HP 54522A - Page 115

See Also
Display Menu
Real-Time Acquisition Display Menu (seq off)
Normal Mode
This key is used to select persistence during the real-time mode. Persistence
has two choices: single and infinite.
Single Single persistence is a very fast overwrite. As each new
acquisition is displayed, it overwrites the previous data. The current
display is always the most recent acquisition.
Infinite Infinite persistence is used for worst-case characterizations of
signal noise, jitter, and drift. In this mode the oscilloscope is used as a
storage oscilloscope because waveforms are not erased. Measurements
are performed using the newest data in each pixel column.
Peak Detect Mode
Peak detect is only available in the real-time mode when the sampling rate is
less than or equal to 1 GSa/s and with sequential single-shot turned off.
When the sample rate is greater than 1 GSa/s, the peak detect mode is not
displayed on the softkey. Peak detect is an acquisition mode rather than a
display mode. An acquisition mode affects how the oscilloscope acquires
data. A display mode does not affect how the data is acquired; rather, it is a
postprocessing feature that affects how the data is displayed on the screen,
like connect the dots and persistence.
Peak detect stores the minimum and maximum values (pairs) for each time
bucket. Peak detect can detect excursions as narrow as | ns. When peak
detect is on, the sample rate that appears in the time base menu is the
sample rate at which the minimum and maximum pairs are stored. You may
notice that peak detects functions at sample rates up to 250 MSa/s. Because
peak detect stores two data points per sample clock, the memory size divides
in half. For example, if the record length is set to 32,768 and you turn on
peak detect, the record length changes to 16,384.
"# of Screens Softkey" and "Off/Frame/Axes/Grid Softkey" earlier in this
chapter for information on these keys.
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