N5454A Datasheet, PDF (4/13 Pages) Agilent(Hewlett-Packard) – Segmented Memory Acquisition for Agilent InfiniiVision Series Oscilloscopes

High-energy physics and laser pulse applications
Segmented memory acquisition
in an oscilloscope is commonly
used for capturing electrical pulses
generated by high-energy physics
(HEP) experiments, such as capturing
and analyzing laser pulses. With
segmented memory acquisition,
the scope is able to capture every
consecutive laser pulse (up to a
maximum of 2000 pulses), even if the
pulses are widely separated.
Figure 1 shows the capture of 300
successive laser pulses with a pulse
separation time of approximately 12
µs and an approximate pulse width
of 3.3 ns. All 300 captured pulses are
displayed in the infinite-persistence
gray color, while the current selected
segment is shown in the channel’s
assigned color (yellow for channel 1).
Note that the 300th captured pulse
occurred exactly 3.62352380 ms after
the first captured pulse, as indicated
by the segment time-tag shown in the
lower left-hand region of the scope’s
display. With the scope sampling
at 4 GSa/s, capturing this amount
of time would require more than 14
Megapoints of conventional acquisition
memory. If these laser pulses were
separated by 12 ms, the amount of
conventional acquisition memory to
capture nearly 4 seconds of continuous
acquisition time would be more than
14 Gigapoints. Unfortunately, there
are no oscilloscopes on the market
today that have this much acquisition
memory. But since segmented memory
only captures a small and selective
segment of time around each pulse
while shutting down the scope’s
digitizers during signal idle time,
Agilent’s InfiniiVision scopes can
easily capture this much information
using just 8 Megapoints of memory.
Figure 1: Segmented memory acquisition captures 300 consecutive laser
pulses for analysis.
A similar high-energy physics
application involves the measurement
of energy and pulse shapes of signals
generated from subatomic particles
flying around an accelerator ring
(particle physics). Assuming that
sub-atomic particles have been slung
around a 3-km accelerator ring at a
speed approaching the speed of light
(299,792,458 meters/sec), electrical
pulses generated at a single detector
at one location along the 3-km ring
would occur approximately every
10 µs. With segmented memory, you
can easily capture, compare and
analyze successive pulses generated
by the subatomic particles with precise
time-tagging.
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