scope View analysis. Page 5/8

6 If the comments are to be filtered for text for inclusion as sweeps, tick the Containing check box and enter the text on against which are to be matched. In the Page Settings section enter the before and after the Comment time to determine the width of the sweep. Tick the Average check box and choose the number pages to average. In the example shown no averages were made. The example below shows an overlay of seven pages corresponding to the selected comment. Figure 6. The Comment Mode sampling parameters are set in the Comment Mode Settings dialog window. Analysis in Scope View Averaging Pages Sweeps are recorded and displayed in the Page Explorer at the left hand side of the Scope View. When averaging a page becomes an average of subpages (sweeps). The sweep data remains available The averaging options can be accessed through the Averaging and Overlay icons in the Scope View menu or by right clicking in Page Explorer to list the Averaging options. Average: the pages or subpages selected by the user are averaged. Un-average: the pages or subpages averaged by the user are un-averaged (revert to raw). Multiple average: To recalculate and apply averaging for selected/all pages. There is an option to choose between page-based or time-based averaging. Page 6/8

7 Overlaying Sweeps Tick the Overlay Pages checkbox and set the number of pages to be overlaid using the Overlay page control slider (Fig. 7). Overlaid pages will be indicated on the left by the green bracket with the averaged trace appearing in black on the right. Select the padlock icon or right click in the Page Explorer to lock a page so that it will always show the locked page(s) in the overlay. Excluding Pages from Analysis Figure 7. The panel used to overlay page sweeps. To exclude a selected page or sweep from the averaging, click on the Scope Averaging Exclusion icon in the settings dialog window. For exclusion by defined criteria right click in the Page Explorer pane. The options are shown in the following Figure. Criteria include: The length of the sweep proportional to the longest sweep in the set. Where a sweep contains data that is out of range or exceeds voltages defined by the user. Figure 8. The Scope Averaging Exclusion dialog window. Detailed information on the Scope View features is available in the Help Center in LabChart. Page 7/8

8 Page 8/8