Agilent Technologies J-BERT N4903, User Manual

Page: 323 / 434

N O T E
The two delay lines will be longer than 200ps and 500ps respectively, but the final
value is instrument dependent.
Two delay lines are provided for generating data jitter, a 500
+
ps delay
line and a 200
+
ps delay line. Considering the data output, they are
connected in series.
The 500
+
ps delay line is provided for generating large jitter amplitudes
at low bit rates. It cannot be used for bit rates higher than 3.37Gbit/s.
The source for periodic jitter (PJ) can be connected to the 500
+
ps delay
line or to the 200 + ps delay line.
All other sources can only be connected to the 200
+
ps delay line.
The Subrate Clock Output follows the 500
+
ps delay line. It is not
influenced by any jitter produced by the 200
+
ps delay line.
Interference Channel
The option J20 Interference Channel is available for simulating
intersymbol interference (ISI) with or without sinusoidal interference
(SI).
This is a hardware module that can be plugged into the instrument. It
has two ports, P1/P1 and P2/P2. Both can be connected single-ended or
differentially.
The Interference Channel provides a switchable signal path with Nelco
4000-6 FR4 characteristics. This path can be connected between the
pattern generator's Data Out port and the DUT. For instructions refer
to
“Connecting the J20 Option” on page 407 .
The Interference Channel provides also a sinewave generator and a
resistive combiner. This makes it possible to add sinusoidal interference
(amplitude modulation) to the data signal.
The Interference Channel is built up as shown in the following figure.
Jitter Tolerance Tests
7
Agilent J-BERT N4903 High-Performance Serial BERT 323
Delay lines
Subrate clock