# Free marker

Free markers can be added to any position on a 2D graph. Right click with the mouse on the wanted position and add a free marker.

The marker shows us the frequency and amplitude at its position.

With ‘Show marker table’ selected you can see the table of markers - its ID, type, channel, color, its frequency (X-axis), and its amplitude (Y-axis). Here you can adjust the marker visibility, as well as edit their settings, or remove them.

Free markers offer additional options that can be accessed through the marker table Edit button, or by selecting the marker via left-click and then selecting the “Edit processing marker” item in the right-click popup menu.

• Snap to data points - if this option is selected, the position of the marker will be snapped to the FFT bin, otherwise the marker can be placed at any frequency with the value being interpolated at that exact frequency
• Find peak in region - if this option is selected, the marker will automatically search for the peak in the selected frequency band centered on the position of the marker
• Improve peak accuracy - if this option is selected the peak position and value are interpolated from the FFT data
• Current value - shows only the current value of the marker and can be interacted with while storing
• Full history - stores calculated values in output channels and can be used as input in other modules
• Position source - the position source has two modes - Widget marker andChannel. If widget marker is selected, the position of the marker is defined manually. If Channel mode is selected, the position of the marker is defined by the current value of our chosen channel.

Free markers are also visible and adjustable on the 3D graph widget.