To Capture Glitches Or Narrow Pulses With Peak Detect And Infinite Persistence - Agilent Technologies 54622A User Manual

Making Measurements

To capture glitches or narrow pulses with peak detect and infinite persistence

To capture glitches or narrow pulses with peak detect
and infinite persistence
A glitch is a rapid change in the waveform that is usually narrow as compared
to the waveform. To capture glitches or narrow pulses:
1 Connect a signal to the oscilloscope and obtain a stable display.
2 To find the glitch, press the
Peak detect acquire mode displays any signal pulse wider than 5 ns, allowing
you to find glitches and narrow spikes regardless of sweep speed. Because of
MegaZoom memory, peak detect is only necessary at sweep speeds of 1 ms/div
and slower. At faster sweep speeds, Normal acquire mode can capture the
narrow peaks.
At sweep speeds slower than 1 ms/div, the oscilloscope can acquire more
samples than can fit into MegaZoom memory. The oscilloscope selects samples
to store such that no local minimum or maximum wider than 5 ns is missed. In
peak detect mode, narrow glitches and sharp edges are displayed more brightly
than when in Normal acquire mode, making them easier to see.
3 Press the key then press the
Display
softkey.
Infinite persistence updates the display with new acquisitions but does not erase
previous acquisitions. New sample points are shown 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, vertical sensitivity, or offset, the
previous acquisitions will be erased, then begin to accumulate again.
Use infinite persistence to measure noise and jitter, to see the worst-case
extremes of varying waveforms, to look for timing 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
off.
5- 10
Acquire key, then, press the
∞
(infinite persistence)
Persist
Peak Det softkey.
∞
Persist is turned