81250 Datasheet, PDF (43/64 Pages) Keysight Technologies – Agilent ParBERT 81250 Parallel Bit Error Ratio Tester

Analyzer front end (E4863B)
The analyzer features are:
• Acquire data from start
• Compare and acquire data
around error
• Compare and count erro
neous ones and zeros to
calculate the bit error rate
The receive memory for acquired
data is up to 16 Mbit deep,
depending on the segment length
resolution. The stimulus portion
of the channel generates expect-
ed data and mask data. Mask
data is also available at the maxi-
mum granularity.
The analyzer is able to synchro-
nize on a received data stream by
means of a user-defined detect
word. The detect word is defined
by the first bits within the
expected segment, it has a length
of 48 bits and is composed of
zeros, ones and Xs (“don’t
cares”). The detect word must be
unique within the data stream.
Synchronization on a pure-PRBS
data-stream is done without a
detect-word, by simply loading a
number of the incoming bits into
the internal PRBS generator. A
pre-condition for this is that the
polynomial of the received PRBS
is known.
The input comparator has differ-
ential inputs with 50 Ω imped-
ance. The sensitivity is down to
50 mV and the common mode
range of the comparator allows
the testing of all common differ-
ential high-speed devices.The
user has the option of using the
differential input with or without
a termination voltage or as sin-
gle-ended input (with a termina-
tion voltage). The differential
mode does not need a threshold
Figure 26. Eye diagram of E4863B analyzer
Table 50. Parameters for analyzer front-ends E4863B 3.35 Gb/s
Number of channels
Impedance
Internal termination voltage
(can be switched off)
Threshold voltage range
Threshold resolution
Threshold accuracy
Input sensitivity
(single-ended and differential)
Minimum detectable
pulse width
Maximum input voltage range
Maximum differential voltage
Phase margin with
ideal input signal
Phase margin with
E4862B generator
Auxilary out
Sampling delay resolution
1, differential or single-ended
50 Ω typ.
(100 Ω differential if termination
voltage is switched off)
-2.0 to +3.0 V
-2.0 to +3.0 V
1 mV
±20 mV ±1%
< 50 mV
< 150 ps
Three ranges selectable:
-2 V to +1 V
-1 V to +2 V
0 V to 3 V
1.8 V
> 1 UI - 30 ps
(1)
> 1 UI - 50 ps
(1)
V out: 350 mV pp typ., AC coupled (2)
1 ps
(1) Measured with E4808A central module
(2) Terminate with 50 Ω to GND, if not used
voltage, whereas the single-ended
mode does. But also in differen-
tial mode the user can select one
of the two inputs and compare
the signal to a threshold voltage.
Protection
Input and output relays switch
off automatically, if the absolute
maximum voltage window is
exceeded.
ParBERT 81250 Main Overview
Page 43/64