Agilent Technologies 71612 User manual

Thisbookletisintended as a handy reminder of the fundamen-
tals of BER measurement and of how to use the Agilent
71612Error PerformanceAnalyzer for BERmeasurements.
Fulldetails of allthe stepsand procedures are given inthe
71612Operating and Programming Manual.Werecommend
that you readthe fullmanual before using thisbooklet.
Contents
TabTitlePage
Introtothe71612 Agilent 71612 12.5 Gb/sError
Performance Analyzer5
TheFront Panel6
Front/Rear CablingFrontand RearPanelCabling9
Initial Switch-onInitial Switch-on11
PatGen Setup PatternGeneratorSetup12
Error Det SetupError Detector Setup14
Meas Gating MeasurementGating 16
MeasurementsMeasurements17
Pat EditorOperationPatternEditorOperation19
DiskOperationDisk Operation21
GeneralFunctions General Functions 22
The Menus The Menus23
BER - What is it?BER Basics43
BERTDecisionThreshold45
FalseSync 46
TestTime, Confidence Interval
and ResidualBER47
Q Factor48
Eye Contour Measurements50
BERTTroubleshooting 51
Properties of PRBSs54
Logic Levels,Terminations and
DataRate 59
Agilent 71612 Error Performance Analyzer
Quick Reference (71612-90017)

3
CAUTION
All of the 71612 data and clock outputs
are dc-coupled.
DO NOT APPLY ANY EXTERNAL
VOLTAGE TO THESE OUTPUTS.
This will damage the internal
amplifiers.
Take particular care when using a bias
tee to connect it the correct way.
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Intro to the
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Agilent 71612
12.5 Gb/s Error Performance Analyzer Intro to the
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6
The Front Panel
The 70004A Display serves as the front panel for
instruments in the 71612 Series, and as your window for
viewing current system configuration and measurement
results.
Instrument Hardkeys
gain instant access to primary
instrument functions such as data output or result pages.
The keys are color-coded to indicate their function:
•Green for configuration keys
•Blue for result pages
•Black for immediate selection keys for gating and audio.
instrument hardkeys
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Instrument Softkeys
select instrument functions. The functions are
organized in groups, called softkey menus.
NOTE Softkeys that are selected are displayed in
inverse video or are underlined.
Some softkeys switch between two states, such as
and . An underline
on the key labels indicates which keys and conditions are
selected.
Softkeys and Windows Color Coding
Softkeys and windows are color coded to indicate the
primary instrument functions with which they are
associated. They are:
•Blue softkeys/window: assigned to Results Page
occupies two thirds of screen.
•Green softkeys/window: assigned to pattern generator/
error detector configuration
•Yellow softkeys - green/yellow window: assigned to
Pattern Editor
•Grey softkeys/window: assigned to user pattern
selection and save.
•Softkeys that are “greyed out”are not valid for the
currently selected instrument function.
Fixed Label Keys
keys select major system functions such
as PRINT, PLOT, INSTR PRESET, DISPLAY or MENU.
softkeys
LOGGING OFF ON SYNC AUTO/MAN
FIXED LABEL
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Access display functions by pressing .This
provides the softkeys on the left and right of the display,
and allows you to set up the display functions.
Access primary instrument functions by pressing .
Both methods enable menus of softkeys that give access to
all instrument functions.
Parameter Control Keys
Display knob Use the display RPG knob to change
parameters and select operating
values.
Numeric keypad Use the numeric keypad to enter
numeric values.
Use the two step keys to change
parameters up or down.
DISPLAY
MENU
▲ ▼
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9
Front and Rear Panel Cabling
System Back-to-Back Connection
Front/Rear
Cabling
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10
HP-MSIB Cabling, rear panel
Front/Rear
Cabling
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Initial Switch-on
1.For a back-to-back system check, connect up the front
panel as shown on page 9. Otherwise, connect up as
appropriate to your application.
2.Connect the 70843 and 70004A rear-panel HP-MSIB
ports as shown on page 10. If not, the red HP-MSIB
LED on the display will light up.
3.Switch on the instruments in your system and check that
all LEDs light up then go off after a few seconds. The
green ACT LED on the 70843 will be lit up when the
instrument owns the keyboard and display.
4.A lit up red E at the top left of the screen indicates an
error in any instrument on row 0 of the address map.
Refer to the 70004A Display Operation Manual for
information about the address map. The red Ealso blinks
if the display detects a fault on the HP-MSIB at
power-up.
Initial
Switch-on
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12
Pattern Generator Setup
Set Up Clock Output
Select and setup the clock source
frequency using the , ,
and softkeys.
Setup the internal clock parameters using the available
softkeys.
The CLOCK and CLOCK OUT ports can be set to be
independent, , or track together,
.
Set Up Data Output
Select and use the softkeys displayed to
select data output parameters.
The DATA and DATA OUT ports can be set to be
independent, , or track together,
.
Set Up Subrate Outputs
Select then use the available softkeys
to setup clock/data parameters.
Add Errors
Select then either ,
, , or
.
clock output
SIG GEN FREQ FREQ STEP
SIG GEN AMPLTD SIG GEN ON OFF
C/TRCK ON OFF
C/TRCK ON OFF
data output
D/TRCK ON OFF
D/TRCK ON OFF
subrate outputs
error add
ERR-ADD SINGLE
ERR-ADD EXTRNAL ERR-ADD FIXED
ERR-ADD OFF
Pat Gen
Setup
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Select Pattern Generator Trigger Output Pulse
The TRIGGER OUTPUT port gives an electrical trigger
for use with an oscilloscope or other test equipment.
Pattern or clock triggers are provided.
Clock trigger is a square wave at 1/8 or 1/32 of clock rate.
Pattern trigger is synchronized to repetitions of the output
pattern. For a pure PRBS, it is one pulse per 32
repetitions; for alternate patterns, the trigger alternates
with the pattern; and for all other patterns, the trigger
pulse occurs at lowest common multiple of 256 and pattern
length.
Select a pattern trigger as follows:
•For a pure PRBS: select ,
, - enter PRBS
code word using numeric keypad.
•For alternate patterns: select .
Trigger pulse is at bit 0 of pattern or alternates with
pattern A-B changeover.
•For all other patterns: select , then
select pattern bit number using and
display RPG knob or numeric keypad.
trigger & setup
PG TRIG PAT CLK PG TRIG PATTERN
PG TRIG A-B PAT
trigger & setup
PG TRIG BIT
Pat Gen
Setup
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Error Detector Setup
Set Up Data Input
Ensure the Error Detector is cabled correctly.
Select then setup input polarity, termination
and delay using the available softkeys.
Perform clock-data alignment to ensure the Error Detector
samples in the middle of the date eye as follows:
Select , ,
, , ,
, then view results.
On input signals with an unequal mark-density, perform a
0/1 threshold center operation as follows:
Select , ,
, select eye edge threshold ratio using
numeric keypad, then ,
, then view results.
Control Synchronization and Audible Tone
Select and use the softkeys to control
Error Detector synchronization and the audible tone that
sounds when errors occur.
Synchronization to the incoming pattern can be performed
automatically or manually. In manual, forces
the Error Detector to attempt synchronization with the
received pattern. Synchronization is gained when the
measured error rate is less than the set sync threshold.
input & eye
input & eye
0/1 THR AUTOMAN
EYE EDG THRSHLD CLK-DAT ALIGN
result pages
EYE RESULTS
input & eye
0/1 THR AUTOMAN
EYE EDG THRSHLD CLK-DAT ALIG
N
0/1 THR CENTE
R
sync & audio
START SYNC
Error Det
Setup
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Note that the sync softkeys are disabled (greyed out) when
BURST GATING (on gating menu) is selected.
Errors Output Port
Produces a pulse that is the logical OR of errors in a 32-bit
segment of data. Pulse length switchable - RZ or stretched
(200 ns).
Select , .
Select Error Detector Trigger Output Pulse
Select then set
softkey to or .
Provides pattern and clock trigger.
Clock Trigger: a square wave at 1/8 of clock rate.
Pattern Trigger: for a pure PRBS, it is 1 pulse per 32
pattern repetitions. For all other patterns, pulse occurs at
lowest common multiple of 256 and pattern length.
trigger & setup
ERR O/P RZ 200ns
trigger & setup
ED TRIG PAT CLK
PAT CLK
Error Det
Setup
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Measurement Gating
Start or Stop Gating
Start or stop gating at any time using and
.
If your Display does not have a hardkey panel, select
, and use the and
.
Note the green Gate flag at top right of the display during
the measurement period.
Select a Measurement Period
Select then , or .
Gate by Time, Bits or Errors
Select or ; then ,
or , then .
If you select , use the numeric keypad then
softkeys to select gating period.
RUN GATING
STOP GATING
MENU
gating RUN GATING
STOP GATING
gating
MANUAL SINGLE
REPEAT
SINGLE REPEAT GATE BY TIME
GATE BY ERRS GATE BY BITS
GATING PERIOD
GATE BY TIME
Meas
Gating
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Measurements
Basic BER Measurement
Press to start measurement.
Press to end measurement; view results
on display.
Data Eye Measurement
Select , ,
, , ,
.
On input signals with an unequal mark-density, perform a
0/1 threshold center operation. Select ,
, , then select
BER using numeric keypad, then ,
, , .
Error Location Measurement
Define a specific bit in a ram-based pattern and perform
measurements at that location. The bit specified is known
as the BER location. There are three measurements: Bit
BER, Block BER and Error Location Capture.
Bit BER
Select , - use numeric
keypad or display knob to select BIT ERR ADDRESS.
Press , at end of measurement period
select , to view Bit BER
results.
RUN GATING
STOP GATING
input & eye
0/1 THR AUTOMAN
EYE EDG THRSHLD CLK-DAT ALIGN
result pages
EYE RESULTS
input & eye
0/1 THR AUTOMAN EYE EDG THRSHLD
CLK-DAT ALIGN
0/1 THR CENTER
result pages
EYE RESULTS
error location
BIT ERR ADDRESS
RUN GATING
result pages
OTHER RESULTS
Measure-
ments
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Block BER
Select , , - use
display knob or numeric keypad to select BLOCK START
address, select , enter block length (must be
a multiple of 32). Press , ,
view results on page at end of
measurement period.
Error Location Capture
Select , , view the error
location in the Error Location Config window. Note, the
softkey is greyed out if BLOCK BER is
currently selected.
error location
BLOCK BER BLOCK START
BLOCK LENGTH
RUN GATING
result pages
MAIN RESULTS
error location
CAPTURE ERROR
CAPTURE ERROR
Measure-
ments
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Pattern Editor Operation
Select a Pattern
Select then choose from one of five fixed pure
patterns, or a ram-based ,
or .
Edit User Patterns
Select , or ,
or . Select
for full screen. Use the softkeys displayed to edit the
pattern.
Save a Pattern
Select then choose an or
store.
Load a Block of Data
The block is loaded at the cursor point and tailored to fit
between cursor and pattern end.
determines whether bits are inserted or replaced.
Select , or ,
or - set screen cursor to bit
position where data block is to be loaded.
Set mode; - select a
or .
pattern
prbs zero sub
mark density
user pattern
pattern
edit ram user
edit disk user
INTERNL PATT DISK PATT
toggle screen
save pattern INTERNL PATT
DISK PATT
INSERT/REPLACE
pattern
edit ram user
edit disk user
INTERNL PATT DISK PATT
INSERT/REPLACE load block
prbs user pattern
Pat Editor
Operation
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Save a Block of Data
Define a block of data within the current editor user pattern
memory, then save the block to any pattern store large
enough to hold the pattern. The current pattern store
contents are overwritten by the new data being saved.
Select , or ,
or - set cursor on first bit of
block to be saved - select - set cursor on
last bit of block (block shown underlined) - select
or , or
store.
Generate an Alternate Pattern
Select , or ,
, , , ,
use numeric keypad, then press . You can load a
prbs or user pattern into each half of the alternate pattern
(use load block function).
Control Alternate Pattern Switching
You can control alternate patterns from the front panel
AUXILIARY INPUT port or over HP-IB.
Select - select an alternate pattern
or , set
to for control via the
AUXILIARY INPUT, and for front panel control.
pattern
edit ram user
edit disk user
INTERNL PATT DISK PATT
savedel block
save to ram save to disk INTERNL PATT
DISK PATT
pattern
edit ram user
edit disk user
CURRENT PATT ALTPAT ON YES SET PAT LENGTH
ENTER
pattern
ram user pattern disk user pattern
ALT PAT AUX USR AUX
USR
Pat Editor
Operation
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Disk Operation
Format a New Disk
Select , , ,
.
Delete a Disk Pattern Store
Select , , , then
select the store to be deleted.
pattern
disk utils format disk
FORMAT YES
pattern
disk utils delete diskpat
DISK PATT
Disk
Operation
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