Triggering on Waveforms
3–90
TDS 500B, TDS 600B, & TDS 700A User Manual
NOTE. When you set the Vertical SCALE smaller than 200 mV, the oscilloscope
reduces the Set to TTL or Set to ECL trigger levels below standard TTL and
ECL levels. That happens because the trigger level range is fixed at ±12
divisions from the center. At 100 mV (the next smaller setting after 200 mV) the
trigger range is ±1.2 V which is smaller than the typical TTL (+1.4 V) or ECL
(–1.3 V) level.