111: Difference between revisions

The Tektronix Type 111 Pretrigger Pulse Generator produces two pulse signals: one to trigger an oscilloscope sweep and a main output pulse to stimulate the device under test.  The trigger pulse comes between 30 and 250 nanoseconds before the output pulse; this is controlled by a knob on the 111.  This gives adequate time for the oscilloscope to start sweeping so that the leading edge of the input or output signals of the device under test can be viewed.  The alternative is to have a [[delay line]] in the signal path, after the trigger pickoff, but delay lines degrade transient performance.  Using a pretrigger eliminates the need for a delay line in the vertical signal path and therefore enables accurate high-speed measurements.