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HP HP 83491A Скачать руководство пользователя страница 47

4-13

Reference

Cleaning Connections for Accurate Measurements

The soft core, while allowing precise centering, is also the chief liability of the
connector. The soft material is easily damaged. Care must be taken to mini-
mize excessive scratching and wear. While minor wear is not a problem if the
glass face is not affected, scratches or grit can cause the glass fiber to move
out of alignment. Also, if unkeyed connectors are used, the nickel silver can be
pushed onto the glass surface. Scratches, fiber movement, or glass contamina-
tion will cause loss of signal and increased reflections, resulting in poor return
loss.

Inspecting Connectors

Because fiber-optic connectors are susceptible to damage that is not immedi-
ately obvious to the naked eye, bad measurements can be made without the
user even being aware of a connector problem. Although microscopic exami-
nation and return loss measurements are the best way to ensure good connec-
tions, they are not always practical. An awareness of potential problems, along
with good cleaning practices, can ensure that optimum connector perfor-
mance is maintained. With glass-to-glass interfaces, it is clear that any degra-
dation of a ferrule or the end of the fiber, any stray particles, or finger oil can
have a significant effect on connector performance.

shows the end of a clean fiber-optic cable. The dark circle in the

center of the micrograph is the fiber’s 125

µ

m core and cladding which carries

the light. The surrounding area is the soft nickel-silver ferrule.

shows a dirty fiber end from neglect or perhaps improper cleaning. Material is
smeared and ground into the end of the fiber causing light scattering and poor
reflection. Not only is the precision polish lost, but this action can grind off the
glass face and destroy the connector.

shows physical damage to the glass fiber end caused by either

repeated connections made without removing loose particles or using
improper cleaning tools. When severe, the damage on one connector end can
be transferred to another good connector that comes in contact with it.

The cure for these problems is disciplined connector care as described in the
following list and in

“Cleaning Connectors” on page 4-16

.

Use the following guidelines to achieve the best possible performance when
making measurements on a fiber-optic system:

• Never use metal or sharp objects to clean a connector and never scrape the

connector.

• Avoid matching gel and oils.

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Содержание HP 83491A

Страница 1: ...User s Guide HP 83491 2 3A Clock Recovery Modules ...

Страница 2: ...nstalled on that instrument Hewlett Packard does not warrant that the operation of the instrument or software or firmware will be uninter rupted or error free Limitation of Warranty The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by Buyer Buyer supplied software or interfac ing unauthorized modifica tion or misuse operation outside of the environ...

Страница 3: ... This product is designed for use in INSTALLATION CATEGORY II and POLLUTION DEGREE 2 per IEC 1010 and 664 respectively C AUT IO N Electrostatic discharge ESD on or near input connectors can damage circuits inside the instrument Repair of damage due to misuse is not covered under warranty Before connecting any cable to the electrical input momentarily short the center and outer conductors of the ca...

Страница 4: ...iv General Safety Considerations ...

Страница 5: ...1A 2 10 3 Specifications and Regulatory Information HP 83491A Specifications 3 3 HP 83492A Specifications 3 4 HP 83493A Specifications 3 6 HP 83491 2 3A Operating Specifications 3 7 Declaration of Conformity 3 8 4 Reference Front Panel Optical Adapters 4 2 In Case of Difficulty 4 3 Error Messages 4 5 Electrostatic Discharge Information 4 8 Cleaning Connections for Accurate Measurements 4 10 Return...

Страница 6: ...Contents 2 Contents ...

Страница 7: ...1 To install the module 1 3 To connect cables to an HP 83492A 1 7 Installation ...

Страница 8: ...ption When you use improper cleaning and handling techniques you risk expensive instrument repairs damaged cables and compromised measurements Before you connect any fiber optic cable to an HP 83492A or HP 83493A module refer to Cleaning Connections for Accurate Measurements on page 4 10 C AUT IO N The circuits on electrical inputs and outputs can be damaged by electrostatic discharge ESD Therefor...

Страница 9: ...he nearest Hewlett Packard Sales and Service office HP will arrange for repair or replacement of damaged or incom plete shipments without waiting for a settlement from the transportation com pany Notify the HP customer engineer of any problems 1 Make sure that the serial number listed on the module s rear panel label matches the serial number listed on the shipping document Figure 1 1 Serial numbe...

Страница 10: ... was removed in the previous step onto the HP 83492 3A module s front panel Input connector On HP 83492A module s the input connector used depends on the wavelength of the input signal Refer to To connect cables to an HP 83492A on page 1 7 5 Connect the supplied adapter cable as shown in Figure 1 3 WA R N IN G Light energy can radiate from the front panel Output connectors on HP 83492A and HP 8349...

Страница 11: ... HP 83480A press the Trigger key and then the Source softkey Then select trigger 2 the HP 83491 2 3A module for the trigger source 8 On the HP 83491 2 3A module repeatedly press the SELECT key until a front panel light indicates the data rate of the signal See Figure 1 4 on page 1 6 Green and red data rate lights The data rate indicator lights change color between red and green to show which data ...

Страница 12: ...ation Figure 1 4 Front panel lights 9 Confirm that the Unlocked light is off 10 Observe the Clock and Data outputs on an oscilloscope Waveforms should be present The instrument is now ready for you to begin making measurements ...

Страница 13: ...tput roles depending on the wavelength of the signal Signals in the 750 nm to 860 nm wavelength range are input to the left connector and output from the right connector Signals in the 1000 nm to 1600 nm wavelength range are input to the right connector and output from the left connector Figure 1 5 Input and output connections versus wavelength ...

Страница 14: ...1 8 Installation Installation ...

Страница 15: ...es 2 4 Block Diagrams 2 7 To display a signal 2 8 To compensate for module insertion loss 2 9 Using Probes with an HP 83491A 2 10 To compensate for a passive probe 2 11 To compensate an HP 54701A active probe 2 11 To compensate for other devices 2 11 Operation ...

Страница 16: ... made available to the HP 83480A mainframe via a connector located on the module s rear panel An external front panel cable passes the data signal with some insertion loss to the receiver module Figure 2 1 An HP 83493A installed in an HP 83480A mainframe Table 2 1 Module Features Module Input Connector Selectable Rates Mb s HP 83491A 50Ω electrical 155 622 1060 1250 2120 2488 2500 HP 83492A Multim...

Страница 17: ... using the HP 83492A multimode module with single mode reference receivers such as the HP 83481A HP 83482A or HP 83485A B modules Connecting multimode to single mode fibers causes large reflections and insertion loss because of the reduction of the optical fiber s core from 62 5 µm to 9 µm Single mode module and multimode reference receivers It is acceptable to use an HP 83493A single mode module ...

Страница 18: ...ressing this key changes the modulation rate of the input signal The recov ered and retimed clock trigger is sent to the mainframe The Trigger On Data selection is a bypass mode where the data stream directly triggers the main frame Refer to Block Diagrams on page 2 7 to view a schematic of the nor mal and bypass paths ...

Страница 19: ...ransfer func tion when compared to the recovered clock signal which is routed through a rear panel connector to the mainframe for triggering Note that the CLOCK Aux iliary Output remains synchronized to input signals several dB below the onset of errors at the DATA Auxiliary Output Input and Output connectors The input connectors pass the digitally modulated signal to the receiver mod ule The inpu...

Страница 20: ...ulation bandwidth on the mainframe trigger signal a more complete view of the jitter on the waveform data is obtained Multimode and single mode connections HP 83492A modules use multimode fiber Connecting the output to the Optical Input con nector on HP 83481 2 5 single mode modules results in large reflections and insertion loss HP 83493A modules use 9 125 µm single mode fiber Connecting multimod...

Страница 21: ...2 7 Operation Block Diagrams Block Diagrams Figure 2 3 HP 83491A Block Diagram Figure 2 4 HP 83492A and HP 83493A Block Diagram ...

Страница 22: ...ave selected the correct data rate and that the HP 83480A or HP 54750A mainframe trigger level is adjusted appropriately Signals displayed using a data trigger are less reliable than using a recovered clock Signals triggered on data can also vary depending upon the trigger level Green and red data rate lights The data rate indicator lights change color between red and green to show which data rate...

Страница 23: ...e either the HP 83480A s built in power meter or an external power meter 3 Reconnect the cable to the clock recovery module 4 Disconnect the cable from the reference receiver module s input connector 5 Measure the signal using a power meter You can use either the HP 83480A s built in power meter or an external power meter 6 Subtract the two measurements to determine the insertion loss of the modul...

Страница 24: ...recovery module do not perform the procedure To compensate for module insertion loss on page 2 9 The following probes are available for use with HP 83491A clock recovery modules HP N1020A TDR probe HP N1020A TDR probe HP N1020A TDR probe HP N1020A TDR probe This passive probe 1 1 50Ω provides a fixture for po sitioning and holding the probe tip on the device being tested HP 54701A 2 5 GHz active p...

Страница 25: ... the probe tip to the CAL hook that is located near the floppy disk drive 5 Press the reference receiver module s front panel channel SETUP key 6 Press Calibrate and then Calibrate probe To compensate for other devices The information in this section applies to both optical and electrical measure ments Since the mainframe s CAL signal is a voltage source it cannot be used to calibrate to the probe...

Страница 26: ...2 12 Operation Using Probes with an HP 83491A 4 Press Ext gain and enter the actual gain characteristics of the device 5 Press Ext offset and enter the offset introduced by the device ...

Страница 27: ... HP 83491A Specifications 3 3 HP 83492A Specifications 3 4 HP 83493A Specifications 3 6 HP 83491 2 3A Operating Specifications 3 7 Declaration of Conformity 3 8 Specifications and Regulatory Information ...

Страница 28: ...stabilized after 60 minutes of continuous operation Specifications Specifications described warranted performance Characteristics Characteristics provide useful nonwarranted information about the func tions and performance of the instrument Characteristics are printed in italics Calibration cycle HP warrants instrument specifications over the recommended calibration interval To maintain specificat...

Страница 29: ...ing power level applies over temperature range 25 C 5 c Better than 10 10 BER when tested with PRBS 223 1 pattern 10 dBm to 3 dBm 10 dBm to 3 dBm Insertion loss through path DC through 2500 MHz 7 dB Output jitter all rates d d Measured on an oscilloscope eye diagram with PRBS 223 1 test pattern 0 0125 UIrms Maximum continuous electrical power before damage characteristic 1W peak DATA and CLOCK out...

Страница 30: ... 2125 00 Mb s 2488 32 Mb s 2500 00 Mb s 0 1 0 1 0 1 0 1 0 1 0 1 0 1 Data triggering characteristic 50 Mb s to 2500 Mb s Operating input power level c d 750 nm to 860 nm Triggering operation all rates 10 10 BER all rates e 1000 nm to 1600 nm Triggering operation all rates 10 10 BER all rates f 10 dBm to 3 dBm 10 dBm to 3 dBm 13 dBm to 3 dBm 13 dBm to 3 dBm Output jitter all rates g 0 0125 UIrms Max...

Страница 31: ...dB return loss Return loss with fully filled 62 5 µm core multimode fiber may be slightly lower c Source extinction ratio 8 2 dB when measured per TIA EIA OFSTP 4A d Operating power level applies over temperature range 25 C 5 e Better than 10 10 BER when tested with PRBS 223 1 pattern f Better than 10 10 BER when tested with PRBS 223 1 pattern g Measured on an oscilloscope eye diagram with PRBS 22...

Страница 32: ...cteristic 50 Mb s to 2500 Mb s Operating input power level b c Triggering operation all rates 10 10 BER all rates d b Source extinction ratio 8 2 dB when measured per TIA EIA OFSTP 4A c Operating power level applies over temperature range 25 C 5 d Better than 10 10 BER when tested with PRBS 223 1 pattern 20 dBm to 3 dBm 17 dBm to 3 dBm Output jitter all rates e e Measured on an oscilloscope eye di...

Страница 33: ...ns Use Iindoor Temperature Operating Non operating 0 C to 55 C 40 C to 70 C Altitude Operating Non operating 4600 m 15 000 ft 15 300 m 50 000 ft Humidity Operating Non operating up to 90 relative humidity at 35 C up to 90 relative humidity at 35 C Net weight approximately 1 2 kg 2 6 lb Shipping weight approximately 2 1 kg 4 6 lb Power Requirements Supplied by mainframe ...

Страница 34: ...3 8 Specifications and Regulatory Information Declaration of Conformity Declaration of Conformity ...

Страница 35: ... 2 In Case of Difficulty 4 3 Error Messages 4 5 Electrostatic Discharge Information 4 8 Cleaning Connections for Accurate Measurements 4 10 Returning the Module for Service 4 21 Hewlett Packard Sales and Service Offices 4 24 Reference ...

Страница 36: ...4 2 Reference Front Panel Optical Adapters Front Panel Optical Adapters Figure 4 1 Front panel adapters for input and output connectors ...

Страница 37: ...r source Is the mainframe turned on Is the rear panel line switch set to on Will the mainframe power up without the plug in module installed If the mainframe still does not power up refer to the optional HP 83480A HP 54750A Service Guide or return the mainframe to a qualified service department If the plug in does not operate Is the plug in module firmly seated in the mainframe slot Are the knurle...

Страница 38: ...em config The calibration status of the plug in modules is listed near the bottom of the display in the box labeled Plug ins If the model number of the plug in module is listed next to the appropriate slot number then the mainframe has identified the plug in If known is displayed instead of the model number of the plug in module remove and reinsert the plug in module in the same slot If known is s...

Страница 39: ...quired that is beyond the scope of this book Additional error messages are listed in the HP 83480A HP 54750A User s Guide for the mainframe Memory error occurred in plug in_ Try reinstalling plug in The mainframe could not correctly read the contents of the memory in the plug in Remove and reinstall the plug in module Each time a plug in is installed the mainframe re reads the memory in the plug i...

Страница 40: ...the slot is empty there is a mainframe hardware problem Refer to the HP 83480A HP 54750A Service Guide If a plug in is installed in the slot there is a plug in module hardware problem Return the plug in module to a qualified service department ID error occurred in plug in_ Service is required The information read from the memory of the plug in module does not match the hardware in the plug in modu...

Страница 41: ...ccept plug in modules de signed for use with the HP 54710A 54720A Plug in is not supported System firmware upgrade is needed The mainframe may need to have the latest operating system firmware installed Options 001 and 002 provide this firmware on a 3 5 inch diskette To load the new firmware follow the instructions provided with the diskette If you do not have the optional diskette contact your lo...

Страница 42: ...lectronic components All work on electronic assemblies should be performed at a static safe work station The following figure shows an example of a static safe work station using two types of ESD protection Conductive table mat and wrist strap combination Conductive floor mat and heel strap combination Figure 4 2 Static safe work station ...

Страница 43: ...g ESD Damage The following suggestions may help reduce ESD damage that occurs during testing and servicing operations Personnel should be grounded with a resistor isolated wrist strap before re moving any assembly from the unit Be sure all instruments are properly earth grounded to prevent a buildup of static charge Table 4 1 Static Safe Accessories HP Part Number Description 9300 0797 Set include...

Страница 44: ...the mechanical assembly that holds the ferrule in position against another identical ferrule Connectors also vary in the polish curve and concentricity of the core within the cladding Mating one style of cable to another requires an adapter Hewlett Packard offers adapters for most instru ments to allow testing with many different cables The Figure 4 3 on page 4 11 shows the basic components of a t...

Страница 45: ...r it represents a good compromise between performance reli ability and cost If properly maintained and cleaned this connector can withstand many repeated connections However many instrument specifications require tighter tolerances than most connectors including the FC PC style can deliver These instruments cannot tolerate connectors with the large non concentricities of the fiber common with cera...

Страница 46: ...ss section of the Diamond HMS 10 connector The nickel silver allows an active centering process that permits the glass fiber to be moved to the desired position This process first stakes the soft nickel silver to fix the fiber in a near center location then uses a post active staking to shift the fiber into the desired position within 0 2 µm This process plus the keyed axis allows very precise cor...

Страница 47: ...aces it is clear that any degra dation of a ferrule or the end of the fiber any stray particles or finger oil can have a significant effect on connector performance Figure 4 6 shows the end of a clean fiber optic cable The dark circle in the center of the micrograph is the fiber s 125 µm core and cladding which carries the light The surrounding area is the soft nickel silver ferrule Figure 4 7 sho...

Страница 48: ...4 7 Dirty fiber end and ferrule from poor cleaning Figure 4 8 Damage from improper cleaning While these often work well on first insertion they are great dirt magnets The oil or gel grabs and holds grit that is then ground into the end of the fiber Also some early gels were designed for use with the FC non contacting con ...

Страница 49: ...rs that have a convex fiber end the end can be pushed off axis resulting in misalignment and excessive return loss Many measurements are actually improved by backing off the connector pressure Also if a piece of grit does happen to get by the cleaning procedure the tighter connection is more likely to damage the glass Tighten the connectors just until the two fibers touch Keep connectors covered w...

Страница 50: ... loss the smaller the reflection The best physically contacting connectors have return losses better than 50 dB although 30 to 40 dB is more common Visual inspection of fiber ends Visual inspection of fiber ends can be helpful Contamination or imperfections on the cable end face can be detected as well as cracks or chips in the fiber itself Use a microscope 100X to 200X magnification to inspect th...

Страница 51: ...oam swab to clean optical fiber ends Foam swabs can leave filmy deposits on fiber ends that can degrade performance 1 Apply pure isopropyl alcohol to a clean lint free cotton swab or lens paper Cotton swabs can be used as long as no cotton fibers remain on the fiber end after cleaning Table 4 2 Cleaning Accessories Item HP Part Number Isopropyl alcohol 8500 5344 Cotton swabs 8520 0023 Small foam s...

Страница 52: ...tip or invert compressed air canisters because this releases particles in the can into the air Refer to instructions provided on the compressed air canister 7 As soon as the connector is dry connect or cover it for later use If the performance after the initial cleaning seems poor try cleaning the con nector again Often a second cleaning will restore proper performance The second cleaning should b...

Страница 53: ...efer to instructions provided on the compressed air canister Caring for electrical connections The following list includes the basic principles of microwave connector care For more information on microwave connectors and connector care consult the Hewlett Packard Microwave Connector Care Manual HP part number 08510 90064 Handling and Storage Keep connectors clean Extend sleeve or connector nut Use...

Страница 54: ...ions Align connectors carefully Make preliminary connection lightly To tighten turn connector nut only Do not apply bending force to connection Do not overtighten preliminary connection Do not twist or screw in connectors Do not tighten past the break point of the torque wrench ...

Страница 55: ...paired under the terms of the warranty or contract the war ranty is at the front of this manual If the module is no longer under warranty or is not covered by an HP maintenance plan Hewlett Packard will notify you of the cost of the repair after examining the unit When an module is returned to a Hewlett Packard service office for servicing it must be adequately packaged and have a complete descrip...

Страница 56: ...g packaging materials other than the original materials Never use styrene pellets as packaging material They do not adequately cushion the module or prevent it from shifting in the carton They may also cause module damage by generating static electricity 3 Pack the module in the original shipping containers Original materials are available through any Hewlett Packard office Or use the following gu...

Страница 57: ...nk antistatic Air Cap to reduce static electricity Wrapping the module several times in this material will protect the module and prevent it from moving in the carton 4 Seal the carton with strong nylon adhesive tape 5 Mark the carton FRAGILE HANDLE WITH CARE 6 Retain copies of all shipping papers ...

Страница 58: ...wood CO 80112 303 649 5000 Georgia Hewlett Packard Company 2000 South Park Place Atlanta GA 30339 404 955 1500 Illinois Hewlett Packard Company 5201 Tollview Drive Rolling Meadows IL 60008 708 342 2000 New Jersey Hewlett Packard Company 150 Green Pond Road Dock 1 Rockaway NJ 07866 201 586 5910 Texas Hewlett Packard Company 930 East Campbell Road Richardson TX 75081 214 231 6101 EUROPEAN FIELD OPER...

Страница 59: ...oad Trans Canada Highway Kirkland Quebec H9J 2X8 Canada 514 697 4232 China China Hewlett Packard Company 38 Bei San Huan X1 Road Shuang Yu Shu Hai Dian District Beijing China 86 1 256 6888 Japan Hewlett Packard Japan Ltd 9 1 Takakura Cho Hachioji Shi Tokyo 192 Japan 81 427 59 1311 Singapore Hewlett Packard Singapore Ltd Pte Ltd Alexandra P O Box 87 Singapore 9115 65 271 9444 Taiwan Hewlett Packard...

Страница 60: ...4 26 Reference Hewlett Packard Sales and Service Offices ...

Страница 61: ...dicator lights 1 5 data rates 2 2 multiple of 2 8 declaration of conformity 3 8 dust caps 4 17 E electrostatic discharge 1 2 4 8 error messages 4 5 error performance analyzers use with 2 3 ESD reducing damage caused by ESD 4 9 static safe work station 4 9 extender cables 1 3 F fiber adapters 4 2 care of 1 2 cleaning connections 4 10 connections on HP 83492A 1 7 connectors covering 4 22 multimode 2...

Страница 62: ...ion degree 2 iii programming 2 3 R red light 1 5 regulatory information 3 2 responsivity testing 1 4 returning for service 4 21 S safety information iii 1 3 2 3 sales and service offices 4 24 SELECT key 1 5 2 4 serial number 1 3 service 4 21 returning for 4 21 sales and service offices 4 24 shipping procedure 4 21 single mode fiber 2 6 specifications 3 2 defined 3 2 HP 83491A 3 3 HP 83492A 3 4 HP ...

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