Cursor Time Constant (TC)

Controls: Edit Menu >> Run Preferences >> Cursor TC
Macro: CursTC

This controls the rate at which cursor readout values can change. If the actual data values at the cursor positions are jumping around due to noise, they can be hard to read. The cursor time constant controls an exponential smoothing operation on the stream of changing values, so that each readout shows an average value over time.

Cursor TC settings may range from 0 to 31, where 0 is no smoothing at all: The readouts change immediately when the data values change. The default setting is 5.

To convert TC values to time constants in seconds, see Voltmeter Time Constant.

If the actual data stream changes suddenly, the readout values may exhibit a lag before they settle to the new averages. This becomes more of a problem at large Cursor TCs, so you must select a TC that is a compromise between jittery readouts on noisy data, and lagging response on true data changes.

You can reset the readout averages to the current instantaneous data values via ALT+K. This allows you to set a high TC for smooth response, then manually reset as needed if you see some obvious change in the trace that the cursors are slow in responding to.

A cursor readout is also reset with the current data value whenever that cursor is moved.

See also Run Preferences Dialog