Tektronix TBS1000B Series

Counter
Use the counter function from the Function button menu to simultaneously
monitor two different signal frequencies. This feature provides a more accurate
reading than is available with the oscilloscope’s frequency measurement.
Options Settings Comments
Ch1 On, Off
Ch2 On, Off
Ch1 Trigger Use the multipurpose knob to set the trigger
level.
Ch2 Trigger Use the multipurpose knob to set the trigger
level.
Reference
TBS1000B and TBS1000B-EDU Series Oscilloscopes User Manual 81