HP 83480A

How the Instrument Works
Standard and Enhanced Trigger Modes
Figure
13-12.
Viewing
a
10
Gb/s
eye
diagram
using 12
GHz
trigger
.
An
eye
diagram
usually
consists
of
the
overlay
of
samples
from
many
dierent
bits
of
a
random (or
pseudo-random
with
length
2
n
0
1
)
digital
signal.
Therefore
,
the
fact
that the
trigger only
recognizes
every
sixteenth
event
will
not
reduce
the
signicance
of
the
data.
However
,
if
viewing
a
signal
with
a
pattern
length
of modulus
16 (where
the
number
of
trigger
transitions
is
an
integer
multiple
of
16),
the analyzer
will
only
acquire
data
from
certain
bits
,
which
will
reduce
the
signicance
of the
data. PRBS signals are of odd length, so this is usually not a problem.
13-24