Agilent Technologies N4962A User manual

Agilent N4962A
Serial BERT 12.5 Gb/s
User Guide

Notices
© Agilent Technologies, Inc. 2012
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copyright laws.
Manual Part Number
N4962-91021
Edition
Third edition, May 2013
Agilent Technologies, Deutschland GmbH
Herrenberger Str. 130
71034 Böblingen, Germany
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maintenance by Buyer, Buyer-supplied software or
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specifically disclaims the implied warranties of
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Purpose.
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Safety Notices
A CAUTION notice denotes a hazard. It
calls attention to an operating
procedure, practice, or the like that, if
not correctly performed or adhered to,
could result in damage to the product
or loss of important data. Do not
proceed beyond a CAUTION notice until
the indicated conditions are fully
understood and met.
A WARNING notice denotes a hazard.
It calls attention to an operating
procedure, practice, or the like that, if
not correctly performed or adhered to,
could result in personal injury or
death. Do not proceed beyond a
WARNING notice until the indicated
conditions are fully understood and
met.
A NOTE provides important or special
information.
CAUTION
WARNING
NOTE

Safety Summary
General Safety Precautions
The following general safety precautions
must be observed during all phases of
operation of this instrument. Failure to
comply with these precautions or with
specific warnings elsewhere in this manual
violates safety standards of design,
manufacture, and intended use of the
instrument.
Agilent Technologies Inc. assumes no
liability for the customer's failure to comply
with these requirements.
Before operation, review the instrument and
manual for safety markings and instructions.
You must follow these to ensure safe
operation and to maintain the instrument in
safe condition.
Initial Inspection
Inspect the shipping container for damage. If
there is damage to the container or
cushioning, keep them until you have
checked the contents of the shipment for
completeness and verified the instrument
both mechanically and electrically. The
Performance Tests give procedures for
checking the operation of the instrument. If
the contents are incomplete, mechanical
damage or defect is apparent, or if an
instrument does not pass the operator’s
checks, notify the nearest Agilent
Technologies Sales/Service Office.
WARNING To avoid hazardous electrical
shock, do not perform electrical tests when
there are signs of shipping damage to any
portion of the outer enclosure (covers,
panels, etc.).
General
This product is a Safety Class 1 product
(provided with a protective earthing ground
incorporated in the power cord). The mains
plug shall only be inserted in a socket outlet
provided with a protective earth contact.
Any interruption of the protective conductor,
inside or outside of the instrument, will
make the instrument dangerous. Intentional
interruption is prohibited.
Environment Conditions
This instrument is intended for indoor use in
an installation category II, pollution degree 2
environment per IEC 61010 Second Edition
and 664 respectively. It is designed to
operate within a temperature range of 10 to
40 °C at a maximum relative humidity of 80%
for temperatures up to 31 °C, decreasing
linearly to 50% relative humidity at 40 °C at
an altitude of 2000 meters.
This module can be stored or shipped at
temperatures between -40°C and +70°C.
Protect the module from temperature
extremes that may cause condensation
within it.
Before Applying Power
Verify that all safety precautions are taken.
The power cable inlet of the instrument
serves as a device to disconnect from the
mains in case of hazard. The instrument
must be positioned so that the operator can
easily access the power cable inlet. When
the instrument is rack mounted the rack
must be provided with an easily accessible
mains switch.
Ground the Instrument
Install the instrument so that the ON / OFF
switch is readily identifiable and is easily
reached by the operator. The ON / OFF
switch is the instrument disconnecting
device. It disconnects the mains circuits
from the mains supply before other parts of
the instrument. Or the detachable power
cord can be removed from the electrical
supply. Alternately, an externally installed
switch or circuit breaker which is readily
identifiable and is easily reached by the
operator may be used as a disconnecting
device.
Do Not Operate in an Explosive
Atmosphere
Do not operate the instrument in the
presence of flammable gases or fumes.
Do Not Remove the Instrument
Cover
Operating personnel must not remove
instrument covers. Component replacement
and internal adjustments must be made only
by qualified personnel.
Instruments that appear damaged or
defective should be made inoperative and
secured against unintended operation until
they can be repaired by qualified service
personnel.

Symbols on Instruments
Indicates warning or caution. If you see this
symbol on a product, you must refer to the
manuals for specific Warning or Caution
information to avoid personal injury or damage to
the product.
C-Tick Conformity Mark of the Australian ACA for
EMC compliance.
Indicates that protective earthing ground is
incorporated in the power cord.
This symbol indicates that internal circuits can be
damaged by electrostatic discharge (ESD),
therefore, avoid applying static discharges to the
panel input connectors.
This mark indicates compliance with the Canadian
EMC regulations.
ISM 1-A
This text denotes the instrument is an Industrial
Scientific and Medical Group 1 Class A product.
CE Marking to state compliance within the
European Community: This product is in
conformity with the relevant European Directives:
EMC Directive 2004/108/EC and Low Voltage
Directive 2006/95/EC.
China RoHS regulations include requirements
related to packaging, and require compliance to
China standard GB18455-2001. This symbol
indicates compliance with the China RoHS
regulations for paper/fiberboard packaging.
Indicates the time period during which no
hazardous or toxic substance elements are
expected to leak or deteriorate during normal use.
Forty years is the expected useful life of the
product.
The Korean Certification (KC) mark is required for
products that are subject to legally compulsory
certification.
The KC mark includes the marking’s identifier
code that has up to 26 digits and follows this
format: KCC-VWX-YYY-ZZZZZZZZZZZZZ.
This symbol indicates that the instrument requires
alternating current (AC) input.
This symbol indicates that the power line switch
is in the ON position.
O
This symbol indicates that the power line switch
is in the OFF position.

Environmental Information
This product complies with the WEEE Directive
(2002/96/EC) marketing requirements. The affixed
label indicates that you must not discard this
electrical/electronic product in domestic household
waste.
Product category: With reference to the equipment
types in the WEEE Directive Annexure I, this product
is classed as a “Monitoring and Control
instrumentation” product.
Do not dispose in domestic household waste.
To return unwanted products, contact your local
Agilent office, or see
www.agilent.com/environment/product/ for more
information.

Contents
Serial BERT 12.5 Gb/s User Guide 7
Contents
1Getting Started ......................................................................................................... 9
1.1 General.............................................................................................................. 9
1.2 N4962A Operation Overview ....................................................................... 11
1.3 Getting Started with the N4962A Serial BERT 12.5 Gb/s...................... 12
1.3.1 Unpacking and Installation........................................................... 12
1.3.2 Safety and Regulatory.................................................................... 12
1.3.3 Declaration of Conformity............................................................. 13
1.3.4 Important Notes.............................................................................. 13
1.3.5 Performance Recommendations.................................................. 14
1.4 Connect the Hardware.................................................................................. 14
1.5 Turn It On........................................................................................................ 15
1.6 Align Clock and Data .................................................................................... 15
1.7 Make the Measurement............................................................................... 15
2N4962A System Overview..................................................................................... 17
2.1 Front Panel Quick Reference....................................................................... 19
2.2 Rear Panel Quick Reference........................................................................ 22
2.3Connector Care .............................................................................................. 23
3System Details and Performance Specifications............................................... 25
3.1 General............................................................................................................ 25
3.2 Safety and Regulatory................................................................................... 26
3.3 Internal Clock ................................................................................................. 27
3.4 PRBS Generator............................................................................................. 30
3.5 Error Detector................................................................................................. 32
3.6 Data Path ........................................................................................................ 34
4Operation................................................................................................................. 37
4.1 General Information ...................................................................................... 37
4.1.1 Performance Recommendations.................................................. 38
4.1.2 Connector Care............................................................................... 38
4.2 Front Panel Interface .................................................................................... 39

Contents
8 Serial BERT 12.5 Gb/s User Guide
4.2.1 Front Panel – Display Panel.......................................................... 40
4.2.2 Front Panel – Local, Receiver, and Data Path Controls........... 41
4.2.3 Front Panel – Configuration Adjustment Controls.................... 43
4.2.4 Front Panel – Display Selection Controls................................... 48
4.3 Rear Panel Interface ..................................................................................... 51
4.4 Power-On State.............................................................................................. 53
4.5 System Verification ....................................................................................... 54
4.5.1 Self Test Mode................................................................................ 54
4.5.2 Error Free Test ................................................................................ 55
4.5.3 High BER Test................................................................................. 55
4.5.4 Low BER Test.................................................................................. 56
4.6 BER Detector Clock Phase Adjustment..................................................... 56
4.7 Basic BER Measurement............................................................................. 59
5Remote GPIB Interface.......................................................................................... 61
5.1 GPIB Capabilities........................................................................................... 62
5.2 GPIB Command Syntax ................................................................................ 63
5.2.1 Command Structure....................................................................... 64
5.3 IEEE Common Commands............................................................................ 65
5.4 SCPI Mandated Commands......................................................................... 66
5.5 N4962A Device Commands ......................................................................... 66
5.5.1 Internal Clock Commands............................................................. 67
5.5.2 PRBS Pattern Commands ............................................................. 70
5.5.3 Measurment Commands............................................................... 74
5.6 Examples......................................................................................................... 83
6Returning the N4962A Serial BERT to Agilent Technologies ......................... 87

Getting Started
Serial BERT 12.5 Gb/s User Guide 9
1Getting Started
1.1 General
The N4962A serial BERT 12.5 Gb/s operates from 500 Mb/s
– 12.5 Gb/s
referencing an external clock, and from 9.85
– 11.35 Gb/s with the
programmable internal clock.
The N4962A includes:
•Internal clock system
•PRBS generator
•Error detector
Key Features
•Low cost, high performance
•Programmable output amplitude control
•Electronic receiver clock phase adjust
•Differential inputs and outputs
•Synchronous clock & pattern triggers
•Selectable pattern lengths, mark density
•Data Thru switch on Receiver for use with Oscilloscope on received
data
•Controlled with GPIB control bus format
Internal clock system
•
Internal clock 9.85 to 11.35 GHz
•External clock input for 0.5 to 12.5 GHz operation
PRBS generator
•
Selectable PRBS patterns:
oLengths: 27-1, 210-1, 215-1, 223-1, 231-1
oMark densities: 1/2, 1/4, 1/8
•Adjustable PRBS amplitude:
oVoltage: 0.3 - 1.8 V pp per output
oStep size: 10 mV

Getting Started
10 Serial BERT 12.5 Gb/s User Guide
Error detector
•Automatic sampling point adjustment
•Elapsed time BER measurements
•Manual threshold adjustment)
Operating modes
•
Disabled ('safe mode': no output)
•Enabled (PRBS output enabled)
•Thru (no detector; inputs connected to Data Thru connectors on back
panel)
Display
•
LED indicators
•Multifunction alphanumeric display
Data entry / interface
•
Push-button control (local)
•Remote GPIB (IEEE 488.2-1992)
•Compatible with N4980A multi-instrument BERT software user
interface

Getting Started
Serial BERT 12.5 Gb/s User Guide 11
1.2 N4962A Operation Overview
The Agilent Technologies N4962A is a cost
-effective serial BERT 12.5 Gb/s,
consisting of an internal clock system, PRBS generator, and error detector. It is
designed for automated production
-line testing, manufacturing,
characterization, and R&D lab use. The N4962A features high
-
UI jitter injection
and programmable output amplitude.
Figure 1. Eye waveform
The N4962A generates a continuous bit pattern that is applied to the DUT
then fed back into the error detector. The input is automatically synchronized
and compared with the original bit stream. The bit error rate is calculated by
comparing the number of bit errors to the total number of bits transmitted.
The BER can be shown on the display and can be captured through the
remote GPIB interface.

Getting Started
12 Serial BERT 12.5 Gb/s User Guide
1.3 Getting Started with the N4962A Serial BERT 12.5 Gb/s
1.3.1 Unpacking and Installation
The N4962A serial BERT 12.5 Gb/s is shipped with all the accessories required
for the self
-test mode and verification. The contents includes:
•N4962A serial BERT 12.5 Gb/s
•Two coax cables to connect rear-panel clocks (TX CKO, RX CKO to TX
CKI, RX CKI)
•Two phase balanced 50 Ωcoaxial cables for self-test mode (IN, IN¯¯ to
OUT, OUT¯¯¯)
•AC power converter module
•AC power cord
•
CD containing the N4962A User Guide and N4962A Data Sheet
If this product is not used as specified, the protection provided by the
equipment could be impaired. This product must be used in a normal condition
(in which all means for protection are intact) only.
Before switching on this instrument, make sure the supply voltage is in the
specified range.
This instrument has autoranging line
voltage input. Be sure the supply voltage
is within the specified range.
In an ESD
-safe environment, carefully remove the N4962A. Install on a flat
surface with unobstructed air flow to the back panel. Plug the AC power cord
into the power converter mo
dule and a wall socket, then plug the converter
module into the N4962A.
1.3.2 Safety and Regulatory
This product has been designed and tested in accordance with accepted
industry standards, and has been supplied in a safe condition. The
documentation contains information and warnings that must be followed by
the user to ensure safe operation and to maintain the product in a safe
condition.

Getting Started
Serial BERT 12.5 Gb/s User Guide 13
Do not remove instrument covers. There are no user serviceable parts within.
Operation of the instrument in a manner
not specified by Agilent Technologies
may result in personal injury or loss of life.
For continued protection against fire hazard, replace fuses, and or circuit
breakers only with same type and ratings. The use of other fuses, circuit
breakers or ma
terials is prohibited.
To prevent electrical shock, disconnect instrument from mains before cleaning.
Use a dry cloth or one slightly dampened with water to clean the external case
parts. Do not attempt to clean internally.
The Mains wiring and connectors shall be compatible with the connector used
in the premise electrical system. Failure, to ensure adequate earth grounding
by not using the correct components may cause product damage, and serious
injury
.
1.3.3 Declaration of Conformity
A EU declaration of conformity is available at
http://regulations.corporate.agilent.com/doc/search.htm
1.3.4 Important Notes
•
Use ESD protection at all times when using the instrument
•Review min/max specifications before applying input signals
•Use only K-connectors on the OUT and OUT¯¯¯ ports
•Handle the pair of self-test and clock loop coaxial cables with care
•Leave dust jackets on unused back panel connectors
•
Situate the instrument away from heat sources, do not block the fan

Getting Started
14 Serial BERT 12.5 Gb/s User Guide
1.3.5 Performance Recommendations
•
When using differential-mode connections, ensure the cables are
phase balanced
•Differential connectors may be used single-ended if unused ports are
terminated in 50 Ω
•Use high quality cables and connector savers (or adaptors)
•Keep cable lengths short and minimize number of cable bends
•Use a 7-10 in-lbs torque wrench when attaching connectors
•Terminate all unused RF connectors with 50 Ωterminations
1.4 Connect the Hardware
•
Connect power cord to adaptor to N4962A; plug in the power cord
•Connect TX CKO to TX CKI with included coaxial cable
•Connect RX CKO to RX CKI with included coaxial cable
•Connect the OUT (and optionally OUT¯¯¯ to your DUT input
•Connect your DUT output to IN (and optionally IN¯¯)

Getting Started
Serial BERT 12.5 Gb/s User Guide 15
1.5 Turn It On
•
Turn on the power switch from the back panel
•Press the Data Path > Select Path button and select Enabled
oThis will turn on the PRBS output; when Disabled is selected,
the instrument is in a 'safe mode' and no output is generated
•Press the Display > Scroll ↓ button and select Ampl (V)
•Press the Adjust > Ampl +/- buttons to set the single-ended output
voltage
1.6 Align Clock and Data
•
Press the Data Path > PRBS¯¯¯¯ button only if the DUT is inverting
oWhen on, the PRBS will generate an inverted output signal
•Press the Display > Scroll ↓ button and select Ø
•Press the Adjust > Config State + button to auto-set the detector phase
•Observe the Error εlight
oThe light indicates errors are being measured by the error detector,
if the light is on, no error-free sampling point could be found
1.7 Make the Measurement
•Press the Receiver > On button and ensure the light is on
•Press the Display > Scroll ↓ button and view Err (error counter)
•Press the Display > Scroll ↓ button and view BER
•Press the Display > Scroll ↓ button and view є time (sec)
•Press the Receiver > On button to end the measurement

Getting Started
16 Serial BERT 12.5 Gb/s User Guide

N4962A System Overview
Serial BERT 12.5 Gb/s User Guide 17
2N4962A System Overview
The N4962A consists of three functional blocks:
•Internal/external clock system with analog jitter injection
•PRBS generator (TX) with variable output amplitude control
•Error detector (RX) with electronic clock phase adjustment
The N4962A is controlled by front-panel buttons and remote GPIB (IEEE
488.2) commands; information is conveyed with LED indicators and a display
on the front panel, along with GPIB data communication.
Figure 2. N4962A simplified block diagram; system overview

N4962A System Overview
18 Serial BERT 12.5 Gb/s User Guide
The clock system features an internal generator that creates a 9.
85 to
11.35
GHz system clock from an internal 1/16th-rate clock generator. The
internal clock/16
can also be phase locked to an external 1/16th clock if
desired
. The high-frequency TX clock and trigger output can be FM-modulated
with an optional external
jitter signal. Alternatively, external 500 Mb/s to
12.5
Gb/s clocks can be used in place of the internal high-
frequency clocks for
the PRBS generator and error detector.
The PRBS generator creates a continuous bit stream triggered by the input
clock rate
, configured by the selectable pattern length, mark space density,
data inversion, and error injection settings. The output is amplified by a
programmable gain stage.
The error detector compares the input to an automatically
-synchronized bit
stream genera
ted with the same system settings. The clock input features an
electronic phase adjuster to correctly align the clock and data sampling point.
The system settings can be set by the local push
-button interface or remote
GPIB (IEEE 488.2) interface. All set
tings can be accessed through the menu
system or through GPIB commands.
The N4962A is compatible with the
N4980A multi
-instrument BERT software which is available through Agilent
Technologies to help speed up programming time.

N4962A System Overview
Serial BERT 12.5 Gb/s User Guide 19
2.1 Front Panel Quick Reference
Figure 3. N4962A front panel
Connectors
RECEIVER
: IN, IN¯¯ (SMA) – input to error detector (differential or single-ended)
SOURCE
: OUT, OUT¯¯¯ (2.92 mm K) – PRBS generator output (differential or
sing
le-ended)
Display
(display panel)
– eight-character display to show display status and configure
system
Error ε (light)
– indicates errors are being detected by the error detector

N4962A System Overview
20 Serial BERT 12.5 Gb/s User Guide
Controls
Local (button & light)
– indicates local (vs. remote) control; b
utton selects local
control
Receiver
>
On (button & light)
– indicates detector state; button toggles & resets BER
Data Path
>
PRBS
¯¯¯¯ (button & light) – indicates inversion of PRBS signal; button toggles
Select Path (button & 3 lights)
– data path (disabled, enabled, thru); button
cycles
Adjust
>
Freq (2 buttons)
– adjust the internal clock frequency up or down (shown on
display)
Ampl (2 buttons)
– adjust the PRBS output amplitude up or down (shown on
display)
ø (2 buttons)
– adjust the detector clock phase up or down (shown on display)
Config State (2 buttons)
– change value of the currently-displayed
configuration state
.
Display
>
Scroll (2 buttons & 6 lights)
– select which feature is shown on the display
panel:
•BER – measured BER (# bit errors / total # bits)
•ε time (sec) – elapsed time of BER measurement, in seconds
•Ampl (V) – single-
ended PRBS generator output amplitude, in volts per
side
•Freq (GHz) – internal clock frequency, in GHz (10 GHz corresponds to
10 Gb/s)
•Ø – BER clock phase adjustment, in degrees (360-degrees = 1 UI)
•Config State– selects one of the configuration states shown in Table 1
.