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User Manual 1503C Metallic Time-Domain

1. i METALLIC TDR fo Tektronix 1503C CABLE TESTER DP POSITION I G3 a Wm 3 INPUT i 3 E E d MILIA mom er STORE Peeche eosar ahea ee ied iad T E I ER nik E EE OE Ue Ee had sans NE 15 store JC ME QE CA 23 a MU UN ME nase oy INPUT PROTECTED 500 1 avg 0 00 db 1ft 2ns f 400 M MAX IMPEDANCE NOISE FILTER VERT SCALE DIST DIV Vp Q Cx Os POWER NO l SET REF 9 oN od PULLON c Y d 2 G Figure 1 3 1503C Front Panel Controls CAUTION Do not connect to circuits or cables with live voltages greater than 400 V peak Voltages exceeding 400 V might damage the 1503C front end circuits 1 4 1503C MTDR User Manual Operating Instructions Display Power Front Panel to Cursor Type Cursor Waveform Distance Window ee ee er eer ow ee Indicator f m Grid View Store Indicator View Difference Indicator Store Indicator JFL usus eau 50 Q 1 avg 0 00 dB 5000 ft 2ns Selected Selected Selected Selected Selected Impedance Noise Filter Vertical Scale Distance per Pulse Width Division Figure 1 4 Display and Indicators Front Panel Controls 1 CABLE A female BNC connector for attaching a cable to the 1503C for testing IMPEDANC
2. 1 Q move cursor to reference and Press STORE jeu Fl 1 F I Figure 1 23 Cursor Moved to End of Three Foot Lead in Cable 3 Push STORE 4 Turnthe NOISE FILTER control to 1 avg The instrument is now in HORZ SET REF or delta mode The distance window should now read 0 00 ft As the cursor is scrolled down the cable the distance reading will now be from the new zero reference point NENNEN 7 Figure 1 24 Cursor Moved to End of Three Foot Lead in Cable NOTE Vp changes will affect where the reference is set on the cable Be sure to set the Vp first then set the delta to the desired location 5 To exit HORZ SET REF use the following procedure a Turn the NOISE FILTER control to HORZ SET REF b Turn DIST DIV to 1 ft div If the distance reading is extremely high you might want to use a higher setting initially then turn to 1 ft div for the next adjustment c Turn the P POSITION control until the distance window reads 0 00 ft 1503C MTDR User Manual Operating Instructions Using Vertical Set Reference 1503C MTDR User Manual i move cursor to reference and Press STORE a i oie ees oe r C cm Figure 1 25 Cursor Moved to 0 00 f d Push STORE e Turn NOISE FILTER to desired setting VERT SET REF works similar to HORZ SET REF except that it sets a reference for gain pulse height instead of distance This feature allows zeroing the dB scale at
3. B 1 Appendix C Operator Troubleshooting C 1 Error Messages Mm C 3 Appendix D Application Note eere D 1 Glossary quaes xa XxxeRE d RES PARARE A HEALTH Glossary 1 linis dec EM Index 1 1503C MTDR User Manual Table of Contents List of Figures 1503C MTDR User Manual Figure 1 1 Rear Panel Voltage Selector Fuse AC Receptacle Figure 1 2 Display Showing Low Battery Indication Figure 1 3 1503C Front Panel Controls 000000 Figure 1 4 Display and Indicators 0 0 00 cece eee eee Figure 1 5 Vp Set at 30 Cursor Beyond Reflected Pulse Setting Too LOW cete ERE dew doe Rhee tee eed Figure 1 6 Vp Set at 99 Cursor Less Than Reflected Pulse Setting o0 HIgh cea fice neato eae eme eee Re Rs Figure 1 7 Vp Set at 66 Cursor on Rising Edge of Reflected Pulse Set Correctly 4 coe ret Rh See CRI EROR Cen Figure 1 8 20 ft Cable at 5 ft div 0 0 ee eee ee eee ee Figure 1 9 Short in the Cable 0 0 0 0 0 0 ee eee eee eee ee Figure 1 10 Open in the Cable lesen Figure 1 11 455 ft Cabl 2 5 eror Re m Reg Figure 1 12 455 ft Cable with 20 ft div Cursor Off Screen Figure 1 13 Return Loss leleeeeeee eh Figure 1 14 Reflection Adjusted to One Division in Height Figure 1 15 Display with VIEW INPUT Turned Off Figure 1 16 Display of a Stor
4. RETURN LOSS i IMPULSE ONLY TTL ETTITTEERTEHT T TERTII ETT TET 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 Figure D 1 Slide Rule of VSWR vs Percent Reflected Voltage SINGLE RESISTIVE ll DISCONTINUITY ONLY 1 00 On the upper scale locate the known value of VSWR or Adjacent to that point is the corresponding value for or VSWR VSWR is the peak to valley ratio of standing sine waves NOTE The relationship between holds only when the loss is a single impedance discontinuity with negligible capacitive or inductive components e g a 75 Q termination at the end of a 50 Q cable The VSWR must be essentially the same for all sine wave frequencies 1503C MTDR User Manual Operator Troubleshooting Return Loss dB vs Percent Reflected Voltage To find return loss in decibels knowing the or vice versa use the bottom scale of the Frequency Domain Conversions section of the slide rule see Figure AN 2 SINGLE 0 2 4 6 8 10 12 14 16 18 20 mEsieTIVE utitur Prot t b uu b n ud Lt buda o E LLL DISCONTINUITY METI IT T E E n ETT ONLY 1 00 1 05 1 10 1 15 1 20 1 25 1 30 1 35 1 40 1 45 1 50 VWSR 01 02 03 05 10 2 3 5 71 0 2 3 5710 2030 50 100 RETURN LOSS uu itt et Pe n rbd b ba Lb Pee LI IMPULSE ONLY JT i ITT 80
5. Display with VIEW INPUT Turned On Waveform Moved to Upper Portion of the Display Waveform with Cable Shorted 04 Waveform with Both Current and Stored Waveforms Stored Current and Difference Waveforms Display with VIEW STORE and VIEW DIFF Disabled Short and Open Viewed via Max Hold Waveform Strobed Down Display in Max Hold Display with Pulse Turned Off 00 2 3 2 3 2 7 2 8 2 10 2 10 2 11 2 12 2 12 1503C MTDR User Manual Table of Contents 1503C MTDR User Manual Figure 2 33 Test Cable cee ce u Ra E esae RR E ee Figure 2 34 Shorted Test Cable with a Captured Single Sweep Figure 3 1 A Typical Ethernet System 0000000005 Figure 3 2 N Type Male T Connector llle esee Figure 3 3 N Type Female T Connector 0000000005 Figure 3 4 System 1 Tap Hidden by Traffic lave 50 TUdiv 35 dB osaa e tette E EUER ERR Figure 3 5 System 1 Traffic and Tap Nearly Identical 4 avg 50 fUdiv 35 dB ise yer o te Rea RR adie Figure 3 6 System 1 Tap Becoming Visible 16 avg 50 TUdiv 35 dB oce coe eee is awa diesen Figure 3 7 System 1 Tap Quite Visible 128 avg 50 tUdiv 35 dB rose pte rem Figure 3 8 System 1 No Traffic have 50 fUdIy 35 dB ides RR SERRE ce ERE Figure 3 9 System 1 Tap Expanded No Traffic
6. POWER PULL ON Q PULSE WIDTH wu e 92 E eo a lt I gt POSITION vam MENU VEW INPUT VIEW STORE VIEW DIFF p STORE 10 11 12 13 14 15 A standard instrument defaults to ft div A metric instrument Option 05 defaults to m div but either may be changed temporarily from the menu The default can be changed by changing an internal jumper see 1503C Service Manual and always refer such changes to qualified service personnel Vp The two Velocity of Propagation controls are set according to the propagation velocity factor of the cable being tested For example solid polyethylene commonly has a Vp of 0 66 Solid polytetraflourethylene Teflon is approximately 0 70 Air is 0 99 The controls are decaded the left control is the first digit and the right control is the second digit For example with a Vp of 0 30 the first knob would be set to 3 and the second knob to 00 POWER Pull for power ON and push in for power OFF When the front cover is installed this switch is automatically pushed OFF PULSE WIDTH This is a five position rotary switch that selects the pulse width of the cable test signal The available settings are 2 10 100 1000 nanoseconds and AUTO The selected value is displayed on the LCD adjacent to the control The AUTO setting sets
7. CAUTION Any time the instrument smells hot repeatedly blows fuses or repeats the same error message you should have the instrument serviced by qualified technicians using the procedures in the 1503C Service Manual These are the first checks you should perform when you think you might have a problem with the instrument The first step asks you to preset the instrument controls Here is how to do that Set Vp to 66 turn the IMPEDANCE knob all the way counterclockwise turn the FILTER knob all the way counterclockwise then back two clicks turn the DIST DIV knob all the way counterclockwise then back three clicks turn the PULSE WIDTH knob all the way counterclockwise remove any accessories that might be plugged into the Option Port e g chart printer and disconnect any cable that might be attached to the front panel connector To complete the tests you might need a Volt Ohmmeter VOM a flat bladed screw driver to set the line voltage switch and possibly some spare fuses When you have completed these tests you will know that it is safe to use the instrument or that it needs repair or adjustment internally You do not remove the case for these tests IMPORTANT It is possible for the instrument to continue to make some measurements even after reporting an error message Do not ignore repeated error messages They indicate something is wrong and should be used with the 1503C Service Manual troubleshooting procedures
8. Meets intent of Directive 89 336 EEC for Electromagnetic Compatibility Compliance was demonstrated to the following specifications as listed in the Official J ournal of the European Union EN 50081 1 Emissions EN 55022 Class B Radiated and Conducted Emissions EN 60555 2 AC Power Line Harmonic Emissions EN 50082 1 Immunity IEC 801 2 Electrostatic Discharge Immunity IEC 801 3 RF Electromagnetic Field Immunity IEC 801 4 Electrical Fast Transient B urst Immunity IEC 801 5 Power Line Surge Immunity Australia New Zealand Declaration of Conformity EMC Complies with EMC provision of Radiocommunications Act per the following standard s AS NZS 2064 1 2 Industrial Scientific and Medical Equipment 1992 EMC Compliance FCC Compliance Safety Standards U S Nationally Recognized Testing Laboratory Listing Canadian Certification European Union Compliance Additional Compliance Safety Certification Compliance Equipment Type Safety Class Overvoltage Category Pollution Degree Installation Overvoltage Category Meets the intent of Directive 89 336 EEC for Electromagnetic Compatibility when it is used with the product s stated in the specifications table Refer to the EMC specification published for the stated products May not meet the intent of the directive if used with other products Emissions comply with FCC Code of Federal Regulations 47 Part 15 Subpart B Class A Limits UL1244 Standard for elect
9. Reflection Coefficient divided by 1 000 millirho Ratio of the incident voltage to reflected voltage multiplied by 100 VSWR Voltage Standing Wave Ration peak to valley C Velocity of light in air Vp Propagation Velocity of a signal in a transmission line V Velocity Factor fraction of the velocity of light Dielectric Constant Outer Diameter of the dielectric in a coaxial cable Diameter of the center conductor in a coaxial cable Inductance in nanoHenries nH per foot Capacitance in picoFarads pF per foot areae g7 1503C MTDR User Manual D 1 Operator Troubleshooting Relationships Zo et3eok logio D d for coaxial cable p 100 VSWR 1 9 1 o for the case where VSWR is the same for all frequencies c 30 cm nanosecond 0 984 ft ns Vg elf Vp 30 cm ns 0 984 K ft ns C 7 36 logio D d L 140 logjgD d lin 2 54cm 1 ft 30 48 cm 1m 3 28 ft VSWR vs Percent Reflected Voltage D 2 To find the Voltage Standing Wave Ratio VSWR knowing the percent reflected voltage 46 or vice versa use the Frequency Domain Conversions section of the slide rule see Figure AN 1 1 04 VSWR 296 REFLECTION 2096 2 1 5 VSWR 0 2 4 6 8 10 12 14 16 18 20 pui need tt Loud ubt LE LLL DELL COANA PTT TTT TTT T THTTTTTTITETE TETTE TETTE TAEDA TTT 1 05 1 10 1 15 1 20 1 25 1 30 1 35 1 40 1 45 1 50 VWSR 01 02 03 y 10 2 3 5 710 2 3 57 10 2030 50 100
10. 1503C MTDR User Manual Options and Accessories 334 Introduction BW Use the shortest pulse width possible Do not use Auto pulse width mode If it selects the 100 ns or 1000 ns pulse it might disrupt traffic on working networks W Use the simplest possible test first M Operate the 1503C on AC power when using the option chart printer m Changes made in the menus do not take effect until the instrument is returned to normal operation This prevents erroneous menu selections from creating disruptions m Have the network documentation ready If available have prior TDR profiles of the network that you will be comparing M If possible turn off repeaters and bridges to other networks to minimize the extent of a possible disruption the 1503C might cause m If you use a jumper cable make sure that it matches the network cable impedance The three foot jumper furnished with the instrument is 50 Q The IEEE 802 3 standard recommends only one earth ground per segment When connected to AC power the 1503C provides an earth ground to the coaxial shield There is no connection to ground when the 1503C is used with the optional battery pack and the AC power cord is disconnected The first test usually run on an active network is the normal sweep with the 2 ns or 10 ns pulse and the DC 50 Q termination is On from the Ethernet Menu This test provides basic TDR tests with a 50 O termination for the net If the network traffic is
11. This procedure will give you confidence that the instrument is functioning properly It is not an exhaustive set of tests that guarantee that the instrument meets all specifications and is perfectly calibrated The calibration procedures in the 1503C Service Manual are the best method for assuring that the instrument meets all specifications 1503C MTDR User Manual C 1 Appendix C Operator Troubleshooting with cases on Operator Troubleshooting Is the power source a battery NO Preset front panel and turn the power on there a greed display Did Initializing message appear on LCD Y If error message s appear follow the displayed instructions Is waveform YES Replace fuse DO NOT USE INSTRUMENT Serious problems need repair Refer to 1502C Service Manual Troubleshooting procedures Refer to Option Port and Accessories Trouble shooting procedure If no accessories then OK to use instrument Y Check line voltage switch for correct Turn instrument Using VOM setting and change if necessary off immediately to check for With VOM check wall outlet voltage avoid possible near zero Ohms and plug in somewhere else if no damage to LCD in fuse voltage Check fuse and power cord display for near zero Ohms Is YES fuse OK
12. A 4 Error Messages C 3 Ethernet Test Procedure 3 5 Ethernet Bridge 3 2 Carrier 3 9 Collision 3 10 Custom Tests 3 10 Electrical Characteristics 3 16 Frequency Response Curve 3 17 Introduction 3 4 Menu 3 7 Carrier 3 8 Collision 3 9 Single Sweep 3 8 Termination 3 7 N Type Female T Connector 3 6 Index N Type Male T Connector 3 5 Repeaters 3 2 Segments 3 2 Servers 3 2 Specifications 3 16 Taps 3 2 3 10 Termination 3 9 3 10 Testing Networks 3 3 Transceivers 3 2 Typical System 3 3 What is it 3 1 Waveform Signatures 3 10 F Features see Menu 1 24 Frequency Response Curve 3 17 Fungus Spec A 3 Fuse 3 19 Fuse see Power 1 2 G Getting Started 2 2 H Handling 1 1 Height Spec A 5 Help 2 1 Horizontal Scale Spec A 2 Horizontal Set Reference 1 21 2 11 HORZ SET REF see Horizontal Set Reference 2 11 Humidity Spec A 3 Impedance see also Controls 1 5 Impedance of Cables 1 11 Indicators 1 5 Isolation Network 3 20 L Loss 1 15 Maintenance C 1 D 1 Max Hold see Maximum Hold 2 18 Index 2 Maximum Hold 1 24 2 18 Menu 1 7 1 24 2 1 2 18 Cables 1 7 Diagnostics 1 8 Chart Recorder 1 9 Head Alignment 1 9 LCD Chart 1 9 Front Panel 1 8 LCD 1 8 Alignment 1 8 Contrast 1 9 Drive Test 1 9 Response Time 1 8 Service 1 8 Impedance 1 8 Noise 1 8 Offset Gain 1 8 RAM ROM 1 8 Sa
13. Figure B 5 Flatline e Display O Out to 50 0000 Feet If the instrument fails this test it can be used but should be serviced when possible Not all of the waveforms will be viewable at all gain settings 1 Using the POSITION control verify that the entire waveform can be moved to the very top of the display off the graticule area Baw 9080000 IN Waveform p F B F PU Fi Figure B 6 Waveform Off the Top of the Display 2 Using the 5 POSITION control verify that the entire waveform can be moved to the very bottom of the display to the bottom graticule line bat 50600 00t ee ere MM NE E Waveform amo Figure B 7 Waveform at the Bottom of the Display 1503C MTDR User Manual Appendis B Operator Performance Checks 3 Noise Check If the instrument fails this check it may still be usable for measurements of large faults that do not require a lot of gain A great deal of noise reduction can be made using the NOISE FILTER control Send your instrument to be serviced when possible 1 Set the PULSE WIDTH to 2 ns Using the POSITION control and VERT SCALE control set the gain to 57 dB with the waveform centered vertically in the display Pe F Figure B 8 Waveform with Gain at 57 dB Press MENU Using the S POSITION control select Diagnostics Menu Press MENU again Using the 5 POSITION control select Service Diagnostic Menu Press
14. It can also disrupt devices or applications that require periodic network traffic When this test is selected the 1503C will assert a 1 05 VDC signal on the net long enough to take a single waveform at the NOISE FILTER level selected This is the equivalent to the average voltage level of a normal transmission and should cause the transceivers to assert Carrier Detect This has the effect of causing most devices on the net to defer transmission until the 1503C is finished This takes from about one to 20 seconds depending on noise averaging and reduces the traffic displayed on the waveform NOTE Movement of any control that would change or move the waveform will start a new sweep and assert the 1 05 VDC For example if you use the vertical position control continuously for 20 seconds you would be asserting the false traffic for that duration and you are likely to disrupt the network Carrier Test is Off On CAUTION This carrier signal will stop traffic on the network This might abort many application programs and might cause communications problems This test asserts the 1 05 VDC signal on the network turns off the normal 1503C pulse and sets up the MAX HOLD mode This is intended to help find transceivers that have a faulty Carrier Detect To use this test have the network prepared for disruption and turn the test on via the Ethernet Menu Any traffic observed is being transmitted in spite of a signal simulating
15. NOISE PTT 2 9 Set Ref AMO ceric e caict a GrP RP PIE Es TREE Is Pg 2 11 VIEW INPUT aiaiai eese etae d een eR ORE a ee a eee ANE 2 14 STORE and VIEW STORE oe ce eee Ree PERRO PEE FE ER 2 15 VIEW DIEE eet eoe te teh o decl Er oso RR RS 2 17 1503C MTDR User Manual i Table of Contents Menu Accessed Functions 0 0 0 0 eee eee eee ee 2 18 TDR Questions and Answers 0 00 cece cette eee ene 2 23 Options and Accessories cece cece cece ccc eceeees 3 1 Option 04 YT 1 Chart Recorder 0 0 00 02 cee ee eee eee 3 1 Option 05 Metric Default 2 suc esae ga RR nd ee REFERRE 3 1 Option 06 Bth rnet oss o ro Ee SU Be SRE E Pu RP ota ets 3 1 Option 07 YT 18 Chart Recorder sese 3 17 Option 08 Token Ring Adapter cc sssccsuecisusii te tipust Erpes reski 3 17 Option 09 Universal Service Ordering Code 000 00000 3 18 Option 10 Token Ring Interface 0 0 0 0 0c eee eee 3 18 Power Cord Options ssie cso ene ee eee udo ex ne px eed E 3 18 ACCESSO E Saare 5 oa pbs ES DG DURER RM RS DICES Fae Sales SUM Dauegpp ve 3 19 Appendix A Specifications ccc cece cece eee ees A 1 Electrical haracteristies sect h RR RR er ERE ERE EURESCEREWGTRERE A 1 Environmental Characteristics eee A 3 Certifications and Compliances siss 2 0 eee cee tsd A 4 Physical Characteristics iss sese er E REX E ERR Re ER S A 5 Appendix B Operator Performance Checks
16. PULSE WIDTH per cable 2 If you know approximately how long the cable is set the DIST DIV appropriately e g 20 ft cable would occupy four divisions on the LCD if 5 ft div was used The entire cable should be displayed 1 12 1503C MTDR User Manual Operating Instructions 1503C MTDR User Manual Figure 1 8 20 ft Cable at 5 ftidiv Ifthe cable length is unknown set DIST DIV to 5000 ft div and continue to decrease the setting until the reflected pulse is visible Depending on the cable length and the amount of pulse energy absorbed by the cable it might be necessary to increase the VERT SCALE to provide more gain to see the reflected pulse The best pulse width is dependent on the cable length A short pulse can be completely dissipated in a long cable Increasing the pulse width will allow the reflected pulse to be more visible when testing long cables AUTO will select the pulse width for you depending on the distance on the right side of the LCD CABLE LENGTH SUGGESTED PULSE SUGGESTED ft div 0 to 100 ft 2 ns 10 ft div 51 to 500 ft 10 ns 50 ft div 501 to 5000 ft 100 ns 500 ft div 5001 to 50 000 ft 1000 ns 5000 ft div When the entire cable is displayed you can tell if there is an open or a short Essentially a drop in the pulse is a short and a rise in the pulse is an open Less catastrophic faults can be seen as hills and valleys in the waveform Bends and kinks frays water and inter
17. Pulse Spec A 1 Q Questions and Answers 2 23 1503C MTDR User Manual R Reflection Coefficient 1 16 Repeaters 3 2 Return Loss 1 15 S Salt Atmosphere Spec A 3 Sand and Dust Spec A 3 Scale see Controls Segments 3 2 Servers 3 2 Service Manual 3 19 Ship Carton Strength ix Shock Spec A 3 Short 1 13 2 4 2 16 Single Sweep 1 26 221 Slide Rule 3 19 Specifications A 1 Electrical A 1 A 2 A 3 Environmental A 3 Physical A 5 Store 2 15 Store the Waveform 1 18 T Taps 3 2 3 10 Temperature Low 1 Terminator 3 2 3 5 Test Cable 3 19 Thin Ethernet 3 1 ThinWire 3 1 Token Ring Adapter 3 20 Interface 3 20 Transceivers 3 1 Troubleshooting C 1 Tutorial 2 1 3 3 6 3 9 3 10 3 19 U USOC Adapter 3 20 Index 3 Index V Velocity of Propagation see also Controls 1 6 1 10 Table of Types 1 10 Unknown Vp 1 11 Velocity of Propagation Spec A 2 VERT SET REF see Vertical Set Reference 2 12 Vertical Scale 2 5 2 13 Vertical Scale Spec A 1 Vertical Set Reference 1 23 2 12 Vibration Spec A 3 View Diff see View Difference View Difference 1 18 2 17 Index 4 View Input 1 17 2 14 View Store 1 18 2 15 Voltage see Power Voltage Spec A 2 Vp see Velocity of Propagation 1 10 W Water Resistance Spec A 3 Waveform Storage 1 18 Weight Spec A 5 Whatis a 1503C 2 1 1503C MTDR User Manual
18. across the LCD iv Contrast Adjust allows you to adjust the contrast of the LCD It generates an alternating four pixel pattern The nominal contrast is set internally When in Contrast Adjust mode VERT SCALE is used as the contrast adjustment control This value ranges from 0 to 255 units and is used by the processor to evaluate and correct circuit variations caused by temperature changes in the environment d Chart Diagnostics Menu offers various tests for the optional chart recorder i LCD Chart allows adjusting the number of dots per segment and the number of prints strikes per segment ii Head Alignment Chart generates a pattern to allow mechanical alignment of the optional chart recorder View Stored Waveform Settings displays the instrument settings for the stored waveform Option Port Menu contains three items Two items allow configuration of the option port for communicating with devices other than the optional chart recorder and one item test the option port a Option Port Diagnostic creates a repeating pattern of signals at the option port to allow service technicians to verify that all signals are present and working correctly b Set Option Port Timing allows adjustment of the data rate used to communicate with external devices The timing rate between bytes can be set from about 0 05 to 12 8 milliseconds c Option Port Debugging Is Off On Off is quiet On is verbose This chooses how detailed the error mess
19. convenience Most of the tests in the Ethernet Menu can be recreated or modified That is explained at the end of this section Changes made in the Ethernet Menu will affect some of the Setup Menu and Acquisition Control Menu functions For example if Carrier Test is Off On is turned on the 50 Q termination will also be turned on because it is necessary for the carrier test to work 500 DC Termination is Off On CAUTION This must be on when testing on a working network or reflections will cause collisions on the network This entry is a duplicate of the entry in the Setup Menu Acquisition Control Menu Its function is to allow direct control of the termination inside the 1503C With the 50 Q DC termination on the 1503C will function normally as a cable tester This is usually the only test needed to check a network cable CAUTION The 100 ns and 1000 ns pulses might cause collisions Options and Accessories 3 8 Longer pulses are more likely to generate collisions than shorter pulses On networks with traffic less than 3 to 4 a 2 ns pulse causes no measurable change in network statistics Even on heavily tapped cables the 2 ns pulse can usually be used for distances to 700 feet The 10 ns pulse should be suitable for those longer segments that still fall within the 802 3 specifications under 500 meters Single Sweep with Carrier is Off On CAUTION This can interrupt prior traffic and cause late collisions
20. 003 1419 00 Accessory Pouch ue bie ee tia eet oe Dre dee eras ie ee 016 0814 00 Service Manual 4 ossis rede a re Ed 070 7170 xx bruni pM Pr aaa a Ria EEA EEA E E T E 040 1276 00 Chart Recorder YEIS is eoa rm ew Ha o e 119 3616 00 Chart Paper single roll ors ccr 0 0 0 0 0 0 00 ee eee eee 006 7647 00 Chart Paper 25 roll pack 0 0 0 0 00 e eee eee 006 7677 00 Chart Paper 100 roll pack 0 0 0 0 00005 006 768 1 00 Cable Interconnect 360 inches leere 012 0671 03 Connector BNC male to BNC male 103 0029 00 Connector BNC female to Alligator Clip S N z B010625 013 0261 00 Connector BNC female to Hook tip Leads 013 0076 01 Connector BNC female to Dual Banana Plug 103 0090 00 Connector BNC male to Dual Binding Post 103 0035 00 Connector BNC male to N female 103 0058 00 3 19 Options and Accessories 3 20 Connector BNC female to N male 103 0045 00 Connector BNC female to UHF male 103 0015 00 Connector BNC female to UHF female 103 0032 00 Connector BNC female to Type Fmale 103 0158 00 Connector BNC male to Type F female 013 0126 00 Connector BNC female to GR 00000000 000 017 0063 00 Connector BNC male to GR 000 0000008 017 0064 00 Precision 50 Q Cable S N B
21. 50 Q reference level For a reference level use either a section of line of known impedance ahead of the line under test load or use a termination of known resistance at the end of the line The slide rule can then be used by selecting the side with the same source resistance and the same scale as the TDR p DIV OHMS 55 I e aa a a a a a P g aM arra S MAE qe d Sig RG8 U P aed ser 5150 iiie tee 51 E RG213U gp oon 4950 49 SE OGNUNO ee Cees ot ee z 2ns d gt E E 500 SOURCE Precision Load Resistor used for 50 Q Reference Lev el Figure D 5 Calculating Resistance Impedance from Waveform Amplitude Position the 50 Q or 75 Q reference level on the sliding scale to correspond with the one selected as the reference level on the TDR display The impedance Ohms causing the reflection can then be read from the sliding scale by noting the position on the fixed scale that corresponds to the position of the reflection on the TDR display You should note that the peak level of any reflection that does not have a discernable plateau might be an erroneous indication of the impedance discontinuity that caused it There might be several reasons for the error 1 The discontinuity might occupy such a short segment of the line compared to the Vp of the line and the risetime of the test pulse wavefront that part of the wavefront starts to emerge from the segment while t
22. 75 70 65 60 55 50 p 35 30 25 20 15 10 5 0 1 REFLECTION 40 dB RETURN LOSS Figure D 2 Slide Rule of Return Loss vs Percent Reflected Voltage Locate the known value of or the known dB return loss then locate the value of the corresponding expression on the adjacent scale NOTE Only the impulse mode of Time Domain Reflectometry can be accurately expressed in terms of return loss A narrow impulse will be attenuated by losses in the cable and reflections will be attenuated likewise As with measurements on VSWR there is only a simple mathematical relationship between reflection measurements using sine waves and reflection measurements using pulses when one resistive discontinuity is the whole cause for the sizable reflections Percent Reflected Voltage vs Characteristic Line Impedance 50 Q or 75 Q Source To find the characteristic impedance of a line or section of a line knowing the reflection coefficient or the you should first know the impedance of the pulse generator It should be as close as possible to the nominal impedance of the line and should be connected to the line through a length of cable having the same impedance as the source Select the side of the slide rule that corresponds to the source resistance Rs of the generator used then select the longest scale as follows 1503C MTDR User Manual D 3 Operator Troubl
23. Hold can be deactivated by pushing STORE or the mode exited by using the Setup Menu ii Pulse Is On Off Turns the pulse generator off so the 1503C does not send out pulses iii Single Sweep Is On Off This function is much like a still camera it will acquire one waveform and hold it Vertical Scale Is dB mp This offers you a choice as to how the vertical gain of the instrument is displayed You may choose decibels or millirho When powered down the instrument will default to decibels when powered back up Operating Instructions 1 8 c Distance Div Is ft m Offers you a choice of how the horizontal scale is displayed You may choose from feet per division or meters per division When powered up the instrument will default to feet unless the internal jumper has been moved to the meters position Instructions on changing this default are contained in the 7503C Service Manual Light Is On Off This control turns the electroluminescent backlight behind the LCD on or off 5 Diagnostics Menu lists an extensive selection of diagnostics to test the operation of the instrument NOTE The Diagnostics Menu is intended for instrument repair and calibration Proper instrument setup is important for correct diagnostics results Refer to the 1503C Service Manual for more information on diagnostics a Service Diagnostics Menu has these choices i ii iii iv vi Sampling Efficiency Diagnostic display
24. MENU again Using the 4 POSITION control select Noise Diagnostics Press MENU again and follow the instructions on the display S F un mp we Rom Exit from Noise Diagnostics but do not exit from the Service Diagnostic Menu yet 4 Offset Gain Check If the instrument fails this check it should not be used for loss or impedance measurements Send it to be serviced when possible 1 In the Service Diagnostic Menu select the Offset Gain Diagnostic and follow the directions on the display 1503C MTDR User Manual B 5 Appendis B Operator Performance Checks 5 Impedance Check 6 Sampling Efficiency Check 7 Aberrations Check There are three screens of data presented in this diagnostic The Pass Fail level is 3 for any single gain setting tested 2 Exit from Offset Gain Diagnostic but do not leave the Service Diagnostic Menu yet If the instrument fails this check it should not be used for loss or impedance measurements 1 In the Service Diagnostic Menu select the Impedance Diagnostic and follow the directions on the screen Passable tolerances are 50Q 47 0 to 50 0 Q 750 71 0 to 75 0 Q 93 Q 88 to 93 Q 125 Q 118 to 125 Q 2 Exit from the Impedance Diagnostic but do not leave the Service Diagnostic Menu yet If the instrument fails this check the waveforms might not look normal If the efficiency is more than 100 the waveforms will appear noisy If the efficiency is below the lower limit the waveform
25. METERS then reading the distance in feet next to the point of the arrow labeled FEET Likewise feet are converted to meters using these directions in reverse Velocity Factor Dielectric Constant and Velocity Factor appear on two identical scales next to a sliding scale labeled ROUND TRIP TIME To find one knowing the other read across the sliding scale Any major division on the sliding scale can be placed next to the known value to help read directly across the sliding scale Time vs Short Distances in Centimeters or Inches any dielectric 1503C MTDR User Manual To find the distances to or between discontinuities in a transmission line knowing the time for a pulse edge to travel that distance and back round trip time it is necessary to know either the dielectric constant of the material between the conductors or the velocity factor of the line For distances less than about three meters or 10 feet use the INCHES and CENTIMETERS scale D 7 Operator Troubleshooting 31 0 425 2 4 D CONSTANT mi dl Wi Dieletric is Air ROUND Pup rp pu n pr EH p n HH HE TRIP J0ps 150ps 200ps 300ps sops sax Time 200 ps TIME olihi hitainta aa THAT ETT TE FACTOR 10 8 7 6 5 4 Velocity Factor 1 INCHES CENTIMETERS wp wp O EA E O EYEE ETAT Distance is 67810 15 20 A 3 0 cm or 1 18 inches ONE WAY DISTANCE TO OR BETWEEN FAULT SPLICE CONNECTOR LOAD END OR OTHER IMPEDANCE DISCONTINUITY Figure D 7 Dielectric Co
26. Press STORE 9 Turn the NOISE FILTER control back to 1 avg Appendis B Operator Performance Checks 10 Place the baseline of the waveform on the center graticule using the SPOSITION control 11 Increase VERT SCALE to 25 00 dB 12 Using the gt POSITION control verify that the aberrations are less than four divisions high out to 10 feet 3 05 m ac 10 00 ft Figure B 11 Waveform Centered Cursor at 10 00 ft 13 Return the cursor to 2 00 ft 0 61 m 14 Turn NOISE FILTER back to VERT SET REF 15 Set the DIST DIV to 2 ft div 0 5 m div 16 Turn PULSE WIDTH to 10 ns 17 Adjust the pulse height to four major divisions Le eS Su SS Se St Sa SS ete SG ee Figure B 12 Pulse Adjusted amp to Four Major Divisions i in Height 18 Press STORE 19 Return the NOISE FILTER control to 1 avg 1503C MTDR User Manual Appendis B Operator Performance Checks 1503C MTDR User Manual 20 Place the baseline of the waveform on the center graticule using the SPOSITION control 21 Increase VERT SCALE to 30 00 dB 22 Using the lt gt POSITION control verify that the aberrations are less than four divisions high out to 30 feet 9 15 m ac 30 00 ft Figure B 13 Aberrations Leas Than Four Divisions Out to 30 00 ft 23 Return the cursor to 2 00 ft 0 61 m 24 Turn NOISE FILTER back to VERT SET REF 25 Set the DIST DIV to 5
27. a carrier This might be due to a transceiver not asserting its carrier detect line a host not reading its carrier detect line or some other reason This is not unusual with some equipment One way to isolate which units are doing this is to disconnect them one at a time until it stops 1503C MTDR User Manual Options and Accessories A Descriptions of Tests in the Setup Menu Acquisition Control Menu 1503C MTDR User Manual Collision Test is Off On CAUTION The collision signal will stop traffic on the network This might abort many application programs and might cause communications problems This test is similar to the carrier test except that it asserts a 1 7 VDC signal to simulate a collision on the network The entries in this menu allow you to set up custom tests on networks in addition to the preset ones in the Ethernet Menu This is intended for users who are familiar enough with Ethernet to anticipate the results Changes in this menu can affect the state of other entries that are mutually exclusive or necessary for the chosen entry For example turning on the Collision Output Signal is Off On will also turn off the carrier output signal because only one voltage can be sent out Only the function of the entries unique to Option 06 will be explained For the others refer to the Operating Instructions chapter of this manual 50 Q DC Termination is Off On CAUTION This must be on for use on a working ne
28. made and displayed showing the change in the cable Single Sweep is useful for snap shot tests of the cable capturing only one waveform 15 To exit Single Sweep access the Acquisition Control Menu again toggle the Single Sweep is line back to Off then push the MENU button repeatedly until the instrument returns to normal operations 1503C MTDR User Manual Operator Tutorial TDR Questions and Answers 1503C MTDR User Manual QI Al Q2 A2 Q3 A3 Q4 A4 Q5 A5 Q6 A6 Q7 AT Q8 A8 What does TDR stand for Time Domain Reflectometer What is the difference between time domain and frequency domain Within the time domain things are expressed in units of time e g nanoseconds In frequency domain things are expressed in frequency cycles per second e g kiloHertz What does a TDR actually measure Voltage over time How does a TDR display this information Voltage on the vertical axis as amplitude of the waveform and time on the horizontal axis as distance to the event Does electricity travel the same speed velocity in all materials No Hlectricity is like light its velocity is affected by the material through which it passes What is that difference called The relative velocity of propagation Vp The velocity of the cable is expressed in time distance e g feet per nanosecond The velocity of electricity traveling in a vacuum is compared to the velocity of e
29. most cables changes very little over the range of frequencies they are designed for A point in a cable or system where the incident electrical energy is redistributed into absorbed reflected and or transmitted electrical energy The transmitted electrical energy after the mismatch is less than the incident electrical energy The pulse of electrical energy sent out by the TDR The waveform shown by the TDR consists of this pulse and the reflections of it coming back from the cable or circuit being tested see Reactance 1503C MTDR User Manual Glossary Insulation Jitter LCD Millirho Noise 1503C MTDR User Manual A protective coating on an electrical conductor that will not readily allow electrical energy to flow away from the conductive part of the cable or circuit Insulation is also called dielectric The kind of dielectric used in a cable determines how fast electricity can travel through the cable see Velocity of Propagation The short term error or uncertainty in the clock timebase of a TDR If the timing from sample to sample is not exact the waveform will appear to move back and forth rapidly An acronym for Liquid Crystal Display It is the kind of display used on this instrument so the terms display and LCD are often used interchangeably rho p is the reflection coefficient of a cable or power delivery system It is the ratio of the voltage reflected back from the cable or circuit due to cable faul
30. of signal that is absorbed in the cable as the signal propagates down it Cable attenuation is typically low at low frequencies and higher at high frequencies and should be corrected for in some TDR measurements Cable attenuation is usually expressed in decibels at one or several frequencies See also dB and Series Loss Any condition that makes the cable less efficient at delivering electrical energy than it was designed to be Water leaking through the insulation poorly mated connectors and bad splices are typical types cable faults see Reactance Cables are designed to match the source and load for the electrical energy that they carry The designed impedance is often called the characteristic impedance of the cable The arrangement of the conductors with respect to each other is the major factor in designing the impedance of cables Glossary 1 Glossary Conductor dB DC Dielectric Domain Impedance Impedance Mismatch Glossary 2 Incident Pulse Inductance Any substance that will readily allow electricity to flow through it Good conductors are metals such as silver copper gold aluminum and zinc in that order dB is an abbreviation for decibel Decibels are a method of expressing power or voltage ratios The decibel scale is logarithmic It is often used to express the efficiency of power distribution systems when the ratio consists of the energy put into the system divided by the energy delivered
31. the incident pulse are the aberrations from the internal circuitry and reflections between the open end of the cable and the front panel Figure 2 7 10 ioci Cable with Cursor at Incident Pulse Vertical Scale at 25 dB 1503C MTDR User Manual 2 5 Operator Tutorial A Longer Cable 2 6 Longer cables might not fit in the display Let s demonstrate that with a longer cable Obtain a known length of cable preferably 50 Q For this example we are using a coaxial cable approximately 455 feet long Your cable length will probably differ but the following test procedure remains fundamentally correct for any cable length up to 50 000 feet 1 Set the 1503C front panel controls CABLE available longer cable IMPEDANCE 50Q NOISE FILTER avg VERT SCALE 10 dB DIST DIV 100 ft 25 m Vp appropriate setting for your cable PULSE WIDTH Auto clockwise 2 With these settings we can view the entire cable By placing the cursor at the rise of the reflected pulse we can see this particular cable is 456 00 ft BE om auto 3 By decreasing the DIST DIV control the cable can be more closely inspected at the point of the cursor Decrease the DIST DIV to 10 ft div This has expanded the cable across the display 4 Turn the lt gt POSITION control counterclockwise Note that the distance window changes as you scroll down the cable In reality you are electrically inspecting the cable foot by foot 1503C MTDR User Manu
32. the pulse width according to the distance registered at the right side of the LCD The selected value is displayed to the left of this control on the LCD 5 POSITION This is a continuously rotating control that positions the displayed waveform vertically up or down the LCD lt gt POSITION This is a continuously rotating control that moves a vertical cursor completely across the LCD graticule In addition the waveform is also moved when the cursor reaches the extreme right or left side of the display A readout seven digits maximum is displayed in the upper right corner of the LCD showing the distance from the front panel BNC to the current cursor location MENU This pushbutton provides access to the menus and selects items chosen from the menus VIEW INPUT When pushed momentarily this button toggles the display of the waveform acquired at the CABLE connector This function is useful to stop displaying a current waveform to avoid confusion when looking at a stored waveform This function defaults to ON when the instrument is powered up VIEW STORE When pushed momentarily this button toggles the display of the stored waveform VIEW DIFF When pushed momentarily this button toggles the display of the current waveform minus the stored waveform and shows the difference between them STORE When pushed momentarily the waveform currently displayed will be stored in the instrument memory If a waveform is already stored pushing
33. whatever pulse height is desired 1 Turn NOISE FILTER fully counterclockwise Set Ref will appear in the noise averaging area of the LCD 2 Adjustthe incident pulse to the desired height e g four divisions It might be necessary to adjust POSITION i Queer a return FILTER to desired LE aveva Em doen Figure 1 26 Incident Pulse at Four Divisions FILTER at Desired Setting 3 Push STORE 4 Return NOISE FILTER to the desired setting Notice that the dB scale is now set to 0 00 dB 5 To exit VERT SET REF use the following procedure a Make sure the vertical scale is in dB mode access the Setup Menu if change is needed 1 23 Operating Instructions d e Turn NOISE FILTER to VERT SET REF Adjust VERT SCALE to obtain 0 00 dB Push STORE Turn NOISE FILTER to desire filter setting Because dB is actually a ratio between the energy sent out and the energy reflected back using VERT SET REF does not affect the dB difference measured NOTE Do not use Auto Pulse Width when making measurements in VERT SET REF Auto Pulse Width changes the pulse width at 100 500 and 5000 feet If the pulse width changes while in VERT SET REF it could result in an erroneous reading Manually controlling the pulse width assures the pulse width remains the same for both the incident and reflective pulses Additional Features Menu Selected 1 24 Max Hold The 1503C will capture and store w
34. will provide fast accurate measurements Because of electrical and environmental differences in cables and their applications each waveform will likely differ The best way to learn these differences is experience with the instrument You are the 1503C s most important feature Experiment with different cables in known conditions and see how they compare Subject cables to situations you might find in your application and learn the effects We have included some examples of cable faults in this manual to help you gain familiarity With practice you will quickly become familiar with even the most subtle differences in waveforms The 1503C is equipped with various help screens Simply press MENU for assistance The instrument will prompt you More information on MENU is located in the Operating Instructions chapter of this manual 2 1 Operator Tutorial Getting Started Let s start by inspecting a cable For the next few examples we will use the 93 Q 10 foot precision test cable provided with the 1503C Tektronix part number 012 1351 00 1 Pull onthe POWER switch The instrument will initialize give instructions for accessing the menu and enter normal operation mode 2 Set the 1503C front panel controls to CABLE Attach 10 ft cable IMPEDANCE 93 Q NOISE FILTER l avg VERT SCALE 0 00 dB default DIST DIV ft div 0 25 m if using metric Vp 84 PULSE WIDTH 2 ns NOTE Vp velocity of propagation of the test cabl
35. 0 125 Q Accuracy 1 Pulse Repetition Time 350 Us nominal Vertical Scale 0 dB to 63 75 dB gain 256 values at 0 25 dB increments Accuracy 3 SetAdjustment Setincident pulse within 3 Combined with vertical scale control Vertical P osition Any waveform point moveable to center screen Displayed Noise With matching terminator at panel Beyond three test pulse widths after test pulse Random lt 1 0 division peak with 57 dB gain filter setto 1 lt 1 0 division peak with 63 dB gain filter set to 8 Aberrations x 30 dB p p for 10 ns 100 ns 1000 ns test Within three test pulse widths after test pulse dB is relative to test pulse continued next page 1503C MTDR User Manual Appendix A Specifications Characteristic Cable Connection Coupling Max Input Susceptibility Performance Requirement Capacitively coupled 400 V DC peak AC at maximum frequen Cy of 440 Hz No damage with application for up to 30 seconds might affect measurement capability Supplemental Information Distance Cursor Resolution 1 25 of 1 major division Cursor Readout Range 2 ft to 250 000 ft 0 61 m to 15 230 m 5 digit readout Resolution 0 04 ft Accuracy Within 2 0 02 ft at 1 ftdiv Vp must be set within 0 596 of cable Horizontal Scale 1 ft div to 5000 ft div 0 25 m div to 1000 m div 12 values 1 2 5 sequence Range 0 to 50 000 ft 0 to 10 000 m Horizontal Position Any distance to full
36. 0 ft div 10 m div 26 Turn PULSE WIDTH to 100 ns 27 Adjust the pulse height to four major divisions Figure B 14 Pulse Adistedi to Four r Major Divisions in Height 28 Press STORE 29 Return the NOISE FILTER control to 1 avg Appendis B Operator Performance Checks B 10 30 Place the baseline of the waveform on the center graticule using the SPOSITION control 31 Increase VERT SCALE to 30 00 dB 32 Using the lt gt POSITION control verify that the aberrations are less than four divisions high out to 300 feet 91 50 m 300 00 ft Figure B 15 Aberrations ios Than Four Divisions Out to 300 00 ft 33 Return the cursor to 2 00 ft 0 61 m 34 Turn NOISE FILTER back to VERT SET REF 35 Set the DIST DIV to 500 ft div 10 m div 36 Turn PULSE WIDTH to 1000 ns 37 Adjust the pulse height to four major divisions ccr Figure B 16 Pulse Adjusted to Four Major Divisions i in Height 38 Press STORE 39 Return the NOISE FILTER control to 1 avg 40 Place the baseline of the waveform on the center graticule using the SPOSITION control 1503C MTDR User Manual Appendis B Operator Performance Checks Conclusions 1503C MTDR User Manual 41 Increase VERT SCALE to 30 00 dB 42 Using the lt gt POSITION control verify that the aberrations are less than four divisions high out to 3000 feet 915 00 m ac 3000 00 ft Figure B 17 Aberrations Less Than Fo
37. 010625 012 1350 00 Terminator 75 Q BNC sese 011 0102 00 Adapter Direct Current 015 0327 00 Isolation Network 0 0 000 cece eee 013 0169 00 Pulse Inverter ss cea ete eR ohh whew code cuwa bee Heed 015 0495 00 Token Ring Network Adapter 00005 015 0500 00 Twisted Pair Adapter USOC Adapter 015 0579 00 Token Ring Interface resis ucxdczc Ax ER CER eR Ed e 015 0600 00 1503C MTDR User Manual EN ANNE Appendix A Specifications The tables in this chapter list the characteristics and features that apply to this instrument after it has had a warm up period of at least five minutes The Performance Requirement column describes the limits of the Characteristic Supplemental Information describes features and typical values or other helpful information Electrical Characteristics Unterminated 2ns 20 5 0 VDC 10 for 10 ns 100 ns 1000 ns Characteristic Performance Requirement Supplemental Information Test Pulse Width Selected 2 ns 10 ns 100 ns 1000 ns Measured at half sine amplitude point with matching termination Accuracy 2ns 1ns 10ns 100 ns 1000 ns 10 Pulse Amplitude Terminated 2 5 VDC 10 for 10 ns 100 ns 1000 ns Internal cable length prevents 2 ns pulse from reaching full unterminated voltage pulse x 25 dB p p for 2 ns test pulse Pulse Shape 1 2 sine Pulse Output Impedance Selected 50 Q 75 Q 93
38. 03C MTDR User Manual A 5 Appendix A Specifications A 6 1503C MTDR User Manual SS aa Appendix B Operator Performance Checks Equipment Required Getting Ready Power On Metric Instruments 1503C MTDR User Manual This appendix contains performance checks for many of the functions of the 1503C They are recommended for incoming inspections to verify that the instrument is functioning properly Procedures to verify the actual performance requirements are provided in the 503C Service Manual Performing these checks will assure you that your instrument is in good working condition These checks should be performed upon receipt of a new instrument or one that has been serviced or repaired It does not test all portions of the instrument to Calibration specifications The purpose of these checks is not to familiarize a new operator with the instrument If you are not experienced with the instrument you should read the Operating Instructions chapter of this manual before going on with these checks Ifthe instrument fails any of these checks it should be serviced Many failure modes affect only some of the instrument functions Item Tektronix Part Number 50 Q precision terminator 011 0123 00 93 Q 10 foot coaxial cable 012 1351 00 Disconnect any cables from the front panel CABLE connector Connect the instrument to a suitable power source a fully charged battery pack or AC line source If you are usin
39. 10 foot Cable 005 B 3 Figure B 4 Cursor at End of 10 foot Cable Vp Set to 30 B 3 Figure B 5 Flatline Display Out to 50 0000 Feet B 4 Figure B 6 Waveform Off the Top of the Display B 4 Figure B 7 Waveform at the Bottom of the Display B 4 Figure B 8 Waveform with Gain at 57 dB 0 00000 005 B 5 Figure B 9 Distance at 2 00 ft llle B 7 Figure B 10 Pulse Adjusted to Four Major Divisions in Height B 7 Figure B 11 Waveform Centered Cursor at 10 00 ft B 8 Figure B 12 Pulse Adjusted to Four Major Divisions in Height B 8 Figure B 13 Aberrations Less Than Four Divisions Out to 30 00 ft B 9 Figure B 14 Pulse Adjusted to Four Major Divisions in Height B 9 Figure B 15 Aberrations Less Than Four Divisions Out to 300 00 ft B 10 Figure B 16 Pulse Adjusted to Four Major Divisions in Height B 10 Figure B 17 Aberrations Less Than Four Divisions Out to 3000 00 TU oeira cereias ERE DES COURS PEOORRR RE EQ RAE aco B 11 List of Tables Shipping Carton Test Strength icce 0 0 0 eee eee ix Fuse and Voltage Ratings sock erbkR Rub E 4 Be eee eS 1 2 Vpot Various Dielectric Types etc cei eere err e ld eon 1 10 Impedance of Various Cable Types 12 2 2 0 cece eee eee 1 11 Suggested Pulse and Ft Div for Cable Lengths 00 0 000 1 13 Option 06 Electrical Characterist
40. DM E Ei ip Meme ea es edlen um ine iip ee Ee eee kei e quis te Ss iei eie wes Se denis Figure 2 17 Incident and Reflected Pulses with Cursor at 0 00 ft 2 Turn the NOISE FILTER control counterclockwise to HORZ SET REF The noise filter reading on the LCD will indicate set A 3 Adjust the gt POSITION control so the cursor is on the rising edge of the reflected pulse In this case the distance window should read 10 0 ft 1503C MTDR User Manual 2 11 Operator Tutorial 2 12 VERT SET REF ae 10000 ft 2 E return FILTER to desired setting sept SET SVP 1 1 Figure 2 18 Incident and Reflected Pulses with Cursor at 10 0 ft 4 Press STORE 5 Turn the NOISE FILTER control to 1 avg Note that the distance window now reads 0 00 ftA This means that everything from the front panel BNC to the end ofthe cable is subtracted from the distance calculations You have set zero at the far end of the test cable a 00088 Flare 2 19 New Zero Set at End of Test Cable 6 To change the HORZ SET REF position turn the NOISE FILTER back to HORZ SET REF and repeat the above procedure with a new cursor location 7 To exit HORZ SET REF do the following a Set the gt POSITION control to exactly 0 00 ft you might have to set DIST DIV to 1 ft div b Push STORE c Turn the NOISE FILTER control to the desired noise setting This control is nearly the same as HORZ SET REF except it sets the
41. E 2 IMPEDANCE A four position rotary switch that selects the output impedance of the cable test signal Available settings are 50 75 93 and 125 Ohms The selected value is displayed above the control on the LCD 3 NOISE FILTER If the displayed waveform is noisy the apparent noise can NOISE FILTER be reduced by using noise averaging Averaging settings are between 1 and 128 The time for averaging is directly proportional to the averaging setting chosen A setting of 128 might take the instrument up to 35 seconds to acquire and Horz display a waveform The first two positions on the NOISE FILTER control are vert SET REF used for setting the vertical and horizontal reference points The selected value or function is displayed above the control on the LCD VERT SCALE 4 VERT SCALE This control sets the vertical gain displayed in dB or the vertical sensitivity displayed in mp per division Although the instrument defaults to dB you may choose the preferred mode from the Setup Menu The selected value is displayed above the control on the LCD 5 DIST DIV Determines the number of feet or meters per division across the DIST DIV display The minimum setting is 1 ft div 0 25 meters and the maximum setting is 5000 ft div 1000 meters The selected value is displayed above the control on the LCD 1503C MTDR User Manual 1 5 Operating Instructions 16 4 5 Vp 04 05 3 6 03 06 7 02 07 8 0 08 9 00 09
42. Hd mom FF SY BN 10 A coastal phone line only has problems during high tide Overnight monitoring reveals water in the line during the high tide period A data communications line is monitored for an intermittent short Three days of monitoring reveals the shorts occur only during the hours of darkness Rodents are found in the cable ducts A cable becomes defective only during daytime hours Monitoring reveals the line length increases sags during the heat of the day shorting out on a tree limb During the night the cable cools tightens and is no longer shorted on the tree limb To exit Max Hold access the Acquisition Control Menu again turn off Max Hold and push MENU repeatedly until the instrument returns to normal operation Set the 1503C front panel controls to CABLE Attach 10 ft cable IMPEDANCE 93 Q NOISE FILTER 1 avg VERT SCALE 0 00 dB default DIST DIV 1 ft div 0 25 m Vp 84 PULSE WIDTH 2 ns Pull POWER on Press MENU to access the Main Menu Using the POSITION control scroll down to Setup Menu Press MENU to accept this selection Scroll down to Acquisition Control Menu Press MENU to accept this selection Scroll down to Pulse is On Press MENU to toggle this selection It should now read Pulse is Off Press MENU repeatedly until the instrument returns to normal operation 1503C MTDR User Manual Operator Tutorial Single Sweep 1503C MTDR User Manual Note that there is no pu
43. NPUT 2 14 i f return FILTER to desired setting 7 5 The vertical scale now reads 0 00 dB Return loss measurements at the far end of the cable can now be made using normal methods To make measurements closer or farther from the instrument requires that you reset the VERT SET REF 5 To change the VERT SET REF turn the noise filter back to VERT SET REF and repeat the preceding procedure 6 If you wish to totally exit VERT SET REF do the following a b Turn NOISE FILTER to VERT SET REF Turn VERT SCALE for a display reading of 0 00 dB or 500 mp Push STORE Return the NOISE FILTER control to the desired setting This push button allows you to view what is coming in the CABLE connector or to eliminate it from the display 1 Set the 1503C front panel controls to CABLE Attach 10 ft cable IMPEDANCE 93 Q NOISE FILTER avg VERT SCALE 0 00 dB DIST DIV ft div 0 25 m PULSE WIDTH 2 ns Press VIEW INPUT The indicator block on the LCD should read OFF and the waveform should disappear from the display 1503C MTDR User Manual Operator Tutorial ae 0 00 ft 656 2205 26 Gia S55 Se She Figure 2 23 Display with VIEW INPUT Turned Off 3 Press VIEW INPUT again The indicator block will reappear and the waveform should be displayed again gt H E A Fi k i s Figure 2 24 Display with VIEW INPUT Turned On This function can
44. Start up Measurement Display 2 Connect the 10 foot cable to the front panel CABLE connector The display should now look like Figure B 2 Figure B 2 Measurement Display with 10 foot Cable 3 Using the lt gt POSITION control measure the distance to the rising edge of the waveform at the open end of the cable The distance shown on the display distance window upper right corner of the LCD should be from 9 7 to 10 3 feet 2 95 to 3 14 m 1503C MTDR User Manual Appendis B Operator Performance Checks 1503C MTDR User Manual AN Xx Fi 2 Figure B 3 Cursor at End of 10 foot Cable 4 Change the Vp to 30 Using the gt POSITION control measure the distance to the rising edge of the waveform at the open end of the cable The distance shown on the display distance window upper right corner of the LCD should be from 3 50 to 3 70 feet 1 05 to 1 11 m Figure B 4 Cursor at End of 10 foot Cable Vp Set to 30 5 Remove the 10 foot cable and connect the 50 O terminator Change the 1503C front panel controls to VERT SCALE 0 00 dB DIST DIV 5000 ft div 1000 m div PULSE WIDTH 1000 ns 6 Turn the lt gt POSITION control clockwise until the display distance window reads a distance greater the 50 000 feet 15 259 m The waveform should remain a flat line from zero to this distance Appendis B Operator Performance Checks 2 Vertical Position Offset Check bat 50600 00 ft mmo
45. The following table shows the relationship between the distance on the display and the Auto pulse width 1503C MTDR User Manual Operator Tutorial Noise 1503C MTDR User Manual CABLE LENGTH SUGGESTED PULSE SUGGESTED ft div 0 to 100 ft 2 ns 10 ft div 51 to 500 ft 10 ns 50 ft div 501 to 5000 ft 100 ns 500 ft div 5001 to 50 000 ft 1000 ns 5000 ft div On a longer cable grass might appear on the displayed waveform This is primarily caused by the cable acting as an antenna picking up nearby electrical noise 1 Set the 1503C front panel controls CABLE IMPEDANCE NOISE FILTER VERT SCALE DIST DIV Vp PULSE WIDTH lt I gt POSITION 10 ft cable 93 Q avg 0 00 dB ft 0 25 m 84 2 ns 50 0 ft 2 Attach the 50 Q terminator to the end of the test cable using the female to fe male BNC adaptor both of these items are supplied with the instrument 3 Increase VERT SCALE to 50 dB Use the SPOSITION control to keep the waveform on the display As the VERT SCALE setting increases there will be noise in the form of a moving fuzz like waveform with a few random spikes ac NK o Figure 2 14 Noise on the Waveform 4 Turn the NOISE FILTER control clockwise to 8 This will average out much of the noise Operator Tutorial 2 10 mM dg hb ate E pacha ae mmo mmo Bia 2 202662 deem E SS Se eee db mm mem ee S 20S ee ee oe Figure 2 15 Noise Re
46. U again This will change to Pulse is Off 6 Repeatedly press MENU until the instrument returns to normal operation 1 25 Operating Instructions 1 26 Single Sweep This feature allows the 1503C to act much like a non triggered oscilloscope In this mode the 1503C is acting as a detector only Any pulses detected will not originate from the instrument so any distance readings will be invalid If you are listening to a local area network for example it is possible to detect traffic but not possible to measure the distance to its origin Pulse is Off can be used in conjunction with Max Hold is On 7 To exit Pulse is Off access the Acquisition Control Menu again turn the pulse back on then repeatedly push MENU until the instrument returns to normal operation The single sweep function will acquire one waveform only and display it 1 Attach a cable to the 1503C front panel CABLE connector Push MENU to access the Main Menu 2 3 Scroll to Setup Menu and push MENU again 4 Scroll to Acquisition Control Menu and push MENU again 5 Scroll to Single Sweep is Off and push MENU again This will change to Single Sweep is On e Repeatedly press MENU until the instrument returns to normal operation 7 When you are ready to begin a sweep push VIEW INPUT A sweep will also be initiated when you change any of the front panel controls This allows you to observe front panel changes without exiting the Single Swe
47. User Manual Tektronix 7 1503C Metallic Time Domain Reflectometer 070 7323 05 This document applies to firmware version 5 04 and above www tektronix com Copyright Tektronix Inc All rights reserved Tektronix products are covered by U S and foreign patents issued and pending Information in this publication supercedes that in all previously published material Specifications and price change privileges reserved Tektronix Inc P O Box 500 Beaverton OR 97077 TEKTRONIX and TEK are registered trademarks of Tektronix Inc WARRANTY Tektronix warrants that the products that it manufactures and sells will be free from defects in materials and workmanship for a period of one 1 year from the date of shipment If a product proves defective during this warranty period Tektronix at its option either will repair the defective product without charge for parts and labor or will provide a replacement in exchange for the defective product In order to obtain service under this warranty Customer must notify Tektronix of the defect before the expiration of the warranty period and make suitable arrangements for the performance of service Customer shall be responsible for packaging and shipping the defective product to the service center designated by Tektronix with shipping charges prepaid Tektronix shall pay for the return of the product to Customer if the shipment is to a location within the country in which the Tektronix ser
48. Y Y NO missing erratic or badly distorted d Perform initial operator performance verification checks NO Did instrument pass checks C 2 1503C MTDR User Manual Appendix C Operator Troubleshooting Error Messages Message Occurrences Meanings Remedies Message 1503C MTDR User Manual Any time the instrument displays an error message the troubleshooting procedures should be used to judge the extent and severity of the problem Some errors will still permit some kinds of measurements If there is any doubt about the ability to make a particular kind of measurement do not make that measurement until the problem has been corrected Option Port Device Not Responding Please check for correct installation push MENU button to Continue This can occur anytime a chart printer SP 232 or other Option Port device requests attention from the TDR This error indicates that the TDR has received a signal indicating a request from the Option Port device and either there is no device installed or the device is not responding with a recognized ID byte when polled by the TDR This error might be very annoying because the Option Port is checked once each time the TDR gets a waveform If the TDR is being controlled by or through the Option Port device you will probably have to remove that device and make manual measurements until the failure is co
49. able Attenuation on Return Loss and Reflection Coefficient Measurements Using VIEW INPUT 1503C MTDR User Manual Small impedance changes like those from a connector might have reflections from 10 to 100 mo If rho is positive it indicates an impedance higher than that of the cable before the reflection It will show as an upward shift or bump on the waveform If rho is negative it indicates an impedance lower than that of the cable prior to the reflection It will show as a downward shift or dip on the waveform If the cable has an open or short all the energy sent out by the 1503C will be reflected This is a reflection coefficient of rho 1 or 1000 mp for the open and 1000 mp for the short Cable attenuation influences the return loss and reflection coefficient measurements made with the 1503C If you desire to measure the return loss of only an impedance mismatch the cable attenuation as measured with an open or short circuit on the cable must be subtracted from the directly measured value For reflection coefficient the directly measured value of rho must be divided by the value measured with an open or short circuit on the cable These calculations can be done manually or the instrument can perform them by proper use of the VERT SET REF function It is is not possible to measure the cable under test with an open or short sometimes another cable of similar type is available to use as a reference Note that cable attenu
50. age reporting will be when communi cating with an external device Itis possible to connect the instrument to a computer through a parallel interface with a unique software driver Because different computers vary widely in processing speed the instrument must be able to adapt to differing data rates while communicating with those computers With user developed software drivers the ability to obtain detailed error messages during the development can be very useful For more information contact your Tektronix Customer Service representatives They have information describing the option port hardware and software protocol and custom development methods available Operating Instructions Test Preparations The Importance of Vp Velocity of Propagation Vp of Various Dielectric 1 10 Types The SP 232 a serial interface product also allows for connection of the 1503C to other instrumentation including computers via the option port SP 232 is an RS 232C compatible interface For more information contact your Tektronix Customer Service Representative They can provide you with additional details on the hardware and software protocol 8 Display Contrast Software Version 5 02 and above a Press the MENU button firmly once If the display is very light or very dark you might not be able to see a change in the contrast b Turn the VERTICAL SCALE knob slowly clockwise to darken the display or counterclockwise to lighten th
51. al Operator Tutorial 1503C MTDR User Manual C AMNEM Bee Wee M UE Cursor Cable Scrolling In this direction NOTE When testing a long cable it is helpful to set DIST DIV to a higher setting when scrolling to either end of the cable For example if testing a 5 000 ft cable it would be very tiring to scroll the entire length from end to end at 1 ft div 5 Turn the POSITION control to return the cursor to the rise of the reflected pulse 6 Increase DIST DIV to 100 ft div 7 SetPULSE WIDTH to2 ns Notice that the pulse has nearly disappeared Nearly all of the electrical energy set through the cable is absorbed ea E E T E E i F s i 4 Figure 2 10 Pulse Width at 2 ns 8 Set PULSE WIDTH to 10 ns The pulse height increases because there is more energy being sent through the cable Operator Tutorial 2 8 oe ee ee ee ere T Figure 2411 Pulse Width at 10 ns 9 Set PULSE WIDTH to 100 ns Now the pulse is even larger and quite easy to see NN x Figure 2 12 Pulse Width at 100 ns 10 Set PULSE WIDTH to 1000 ns The pulse is now longer than the example cable This would be a good pulse for a very long cable 49600f Figure 2 13 Pulse Width at 1000 ns iones than the Cable Being Tested When the PULSE WIDTH control is set to Auto the instrument automatically sets the pulse width in relation to the distance on the right side of the display
52. and the stored waveform will appear above the current waveform Ee ee Ga eens Figure 1 20 Current Waveform Centered Stored Waveform Above 5 Push VIEW DIFF and the difference waveform will appear below the current waveform Figure 1 21 Current Waveform Center Stored Waveform Above Difference Below Notice the VIEW INPUT waveform is solid VIEW DIFF is dotted and VIEW STORE is dot dash There are many situations where the VIEW DIFF function can be useful One common situation is to store the waveform of a suspect cable repair the cable then compare the two waveforms after the repair During repairs the VIEW INPUT VIEW DIFF and VIEW STORE waveforms can be used to judge the effectiveness of the repairs The optional chart recorder can be used to make a chart of the three waveforms to document the repair Another valuable use for the VIEW DIFF function is for verifying cable integrity before and after servicing or periodic maintenance that requires moving or disconnecting the cable The VIEW DIFF function is useful when you want to see any changes in the cable In some systems there might be several reflections coming back from each branch of the network It might become necessary to disconnect branch lines from the cable 1503C MTDR User Manual Operating Instructions Using Horizontal Set Reference 1503C MTDR User Manual under test to determine whether a waveform represents a physical fault or is simply a
53. ation is strongly influenced by signal frequency and therefore will be different from one pulse width to another on the 1503C When pushed the VIEW INPUT button displays the input at the front panel CABLE connector When VIEW INPUT is turned off and no other buttons are pushed the display will not have a waveform on it see Figure 1 15 The default condition when the instrument is powered up is to have VIEW INPUT on 0 H i 1 j A 4 j J F i M Figure 1 15 Display with VIEW INPUT Turned Off 1 17 Operating Instructions 1 18 How to Store the Waveform Using VIEW STORE Using VIEW DIFF When pushed the STORE button puts the current waveform being displayed into memory If already stored pushing STORE again will erase the stored waveform Figure 1 16 Display ofa i Stored Waveform The front panel control settings and the menu accessed settings are also stored They are accessed under View Stored Waveform Settings in the first level of the menu The VIEW STORE button when pushed on displays the waveform stored in the memory as a dotted line If there is no waveform in memory a message appears on the LCD informing you of this Stored Waveform Figure 1 17 Di play ofa 5 Stored Wavefoim ind Current Waveform When pushed on the VIEW DIFF button displays the difference between the current waveform and the stored waveform as a dotted line If no waveform has been stored a m
54. aveforms on an ongoing basis This is useful when the cable or wire is subjected to intermittent or periodic conditions The 1503C will monitor the line and display any fluctuations on the LCD 1 Attach the cable to the 1503C front panel CABLE connector Push MENU to access the main menu Scroll to Acquisition Control Menu and push MENU again 2 3 Scroll to Setup Menu and push MENU again 4 5 Scroll to Max Hold is Off and push MENU again This line will change to Max Hold is On The monitoring function is now ready to activate 6 Repeatedly push MENU until the instrument returns to normal operation 1503C MTDR User Manual Operating Instructions Pulse On Off 1503C MTDR User Manual 7 When you are ready to monitor this cable for intermittents push STORE The 1503C will now capture any changes in the cable Captured changes Figure 1 28 Waveform Showing Intermittent Short 8 To exit monitor mode push STORE again 9 To exit Max Hold access the Acquisition Control Menu again turn off Max Hold and push MENU repeatedly until the instrument returns to normal operation This feature puts the 1503C in a listening mode by turning off the pulse generator 1 Attach a cable to the 1503C front panel CABLE connector Push MENU to access the Main Menu 2 3 Scroll to Setup Menu and push MENU again 4 Scroll to Acquisition Control Menu and push MENU again 5 Scroll to Pulse is On and push MEN
55. be used to make the display less busy when viewing stored waveforms STORE and VIEW STORE 1503C MTDR User Manual These functions allow you to store a waveform and view the stored waveform 1 Setthe 1503C front panel controls to CABLE Attach 10 ft cable IMPEDANCE 93 Q NOISE FILTER avg VERT SCALE 0 00 dB DIST DIV ft div 0 25 m PULSE WIDTH 2 ns 2 15 Operator Tutorial 2 Make sure you have a waveform on the LCD then adjust the SPOSITION control to place the waveform in the upper section of the display 3 Press STORE The indicator block should become highlighted black and read ON The waveform is now stored in non volatile memory in the instrument 4 Turn the POWER off for a few seconds then turn it back on Note that the STORE indicator block is ON showing that there is a waveform in memory 5 Short the connector at the far end of the test cable The reflected pulse will invert from the previous open position Adjust the SPOSITION control to place the waveform in the middle portion of the LCD Figure 2 26 Waveform with Cable Shorte 6 Press VIEW STORE to view the stored waveform What you see on the display is the waveform you stored previously with the open cable and the current waveform with the shorted cable 2 16 1503C MTDR User Manual Operator Tutorial VIEW DIFF 1503C MTDR User Manual ac A ERIS EAM S be Figure 2 27 Waveform with Both Current and Store
56. ch Why is that important to us Because a TDR displays the energy reflected back from an impedance mismatch 1503C MTDR User Manual SD LS Options and Accessories The following options are available for the 1503C MTDR Option 04 YT 1 Chart Recorder Option 04 instruments come equipped with a chart printer Refer to the Y7 YT 1S Chart Recorder Instruction Manual that comes with this option for instructions on operation paper replacement and maintenance Option 05 Metric Default Option 06 Ethernet What is Ethernet 1503C MTDR User Manual Option 05 instruments will power up in the metric measurements mode Standard measurements may be selected from the menu but metric will be the default Option 06 instruments include circuitry that allows the 1503C to test an Ethernet bus using time domain reflectometry with minimum disruption to the IEEE 802 3 protocol Ethernet was invented by the Xerox Corporation in 1973 to allow various data devices to use a common communications bus In an Ethernet system signals flow in all directions and the transceivers attached to the Ethernet receive all transmissions Ethernet cable is typically 50 Ohms with 50 Ohm terminators at each end to prevent signal reflections Reflections can interfere with transmissions sent out by the system ThinWire Cheapernet and Thin Ethernet are variations of Ethernet These are usually used as a branch of the main network with a limited numbe
57. circuitry is broken or even because the timebase is not functioning properly The instrument must be sent to service for repair 1503C MTDR User Manual END AEN Appendix D Application Note Pulse Echo Testing of Electrical Transmission Lines Using the Tektronix Time Domain Reflectometry Slide Rule Introduction Most people who make quantitative reflectometry tests or measurements should find the Tektronix TDR Slide Rule helpful Those new to the subject will find the slide rule graphically summarizes a wealth of information on reflectometry M Voltage Standing Wave Ratio vs Percent Reflected Voltage m Return Loss dB vs Percent Reflected Voltage m Percent Reflected Voltage vs Characteristic Line Impedance for either 50 O or 75 Q source m Percent Reflected Voltage vs Load Resistance for either 50 Q or 75 Q source W Characteristic Line Impedance or Load Resistance vs Reflection Amplitude as seen on your TDR m Dielectric Constant vs Velocity Factor m Time vs Short Distance in centimeters or inches any dielectric m Time vs Long Distances in meters or feet any dielectric Terms and Symbols Rs Source Resistance of a signal generator Zs Source Impedance of a signal generator Zo Characteristic Impedance of a transmission line Zi Load Impedance for a transmission line RL Load Resistance for a transmission line p Reflection Coefficient rho the ratio of incident to reflected voltage mp
58. cluded with the instrument unless otherwise specified All other optional power cords are rated for indoor use only Option A1 220 VAC 16 A Universal Europe 161 0066 09 Option A2 240 VAC 13 A United Kingdom 161 0066 10 Option A3 240 VAC 10 A Australia 0004 161 0066 11 Option A4 240 VAC 15A North America 161 0066 12 Option A5 240 VAC 6 A Switzerland 161 0154 00 1503C MTDR User Manual Options and Accessories Accessories Standard Accessories Optional Accessories 1503C MTDR User Manual Internal Lead gel Battery Assembly esse 016 0915 00 Replacement Fuse AC line fuse 115 VAC 159 0029 01 Replacement Fuse AC line fuse 230 VAC 159 0054 00 Power Cord outdoor rated 0 0 0 0 161 0228 00 Option Port Cover Assembly 0 0 0 0 00 eee eee 200 3737 00 300 BNC EctinindlUE croea eae xa Eae eR Reda nS RE ba 011 0123 00 BNC Connector female to female es 103 0028 00 93 Q 10 foot Test Cable S N ZB010625 012 1351 00 Connector BNC female to Alligator Clips S N z B010625 013 0261 00 BNC Connector male to N female w Option 06 only 103 0058 00 50 Q 3 foot Test Cable w Option 06 only 012 1350 00 Operator Manual cee cee bebe eee bee ween ee 070 7323 xx Slide Rule Calculator oscura
59. collision detect circuit on all the transceivers This should cause applications to back off and retry then eventually abort as defined in the 802 3 standard Therefore it can be used to test units that do not respond to this signal or to stop traffic for TDR testing Customizing Your Own Tests Access the Acquisition Control Menu located under the Setup Menu The various tests listed can be used in any combination Remember that the tests will not be activated until you return the 1503C to normal operation so any combination can be chosen then activated Waveform Signatures By now you probably have a good idea what traffic looks like on the display and how you can use the NOISE FILTER to reduce it Other signatures might also appear on the display Terminators are small reflections seen as stationary bumps and dips A perfect terminator would not reflect any energy and theoretically would be invisible on the 1503C display Because of small impedance differences between the cable and the terminator a small amount of energy will be reflected The signature of a terminator tends to go either up or down Because a terminator absorbs nearly all the energy of a pulse the normal ripples in the waveform minor changes in impedance will not be present after a terminator The point where the waveform becomes flat is a clue to the location of a terminator Taps commonly have a characteristic down then up reflection The TDR pulse will continue
60. cted pulse ey ee ee ee eee WEM x Incident Pulse Reflected Pulse P Figure 2 2 Cursor of Rising Edge of Reflected Pulse The upper right corner should read 10 00 ft Note that the reflected pulse rises This is the classic signature of an open cable a point of higher impedance 4 Adjustthe VERT SCALE control This will increase the height of the pulse For accurate measurements the pulse should occupy most of the display Note that the LCD shows the VERT SCALE setting in dB For now set this control to 7 dB N x Open Fi 4 K H x i 1 Figure 2 3 Waveform with VERT SCALE Increased Showin an Open 5 The POSITION control moves the waveform up and down the display Adjust this for best viewing 6 Shortthe end ofthe cable with an electrical clip or other suitable device See the pulse take a dive That is the classic signature of a short a point of lower impedance Operator Tutorial Short Figure 2 4 Waveform with Short The distance window still reads 10 00 ft If the short is not directly across the conductors of the BNC e g needle nose pliers the downward edge of the waveform might be slightly past the cursor indicating the length of the shorting device e g jumper wire 7 Remove the short With a little practice you will be able to identify many kinds of cable faults The Waveform Up Close 2 4 It helps to know what makes up a pulse Here is the wavefo
61. d Wavelofis Comparing new cables with old cables or repaired cables with damaged cables is easy using these two pushbuttons Leave the instrument in this condition for the next lesson Press VIEW DIFF This adds a waveform in the lower portion of the display that is the mathematical difference between the stored waveform and the current waveform 086 lx 10 iU o Lo p es nue TN a E a a Figure 2 28 Stored Current and Difference Waveforms NOTE There must be a waveform stored before it can be compared by the VIEW DIFF function Pressing this button with no waveform in storage will caused an error message to be displayed If the stored waveform and the current waveform are identical the difference waveform will appear as a straight line 2 17 Operator Tutorial Menu Accessed Functions NOTE If you get lost or confused while in a menu repeatedly press the MENU button until the instrument returns to normal operation mode Max Hold 1 Set the 1503C front panel controls to CABLE Attach 10 ft cable IMPEDANCE 93 Q NOISE FILTER 1 avg VERT SCALE 0 00 dB default DIST DIV 1 ft div 0 25 m Vp 84 PULSE WIDTH 2 ns Pull POWER on Press MENU to access the Main Menu Using the POSITION control scroll down to Setup Menu Press MENU to accept this selection Scroll down to Acquisition Control Menu Press MENU to accept this selection Scroll down to Max Hold is Off W FN OA t RD m P
62. duce the battery level or the added load might shut down the instrument T m m OM e Low Battery i Indicator amo 50 Q 1 avg 0 00 dB 5000 ft 2ns Figure 1 2 Display Showing Low Battery Indication Protection circuits in the charger prevent deep discharge of the batteries during instrument operation The circuits automatically shut down the instrument whenever battery voltage falls below approximately 10 V If shutdown occurs the batteries should be fully recharged before further use NOTE Turn the POWER switch off after instrument shutdown to prevent continued discharge of the batteries When the instrument is stored at temperatures below 10 C voids might develop in the liquid crystal display LCD These voids should disappear if the instrument is placed in an ambient temperature 5 C for 24 hours Operating Instructions When operating the 1503C in an environment below 10 C a heater will activate The element is built into the LCD module and will heat the display to permit normal operation Depending on the surrounding temperature it might take up to 15 minutes to completely warm the crystals in the LCD Once warmed the display will operate normally Preparing to Use the 1503C Check the power requirements remove the front cover and you are ready to test cables The following pages explain the front panel controls 4
63. duced 5 Increase the NOISE FILTER setting to 128 NOTE The higher the setting the more time the instrument takes to average the waveform T MEUM TENE m M n m Figure 2 16 Noise Reduced to Minimum 6 Move the POSITION control and notice how averaging restarts at a low value to allow easy positioning The 50 Q terminator was used here because it gives a good impedance match Because there are no large discontinuities it appears to the instrument as an endless cable The noise seen in this demonstration is noise picked up on the cable and a tiny amount of internal noise in the 1503C When testing cables the noise filter is extremely effective in reducing noise 1503C MTDR User Manual Operator Tutorial Set Ref A Mode HORZ SET REF Horizontal Set Reference establishes the starting point at which the distance window begins reading the distance to the cursor If for example you have a 10 foot cable leading to a patch panel you could eliminate this jumper from your distance readings 1 Set the 1503C front panel controls to CABLE Attach 10 ft cable IMPEDANCE 93 Q NOISE FILTER avg VERT SCALE 0 00 dB default DIST DIV 1 ft div 0 25 m PULSE WIDTH 2 ns no terminator NOTE If the POWER was left on from the previous step return the distance window reading to 0 00 ft with the lt gt POSITION control move cursor to reference and Press STORE dd Qr
64. e batteries are charging but this will increase the charging time For longest battery life a full charge is preferred over a partial charge For maximum capacity the batteries should be charged within a temperature range of 420 C to 4 25 C However the batteries can be charged within a temperature range of 0 C to 40 C and operated in temperatures ranging from 10 C to 55 C 1503C MTDR User Manual Operating Instructions Low Battery Low Temperature Operation 1503C MTDR User Manual CAUTION Do not charge battery pack below 0 C or above 40 C Do not discharge battery pack below 10 C or above 55 C If removing the battery pack during or after exposure to these extreme conditions turn the instrument off and remove the AC power cord The battery pack should be stored within a temperature range of 35 C to 4 65 C However the self discharge rate will increase as the temperature increases If the instrument is stored with the battery pack installed the battery pack should be charged every 90 days A fully charged battery pack will lose about 12 of its capacity in three to four months if stored between 20 C and 25 C If the battery is low it will be indicated on the LCD bat low If this is the case protective circuitry will shut down the 1503C within minutes Either switch to AC power or work very fast If the instrument is equipped with a chart recorder using the recorder will further re
65. e display If you turn the knob far enough the contrast will wrap from the darkest to lightest value c When the screen is clearly readable press the MENU button again to return to normal measurement operation The new contrast value will remain in effect until the instrument is turned off Vp is the speed of a signal down the cable given as a percentage of the speed of light in free space It is sometimes expressed as a whole number e g 66 or a percentage e g 66 On the 1503C it is the percentage expressed as a decimal number e g 66 66 If you do not know the velocity of propagation you can get a general idea from the following table or use the Help with Cables section of the Cable Information menu You can also find the Vp with the procedure that follows using a cable sample NOTE If you do not know the Vp of your cable it will not prevent you from finding a fault in your cable However if the Vp is set wrong the distance readings will be affected All Vp settings should be set for the cable under test not the supplied jumper cable Dielectric Probable Vp Jelly Filled 64 Polyethylene PIC PE or SPE 66 PTFE Teflon amp or TFE 70 Pulp Insulation 72 Foam or Cellular PE FPE 78 Semi solid PE SSPE 84 Air helical spacers 98 1503C MTDR User Manual Operating Instructions Impedance of Various Cable Types Finding an Unknown Vp 1503C MTDR User Man
66. e is important for making accurate distance measurements If you do not know the Vp factor of a cable distance readings will be directly affected You can get a general idea from the table on page 1 10 or find the Vp with a sample piece of cable using the procedure on page 1 10 or use the Cable Information Menu If it is impossible to obtain the Vp of the cable the instrument will still show cable faults but the distance readings might be erroneous The test cable used in this tutorial has a Vp of 84 2 1 Display Showing 10 ft Cable i in Start LUpC Conditions VERT SCALE will already be set to 0 00 dB default The cursor will be near the leading edge of the incident pulse at the point on the waveform representing the front panel Other information displayed includes the type of power used ac or bat and the distance window in the upper right corner of the LCD displays the distance from the front panel to the cursor 0 00 ft in this case This data will be displayed when the instrument is turned on Switch status and other instrument functions are also displayed see Figure 1 4 on page 1 5 for descriptions 1503C MTDR User Manual Operator Tutorial 1503C MTDR User Manual 3 The pulse on the left is the test pulse incident pulse leaving the instrument The reflected pulse on the right displays the echo coming back Turn the lt P POSITION control clockwise until the cursor rests on the rising edge of the refle
67. ed Waveform 00005 Figure 1 17 Display of a Stored Waveform and Current Waveform Figure 1 18 Display of a Stored Waveform Current Waveform and Difference Waveform 0 00 00 cece A Figure 1 19 Waveform Moved to Top Half of Display Figure 1 20 Current Waveform Centered Stored Waveform Above cpu ane P RERO PE Ne RSU CER ere ER es Figure 1 21 Current Waveform Center Stored Waveform Above Difference Below e ee nn Figure 1 22 Waveform of Three Foot Lead in Cable Figure 1 23 Cursor Moved to End of Three Foot Lead in Cable Figure 1 24 Cursor Moved to End of Three Foot Lead in Cable Figure 1 25 Cursor Moved to 0 00 ft 0 0 0 eee ee eee eee Figure 1 26 Incident Pulse at Four Divisions FILTER at Desired Setting 24 ccccaiccks cee bead eee Rr REO E Figure 1 27 Waveform Viewed in Normal Operation Figure 1 28 Waveform Showing Intermittent Short Figure 1 29 Waveform Display with No Outgoing Pulses 1 1 1 3 1 4 1 5 1 12 1 13 1 13 1 14 1 14 1 15 1 15 1 16 1 17 1 18 1 18 1 19 1 19 1 20 1 21 1 22 1 22 1 23 1 23 1 24 1 25 1 25 Table of Contents Figure 1 30 Figure 2 1 Display Showing 10 ft Cable in Start Up Conditions Figure 2 2 Cursor of Rising Edge of Reflected Pulse A Captured Single Sweep 0 0 0 0 eee eee Figure 2 3 Wav
68. eform that looks similar to data As a rule repeaters should be shut down prior to testing a segment to prevent such occurrences A E E E E s Noc 13 amo Figure 3 12 System 2 Same Tap with 5 Traffic 1 avg 1 ft div 44 5 dB 3 13 Options and Accessories 3 14 D E ean ee ee ne TTE raul 3 13 Fee 2 Same Tap Increased nee 16 avg 1 ft div 44 5 dB m mu a Figure 3 14 pem 2 Farther Out More Gain 128 avg 10 ft div 53 5 dB ac 714 12 ft Figure 3 15 Syston 2 1000 ft Cable at 10 ns 128 avg 100 ft div 43 75 dB 1503C MTDR User Manual Options and Accessories 1503C MTDR User Manual ee ee ee ee ee D2 S82 646 4 2 38 E 2S st oe oe Se GS Figure 3 16 System 2 Previous Wavetorm Expanded 128 avg 20 ft div 54 75 dB 1 ac IT E 1116 84 ft Figure 3 17 om 2 Next Group of Taps 128 avg 20 ft div 54 75 dB ac O are re O T Figure 3 18 Sit 2 doup of Taps Expanded 128 avg 10 ft div 54 75 dB 3 15 Options and Accessories Electrical Characteristics 1814 84 ft I SS T See Be SS He SS BS Shee Sh Figure 3 19 Sisto 2 Another Group of aos 128 avg 10 ft div 54 75 dB ac l Figure 3 20 Syaiem 2 End of Cable 128 avg 20 ft div 61 25 dB Jeet Following are the specifications for the Ethernet board Characteristic DC Termination Performance Requ
69. eform with VERT SCALE Increased Showing an Open Figure 2 4 Waveform with Short Figure 2 5 10 foot Cable with Cursor at Far Left Figure 2 6 10 foot Cable with Cursor at Incident Pulse Figure 2 7 10 foot Cable with Cursor at Incident Pulse Vertical Scale at 25 dB Figure 2 8 Cursor on End of Longer Cable Figure 2 9 Scrolling Down the Cable Pulse Width at 2 n8 ecce 0th dis haw ew ew NER a ete Pulse Width at 10ns llle Pulse Width at 100 ns 0 0 2 ee eee eee eee Figure 2 10 Figure 2 11 Figure 2 12 Figure 2 13 Being Tested Figure 2 14 Figure 2 15 Figure 2 16 Figure 2 17 Figure 2 18 Figure 2 19 Figure 2 20 VERT SET REF Figure 2 21 Higliz 5 stet ote ow Sant I NEE E dehet UE pud Figure 2 22 Figure 2 23 Figure 2 24 Figure 2 25 Figure 2 26 Figure 2 27 Figure 2 28 Figure 2 29 Figure 2 30 Figure 2 31 Figure 2 32 Pulse Width at 1000 ns Longer than the Cable Noise on the Waveform 0 000 cece eee Noise Reduced 221 i etd ace Ro ae ae a ete Noise Reduced to Minimum esses Incident and Reflected Pulses with Cursor at 0 00 ft Incident and Reflected Pulses with Cursor at 10 0 ft New Zero Set at End of Test Cable Display with 10 ft Cable and NOISE FILTER turned to VERT SCALE adjusted to Make Pulse Two Divisions Filter Returned to Desired Setting Display with VIEW INPUT Turned Off
70. energy so its return loss would be zero The 1503C can be made to display in mp div instead of dB through MENU Press MENU Select Setup Menu Press MENU Select Vertical Scale is Decibels Press MENU This changes the selection to Vertical Scale is Millirho Press MENU again to exit from the Setup Menu a 5 m Rom Press MENU again to return to normal operation The reflection coefficient is a measure of the impedance change at a point in the cable It is the ratio of the signal reflected back from a point divided by the signal going into that point It is designated by the Greek letter p and is written in this manual as Rho The 1503C measures reflection coefficient in millirho thousandths of a rho To measure a reflection adjust VERT SCALE to make the reflection one division high Read the reflection coefficient directly off the display above the VERT SCALE control For reflections that are greater than 500 mp div adjust VERT SCALE for a reflection that is two divisions high and multiply the VERT SCALE reading by two E E ee ee ene Fi Figure 1 14 Reflection Adjusted to One Division in Height In an ideal transmission system with no changes in impedance there will be no reflections so rho is equal to zero A good cable that is terminated in its characteristic impedance is close to ideal and will appear as a flat line on the 1503C display 1503C MTDR User Manual Operating Instructions Effect of C
71. ep mode As in normal operation averaged waveforms will take longer to acquire i i i 9 Fy 0 i 9 F Figure 1 30 A Captured Single Sweep 8 To exit Single Sweep is On access the Acquisition Control Menu again turn the Single Sweep back off then repeatedly push MENU until the instrument returns to normal operation 1503C MTDR User Manual ee Operator Tutorial This chapter will show step by step the features and uses of the 1503C What is the Tektronix 1503C How Does It Do It You the Operator Menus and Help 1503C MTDR User Manual The Tektronix 1503C Metallic Time Domain Reflectometer is a long range metallic cable tester capable of finding faults in metal cable Tests can be made on coaxial cable twisted pair or parallel cable The 1503C sends an electrical pulse down the cable and receives reflections back made by any discontinuities This is known as time domain reflectometry The 1503C is sensitive to impedance changes Problems in the cable will be detected and displayed as changes in impedance along the cable These will be displayed as hills and valleys in the reflected pulse The 1503C is capable of finding shorts opens defects in the shield foreign substances in the cable e g water kinks and more Even though other instruments might show a cable as good the 1503C can show many previously hidden faults The 1503C is a highly accurate cable tester It is easy to use and
72. er Manual Glossary Aberrations AC Accuracy Cable Cable Attenuation Cable Fault Capacitance Characteristic Impedance 1503C MTDR User Manual Imperfections or variations from a desired signal In TDRs a pulse of electrical energy is sent out over the cable As the pulse generating circuitry is turned on and off the pulse is often distorted slightly and no longer is a perfect step or sine shaped waveform Alternating current is a method of delivering electrical energy by periodically changing the direction of the flow of electrons in the circuit or cable Even electrical signals designed to deliver direct current DC usually fluctuate enough to have an AC component The difference between a measured generated or displayed value and the true value Electrical conductors that are usually insulated and often shielded Most cables are made of metal and are designed to deliver electrical energy from a source such as a radio transmitter across a distance to a load such as an antenna with minimal energy loss Most cables consist of two conductors one to deliver the electrical signal and another to act as a return path which keeps both ends of the circuit at nearly the same electrical potential In early electrical systems and modern systems that over long distances use the earth and or air as the return path and the term ground or ground wire is often used to describe one of the wires in a cable pair The amount
73. eshooting D 4 Size of Reflection division p division 100 to 80 1p to 0 8p 20 20 80 to 40 0 8p to 0 40 10 10 40 to 16 0 49 to 0 16p 05 16 to 8 0 16p to 0 080 02 8 to 4 0 08r to 0 04r 1 01 4 or less 0 04 p 0 5 005 SOURCE LINE pouces 1p 100 ce Q aes ae 0 5p 50 1500 i 0p 0 500 A2E AE r 0 5p 50 16 70 y ree 1p 100 oQ STEP INCIDENT REFLECTED LOAD GENERATOR VOLTAGE VOLTAGE RL p REFLECTION COEFFICIENT 1p 100 p DIV OHMS p DIV OHMS p DIV OHMS p DIV 1000 20 600 40 05 4o970 02 01 59 005 Mur 58 4 W E 5 200 909 L gg53 j e 5g 00 150 E 1000 80 60 9 zb zE50 58 5452 300199 70 zE 200 90 56 53 E F 80 3 54 B2541 a 100 70 60 a 70 60 P ERE E s00 502 500 40 45 49 ES z 4n iH 50Q SOURCE 500 SOURCE 50Q SOURCE The risetime or amplitude of received reflections may be signi ficantly degraded or attenuated by two way losses of the line 19 0Q Figure D 3 Slide Rule 50 Q Source 4 03p 53 10 If the reflection is downward from the 50 Q or 75 Q reference le
74. essage will appear The difference waveform is made by subtracting each point in the stored waveform from each point in the current waveform NOTE If the two waveforms are identical e g if STORE is pushed and VIEW DIFF is immediately pushed the difference would be zero Therefore you would see the difference waveform as a straight line 1503C MTDR User Manual Operating Instructions 1503C MTDR User Manual Difference Waveform and Difference Waveform The VIEW DIFF waveform will move up and down with the current input as you move the SPOSITION control Any of the waveforms may be turned on or off independently You might want to turn off some waveforms if the display becomes too busy or confusing NOTE Because the stored waveform is not affected by changes in the instrument controls care should be taken with current waveform settings or the results could be misleading One method to minimize the overlapping of the waveforms in VIEW DIFF is 1 Move the waveform to be stored into the top half of the display RI gt x H 1 H NEN LEGE EE MENS oxi Figure 1 19 Waveform Moved to Top Half of Display 2 Push STORE to capture the waveform Remember once it is stored this waveform cannot be moved on the display 3 Move the current waveform the one you want to compare against the stored waveform to the center of the display 1 19 Operating Instructions 1 20 4 Push VIEW STORE
75. et Physically Option 06 is a piggyback circuit board attached to the Sampler Pulser board in the 1503C A special EPROM replaces the standard EPROM on the main board allowing Option 06 to be transparent to the standard instrument but accessible through the Ethernet Menu and the Setup Acquisition Menu Option 06 performs three functions m a 50 Q terminator for the network W Generates a DC signal that emulates the 1 05 VDC carrier signal m Generates a DC signal that emulates the 1 7 VDC collision signal 1503C MTDR User Manual Options and Accessories Main Frame Server Main Frame Printer x Main Main Frame Frame Host Foreign Term Jen vun Fiber Optic Host Host Link L 9 3 Bridge Network Main Frame E Main Frame Micro Micro PC PC Computer PC Computer Figure 3 1 A Typical Ethernet System Test Procedures for a Working Network Before Starting here are some things you should know to make Ethernet tests easier m You need Option 06 for testing an active network m Make measurements from the end of a segment m If possible isolate the segment you plan to test
76. fy the carrier as well as Tektronix The instrument was inspected both mechanically and electrically before shipment It should be free if mechanical damage and meet or exceed all electrical specifications Procedures to check operational performance are in the Performance Checks appendix These checks should satisfy the requirements for most receiving or incoming inspections The 1503C is intended to be operated from a power source that will not apply more than 250 volts RMS between the supply conductors or between either supply conductor and ground A protective ground connection by way of the grounding conductor in the power cord is essential for safe operation The AC power connector is a three way polarized plug with the ground earth lead connected directly to the instrument frame to provide electrical shock protection If the unit is connected to any other power source the unit frame must be connected to earth ground Power and voltage requirements are printed on the back panel The 1503C can be operated from either 115 VAC or 230 VAC nominal line voltage at 45 Hz to 440 Hz or a battery pack Further information on the 1503C power requirements can be found in the Safety Summary in this section and in the Operating Instructions chapter 1503C MTDR User Manual General Information Repacking for Shipment 1503C MTDR User Manual When the 1503C is to be shipped to a Tektronix Service Center for service or repair attach a ta
77. g AC power make sure the fuse and power switch are correct for the voltage you are using 115 VAC requires a different fuse than 230 VAC Pull the POWER switch on the front panel If a message does not appear on the display within a second or two turn the instrument off There are some failure modes that could permanently damage or ruin the LCD if the power is left on for more than a minute or so Refer to Appendix C Operator Troubleshooting in this manual Option 05 instruments default to metric however you can change the metric scale to ft div in the Setup Menu or use the metric numbers provided To change the readings press the MENU button Using the 2 POSITION control scroll down to Setup Menu and press MENU again Scroll down to Distance Div is m div and press MENU again This will change to ft div Press the MENU button repeatedly to return to normal operation mode If the instrument power is turned off these checks must be repeated again when the instrument is powered on again B 1 Appendis B Operator Performance Checks Set Up 1 Horizontal Scale Timebase Check Set the 1503C front panel controls IMPEDANCE 93 Q NOISE FILTER 1 avg VERT SCALE 10 00 dB DIST DIV 2 ft div 0 25 m Vp 84 PULSE WIDTH 2 ns If the instrument fails this check it must be repaired before any distance measurements can be made with it 1 Turn the 1503C power on The display should look very similar to Figure B 1 Figure B 1
78. g showing the name and address of the owner name of the individual at your firm who may be contacted the complete serial number of the instrument and a description of the service required If the original packaging is unfit for use or is not available repackage the instrument as follows 1 Obtain a carton of corrugated cardboard having inside dimensions that are at least six inches greater than the equipment dimensions to allow for cushioning The test strength of the shipping carton should be 275 pounds 102 5 kg Refer to the following table for test strength requirements SHIPPING CARTON TEST STRENGTH Gross Weight Ib Carton Test Strength Ib 0 10 200 11 30 275 31 120 375 121 140 500 141 160 600 2 Install the front cover on the 1503C and surround the instrument with polyethylene sheeting to protect the finish 3 Cushion the instrument on all sides with packing material or urethane foam between the carton and the sides of the instrument 4 Seal with shipping tape or an industrial stapler If you have any questions contact your local Tektronix Field Office or representative General Information Contacting Tektronix Phone Address Web site Sales support Service support Technical support 1 800 833 9200 Tektronix Inc Department or name if known 14200 SW Karl Braun Drive P O Box 500 Beaverton OR 97077 USA www tektronix com 1 800 833 9200 select
79. he Options and Accessories chapter of this manual Terminology used in this manual is in accordance with industry practice Abbreviations are in accordance with ANSI Y 1 1 19722 with exceptions and additions explained in parentheses in the text Graphic symbology is based on ANSI Y32 2 1975 Logic symbology is based on ANSI Y32 14 1973 and manufacturer s data books or sheets A copy of ANSI standards may be obtained from the Institute of Electrical and Electronic Engineers 345 47th Street New York NY 10017 Changes that involve manual corrections and or additional data will be incorporated into the text and that page will show a revision date on the inside bottom edge History information is included in any diagrams in gray vii General Information Installation and Repacking Power Source and Power viii Unpacking and Initial Inspection Requirements Before unpacking the 1503C from its shipping container or carton inspect for signs of external damage If the carton is damaged notify the carrier The shipping carton contains the basic instrument and its standard accessories Refer to the replaceable parts list in the Service Manual for a complete listing If the contents of the shipping container are incomplete if there is mechanical damage or defect or if the instrument does not meet operational check requirements contact your local Tektronix Field Office or representative If the shipping container is damaged noti
80. he remainder is still entering This causes a spike shaped reflection the amplitude of which might vary depending on the risetime of the test pulse how badly the risetime has been degraded by the cable before it arrives and how much attenuation the cable might impose on the reflection before it arrives back at the source 2 If the risetime of the TDR system is too long a reflection with a plateau will appear as a spike 1503C MTDR User Manual Operator Troubleshooting Centimeters vs Inches or Meters vs Feet Dielectric Constant vs Inches and Centimeters A given number of inches can be converted to centimeters by placing the point on the sliding scale that corresponds to that number next to the stationary arrow labeled INCHES then reading the distance in centimeters next to the point of the arrow labeled CENTIMETERS Likewise centimeters are converted to inches using these directions in reverse 1 inch 2 54 cm INCHES CENTIMETERS Hp E LL LL LE LET HR HH ELTE HL A I 5 6 7 8 1 0 15 2 0 3 E ONE WAY DISTANCE TO OR BETWEEN FAULT SPLICE CONNECTOR LOAD END OR OTHER IMPEDANCE DISCONTINUITY 0 15 20 30 40 50 60708 iib bb ELE Dd do nn tnn p N METERS FEET 15 m 49 2 ft Figure D 6 English Metric Metric English Conversion Scales Meters and Feet A given number of meters can be converted to feet by placing the point on the sliding scale that corresponds to that number next to the stationary arrow labeled
81. hin layers if insulation dielectric to store energy between them Inductance is the ability of a conductor to produce induced voltage when the electrical current through it varies All conductors have some capacitance and inductance so all conductors have some reactance which means they all have impedance An instrument that uses reflections to make measurements Our reflectometers use electrical energy that is reflected back from points along a cable A conductor s opposition to the flow of DC electrical energy through it All conductors have a certain amount of resistance Resistance is the low or zero frequency part of impedance For a given parameter the smallest increment or change in value that can be measured generated or displayed The amount of energy reflected or returned from a cable indicates how much the impedance in the system is mismatched The ratio of the energy sent out by the TDR divided by the energy reflected back expressed in the logarithmic dB scale is called return loss see Millirho The time it takes a pulse signal to go from 10 to 90 of the change in voltage An acronym for Root Mean Squared RMS is a way of measuring how much deviation there is from a known or desired waveform It is also the method used to calculate how much power is contained in an AC waveform Our instruments make measurements by taking a succession of samples in time and displaying them as a waveform with voltage on the ver
82. ics 0 0 0 eee eee eee 3 16 Electrical Characteristics 1 icr E BERE bh state dae ete Bee cae es A 1 Environmental Characteristics ses isene eee eee eee A 3 Certifications and Compliances s soisi oidi aeae oine e eee A 4 Physical Characteristics 2 22 eiie re s EEEE Eei A 5 vi 1503C MTDR User Manual a LE General Information Product Description Battery Pack Options Standards Documents and References Used Changes and History Information 1503C MTDR User Manual The Tektronix 1503C Metallic cable Time Domain Reflectometer MTDR is a cable test instrument that uses radar principles to determine the electrical characteristics of metallic cables The 1503C generates a half sine wave signal applies it to the cable under test and detects and processes the reflected voltage waveform These reflections are displayed in the 1503C liquid crystal display LCD where distance measurements may be made using a cursor technique Impedance information may be obtained through interpreting waveform amplitude The waveform may be temporarily stored within the 1503C and recalled or may be printed using the optional dot matrix strip chart recorder which installs into the front panel Option Port The 1503C may be operated from an AC power source or an internal lead acid battery that supply a minimum of five hours operating time see the Specifications appendix for specifics Options available for the 1503C are explained in t
83. ill turn off the POWER switch automatically The carrying handle rotates 325 and serves as a stand when positioned beneath the instrument The 1503C can be stored in temperatures ranging from 62 C to 85 C if a battery is not installed If a battery is installed and the storage temperature is below 35 C or above 465 C the battery pack should be removed and stored separately see 1503C Service Manual for instructions on removing the battery Battery storage temperature should be between 35 C to 65 C In the field the 1503C can be powered using the internal battery For AC operation check the rear panel for proper voltage setting The voltage selector can be seen through the window of the protective cap If the setting differs from the voltage available it can be easily changed Simply remove the protective cap and select the proper voltage using a screwdriver Q REMOVE O REMOVE CAP TO CAP TO SELECT REPLACE VOLTAGE FUSE Voltage Selector Line Fuse AC Power C Cord Receptacle Figure 1 1 Rear Panel Voltage Selector Fuse AC Receptacle Operating Instructions A Care of the Battery Pack A Battery Charging The 1503C is intended to be operated from a power source that will not apply more than 250 V RMS between the supply conductors or between either supply conductor and ground A protective ground con
84. in this manual WARNING Warning statements identify conditions or practices that could result in injury or loss of life CAUTION Caution statements identify conditions or practices that could result in damage to this product or other property Terms on the Product These terms may appear on the product DANGER indicates an injury hazard immediately accessible as you read the marking WARNING indicates an injury hazard not immediately accessible as you read the marking CAUTION indicates a hazard to property including the product Symbols on the Product The following symbols may appear on the product A A BH CAUTION WARNING Double Protective Ground Refer to Manual High Voltage Insulated Earth Terminal This product contains a Nickel Cadmium NiCd battery which must be recycled or disposed of properly For the location of a local battery recycler in the U S or Canada please contact RBRC 800 BATTERY Rechargeable Battery Recycling Corp 800 227 7379 P O Box 141870 www rbre com Gainesville Florida 32614 1503C MTDR User Manual ke NMEMNMMENENEMMEMMMMMMMMMMMMMMMMMMZSS i Operating Instructions Overview Handling Powering the 1503C 1503C MTDR User Manual The 1503C front panel is protected by a watertight cover in which the standard accessories are stored Secure the front cover by snapping the side latches outward If the instrument is inadvertently left on installing the front cover w
85. ion of individual tests including custom tests follows If you wish to disconnect and reconnect the 1503C to the cable segment use a BNC T connector between the instrument and a 50 Q jumper cable e g RG 58U To one side of the T connector connect a 50 Q terminator the double termination is about a 25Q mismatch much less likely to cause problems than an open circuit The terminator can be removed during testing allowing the 1503C to become the 50 Q load When removing the 1503C or there is a power failure the terminator should be reconnected restoring the normal 50 Q load for the network The BNC T connector also allows another point of access for an oscilloscope if you need to look for signal quality or noise levels Once the 1503C 50 Q termination has been turned on tests are similar to standard measurements on an coaxial 50 Q cable Remember to use only the 2 ns or 10 ns pulse widths However the waveforms might be a little different due to traffic on the network Following are suggestions on how to set up test fixtures that will provide flexibility and provide network safety in case of power interruptions to the 1503C Ethernet A Before Testing Ethemet A During Testing 255745575 we Male type N 25525555 Male type N sesbseseswg MaletypeN 898859665 Male type fsbsSeSese yp VATI HL yp 50 Q terminator T To 1503C 50 Q ter
86. irement 500 10 Supplemental Information See typical frequency response curve below this table to estimate at other fre quencies Once the termination is turned on it will remain on until specifi cally turned off by the operator at which time a warning to remove the 1503C from the network will be shown on the display Leaving the TDR on the net work with the termination turned off will cause traffic disruption and errors DC Voltage Offsets 0 0 V 0 02V 1 05 VDC and 1 7 VDC 0 15 V into 50 Q AC pulse voltage is present on top of DC offsets while measuring Voltages only asserted when 50 O termination is on 1503C MTDR User Manual Options and Accessories Characteristic Performance Requirement Supplemental Information Overvoltage Protection Circuit cuts out leaving standard 1503C protection for voltages great erthan 11V Floating Ground Only when used with battery pack IEEE 802 3 specifies a single ground on the bus eee Option 06 Ru e Board E 1503C 7 E 50 SS E amp ih a 1503C with E Option 06 7 E 30 AN nj EUH T Pitt T PITI nj EENIN a ATH nn KHa T 10 10 10 10 10 109 107 10 Frequency Figure 3 21 Typical Frequency Response Curve with Ethernet Option 06 Option 07 YT 1S Chart Recorder Option 07 instruments come equipped with a splashproof chart printer Refer to the Y I YT 1S Chart Reco
87. lave 2 TUdiy 39 dB ood re d o e RC ee Figure 3 10 System 2 Cable w Revision One Repeater leave 200fUdiv 2 250B 4e bee mer REP EE AE Figure 3 11 System 2 First Tap No Traffic 1 avg 1 ft div 44 5 dB useless Figure 3 12 System 2 Same Tap with 5 Traffic lav Lidy 44 5 dB sep pe EE ete tien ERR Figure 3 13 System 2 Same Tap Increased Averaging 16 avg 1 ft div 44 5 dB 0 eee eee eee Figure 3 14 System 2 Farther Out More Gain 128 avg 10 tUdiv 53 5 dB ces ch te eae eae eS Re Figure 3 15 System 2 1000 ft Cable at 10 ns 128 avg 100 ft div 43 75 dB er 0 0 eee eee Figure 3 16 System 2 Previous Waveform Expanded 128 avg 20 tUdiv 54 75 dB percer cost RR 9h Re Figure 3 17 System 2 Next Group of Taps 128 avg 20 ft div 54 75 dB 2 eee eee eee Figure 3 18 System 2 Group of Taps Expanded 128 avg 10 tUdiv 54 75 dB 4 eee mer E EP IE e Figure 3 19 System 2 Another Group of Taps 128 avg 10 ft div 54 75 dB 6 ee eee Figure 3 20 System 2 End of Cable 128 avg 20 ft div 61 25 dB Figure 3 21 Typical Frequency Response Curve with Ethernet Option 06 L iscseos eve me degaes t Seed Pee ee FO E rig 3 13 3 14 3 14 Table of Contents Figure B 1 Start up Measurement Display B 2 Figure B 2 Measurement Display with 10 foot Cable B 2 Figure B3 Cursor at End of
88. lectricity traveling in a cable This relationship is shown as a decimal number A relative propagation velocity of 50 would mean the electricity will travel at 50 or one half as fast as it would in a vacuum Ifa reflection takes 30 nanoseconds to return in a cable with a Vp of 66 how far away is the point on the cable that caused thee reflection The one way time would be 30 divided by 2 or 15 nanoseconds The velocity of 1 ns ft in a vacuum would mean a distance of 15 feet Because the cable is Slower we multiply the distance by the Vp 66 in this case and arrive at a distance of 10 feet Of course the 1503C does all this automatically and displays the information on the LCD What is resistance Resistance is the opposition to DC current flow or DC voltage divided by DC current 2 23 Operator Tutorial 2 24 Q9 A9 Q10 A10 Q11 All Q12 A12 Q13 A13 What is inpedance Impedance is the total opposition resistance plus reactance a circuit offers to the flow of alternating current at a given frequency What factors determine the resistance of a cable The cross sectional area gauge length and the type of material the conductor is made of usually copper What factors determine the impedance of a cable Dielectric value of the insulation and geometry of the conductors Why should cables of the same impedance be used Because a mismatch of impedance means a loss of energy at the mismat
89. low 3 to 4 this test is very effective The 2 ns and 10 ns pulses are narrower than the time occupied by a single bit and usually will not cause any collisions All other tests in the Ethernet Menu have potentially destructive effects on working networks CAUTION The test just described should find most problems Before going any further know what you are doing Carrier and collision tests have the potential of causing problems on an active network Read the warnings and instructions carefully Try to limit tests to one segment during times of low traffic The second test is the Single Sweep with Carrier is Off On This test asserts the carrier signal of 1 05 V then single sweeps the network and drops the carrier signal The test occupies the network for one to 20 seconds depending on the NOISE FILTER setting The third test Carrier Test is Off On helps track down transceivers suspected if ignoring the carrier sense signal This test holds the carrier signal of 1 05 V turns off the pulse and turns on MAX HOLD The 1503C then acts as a traffic monitor 1503C MTDR User Manual Options and Accessories Basic Test Procedure If spikes appear on the display it is likely a transceiver is not responding to the carrier signal and is babbling The following procedure describes the fundamental tests with 50 Q DC termination is On When performing other Ethernet tests use essentially the same procedure A full descript
90. lse visible on the display The 1503C is now functioning as a listening device much like a non triggered oscilloscope Uses include monitoring the cable for pulses 11 SO c cp om UU GE wo d m To turn the pulse back on enter the Acquisition Control Menu again scroll to Pulse is Off and press MENU to turn the pulse back on Repeatedly press MENU until the instrument returns to normal operation Set the 1503C front panel controls to CABLE Attach 10 ft cable IMPEDANCE 93 Q NOISE FILTER avg VERT SCALE 0 00 dB default DIST DIV ft div 0 25 m Vp 84 PULSE WIDTH 2 ns Pull POWER on Press MENU to access the Main Menu Using the POSITION control scroll down to Setup Menu Press MENU to accept this selection Scroll down to Acquisition Control Menu Press MENU to accept this selection Scroll down to Single Sweep is Off Press MENU to toggle this selection It should now read Single Sweep is On Press MENU repeatedly until the instrument returns to normal operation The waveform on the display is the familiar test cable 2 21 Operator Tutorial 2 22 Figure 2 33 Test Cable 11 Short the far end of the test cable 12 Press VIEW INPUT The 1503C has done a single sweep capturing just one frame Figure 2 34 Shorted Test Cable with a Captured Single Sweep 13 Remove the short and notice that the waveform does not change 14 Press VIEW INPUT again and a new sweep will be
91. minator To 1503C Y P Front Panel Y Front Panel Figure 3 2 N Type Male T Connector 1503C MTDR User Manual gt TUI Y 7 Options and Accessories To 1503C Before Testing During Testing Front Panel A HI To 1503C Front Panel a UUM Female to Female Female to Female BNC to BNC BNC to BNC 50 Q terminator Female type N 50 Q terminator Female type N Y DIUI Y Y QUU UT S Ethernet Ethernet l H f Figure 3 3 N Type Female T Connector 1 Before removing the Ethernet cable terminator make sure you have the correct adapters and cables ready 2 Set the 1503C front panel controls CABLE see below IMPEDANCE 500 NOISE FILTER 1 avg VERT SCALE see below DIST DIV appropriate setting for cable length PULSE WIDTH 2 ns or 10 ns Vp to cable specifications POWER ON see below CAUTION DO NOT use the Auto pulse width mode The longer pulses will cause problems on working networks 3 Request the system administrator to notify network users of possible disruptions Using the POSITION control access the Ethernet Me
92. mpling Efficiency 1 8 Timebase 1 8 Display Contrast 1 10 Impedance 1 7 Main 1 7 Maximum Hold 1 24 Option Port 1 9 Debugging 1 9 Diagnostic 1 9 Timing 1 9 Pulse 1 25 Setup 1 7 Acquisition Control 1 7 Backlight 1 8 Distance Division 1 7 Maximum Hold 1 7 Pulse 1 7 Single Sweep 1 7 Vertical Scale 1 7 Single Sweep 1 26 Velocity of Propagation 1 7 View Stored Waveform 1 9 N Noise see also Controls 1 5 2 9 Reduced 2 10 Noise Filter 2 11 2 12 2 13 Noise Spec A 1 O Open 1 14 2 3 Option Port Cover 3 19 1503C MTDR User Manual Index Options vii 3 1 Chart Recorder 04 3 1 Chart Recorder 07 3 17 Ethernet 06 3 1 Metric Default 05 3 1 Power Cords 3 18 Token Ring Adapter 08 3 17 Token Ring Interface 10 3 18 USCC 09 3 18 P Performance Checks B 1 Aberrations B 6 Conclusions B 11 Equipment Required B 1 Horizontal Scale B 2 Impedance B 6 Noise B 5 Offset Gain B 5 Sampling Efficiency B 6 Set Up B 2 Vertical Position B 4 Pouch 3 19 Power AC Receptacle 1 2 Battery Low Indicator 1 3 Battery Pack Care of 1 2 Charging 1 2 Cords 3 18 Fuse 1 2 Fuse Rating 1 2 Voltage Rating 1 2 Voltage Selector 1 2 Voltages 1 1 Pulse see Controls 1 6 1 13 1 25 2 1 2 9 2 20 1000ns 2 8 100ns 2 8 10ns 2 8 2ns 2 7 Incident 2 3 2 5 2 11 2 12 Reflected 2 3 2 11 2 12 Pulse Inverter 3 20
93. n echo from one of the branches The STORE and VIEW DIFF functions allow you to see and compare the network with and without branches Two important things to be observed when using the VIEW DIFF function m If you change either the VERT SCALE or DIST DIV you will no longer be comparing features that are the same distance apart or of the same magnitude on the display It is possible to save a feature e g a connector or tap at one distance down the cable and compare it to a similar feature at a different distance by moving the lt gt POSITION and POSITION controls m When this is done great care should be taken to make sure the vertical and horizontal scales are identical for the two waveforms being compared If either the stored or current waveform is clipped at the top or bottom of the display the difference waveform will be affected HORZ SET REF A mode allows you to offset the distance reading For example a lead in cable to a switching network is three feet long and you desire to start the measurement after the end of the lead in cable HORZ SET REF makes it simple End of 3 ft cable 1 Turnthe NOISE FILTER control to HORZ SET REF The noise readout on the LCD will show set A 2 Turn the POSITION control to set the cursor where you want to start the distance reading This will be the new zero reference point For a three foot lead in cable the cursor should be set at 3 00 ft 1 21 Operating Instructions 1 22
94. nection by way of the grounding conductor in the power cord is essential for safe operation The AC power connector is a three way polarized plug with the ground earth lead connected to the instrument frame to provide electrical shock protection If the unit is connected to any other power source the unit frame must be connected to an earth ground See Safety and Installation section CAUTION If you change the voltage selector you must change the line fuse to the appropriate value as listed near the fuse holder and in the table below FUSE RATING VOLTAGE RATING 250 V NOMINAL RANGE 0 3 AT 115 VAC 90 132 VAC 0 15 AT 230 VAC 180 250 VAC CAUTION Read these instructions concerning the care of the battery pack They contain instructions that reflect on your safety and the performance of the instrument The 1503C can be powered by a rechargeable lead gel battery pack that is accessible only by removing the case from the instrument When AC power is applied the battery pack is charged at a rate that is dependent on the battery charge state The battery pack will operate the 1503C for a minimum of eight continuous hours including making 30 chart recordings if the LCD backlight is turned off The battery pack will charge fully in 16 hours when the instrument is connected via the power cord to an AC power source with the instrument turned off The instrument may be turned on and operated while th
95. nstant and Velocity Factor Short Distance The round trip time should be located on the sliding scale that is above the INCHES and CENTIMETERS scale Place the point on the sliding scale next to a point on one of the stationary scales that corresponds to the value of the dielectric constant or velocity factor Then read the distance on the INCHES and CENTIMETERS scale If the distance to or between faults is known and you want to find the time or velocity factor set the distance under the appropriate arrow first then read the answer on the ROUND TRIP TIME scales Time vs Long Distances in Meters or Feet any dielectric Distances to or between discontinuities farther apart than about three meters 10 feet can be found on the METERS and FEET scale Use the sliding ROUND TRIP TIME scale just below it and follow the same procedure as above ONE WAY DISTANCE TO OR BETWEEN FAULT SPLICE CONNECTOR LOAD END OR OTHER IMPEDANCE DISCONTINUITY 20 30 40 50 607080 100 15 Distance is Load dn dnt n P db Lo od 30 m or 99 ft p METERS FEET DIELECTRIC E 3 009 04 576 Dieletric is Solid Moos cou WI Polyethylene ROUND IOI IJI prp Ep E TEE EE EE EE EEIE HT IEEE EE EE EE TEN V TRIP 20ns 150ns 200ns 300ns 500ns 700r Time 300 ns TIME ilibibibililulubibulur i bani Bd dn n n B n ud MME EE PPLE LLLI VELOCITY a Velocity Factor 66 FACTOR 10 8 7 6 5 4 Figure D 8 Dielectric Constant and Velocity Factor Long Distance D 8 1503C MTDR Us
96. nu Scroll to 50 Q DC Termination is Off and turn it On Return to normal operation aA R As previously described connect one end of a 50 Q jumper cable to the front panel CABLE connector then connect the other end to one side of the BNC T connector see Figures 4 2 and 4 3 3 6 1503C MTDR User Manual Options and Accessories Descriptions of Test in the Ethernet Menu A A 1503C MTDR User Manual 8 Connect the Ethernet cable to the BNC T connector 9 Remove the 50 Q terminator At this point you are testing on an active network CAUTION The 50 Q termination of the 1503C is not maintained with the power off In case of power failure immediately replace the 50 Q terminator on the BNC T connector 10 With the NOISE FILTER set at 1 avg traffic will appear as large random noise spikes If the traffic is severe enough to make measurements difficult increase the NOISE FILTER setting NOTE The traffic on the display has no relationship to where it came from on the cable In fact traffic can appear on the display beyond the end of the cable 11 A VERT SCALE setting of 30 dB will normally allow you to see normal taps at the near end of a network Greater distances might require more gain depending on the loss of the cable and the pulse width The following tests are composed of several functions found in the Acquisition Control Menu These combinations are displayed in the Ethernet Menu as a user
97. of a reflection can be approximated First select the side of the slide rule having the correct source impedance For cables having a higher impedance than the selected source resistance put the sliding reference level even with the bottom stationary scale markings For cables having a lower impedance than the selected source resistance move the reference level even with the top of the scale markings For best accuracy select the scale farthest to your right in which the impedance level of interest is in view Read from the adjacent stationary scale the reflection coefficient or percent reflected voltage that corresponds to the Ohms selected Percent Reflected Voltage vs Load Resistance 1503C MTDR User Manual To find the terminating load resistance Rj of a line knowing the percent reflected voltage or reflection coefficient use the preceding instructions If the load resistance is known the previous procedures can be used to approximate the size of the return reflection An error might be introduced if the impedance of the connecting cable does not match the source resistance of the pulse generator D 5 Operator Troubleshooting Characteristic Line Impedance or Load Resistance vs Reflection Amplitude as seen on your TDR D 6 Line Impedance Zo or Load Resistance Ry can be derived directly from the amplitude of a reflection displayed on a TDR display The displayed reflection should be positioned vertically to a known
98. open A dramatic lowering of the pulse indicates a short Variations such as inductive and capacitive effects on the cable will appears as bumps and dips in the waveform Capacitive faults appear as a lowering of the pulse e g water in the cable Inductive faults appear as a rising of the pulse e g kinks in the cable Whenever an abnormality is found set the cursor at the beginning of the fault and read the distance to the fault on the distance window of the LCD Return loss is another was of measuring impedance changes in a cable Mathematically return loss is related to rho by the formula Return Loss in dB 20 log base ten of Absolute Value of Rho Vre Vinc To measure return loss with the 1503C note the height of the incident pulse then adjust the reflected pulse to be the same height that the incident pulse was and read the dB on the LCD display The amount of vertical scale change that was needed is the return loss in dB oO Ebel doce s veces IN Loss Figure 1 13 Return ios A large return loss means that most of the pulse energy was lost instead of being returned as a reflection The lost energy might have been sent down the cable or absorbed by a terminator or load on the cable A terminator matched to the cable 1 15 Operating Instructions 1 16 Reflection Coefficient Measurements would absorb most of the pulse so its return loss would be large An open or short would reflect all the
99. option 1 1 800 833 9200 select option 2 Email support tektronix com 1 800 833 9200 select option 3 1 503 627 2400 6 00 a m 5 00 p m Pacific time This phone number is toll free in North America After office hours please leave a voice mail message Outside North America contact a Tektronix sales office or distributor see the Tektronix web site for a list of offices 1503C MTDR User Manual iS General Safety Summary To Avoid Fire or Personal Injury Power Source 1503C MTDR User Manual Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it To avoid potential hazards use this product only as specified Only qualified personnel should perform service procedures Use Proper Power Cord Use only the power cord specified for this product and certified for the country of use Use Proper Voltage Setting Before applying power ensure that the line selector is in the proper position for the power source being used This product is intended to operate from a power source that will not apply more than 250 volts RMS between the supply conductors or between the supply conductor and ground A protective ground connection by way of the grounding conductor in the power cord is essential for safe operation Ground the Product This product is grounded through the grounding conductor of the power cord To avoid electric shock the grounding conductor mu
100. or is some cases lost by the system Our instrument measures return loss The formula for decibels is dB 2 log Vi VI where Vi is the voltage of the incident pulse V1 is the voltage reflected back by the load and log is the decimal based logarithmic function The dB vertical scale on our instrument refers to the amount of voltage gain amplification the instrument applies to the signal before displaying it For example when the instrument is amplifying the voltage by one hundred the dB scale would read 40 dB which is 20 log 100 Direct current is a method of delivering electrical energy by maintaining a constant flow of electrons in one direction Even circuits designed to generate only AC often have a DC component see Insulation A mathematical term that refers to the set of numbers that can be put into a function the set of numbers that comes out of the function is called the range A time domain instrument performs its function by measuring time The total opposition to the flow of electrical energy is a cable or circuit Impedance is made partly of resistance frequency independent and partly of reactance frequency dependent Although impedance is expressed in units of Ohms it must not be confused with the simple resistance that only applies to DC signals Technically impedance is a function of the frequency of the electrical signal so it should be specified at a frequency As a practical matter the impedance of
101. ower Accessories 3 19 Optional 3 19 Standard 3 19 accessories standard 3 19 Altitude Spec A 3 Application Note D 1 Battery see Power Battery Pack Spec A 2 BNC Connector 3 19 Bridge 3 2 C Cable Length vs Pulse 1 13 2 9 Open 1 14 Scrolling 2 7 Short 1 13 2 16 Test Procedure 1 12 Distance to Fault 1 12 Horizontal Set Reference 1 21 Reflection Coefficient 1 16 Return Loss 1 15 Store Waveform 1 18 Vertical Set Reference 1 23 View Difference 1 18 View Input 1 17 View Store 1 18 Cable Connection Spec A 2 Cable Types 1 11 Carrier 3 2 3 9 Characteristics Electrical A 1 A 2 A 3 Ethernet 3 16 Environmental A 3 Physical A 4 Cheapernet 3 1 Checks see Performance Checks Collision 3 2 Connectors BNC BNC 3 19 BNC to Alligator 3 19 BNC to Banana 3 19 1503C MTDR User Manual BNC to Binding Post 3 19 BNC to F Type 3 20 BNC to GR 3 20 BNC to Hook Tips 3 19 BNC to N Type 3 19 BNC to UHF 3 19 Controls Cable Connector 1 5 Distance Division 1 5 Front Panel 1 4 1 5 Horizontal Position 1 6 Impedance 1 5 Menu Button 1 6 Noise Filter 1 5 Power 1 6 Pulse Width 1 6 Store Button 1 6 Velocity of Propagation 1 6 Vertical Position 1 6 Vertical Scale 1 5 View Difference Button 1 6 View Input Button 1 6 View Store Button 1 6 Cursor Spec A 2 D Delta Mode 2 11 Depth Spec A 5 E Electromagnetic Spec
102. r of stations They use a more flexible cable and are usually connected to each Media Access Unit MAU with a T connector instead of a tap Segments are the smaller sub networks in an Ethernet system Each segment can be up to 500 meters long and have up to 100 transceiver taps Each tap must have at least 2 5 meters of cable between itself and the next tap Transceivers transmit data to and from the stations on the Ethernet bus The typical Ethernet data rate is 10 million bits per second At each tap is a transceiver MAU sending and receiving this data They also provide electrical isolation between the 3 1 Options and Accessories 3 2 coaxial cable and the station as well as housing the electronics that detect carrier signals and recognize the collision of two signals Taps are what the transceivers are attached to A bridge connects several network segments Depending on the hardware used e g fiber optics a network might extend up to 22 000 meters Repeaters are used to increase the effective length of a cable to allow more transceivers Due to distance limitations two transceivers can have a maximum of two repeaters between them Servers let a network share resources such as terminals disks printers etc The 1503C with Option 06 allows testing of an Ethernet bus while the network is active This is important because some installations might be interactive with other installations that are dependent on the Ethern
103. rder Instruction Manual that comes with this option for instructions on operation paper replacement and maintenance Option 08 Token Ring Adapter Option 08 instruments come with an adapter that allows you to connect the 1503C to networks containing ECL connectors The adapter isolates the receive pair from the transmit pair at the ECL connector and allows you to select one or the other to be routed to the input BNC connector on the 1503C 1503C MTDR User Manual 3 17 Options and Accessories Option 09 Universal Service Ordering Code A Option 09 instruments come with an adapter that allows you to connect the 1503C to LANs using type RJ 45 connectors using the Universal Service Ordering Code The adapter allows selection of each of the four twisted pairs CAUTION The RJ 45 USOC adapter Option 09 is the same connector used for many telephone installations Active telephone wires will have 40 to 60 VDC on one pair and this will destroy the 1502 series instrument Do not use Option 09 with 1502 1502B or 1502C instruments Option 10 Token Ring Interface Power Cord Options 3 18 Option 10 instruments come with an adapter that allows you to connect the 1503C to Token Ring networks via the MAU The following power cord options are available for the 1503C TDR Note that these options require inserting a 0 15 A fuse in the rear panel fuse holder NOTE The only power cord rated for outdoor use is the standard cord in
104. red waveform might be lost attemps below 40 C Humidity to 100 Altitude MIL T 28800C Class 3 Operating to 10 000 ft Non operating to 40 000 ft Vibration 5 to 15 Hz 0 06 inch p p MIL T 28800C Class 3 15 to 25 Hz 0 04 inch p p 25 to 55 Hz 0 013 inch p p Shock Mechanical Pulse 30 g 11 ms 1 2 sine wave total of 18 shocks Bench Handling Operating 4 drops each face at 4 inches or 45 degrees with opposite edge as pivot Non operating 4 drops each face at 4 inches or 45 degrees with opposite edge as pivot Satisfactory opera tion after drops MIL T 28800C Class 3 MIL STD 810 Method 516 Procedure V Cabinet on front cover off Cabinet off front cover off Loose Cargo Bounce 1 inch double amplitude orbital path at5 Hz MIL STD 810 Method 514 Procedure XI 6 faces Part 2 Water Resistance MIL T 28800C Style A Operating S plash proof and drip proof Front cover off Non operating Watertight with 3 feet of water above top ofcase Front cover on Salt Atmosphere Withstand 48 hours 2096 solution without Corrosion Sand and Dust Operates after test with cover on non operating MIL STD 810 Method 510 Procedure Washability Capable of being washed Fungus Inert Materials are fungus inert continued next page 1503C MTDR User Manual A 3 Appendix A Specifications Certifications and Compliances Category Standard or description EC Declaration of Conformity EMC
105. ress MENU to toggle this selection It should now read Max Hold is On The Max Hold function is now ready 10 Read the instructions on the display and press MENU again 11 Press MENU again to exit the Acquisition Control Menu 12 Press MENU again to exit the Setup Menu 13 Press MENU again to enter normal operations mode Note that the VIEW STORE and VIEW DIFF indicator blocks have disappeared This tells you that both of these functions have been disabled 2 18 1503C MTDR User Manual Operator Tutorial 1503C MTDR User Manual Figure 2 29 Display with VIEW N STORE and VIEW DIFF Disabled 14 Press STORE This activates the Max Hold function Notice that the STORE indicator block has darkened 15 With a clip lead or other device short the far end of the test cable then remove the short Note that both conditions now appear on the display Figure 2 30 Short and Open Viewed via Max Hold 16 Turn the POSITION control counterclockwise THe waveform will strobe down the display leaving traces of its movement Figure 231 Waveform Strobed Down Display in Max Hold 2 19 Operator Tutorial 2 20 Pulse On Off 17 Press STORE The display will clear awaiting STORE to be pressed again which would activate another Max Hold monitor cycle You can probably see how this function is useful for monitoring lines for changes over a period of time or for intermittent conditions For example 18 Sog
106. rical and electronic measuring and test equipment CAN CSA C22 2 No 231 CSA safety requirements for electrical and electronic measuring and test equipment Low Voltage Directive 73 23 EEC amended by 93 68 EEC EN 61010 1 A2 Safety requirements for electrical equipment for measurement control and laboratory use IEC61010 1 A2 Safety requirements for electrical equipment for measurement control and laboratory use Testand measuring Class 1 as defined in IEC 61010 1 Annex H grounded product Overvoltage Category Il as defined in IEC 61010 1 Annex J Pollution Degree 3 as defined in IEC 61010 1 Terminals on this product may have different installation overvoltage category designations The installation categories are CAT III Distribution level mains usually permanently connected Equipment at this level is typically in a fixed industrial location CAT II Local level mains wall sockets Equipment at this level includes appliances portable tools and similar products Equipmentis usually cord connected CATI Secondary signal level or battery operated circuits of electronic equipment continued next page A 4 1503C MTDR User Manual Appendix A Specifications Category Standard or description Pollution Degree 1 Pollution Degree 2 Pollution Degree 3 Pollution Degree A measure of the contaminates that could occur in the environment around and within a product Typically the inte
107. rm anatomy using the 93 Q 10 foot test cable as an example 1 Turn the POSITION control counterclockwise until the distance window reads 2 00 ft The cursor will be on the far left side of the display and the reflected pulse will be near center E Se Oe BE eS oe ae OS ee atte oy et SN eee ey Figure 2 5 10 foot t Cable with bursa at Far Left 1503C MTDR User Manual Operator Tutorial 2 Set the 1503C front panel controls CABLE 10 ft test cable no short IMPEDANCE 93 Q NOISE FILTER avg VERT SCALE 0 00 dB DIST DIV ft 0 25 m Vp 84 PULSE WIDTH 2 ns 3 The first left pulse is the incident pulse as sent from the pulse generator see Figure 2 2 The second bump is the reflected pulse as it bounces back from the end of the cable The reflected pulse and the time between pulses provides the information needed for calculating the distance between faults or the end of the cable 4 Adjust the S gt POSITION control so the cursor is at the beginning of the rise of the incident pulse Note the distance window reads approximately 0 40 ft This is the distance from the front panel BNC connector to the pulse generator circuit board inside the instrument where the test pulse in generated Figure 2 6 10 foot Cable with Cursor at Incident Pulse 5 Adjust the VERT SCALE control to approximately 25 dB Adjust the SPOSITION control to keep the middle portion of the pulse on the display The bumps following
108. rnal environmentinside a productis considered to be the same as the external Products should be used only in the environment for which they are rated No pollution or only dry nonconductive pollution occurs Products in this category are generally encapsulated hermetically sealed or located in clean rooms Normally only dry nonconductive pollution occurs Occasionally a temporary conductivity that is caused by condensation must be expected This location is a typical officelhome environment Temporary condensation occurs only when the productis out of service Conductive pollution or dry nonconductive pollution that becomes conductive due to condensation These are sheltered locations where neither temperature nor humidity is controlled The area is protected from direct sunshine rain or direct wind Pollution Degree 4 Pollution that generates persistent conductivity through conductive dust rain or Snow Typical outdoor locations Physical Characteristics Characteristic Description Weight without cover 14 5 lbs 6 57 kg with cover 16 Ibs 7 25 kg with cover chart recorder and battery pack 20 Ibs 9 07 kg Shipping Weight domestic 25 5 lbs 11 57 kg export 25 5 Ibs 11 57 kg Height 5 0 inches 127 mm Width with handle 12 4 inches 315 mm without handle 11 8 inches 300 mm Depth with cover on 16 5 inches 436 mm with handle extended to front 18 7 inches 490 mm 15
109. rrected This type of failure will not affect measurements made manually If there is no Option Port device there is probably a failure in the option port logic circuitry on the main circuit board or in the cable between the main board and the Option Port connector Refer the instrument to a qualified service technician If the error is in response to a chart printer request the PRINT switch on the chart printer or the wires to that switch are probably bad or shorted to the chassis or other ground point Refer the chart printer to a qualified service technician If the error is in response to another Option Port device remove that device If the error ceases have the device serviced If the error persists have the TDR serviced ERROR Acquisition Initialization TYPE Leading edge of pulse not found ERROR Acquisition Initialization TYPE Top of 50nsec ramp not found C 3 Appendix C Operator Troubleshooting C 4 Occurrences Meanings Remedies This message can occur at power on initialization only These are common error messages because they are triggered by many kinds of failures and come from one of the very first routines that the instrument executes The instrument searches for a point on the leading edge of the pulse that is on the cable inside the instrument about 10 up the pulse This message indicates that the search failed This could be because the pulse is not there or because the sampler or gain
110. s List OF FIgUTGS 5 5 4690 4 a 49 624 469954 ton eve Rete reread es iii List Of Tables ssr acesuuk sese a EREERAR OH ema n vi General Information 5 seocte sees eso annee vii Installation and Repacking 2 0 cece eee III viii Contacting TektrOnlx 4 oorr ERR e DER Ne er dp Rena x General Safety Summary eee xiii Operating Instructions ccc cece cece cece eee e ees 1 1 COVEIVIEW Sih pe ha maana E E ENGH e Den E E EE E dade tele Mays MU Lm DL 1 1 Preparing to Use the 1503C 4 escudeteid lA ue REESE bees eee een 1 4 Display e eco sre Re Ure ipee oon e esa vet ie bis ey POR RE 1 5 Front Panel Gontrols 541 sence DEKEqP PRESE PES EXER DS ERORI 1 5 Menu Selections sete chao etas debe ei atey eye wb E AE ESR QUE 1 7 Test Preparations o eer eme peSoPe eR E RET oe FARE aR pa 1 10 Cable Test Procedure cos ecoscisioi eie ose e e e v ee x vx eb ev 1 12 Additional Features Menu Selected lt gt oser 0 0 0 cece cee eee eee 1 24 Operator Tutorial 60k ecu n RR Soe leek seeded uses 2 1 Whatis the Tektronix 1503 7 santas eget REIHE wh ee Rh 2 1 How Does It Do Lt 3i erro EA E EEE E E RT eU Pee 2 1 You the Operator osse eee vr ore e ee e re es 2 1 Menus and Help oer cas ry es EE dues qaae s ardore EEUU ea Gas 2 1 Gettime Started x eases cer PPP LEPPRMPEPELPS Gate PEE hath Pres 2 2 The Waveform Up Close 00 cece cece tenes 2 4 A Longer Cable 3 254 LseLbRI REM biekinie edo pene E E BATES 2 6
111. s a continuous efficiency diagnostic of the sampling circuits Noise Diagnostic measures the internal RMS noise levels of the instrument Impedance Diagnostic tests the output impedance circuits in the instrument Offset Gain Diagnostic reports out of tolerance steps in the program mable gain stage This can help a service technician to quickly isolate the cause of waveform distortion problems RAM ROM Diagnostics Menu performs tests on the RAM Random Access Memory and the ROM Read Only Memory Timebase Is Normal Auto Correction Diagnostic No Correction When in Normal Auto Correction the instrument compensates for variations in temperature and voltage This condition might not be desirable while calibrating the instrument While in Diagnostic No Correction the circuits will not correct for these variations Front Panel Diagnostics aids in testing the front panel LCD Diagnostics Menu has these choices i ii LCD Alignment Diagnostic generates a dot pattern of every other pixel on the LCD These pixels can be alternated to test the LCD Response Time Diagnostic generates alternate squares of dark and light reversing their order This tests the response time of the LCD and 1503C MTDR User Manual Operating Instructions 1503C MTDR User Manual can give an indication of the effectiveness of the LCD heater in a cold environment iii LCD Drive Test Diagnostic generates a moving vertical bar pattern
112. scale can be moved on screen Vp Range Resolution Accuracy 0 30 to 0 99 0 01 within 1 Propagation velocity relative to air Custom Option Port Tek chart recorder is designed to operate with the 1503C Produces a high resolution thermal dot matrix recording and waveform and control values Line Voltage 115 VAC 90 to 132 VAC 45 to 440 Hz Fused at 0 3 A 230 VAC 180 to 250 VAC 45 to 440 Hz Fused at 0 15 A Battery Pack Operation 8 hours minimum 30 chart recordings maximum 415 C to 425 C charge and discharge temper Full Charge Time Overcharge P rotection Discharge Protection Charge Capacity Charge Indicator 20 hours maximum Charging discontinues once full charge is attained Operation terminates prior to battery damage 3 4 Amp hours typical Bat low will be indicated on LCD when capacity reaches approximately 1096 ature LCD backlight off O peration of instru ment with backlight on or at temperatures below 410 C will degrade battery operation specifica tion A 2 1503C MTDR User Manual Appendix A Specifications Environmental Characteristics Characteristic Performance Requirement Supplemental Information Temperature Operating 10 C to 55 C Battery capacity reduced at other than 15 C to 25 C Non operating 62 C to 405 C With battery removed Storage temp with bat tery in is 20 C to 455 C Contents on non volatile memory sto
113. st be connected to earth ground Before making connections to the input or output terminals of the product ensure that the product is properly grounded The standard power cord 161 0288 00 is rated for outdoor use All other optional power cords are rated for indoor use only Observe All Terminal Ratings To avoid fire or shock hazard observe all ratings and markings on the product Consult the product manual for further ratings information before making connections to the product Do not apply a potential to any terminal including the common terminal that exceeds the maximum rating of that terminal Replace Batteries Properly Replace batteries only with the proper type and rating specified Recharge Batteries Properly Recharge batteries for the recommended charge cycle only Use Proper AC Adapter Use only the AC adapter specified for this product Do Not Operate Without Covers Do not operate this product with covers or panels removed Use Proper Fuse Use only the fuse type and rating specified for this product Avoid Exposed Circuitry Do not touch exposed connections and components when power is present xi General Safety Summary Symbols and Terms A A Battery Recycling xii Do Not Operate With Suspected Failures If you suspect there is damage to this product have it inspected by qualified service personnel Do Not Operate in an Explosive Atmosphere Terms in this Manual These terms may appear
114. stantly constantly moving up and down on the display The NOISE FILTER control sets how many waveforms will be averaged together to make the waveform displayed Noisy waveforms appear to fluctuate around the real signal Because it is random noise will sometimes add to the real signal and sometimes subtract energy from the real signal By adding several noisy waveforms together the noise can be averaged out of the signal because the average amount of noise adding to the signal will be nearly the same as the average amount of noise subtracting from the signal More waveforms in an average are more likely to approach the real signal although it takes longer to acquire and add together more waveforms Glossary 3 Glossary Open Circuit Precision Reactance Reflectometer Resistance Resolution Return Loss Rho p Risetime RMS Sampling Efficiency Glossary 4 In a cable a broken conductor will not allow electrical energy to flow through it These circuits are also called broken circuits The circuit is open to the air which looks like a very high impedance The statistical spread or variation in a value repeatedly measured generated or displayed under constant conditions Also called repeatability A conductor s opposition to the flow of AC electrical energy through it All conductors have some reactance Reactance is made up of capacitance and inductance Capacitance is the ability of conductors separated by t
115. this 1503C MTDR User Manual Operating Instructions Menu Selections Main Menu 1503C MTDR User Manual button will erase it The settings of the stored waveform are available from the first level menu under View Stored Waveform Settings There are several layers of menu as explained below The Main Menu is entered by pushing the MENU button on the front panel 1 Return to Normal Operations puts the instrument into normal operation mode Help with Instrument Controls explains the operation of each control When a control or switch is adjusted or pushed a brief explanation appears on the LCD Cable Information has these choices a b Help with Cables gives a brief explanation of cable parameters Velocity of Propagation Values displays a table of common dielectrics and their Vp values These are nominal values The manufacturer s listed specifications should be used whenever possible Impedance Values displays impedances of common cables In some cases these values have been rounded off Manufacturer s specifications should be checked for precise values Finding Unknown Vp Values describes a procedure for finding an unknown Vp Setup Menu controls the manner in which the instrument obtains and displays its test results a Acquisition Control Menu has these choices i Max Hold Is On Off Turn Max Hold on by pushing MENU then STORE In this mode waveforms are accumulated on the display Max
116. tical scale up and down and 1503C MTDR User Manual Glossary Series Loss Short Circuit Stability TDR Velocity of Propagation Vp Waveform Averaging 1503C MTDR User Manual time along the horizontal scale across the display The circuitry that captures and holds the samples cannot instantly change from one voltage level to another It might take the circuit several samples to settle in at the new voltage after a rapid change in the waveform How efficiently the circuit moves from one sampled voltage level to the next is called sampling efficiency If the efficiency is too low the waveforms will be smoothed or rounded If the efficiency is too high above 100 the circuit will actually move beyond the new voltage level in a phenomenon known as overshoot which becomes an unwanted source of noise in the waveform Conductors all have some DC resistance to the flow of electrical energy through them The amount of resistance per unit length is usually nearly constant for a cable Theenergy lost overcoming this series resistance is called series loss The series loss must be compensated for when measuring the return loss or impedance mismatch at the far end of long cables Ina cable a short circuit is a place where the signal conductor comes into electrical contact with the return path or ground conductor The electrical circuit is actually shorter than was intended Short circuits are caused by worn leaky or missing ins
117. to travel past a tap because only part of the pulse s energy is reflected This allows the 1503C to read signatures well beyond taps Following are examples of tests made on two Ethernet systems 1503C MTDR User Manual Options and Accessories 1503C MTDR User Manual _ 173 36 ft Figure 3 4 gatai 1 Tap Hidden bi Traffic 1 avg 50 ft div 35 dB E WS a lee ad aed Societe X mO mO FIgur 3 5 Syd 1 Traffic and Tap Nearly Identical 4 avg 50 ft div 35 dB E eee NR NONE MET Le nO mO Figure 3 6 Sui 1 E becia Visible 16 avg 50 ft div 35 dB 3 11 Options and Accessories 3 12 ae eee ee ee ee ee Figure 3 7 pm 1 Tap Quite Visible 128 avg 50 ft div 35 dB W MUN NEM T Figure 3 8 System 1 No Traffic 1 avg 50 ft div 35 dB AE CORO NE M re ene o Figure 3 9 Sistemi Tap Eicarided No Traffic 1 avg 2 ft div 35 dB 1503C MTDR User Manual Options and Accessories 1503C MTDR User Manual Figure 3 10 System 2 Cable w Revision One Repeater 1 avg 200ft div 2 25dB Revision One repeaters must sense collisions and place a jam signal on both segments When using the carrier sense voltage level while sending out pulses e g Single Sweep with Carrier is On the pulses might exceed the collision or traffic thresholds of the repeater causing it to send back jamming packets that are synchronized with the 1503C This creates an unusual wav
118. ts or an impedance mismatch at the load divided by the voltage applied to the cable Millirho are thousandths of one rho Rho measurements are often used to judge how well the cable is matched to the load at the other end of the cable If there is an open circuit in the cable nearly all the energy will be reflected back when a pulse is sent down the cable The reflected voltage will equal the incident pulse voltage and rho will be 1 If there is a short circuit in the cable nearly all the energy will be delivered back to the instrument through the ground or return conductor instead of being sent to the load The polarity of the reflected pulse will be the opposite of the incident pulse and rho will be 1 If there is no mismatch between the cable and the load almost no energy will be reflected back and rho will be 0 In general a load or fault with higher impedance than the cable will return a rho measurement of 0 to 1 and a load or fault with a lower impedance will return a rho measurement of 0 to 1 The scale for rho measurements is determined by the height of the incident pulse A pulse two divisions high means that each division is 0 5 rho 500 millirho A pulse set to be four divisions high would make each division 0 25 rho 250 millirho Any unwanted electrical energy that interferes with a signal or measurement Most noise is random with respect to the signals sent by the TDR to make a measurement and will appear on the waveform con
119. twork or reflections will cause collisions on the network This entry is a duplicate of the entry in the Ethernet Menu Its function is to allow direct control of the low frequency termination inside the 1503C With the 50 Q DC termination is On the 1503C will functions normally to test the cable This is usually the only test needed to check a network cable Carrier 1 05 V Output Signal is Off On CAUTION The carrier signal will stop most traffic on the network This might abort many application programs and might cause communications problems When this test is on the 1503C will assert a 1 05 VDC level on a 50 Q load 2 1 VDC open circuit This signal is intended to be equivalent to the average of a standard Ethernet transmission and should trigger the carrier detect circuit on all the transceivers Because most applications will defer transmission when this signal is present it can be used to test transceivers and systems or to reduce traffic for 1503C testing Options and Accessories 3 10 A Collision 1 7 V Output Signal is Off On CAUTION The collision signal will stop most traffic on the network This might abort many application programs and might cause communications problems When this test is on the 1503C will assert a 1 7 VDC level on a 50 Q load 3 4 VDC open circuit This signal is intended to be equivalent to the average of two colliding Ethernet transmissions and should trigger the
120. ual 500 750 930 1250 RG 4 RG 6 U RG 7 U RG 23 U RG 8 U RG 11 U RG 22 U RG 63 U RG 9 U RG 12 U RG 62 U RG 79 U RG 58 U RG 13 U RG 71 U RG 89 U RG 62 U RG 59 U RG 111 U Flat Lead RG 81 RG 124 U Twisted Pair Twisted Pair RG 93 RG 140 U RG 142B U RG 179 U RG 225 U 75 Q Video RG 303B U RG 316 U RG 393 U Vertebrae Helix 1 Obtain a known length of cable of the exact type you wish to test Attach the cable to the CABLE connector on the front panel 2 Pull POWER on 3 Turn the DIST DIV to an appropriate setting e g if trying to find the Vp of a three foot cable turn the DIST DIV to 1 ft div 4 Turn the lt gt POSITION control until the distance reading is the same as the known length of this cable 5 Turn the Vp controls until the cursor is resting on the rising portion of the reflected pulse The Vp controls of the instrument are now set to the Vp of the cable The following three illustrations show settings too low too high and correct for a sample three foot cable E WE UMEN DECIES LT 1 11 Operating Instructions E3 moO mmo Figure 1 7 Vp Set at 66 Cursor on Rising Edge of Reflected Pulse Set Correctly Cable Test Procedure Distance to the Fault Be sure to read the previous paragraphs on Vp 1 Setthe 1503C controls POWER On CABLE Cable to BNC IMPEDANCE 50 Q NOISE FILTER avg DIST DIV see below Vp per cable
121. ulation The change in accuracy of a standard or item of test equipment over an extended period of time Unless otherwise specified the period of time is assumed to be the calibration interval might also apply to range resolution or precision as a function of time The term stability might also be used to denote changes resulting from environmental influences such as temperature humidity vibration and shock An acronym for Time Domain Reflectometer These instruments are also called cable radar They send out pulses of energy and time the interval to reflections If the velocity ofthe energy through the cable is known distances to faults in the cable can be displayed or computed Conversely the speed that the energy travels through a cable of known length can also be computed The way in which the energy is reflected and the amount of the energy reflected indicate the condition of the cable Electrical energy travels at the same speed as light ina vacuum It travels slower than that everywhere else The speed that it travels in a cable is often expressed as the relative velocity of propagation This value is just a ration of the speed in the cable to the speed of light so it is always a number between 0 and 1 A velocity of propagation value of 0 50 indicates that the electrical energy moves through the cable at half the speed of light see Noise Glossary 5 Glossary Glossary 6 1503C MTDR User Manual Index A AC see P
122. ur Divisions Out to 3000 00 ft If the instrument failed Aberrations or Sampling Efficiency checks it is probably still adequate for all but extremely minor fault measurements If it failed the Horizontal Scale check you should not use the instrument until the cause of the failure has been identified and corrected All of the previous checks only test the major functional blocks of the instrument that could prevent you from being able to make measurements It is possible for the front panel controls or the LCD to have problems that would interfere with controlling or displaying measurements Most problems of this type would become evident as you perform the checks If you suspect a problem of this nature you should have the instrument checked by a qualified service technician using the diagnostics in the 1503C Service Manual If the instrument passed all of the previous checks it is ready for use If your instrument is equipped with Option 06 Ethernet refer to the Calibration section of the 503C Service Manual B 11 Appendis B Operator Performance Checks B 12 1503C MTDR User Manual rr Ae Appendix C Operator Troubleshooting For assistance in troubleshooting use the following flow chart to determine if you have a simple problem you can fix or if the instrument needs to be sent to a Tektronix Service Center Use this process to determine whether the instrument should be repaired or is OK to use when you have a problem
123. vel set the reference level to the top of the chosen scale If the reflection is toward a higher impedance than the reference level set the reference level to the bottom of the chosen scale Then count off the right number of divisions and subdivisions to locate the level corresponding to the peak of the reflection and read the corresponding impedance levels Ohms on the adjacent sliding scale 1503C MTDR User Manual Operator Troubleshooting SOURCE 7 0dB 100 Q S RS reac s edB 50 F 2250 or odB 0 750 SE PEAK E 6dB 50 250 75Q e OdB 1009 amp oQ IMPULSE INCIDENT REFLECTED LOAD GENERATOR VOLTAGE VOLTAGE RL DIV OHMS DIV OHMS DIV OHMS DIV eo E Ze w 10 5 750 SEE 1 750 3 5 24 S70 cE Sa SS E gt 65 Z 73 742 d 70 60 72 4 m me I AS 55 En 5 657Z S 70 E 8 30 a 6972 7 0 2 ado 68 E oS Z 60 c e771 lu s SE SEO HE Sia cel 8 SE 35 65 0 fos E See 64 z dg 5 3 Eg 63 P 75Q SOURCE 75Q SOURCE 75Q SOURCE 20 division downward 5 major divisions 100 00 Figure D 4 Slide Rule 75 Q Source If the line impedance and the source resistance are known the expected amplitude
124. vertical zero reference It would be helpful to read the section of VERT SET REF in the Operation Instructions chapter to give you some technical background 1503C MTDR User Manual Operator Tutorial 1503C MTDR User Manual The VERT SET REF function allows manual control of the vertical calibration of the 1503C This can be used to compensate for cable loss or to increase the resolution of the return loss measurements The following example shows how to compensate for cable loss The reflection from an open or a short at the far end of a long cable is often less than two divisions high at 0 00 dB This is because of the energy lost in the cable before it gets to that fault Here is how to correct for this loss and be able to make accurate measurements at the far end of the cable 1 Connect the test cable 2 Turn the NOISE FILTER all the way counterclockwise to VERT SET REF A prompt will appear and the LCD will indicate set ref 0 ME set vertical scale and Press STORE E eim mm mcm cese Aaa SS eoi et 2 cte mue pnus 2 a Figure 2 20 Display with 10 f Cable and NOISE FILTER turned to VERT SET REF 3 Adjust the VERT SCALE control until the reflection from the open is two divisions high PU set vertical scale and Press STORE Q rn Figure 2 21 VERT SCALE adjusted to Make Pulse Two Divisions High 4 Push STORE and return NOISE FILTER to the desired setting 2 13 Operator Tutorial VIEW I
125. vice center is located Customer shall be responsible for paying all shipping charges duties taxes and any other charges for products returned to any other locations This warranty shall not apply to any defect failure or damage caused by improper use or improper or inadequate maintenance and care Tektronix shall not be obligated to furnish service under this warranty a to repair damage resulting from attempts by personnel other than Tektronix representatives to install repair or service the product b to repair damage resulting from improper use or connection to incompatible equipment c to repair any damage or malfunction caused by the use of non Tektronix supplies or d to service a product that has been modified or integrated with other products when the effect of such modification or integration increases the time or difficulty of servicing the product THIS WARRANTY IS GIVEN BY TEKTRONIX IN LIEU OF ANY OTHER WARRANTIES EXPRESS OR IMPLIED TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE TEKTRONIX RESPONSIBILITY TO REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES Ly La eee Table of Content
126. weaving all have distinctive signatures Figure 1 9 Short in the Cable Short 1 13 Operating Instructions 1 14 0 86 i0 o LL usu 20 00 ft Open F 3 To find the distance to the fault or end of the cable turn the lt gt POSITION control until the cursor rests on the leading edge of the rising or falling reflected pulse see Figure 1 10 Read the distance in the distance window in the upper right corner of the display A more thorough inspection might be required This example uses a longer cable 4 Wheninspecting a 455 foot cable a setting of 100 ft div allows a relatively fast inspection If needed turn VERT SCALE to increase the gain The higher the gain the smaller the faults that can be detected If noise increases increase the NOISE FILTER setting sa oim To 5 Change DIST DIV to 20 ft div The entire cable can now be inspected in detail on the LCD Turn the lt gt POSITION control so the cursor travels to the far right side of the LCD Keep turning and the cable will be dragged across the display 1503C MTDR User Manual Operating Instructions Return Loss Measurements 1503C MTDR User Manual ERG 134 pe cursor Sad BS Sele 28 3 a Got Se Si Sie aS Ss SrSs SS Se SS BS SUE Figure 1 12 455 ft Cable with 20 ftidiv Cursor ott Scr A rise or fall is a signature of an impedance mismatch fault A dramatic rise in the pulse indicates and
127. will take longer more pixels to move from the bottom to the top of the reflected pulse This smoothing effect might completely hide some faults that would normally only be one or two pixels wide on the display 1 In the Service Diagnostic Menu select Sampling Efficiency and follow the directions on the screen 2 When done with the test press the MENU button repeatedly until the instrument returns to normal operation If the aberrations are too large they can be confused with minor faults in the cable near the instrument 1 Turn the lt gt POSITION control counterclockwise until the display distance window reads less than 20 00 ft 6 10 m 2 Set the DIST DIV control to 1 ft div 0 25 m div 1503C MTDR User Manual Appendis B Operator Performance Checks 1503C MTDR User Manual Fi Sse SS cee Se eS eS as Se SS SOS Sa oe che a en Figure B 9 Distance at 2 00 ft 3 Turn the I gt POSITION control counterclockwise until the display distance window reads 2 00 ft 0 62 m 4 Setthe 1503C front panel controls IMPEDANCE 50Q NOISE FILTER avg VERT SCALE 0 00 dB PULSE WIDTH 2 ns Vp 99 5 Connect the 50 Q precision terminator to the front panel 6 Turn the NOISE FILTER control completely counterclockwise to the VERT SET REF position 7 Use VERT SCALE to increase the height of the pulse to four major divisions Figure B 10 Pulse Adjusted to Four Major Divisions in Height 8

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