The signal coupling or input coupling selection determines how the signal on the input is passed on.
- DC coupling allows for both the AC and the DC components of the input signal to pass.
- AC coupling rejects the DC component of the input signal and only the AC component is measured.
Use AC coupling when investigating an AC signal on a rather large DC component. Use DC coupling when measuring DC signals, like e.g. a battery voltage.
Changing the signal coupling of a channel in the Multi Channel oscilloscope software can be done in various different ways:
- 
    Using the input coupling button
     on the channel toolbar on the channel toolbar
- 
    Opening the channel settings dialog using the
     Channel settings dialog button and selecting the required coupling in the dialog. Channel settings dialog button and selecting the required coupling in the dialog.
- Using hotkeys A and D in combination with the appropriate channel selection hotkey(s)
- 
    Clicking the input coupling buttons
     (AC) and (AC) and (DC)
    on the channel toolbar (DC)
    on the channel toolbar
- Right-clicking the channel in the Object screen and selecting the appropriate coupling in the channel popup menu
