4-13
MegaZoom Concepts and Oscilloscope Op eration
To setup the Horizontal time base
6 Turn the delay knob ( ) and notice that its value is displayed in the status line.
Changing the delay time moves the sweep horizontally and indicates how far
the trigger point () is from the time referen ce point (). These reference
points are indicated along the top of the graticule. The previous figure shows
the t rig ger poi nt w it h th e de lay tim e se t t o 1. 00 µs . Th e de lay tim e n umb er t ell s
you how far the time reference point is lo ca te d f ro m th e t ri gg er po in t . When
delay time is set to zero, the delay tim e indicator overlays the time reference
indicator.
All events displayed left of the trigger point () happened before the trigger
occurred, and these events are called pre-trigger information. You will find this
fea tu re ve ry u se fu l b ec au s e y ou ca n n ow s ee th e e ve nt s th at le d u p t o th e t ri gg er
point. Everything to the right of the trigger point () is called post-trigger
information. The amount of delay range (pre-trigger and post-trigger
information) available depends on the sw eep speed selected. This range is
much larger than that on an oscilloscope without deep memory.