A symbol appears next to a measurement if a vertical clipping condition
exists. Clipping is when part of the waveform is above or below the display.
Clipping can cause the oscilloscope to take inaccurate measurements. To
obtain an accurate measurement, use the Vertical Scale and Position knobs
to show all of the vertical range of the waveform on the screen.
14. The waveform baseline indicator (left side of the screen) shows the zero-volt
level of a waveform. The icon colors correspond to the waveform colors.
Adjust waveform position with the Vertical Position knob.
Appendices
TBS2000B Series Oscilloscopes User Manual 191