5-11
Making Measurements
To capture glitches or narrow pulses with peak detect and infinite persistence
3Press the Display key then press the Persist (infinite persistence)
softkey.
Inf i n i te p e r si s t e nc e u p da t e s th e d i sp l a y wi t h n ew a c q u is i t io n s b ut d o e s no t e r as e
previous acquisitions. New sample points are s hown at normal intensity while
previous acquisitions are displayed in minimum intensity. Waveform persistence
is not kept beyond the display area boundary. Any time you change a waveform
setting such as sweep speed, delay time, vert ical sensitivity, or offset, the
previous acquisitions will be erased, then b egin to accumulate again.
Use infinite persistence to measure noise and jitter, to see the worst-case
extremes of varying waveforms, to look for tim ing violations, or to find
infrequent events.
Press the Clear Display softkey to erase previously acquired points. The display
will again accumulate points until Clear Display is pressed or Persist is tu rne d
off.
4 Characterize the glitch with delayed sweep.
To characterize the glitch with delayed sweep, follow these steps:
•Press the Main/Delayed key, th en press the Delayed softkey.
To obtain a better resolution of the glitch, expand the time base.
Use the horizontal delay time knob ( )to pan through the waveform to set the
expanded portion of the main sweep around the glitch.
To characterize the glitch, use the cursors or the automatic measurement
capabilities of the oscilloscope.