HP 54753A, 54754A User Manual

User’s Guide

Publication number 54753-97010 Second edition, January 1999

For Safety information, Warranties, and Regulatory information, see pages behind the index

HP 54753A and HP 54754A TDR Plug-in Modules

HP 54753A and HP 54754A Plug-in Modules

The HP 54753A and 54754A TDR plug-in modules provide you with TDR and TDT measurement features. In addition to the TDR and TDT measurement features, the TDR plug-ins provide two accurate oscilloscope measurement channels with user selectable bandwidths of

12.4 or 18 GHz. The lower bandwidth mode provides excellent oscilloscope noise performance for accurate measurement of small signals. The high bandwidth mode provides high-fidelity display and measurement of very high-speed waveforms.

The HP 54753A TDR plug-in module provides:

• Automatic and manual single-ended TDR and TDT measurement capability

• Automatic and manual waveform, histogram, FFT, waveform math, eye pattern measurements, statistical measurements, and limit testing capabilities.

• User selectable 12.4 or 18 GHz bandwidth (Channel 1).

• User selectable 12.4 or 20 GHz bandwidth (Channel 2).

• 2.5 GHz bandwidth trigger channel.

• 3.5 mm (m) connectors.

The HP 54754A TDR plug-in module provides:

• Automatic and manual single-ended and differential TDR and TDT measurement capability.

• Automatic and manual waveform, histogram, FFT, waveform math, eye pattern measurements, statistical measurements, and limit testing capabilities.

• User selectable 12.4 or 18 GHz bandwidth.

• 2.5 GHz bandwidth trigger channel.

• 3.5 mm (m) connectors.

ii

Accessories Supplied

The following accessories are supplied with the TDR plug-in modules:

One 50 ohm SMA (m) terminator, HP part number 1250-2153 Two SMA shorts (m), HP part number 0960-0055 TDR Demo Board, HP part number 54754-66503 One User’s Guide One Programmer’s Guide One Service Guide

Accessories Available

The following accessories are available for use with the TDR plug-in modules.

Options

Option 0B1 Additional set of user documentation Option 001 HP 83480A mainframe operating system upgrade Option 002 HP 54750A mainframe operating system upgrade Option 003 Delete demo board HP 54755A TDR option for HP 83480A mainframe operating system upgrade

Optional Accessories

HP 10086A ECL terminator HP 54006A 6 GHz divider probe HP 54007A accessory kit HP 54008A 22 ns delay line HP 54118A 500 MHz to 18 GHz trigger HP 54701A 2.5 GHz Active Probe with Option 001

Connection Devices

SMA (f-f) adapter, HP part number 1250-1158 APC 3.5 (f-f) adapter, HP part number 1250-1749

iii

In This Book

This book is the operating manual for the HP 54753A and HP 54754A TDR plugin modules, and contains 13 chapters.

General Information Chapter 1 contains overview information, menu and front panel key information, trigger information, and calibration information. Chapter 2 contains important information on the care of the TDR plug-in connectors.

TDR Front Panel and Menu Keys Chapter 3, 4, 5 and 6 describe the front panel keys and all the menu keys.

Task Oriented Examples Chapter 7 contains example single-ended TDR measurements using a demo board included with each TDR plug-in module. Chapter 8 contains example differential TDR measurements.

TDR Theory Chapters 9, 10, and 11 contain in-depth theory of TDR transmission lines and how to use TDR in designing systems.

Specifications and Characteristics Chapter 12 contains the specifications and characteristic for the TDR plug-in modules.

Problems and Error Messages Chapter 13 contains troubleshooting information and error messages.

iv

Contents

1 The Instrument at a Glance

Menu and Key Conventions 1-3 The HP 54753A, 54754A TDR Plug-In Modules 1-4 Plug-in Module Purpose 1-4 Front Panel of the Plug-in Module 1-4 Getting the Best Performance 1-5 Installing a Plug-in Module 1-6 Trigger 1-6

2 Care and Handling of Precision Connectors

3.5 mm Connector Care 2-3 Connector Wear 2-3 Operator Skill 2-3 Device Specifications 2-3 Accuracy Considerations 2-6 Visual Inspection 2-8 Mechanical Inspection 2-8 Connecting the Devices 2-16

3 Setup Channel Menu

Displaying the Setup Channel menu 3-4 Display 3-4 Scale 3-4 Offset 3-5 Bandwidth. . . 3-6 Alternate scale. . . 3-6 Calibrate . . . 3-8 Calibration Overview 3-12 Factory Mainframe Calibration 3-13 User Calibrations 3-16

4 HP 54753A TDR/TDT Setup Menu

Displaying the TDR/TDT Setup Menu 4-4 Stimulus 4-4 TDT 1 dest 4-4

Contents-1

Contents

TDR 1 dest 4-5 Normalize response . . . 4-5 TDR rate automatic . . . (250 kHz) 4-8 Preset TDR/TDT 4-8

5 HP 54754A TDR/TDT Setup Menu

Displaying the TDR/TDT Setup Menu 5-7 Stimulus 5-7 TDT 1 dest 5-8 Normalize response . . . 5-8 TDR rate automatic . . . (250 kHz) 5-11 Preset TDR/TDT 5-12 TDT 2 dest 5-13 Normalize response . . . 5-13 TDR rate automatic . . . (250 kHz) 5-16 Preset TDR/TDT 5-17 TDT 1 dest 5-18 TDT 2 dest 5-18 Normalize 1 response . . . Normalize 2 response . . . 5-19 TDR rate automatic . . . (250 kHz) 5-21 Preset TDR/TDT 5-22 TDR/TDT 5-23 TDR response 1 5-23 TDR response 2 5-24 TDT response 1 5-25 TDT response 2 5-25 Establish ref plane 5-26 TDR rate automatic . . . (250 kHz) 5-27 Preset TDR/TDT 5-28 TDT 1 dest 5-30 TDR 1 dest 5-30 Normalize response . . . 5-31 TDR rate automatic . . . (250 kHz) 5-34 Preset TDR/TDT 5-34

6 Measure and Other TDR Specific Menus

TDR/TDT Measure Menu 6-4

Contents-2

Marker Menu 6-9 Reference 6-9 Marker units . . . 6-9 Response Menu Items 6-10

7 Single-ended TDR Measurements

Single-ended TDR Features 7-3 Establishing the Reference Plane and Normalizing 7-8 Measuring Transmission Line Impedance 7-19 Measuring Transmission Line Percent Reflection 7-25 Measuring Excess L/C 7-32 Measuring the Distance to a Discontinuity 7-37

8 Differential TDR Measurements

Differential TDR Features 8-3 Measuring Differential and Common Mode Impedance 8-5 Making Differential TDT Measurements 8-15

Contents

9 TDR Fundamentals

Propagation on a Transmission Line 9-4 Step Reflection Testing 9-6 Instrument Configuration 9-20

10 Improving Time Domain Network Measurements

Sources of Measurement Error 10-3 Removing Measurement Errors 10-6

11 Transmission Line Theory Applied to Digital Systems

Transmission Line Design 11-2 Signal Propagation Delay for Microstrip and Strip Lines with Distributed or Lumped Loads 11-15 Microstrip Transmission Line Techniques Evaluated Using TDR Measurements 1121 References 11-38

Contents-3

Contents

12 Specifications and Characteristics

Specifications 12-3 Vertical Specifications 12-4 Environmental Specifications 12-5 Power Requirements 12-6 Weight 12-6 Characteristics 12-6 Trigger Input Characteristics 12-6 Product Regulations 12-7

13 In Case of Difficulty

If You Have Problems 13-3 If the Mainframe Does Not Operate 13-3 If the Plug-in Does Not Operate 13-4 Error Messages 13-5

Contents-4

1

The Instrument at a Glance

The Operating the Instrument

What you’ll find in this chapter

This chapter describes:

• the key conventions used in this manual

not

• the front panel, rear panel and keys that do

Understanding the information in this chapter will help you successfully operate the instrument.

display menus on the screen

CAUTION

The input circuits can be damaged by electrostatic discharge (ESD). Therefore, avoid applying static discharges to the front-panel input connectors. Before connecting any coaxial cable to the connectors, momentarily short the center and outer conductors of the cable together. Avoid touching the front-panel input connectors without first touching the frame of the instrument. Be sure the instrument is properly earth-grounded to prevent buildup of static charge.

1-2

The Instrument at a Glance

Menu and Key Conventions

The keys labeled Trigger, Disk, and Run are all examples of front-panel keys. Pressing some front-panel keys accesses menus of functions that are displayed along the right side of the display screen. These menus are called softkey menus.

Softkey menus list functions other than those accessed directly by the frontpanel keys. To activate a function on the softkey menu, press the unlabeled key immediately next to the annotation on the screen. The unlabeled keys next to the annotation on the display are called softkeys.

Additional functions are listed in blue type above and below some of the frontpanel keys. These functions are called shifted functions. To activate a shifted function, press the blue front-panel Shift key and the front-panel key next to the desired function.

Throughout this manual front-panel keys are indicated by bold lettering of the key label, for example, Time base. Softkeys are indicated by italic lettering of the key label, for example, panel key pressed and which menu is selected. Shifted functions are indicated by the front-panel Shift key followed by the shaded shifted function, for example the Local function (above the Stop/Single front-panel key) will be shown as Shift, Local.

A softkey with On and Off in its label can be used to turn the softkey’s function on or off. To turn the function on, press the softkey so On is highlighted. To turn the function off, press the softkey so Off is highlighted. An On or Off softkey function will be indicated throughout this manual as:

A softkey such as this case you could choose Triggered by pressing the softkey until Triggered is highlighted, or choose Freerun by pressing the softkey until Freerun is highlighted. Softkey choices will be indicated throughout this manual as:

Triggered Freerun

When some softkeys, such as calibration will be made. Some softkeys, such as numeric value. To enter or change the value, use the general purpose knob located below the front-panel Measure section.

Sweep Triggered Freerun

Triggered.

Scale

. The softkeys displayed depend on the front-

Tes t

On.

offers you a choice of functions. In

Calibrate Probe

, are pressed the first time, a

Offset

require the entry of a

Sweep

1-3

The Instrument at a Glance

The HP 54753A, 54754A TDR Plug-In Modules

The TDR plug-in modules are two of several plug-in modules available for the HP 83480A and HP 54750A mainframes.

Plug-in Module Purpose

The purpose of the plug-in module is to provide measurement channels, including sampling, for the mainframe. The plug-in module scales the input signal, sets the bandwidth of the system, and allows the offset to be adjusted so the signal can be viewed. The output of the plug-in module is an analog signal that is applied to the ADCs on the acquisition boards inside the mainframe. The plug-in module also provides a trigger signal input to the time base/trigger board inside the mainframe.

Front Panel of the Plug-in Module

The plug-in module takes up two, of the four, mainframe slots. The front panel of the plug-in module has two channel inputs and an external trigger input. The front panel also has two probe power connectors for HP 54700-series probes, an auxiliary power connector for general purpose use, and a key for each channel that displays the softkey menu. The softkey menu allows you to access the channel setup features of the plug-in module for the selected input.

The front-power Probe Power connector allows automatic channel scaling and probe calibration with HP 54700 series probes. The front-panel Aux Power connector provides only power to HP 54700 series probes for use as a trigger input. Probe calibration and scaling are not required for a trigger input.

1-4

Figure 1-1

The Instrument at a Glance

Getting the Best Performance

Front panel of the plug-in module.

Getting the Best Performance

To ensure you obtain the specified accuracy, you must perform a plug-in module vertical calibration. The calibration must also be performed when you move a plug-in module from one slot to another or to a different mainframe. Refer to "Performing a Plug-in Module Vertical Calibration" in Chapter 3 for information on performing a plug-in module vertical calibration.

1-5

The Instrument at a Glance

Installing a Plug-in Module

You do not need to turn off the mainframe to install or remove a plug-in module. The plug-in module can be installed in slots 1 and 2 or 3 and 4 on the HP 83480A, 54750A mainframe. The plug-in module will not function if it is installed in slots 2 and 3.

To make sure the instrument meets all of the published specifications, there must be a good ground connection from the plug-in module to the mainframe. The RF connectors on the rear of the plug-in module are spring loaded, so fingertighten the knurled screw on the front panel of the plug-in module to make sure the plug-in is securely seated in the mainframe.

CAUTION

Do not use extender cables to operate the plug-in module outside of the mainframe. The plug-in module and/or mainframe can be damaged by improper grounding when using extender cables.

Trigger

The external trigger level range for this plug-in module is ±1 V. The trigger source selection follows the slots the plug-in module is installed in. For example, if the plug-in module is installed in slots 1 and 2, then the trigger source is listed as trigger 2. If it is installed in slots 3 and 4, then the trigger source is listed as trigger 4. Because the external trigger capability of this module is restricted to signals of 2.5 GHz or less, use of the HP 54753A and HP 54754A modules with Option 100, extended trigger, is not recommended.

The maximum safe input voltage is ±2 V + peak ac (+16 dBm). Therefore, to

!

avoid damaging the trigger input circuitry, do not apply any voltage outside this range.

The input circuits can be damaged by electrostatic discharge (ESD). Therefore, avoid app lying static discharges to the front-panel i nput connectors. Before connecting any coaxial cable to the connectors, momentarily short the center and outer conductors of the cable together. Avoid touching the frontpanel input connectors without first touching the frame of the instrument. Be sure the instrument is properly earth-grounded to prevent buildup of static charge.

1-6

2

Care and Handling of Precision Connectors

The Care and Handling of Precision Connectors

What you’ll find in this chapter

This chapter describes:

• 3.5 mm connector care

• connector wear

• device specifications

• accuracy considerations

• visual inspection

• mechanical inspection

• connecting devices

Understanding the information in this chapter will help you successfully operate the instrument.

CAUTION

The input circuits can be damaged by electrostatic discharge (ESD). Therefore, avoid applying static discharges to the front-panel input connectors. Before connecting any coaxial cable to the connectors, momentarily short the center and outer conductors of the cable together. Avoid touching the front-panel input connectors without first touching the frame of the instrument. Be sure the instrument is properly earth-grounded to prevent buildup of static charge.

2-2

Care and Handling of Precision Connectors

3.5 mm Connector Care

This chapter shows you how to take care of 3.5 mm connectors so that you can maintain high levels of accuracy, repeatability, and system performance. Taking appropriate care of your connectors will also extend their service life. Most of the information can also be applied to 2.4 mm connectors. For additional information on 2.4 mm connectors, refer to operating note "2.4 mm Adapters and Calibration Accessories" HP part number 11900-90903.

Connector Wear

Connector wear will eventually degrade performance. The calibration devices, which are typically used only a few times each day, should have a very long life. However, because the connectors often undergo many connections a day, they wear rapidly. Therefore, it is essential that all connectors on the HP 54753A or HP 54754A TDR plug-in modules be inspected regularly, both visually (with a magnifying glass) and mechanically (with a connector gage), and replaced as necessary. Procedures for visual and mechanical inspection are given in the next section of this manual. It is easier and cheaper to replace a worn adapter than a worn channel connector.

Operator Skill

Operator skill in making good connections is essential. The mechanical tolerances of the precision 3.5 mm connectors used in the HP 54007A kit are two or three times better than the tolerances in regular 3.5 mm connectors. Slight errors in operator technique that would go unnoticed with regular connectors often appear with precision connectors in the calibration kit. Incorrect operator technique can often result in lack of repeatability. Carefully study and practice the connection procedures that are explained later in this manual until your calibration measurements are consistently repeatable.

Device Specifications

Electrical specifications depend upon several mechanical conditions. A 3.5 mm connector is a precision connector dedicated to very specific tolerances. SMA connectors are not precision mechanical devices. They are not designed for repeated connections and disconnections and are very susceptible to

2-3

Care and Handling of Precision Connectors

Device Specifications

mechanical wear. They are often found, upon assembly, to be out of specification. This makes them potentially destructive to any precision 3.5 mm connectors to which they might be mated.

Use extreme caution when mating SMA connectors with 3.5 mm precision connectors. Prevent accidental damage due to worn or out-of-specification SMA connectors. Such connectors can destroy a precision 3.5 mm connector, even on the first connection.

Hewlett-Packard recommends that you keep three points clearly in mind when you mate SMA and precision 3.5 mm connectors: SMA inspection, alignment, and mechanical mismatch.

SMA Inspection

Before mating an SMA connector (even a new one) with a precision 3.5 mm connector, carefully inspect the SMA connector, both visually and mechanically with a precision connector gauge designed to measure SMA connectors. A male SMA connector pin that is too long can smash or break the delicate fingers on the precision 3.5 mm female connector. Gauging SMA connectors is the most important step you can take to prevent damaging your equipment.

Alignment

Be careful when aligning the connectors. Push the two connectors together with the male contact pin precisely concentric with the female. Do not overtighten or rotate either center conductor. Turn only the outer nut of the male connector and use a torque wrench (5 lb.in., 60 N-cm) for the final connection. Note that this torque is less than that when mating precision 3.5 mm connectors with each other. A torque wrench suitable for SMA connectors preset to 5 lb.in. is available (HP part number 8710-1582, CD 0).

The TDR plug-in modules come with adaptors already installed to prevent damage to the channel connectors. Then, if accidental damage does occur, the adapter is all that needs to be replaced. It is easier and cheaper to replace a damaged adapter than a channel connector. SMA connectors can then be mated with precision 3.5 mm connectors without difficulty or fear of expensive and time-consuming repairs.

Mechanical Mismatch

Significant structural and dimensional differences exist between these two types of connectors. Precision 3.5 mm connectors, also known as APC-3.5 connectors, are air-dielectric devices. Only air exists between the center and outer conductors. The male or female center conductor is supported by a plastic "bead" within the connector. In SMA connectors, a plastic dielectric supports

2-4

Figure 2-1

Care and Handling of Precision Connectors

Device Specifications

the entire length of the center conductor. In addition, the diameter of both the center and outer conductors of an SMA connectors differ from that of a precision

3.5 mm connector. If these precautions and recommendations are followed, SMA connectors can

be mated with 3.5 mm precision connectors without fear of expensive and time consuming repairs.

SMA and a Precision 3.5 mm Connectors

When an SMA connector is mated with a precision 3.5 mm connector, the connection exhibits a continuity mismatch (SWR), typically about 1.10 at 20 GHz. This mismatch is less than when precision 3.5 mm connectors are mated. Keep this fact in mind when making measurements on SMA and precision 3.5 mm coupled junctions.

2-5

Figure 2-2

Care and Handling of Precision Connectors

Accuracy Considerations

Typical SWR of SMA and Precision 3.5 mm Connectors

Accuracy Considerations

Accuracy requires that 3.5 mm precision connectors be used. However, SMA connectors can be used if special care is taken when mating the two, and all connectors are undamaged and clean. Before each use, the mechanical dimensions of all connectors must be checked with a connector gauge to make sure that the center conductors are positioned correctly. All connections must be made for consistent and repeatable mechanical (and therefore electrical) contact between the connector mating surfaces.

Carefully study and practice all procedures in this chapter until you can successfully perform them repeatedly. Accuracy and repeatability are critical for good high frequency measurements. Note that the device connection procedures differ in several important ways from traditional procedures used in the industry. Hewlett-Packard procedures have been developed through careful experimentation.

2-6

Care and Handling of Precision Connectors

Accuracy Considerations

Handling Precision 3.5 mm Connectors

• Precision 3.5 mm connectors must be handled carefully if accurate calibrations and measurements are to be obtained.

• Store the devices in the foam-lined storage case when not in use.

• Avoid bumping or scratching any part of the mating surfaces.

• Be careful to align the center connectors.

• Check the alignment carefully before tightening the connector nuts.

• Use a torque wrench for all final connections in order to avoid overtightening.

• Support the devices being used in order to avoid vertical or lateral force on any connectors. This precaution is critical when using the airline, 6 cm "L", or cables.

When Disconnecting Devices:

• Do not rock or bend any connections.

• Pull the connector straight out without unscrewing or twisting.

• Before storage, screw the connector nut all the way out to help protect the surfaces, and use the plastic caps provided. These plastic caps can be taken off easily by unscrewing, rather than pulling.

CAUTION Do not use a damaged or defective connector. It will damage any good

connector to which it is attached. Throw the connector away or have it repaired.

A connector is bad if it fails either the visual or mechanical examinations or when an experienced operator cannot make repeatable connections. The time and expense involved in replacing channel connectors warrants considerable caution when any connector might be less than perfect.

If any doubts exist about a connector, call your Hewlett-Packard representative. Hewlett-Packard field offices offer limited professional advice and have access to the factory for information.

2-7

Care and Handling of Precision Connectors

Visual Inspection

Always begin a calibration with a careful visual inspection of the connectors, including the test set connectors to make sure they are and undamaged.

CAUTION

Make sure that you and your equipment are grounded before touching any center conductor so you won't cause static electricity and create a potential for electrostatic discharge. When using or cleaning connectors, be aware that you are touching exposed center connectors that are connected directly to the internal circuits of the oscilloscope. Touching the center conductor, especially with a wiping or brushing motion, can cause an electrostatic discharge (ESD) and severely damage these sensitive circuits.

Use an illuminated, 4-power magnifying glass for visual inspection.

1

Before you begin, make sure you and any equipment you are using are grounded to prevent electrostatic discharge.

2

Examine the connectors first for obvious problems, such as deformed threads, contamination, or corrosion.

3

Next concentrate on the mating surfaces of each connector. Look for scratches, rounded shoulders, misalignment, or any other signs of wear or damage.

4

Make sure that the surfaces are clean, free of dust and solvent residues. Dirt or damage visible with a 4-power magnifying glass can cause degraded electrical performance and possible connector damage. All connectors should be repaired or discarded immediately.

Mechanical Inspection

Mechanical inspection of the connectors is the next step. This inspection consists of using the appropriate male or female precision 3.5 mm connector gauge to check the mechanical dimensions of all connectors, including those on the test set. The purpose of doing this is to make sure that perfect mating will occur between the connector surfaces. Perfect mating assures a good electrical match and is very important mechanically to avoid damaging the connectors themselves, especially on the oscilloscope.

2-8

Care and Handling of Precision Connectors

Mechanical Inspection

Center Conductor

The critical dimension to be measured is the recession of the center conductor. This dimension is shown as MP and FP in Figure 2-3 and Figure 2-4. No protrusion of the center conductor's shoulder is allowable on any connector. The maximum allowable recession of the center conductor shoulder is 0.003 in. (0.08 mm) on all connectors, except those on the channel connectors.

On the channel connectors, not only is no protrusion allowable, the shoulder of the center conductor must be recessed at least 0.0002 in. (0.005 mm). The maximum allowable recession of the center conductor shoulder on the channel connectors is 0.0021 in. (0.056 mm).

2-9

Figure 2-3

Care and Handling of Precision Connectors

Mechanical Inspection

D = inside diameter of the outer conductor d = diameter of male/female center connector A = outside diameter of outer conductor at the mating plane r = corner relief for male connector B = protrusion of the male contact pin tip beyond the outer conductor mating plane C = recession of the outer conductor mating plane behind outer face of connector MP = recession of male contact pin shoulder behind outer conductor mating plane

Male Connectors Female Connectors

inches millimeters inches millimeters

D = 0.1378 ± 0.0005 3.500 ± 0.013 D = 0.1378 ± 0.0005 3.500 ± 0.013 d = 0.0598 ± 0.0003 1.519 ± 0.008 d = 0.0598 ± 0.0003 1.519 ± 0.008 A = 0.1803 + 0.000

- 0.002 r = 0.003 0.08 r = 0.003 0.08 B = 0.085 +0.005

- 0.015 C = 0.120 ± 0.015 3.05 ± 0.38 C = 0.176 ± 0.002 1.93 ± 0.05 Mp = 0.00 + 0.003

- 0.000 dm = 0.037 + 0.000

- 0.001

Mechanical Dimensions of Connector Faces

4.580 + 0.00

- 0.05

2.16 + 0.13

- 0.38

0.000 + 0.08

- 0.00

0.94 + 0.00

- 0.03

A = 0.1807 + 0.002

- 0.000

N/A

Fp = 0.000 + 0.003

- 0.00

N/A

4.590 + 0.05

- 0.00

0.000 + 0.08

- 0.00

2-10

Figure 2-4

Care and Handling of Precision Connectors

Mechanical Inspection

Mechanical Dimensions of the Short Circuit

Outer Conductor

If any contact protrudes beyond the outer conductor mating plane, the contact is out of tolerance and must be replaced. If the center conductor is not recessed at least 0.0002 in. (0.005 mm), it is out of tolerance and must be replaced. In both cases the out-of-tolerance connector will permanently damage any connector attached to it. Destructive electrical interference will also result due to buckling of the female contact fingers. This is often noticeable as a power hole several dB deep occurring at about 22 GHz.

If any contact is recessed too far behind the outer conductor mating plane (0.0021 in. 0.056 mm, except in test sets), poor electrical contact will result, causing high electrical reflections. Careful gauging of all connectors will help prevent this condition.

Before using the connector gauge to measure the connectors, visually inspect the end of the gauge and the calibration block in the same way that you inspected the connectors. Dirty or damaged gauge facings can cause dirty or damaged connectors. Two connector gauges are available from HewlettPackard, one for each connector type, male and female. Refer to Figure 2-5. The part number for one gauge is HP 11752D. This gauge has a 3.5 mm connector (male and female). Or, you can use the 85052-60043 gauge with 3.5 mm female connector with an 85052-60042 3.5 mm male gauge.

Figure 2-5 to Figure 2-8 show how to use the connector gauges. Zero the gauge with the calibration block. Refer to Figure 2-5. It is recommended that you zero both gauges first, then measure each of the terminations and/or adapters that will be used. Then, as the last step, measure the channel connectors.

Figure 2-7 and Figure 2-8 show how to measure precision 3.5 mm connectors. Note that a plus (+) reading on the gauge indicates recession of the center conductor and a minus (-) reading indicates protrusion. Since no protrusion of either connector is allowable, readings for connectors within the allowable

2-11

Figure 2-5

Care and Handling of Precision Connectors

Mechanical Inspection

range will be on the plus (+) scale of the gauge. Also note that the allowable tolerance range for the test set connectors is different from the range for other connectors. Both ranges are shown in Figure 2-7 and Figure 2-8. Before measuring test set connectors, be sure that the power to the test set is off and that you and your equipment are grounded to prevent electrostatic discharge.

Precision 3.5 mm Connector Gauges

2-12

Figure 2-6

Care and Handling of Precision Connectors

Mechanical Inspection

Zeroing Precision 3.5 mm Connector Gauge

2-13

Figure 2-7

Care and Handling of Precision Connectors

Mechanical Inspection

Measuring Precision 3.5 mm Male Connectors

2-14

Figure 2-8

Care and Handling of Precision Connectors

Mechanical Inspection

Measuring Precision 3.5 mm Female Connectors

2-15

Care and Handling of Precision Connectors

Connecting the Devices

Figure 2-9 and Figure 2-10 illustrate the Hewlett-Packard recommended procedures for making connections with the calibration devices. Notice that these recommended procedures differ from traditional procedures used in the microwave industry, especially the counter-rotation technique and procedure for connecting the airline.

The counter-rotation technique, recommended here, involves a slight rotation of the termination or adapter just before the final tightening of the connector nut. This eliminates the very small air wedge between the outer conductors that frequently occurs when the body is held stationary during tightening, as it is in the traditional procedure. The HP 54753A or HP 54754A plug-in modules will detect the reflections caused by such small wedges.

The counter-rotation technique does not harm the connectors. The gold plating on the outer conductor surface will become burnished in time. This is normal, and as long as the surface remains smooth, the connector is still good. After much use the gold plating may eventually wear through and expose the beryllium-copper substratum. This too is normal, and if it is smooth the connector is still good, although the beryllium-copper surface may oxidize if the connector is used infrequently.

If the burnished surface is rough, scratched, rippled, or has other irregularities, too much tightening force is being used. If the roughness is severe, the connector is ruined and should not be used.

CAUTION

Damage can result if SMA connectors are overtightened to precision 3.5 mm connectors. Use a torque wrench designed for SMA connectors, set to a 5 in lb (60 N/cm). A torque wrench suitable for SMA connectors is available, HP part number 8710-1582.

2-16

Care and Handling of Precision Connectors

Connecting the Devices

Counter-Rotation Technique

The recommended Hewlett-Packard counter-rotation technique is for precision

3.5 mm connectors. Before making any connections to the channel connectors, ground yourself with a grounded wrist strap. Also, it is good practice to grasp the outer shell of the test port before you make any connections to the channel connectors in order to discharge any static electricity on your body. This is the most effective single safeguard to prevent ESD damage to your instruments.

If the device has a retractable connector nut, fully retract the nut before

1

mating the connectors. Carefully align the male and female contact pins and slide the connectors straight together until the center and the two outer conductors meet. Be careful not to twist or bend the contact pins. You should feel a slight resistance as the connectors mate.

Make the preliminary connection by attaching the connector nut of the

2

male connector to the female. The male connector is held stationary as the female connector is tightened and draws the male pin into the female connector. Refer to Figure 2-9. Any other method used may cause the male pin to damage the female connector. Support the body of the device and turn the connector nut until the mating surfaces make light contact. Do not overtighten. All you want is a connection of the outer conductors with gentle contact at all points of both mating surfaces.

Figure 2-9

Connecting 3.5 mm Devices

2-17

Figure 2-10

Care and Handling of Precision Connectors

Connecting the Devices

3 When you are satisfied with this preliminary connection, use the

following counter-rotation technique to eliminate air wedges between the mating planes. Refer to Figure 2-10. If the calibration device is male, hold the connector nut firmly. Very slowly rotate the body of the device about 10-20 ° counterclockwise. Note that this slight rotation or backwiping is sufficient. Greater rotation does not improve electrical performance and increases wear on the connector surfaces.

Counter-rotation Technique

If the calibration device is female (the connector nut is on the TDR plug-in module), very slowly rotate both the connector nut and the body of the device clockwise 10-20 ° (counterclockwise rotation will loosen the connection).

Light, smooth frictional resistance felt during the counter-rotation indicates you have made the preliminary connection correctly and that the counter-rotation technique has been successful. Roughness felt during counter-rotation indicates either that the connectors are damaged or that there is roughness in the connector nut/thread contact. Inspect both connectors again before proceeding, to make sure that the roughness is due to roughness in the connector nut interface rather than on the connector mating planes.

4 Tighten the connector nut finger tight, allowing the device to turn with

the nut if it tends to do so. A small rotation of the body of the device at this point is acceptable and tends to occur naturally.

5 Use a torque wrench to make the final connection. Use of the torque

wrench assures the final connection will be tight enough for optimum electrical performance, but not so tight as to distort or damage the connectors.

2-18

Care and Handling of Precision Connectors

Connecting the Devices

To disconnect, follow this procedure:

1 Loosen the connector nut on the male connector with the torque

wrench. Leave the connection finger tight.

2 While supporting the calibration device, gently unfasten the connectors

and pull the calibration device straight out of the channel connector. Do not twist either the center conductor or the outer conductor housing or exert lateral or vertical (bending) force on the connection.

Some precision 3.5 mm female connector fingers are very tight and can pull the center pin of their mates out past specifications as they are disconnected. If such a male pin is inserted into a female connector, it can cause considerable damage by pushing the female center conductor back too far. Be aware of this possibility and check all connectors before mating them again.

2-19

2-20

3

Setup Channel Menu

What you’ll find in this chapter

This chapter describes the Setup Channel menu. A key tree and description of the available functions are included. At the end of the chapter, you’ll find a discussion of mainframe and plug-in module calibrations.

CAUTION

The input circuits can be damaged by electrostatic discharge (ESD). Therefore, avoid applying static discharges to the front-panel input connectors. Before connecting any coaxial cable to the connectors, momentarily short the center and outer conductors of the cable together. Avoid touching the front-panel input connectors without first touching the frame of the instrument. Be sure the instrument is properly earth-grounded to prevent buildup of static charge.

The top left keys of the plug-in module are the Channel keys. These keys give you access to the Setup Channel menu for each input. The Setup Channel menu is displayed on the right side of the screen when the Channel key is pressed. There are several types of softkeys available. A description of the different softkeys and their functions is provided in the HP 83480A, 54750A User’s Quick Start Guide supplied with the mainframe.

3-2

Figure 3-1

Setup Channel Menu

Electrical Setup Channel menu.

3-3

Setup Channel Menu

Displaying the Setup Channel menu

To display the Setup Channel menu, press the Channel key.

Display

The

Display

display is on, a waveform is displayed for that channel, unless the offset is adjusted so the waveform is clipped off of the display or the instrument is not triggering.

The channel number, vertical scaling, and offset are displayed at the bottom left of the waveform area. They remain on the display until the channel is turned off, or an automatic measurement is performed. The automatic measurement results share the same area of the display as the channel setups.

When the channel display is off, the waveform display for that channel is turned off, pulse parameter measurements are stopped and acquisition on that channel is stopped, unless it is needed as an operand for waveform math functions or TDR/TDT responses.

Even though the channel display is off, you can still use the plug-in as a function source in the Math menu or as a source for four normalize, differential, or common mode responses. However, the instrument will not trigger unless one or more of the other channel displays are turned on, or unless a math function or TDR/TDT response is using one of the channels.

Key Path Channel

Scale

The

Scale

is off, then the knob and arrow keys change the vertical scaling in a 1-2-5 sequence. When fine mode is on, the knob and arrow keys change the vertical scaling in 1 mV increments. You can also use the keypad to enter values in 1 mV increments, independent of the fine mode selection.

The units the scale is displayed in depend on the unit of measure selected with the

Units

reflect, gain, or unknown.

softkey turns the channel display off and on. When the channel

Display

softkey controls the vertical scaling of the waveform. If the fine mode

softkey. The choices for units are volts, watts, amperes, ohms, %

3-4

Setup Channel Menu

Offset

When the ohm, % reflect, or gain units are selected, the control changes to

Magnify scale

behaves as it would when the units mode is selected for all stimulus except for differential or common mode.

If the TDR/TDT stimulus is set to differential or common mode, the control also changes to displayed waveform is never clipped. The scaling control.

. In this mode of operation, the TDR plug-in’s hardware scale

Magnify scale

. However, the hardware scale is set so that the

Magnify scale

control is a software

Key Path Channel

Offset

The

Offset

control on analog oscilloscopes. The advantage of digital offset is that it is calibrated. The offset voltage is the voltage at the center of the graticule area, and the range of offset is 500 mV. You can use the knob, arrow keys, or keypad to change the offset setting. The fine mode also works with offset.

When an HP 54700-series active probe is used with the plug-in module and is connected to the probe power connector adjacent to the channel input, the offset control adjusts the external scale factor and offset of the hybrid inside the active probe. A probe connected to the auxiliary power connector adjacent to the trigger input will function, but the channel scale factor will not be adjusted automatically.

The units the offset is displayed in depend on the unit of measure selected with the

Units

reflect, gain, or unknown. When the ohm, % reflect or gain units are selected, the control changes to

Magnify offset

behaves as it would when the units mode is selected for all stimulus except for differential or common mode.

If the TDR/TDT stimulus is set to differential or common mode, the control also changes to displayed waveform is never clipped. The offset control.

Scale

softkey moves the waveform vertically. It is similar to the position

softkey. The choices for units are volts, watts, amperes, ohms, %

. In this mode of operation, the TDR plug-in’s hardware offset

Magnify offset

, however, the harrower scale is set so that the

Magnify offset

control is a software

Key Path Channel

Offset

3-5

Setup Channel Menu

Bandwidth. . .

You can use the bandwidth. For the HP 54753A TDR plug-in module, channel 2 can be either

12.4 GHz or 20 GHz bandwidth.

Key Path Channel

Alternate scale. . .

The

Alternate Scale

vertical scale of the display. It also allows you to select the attenuation units and the attenuation factor.

Key Path Channel

Atten units

The

Atten Units

factor represented. The choices are either decibel or ratio. The formula for calculating decibels is:

The

Atten Units

or gain.

Bandwidth

Bandwidth. . .

function to select either 12.4 GHz or 18 GHz

function allows you to change the units used to label the

Alternate scale . . .

function lets you select how you want the probe attenuation

20

V

out

----------

V

or 10

in

P

out

----------loglog

P

in

function is not available when the units are set to ohm, % reflect,

Attenuation

The

Attenuation

function lets you select an attenuation that matches the device connected to the instrument. When the attenuation is set correctly, the instrument maintains the current scale factors, if possible. All marker values and voltage or wattage measurements will reflect the actual signal at the input to the external device.

3-6

Setup Channel Menu

Alternate scale. . .

The attenuation range is from 0.0001:1 to 1,000,000:1. When you connect a compatible active probe to the probe power connector, adjacent to the corresponding channel input, the instrument automatically sets the attenuation. For all other devices, set the probe attenuation with the knob, arrow keys, or keypad.

Refer to "Calibrating Voltage Probes" for information on calibrating to the tip of the probe.

The Attenuation function is not available when ohm, % reflect, or gain units are selected.

Key Path Channel

Units

The Units function lets you select the unit of measure appended to the channel scale, offset, trigger level, and vertical measurement values. For the plug-in module, the units are volts, watts, amperes, ohms, % reflect, gain, or unknown. Use volt for voltage probes, ampere for current probes, watt for optical-toelectrical (O/E) converters, and unknown when there is no unit of measure or when the unit of measure is not one of the available choices. The gain selection is only available when the channel has been chosen as a TDT destination.

The two additional choices, ohms and % reflect are selectable once a TDR/TDT normalization and reference plane have been established (see the 54753A Setup Menu or 54754A Setup Menu chapter under for more information). Use Ohms when TDR/TDT vertical scale units of ohms/ div are required for making measurements. Use % reflect when TDR/TDT percentage of reflection units are required.

Key Path Channel

Ext gain and Ext offset

When you select ampere, watt, or unknown on an electrical channel, two additional functions become available: External Gain and External Offset. These two additional functions allow you to compensate for the actual characteristics of the probe rather than its ideal characteristics. For example, you might have an amplified lightwave converter with ideal characteristics of 300 V/W with 0 V offset. But, its actual characteristics are 324 V/W with 1 mV of output offset. Therefore, set the External Gain to 324 V/W and the External Offset to 1 mV.

Alternate scale . . . Attenuation

Alternate scale . . . Units

Establish normalization & ref plane

3-7

Setup Channel Menu

Calibrate . . .

Key Path Channel

Channel Channel

Calibrate . . .

The calibrate menu allows you to null out any skew between probes or cables and to check the present calibration status of the instrument.

Key Path Channel

Skew

The Skew function changes the horizontal position of a waveform on the display. The Skew function has a range of approximately 100 µs. You can use skew to compensate for differences in cable or probe lengths. It also allows you to place the triggered edge at the center of the display when you are using a power splitter connected between the channel and trigger inputs. Another use for skew is when you are comparing two waveforms that have a timing difference between them. If you are more interested in comparing the shapes of two waveforms rather than the actual timing difference between them, you can use Skew to overlay one waveform on top of the other waveform.

To adjust the skew on two channels

External scale . . . Units Volt Ext gain External scale . . . Units Watt Ext gain

or

Ext Offset

or

External scale . . . Units Unknown Ext gain

Calibrate

. . .

Ext Offset

or

Ext Offset

1. Turn both channels on and overlay the signals vertically.

2. Expand the time base, so the rising edges are about a 45 degree angle.

3. Adjust the skew on one of channels, so that the rising edges overlap at the 50 percent points.

Key Path Channel

3-8

Calibrate . . . Skew

Setup Channel Menu

Calibrate . . .

TDR Skew

The TDR Skew function changes the position of the TDR step. The TDR Skew function has a range of ≅ ±400 pS. The units of the function are shown in % of the maximum range, or ±100%. The Skew function and the TDR Skew function differ in that Skew moves the acquired waveform with respect to the trigger, while the TDR Skew function moves the TDR step with respect to the trigger. TDR Skew can be used to align the TDR steps of the two TDR channels for more accurate differential TDR measurements when cable or probe lengths are different.

To deskew the two TDR channels

1. Turn on both channels and overlay the signals vertically with no cables attached.

2. Expand the time base so the rising edges are about a 45 degree angle.

3. Adjust the TDR skew on one of the channels, so that the rising edges overlap at the 50 percent points.

4. Attach the cables. If the cables differ in length, then the waveforms will not overlay each other.

5. Using the ∆Time auto measurement or manual markers, measure the ∆time (the skew) between the TDR channels.

6. Adjust the channel Skew for the channel whose waveform is to the right of the other channels waveform until the skew is ½ of the measured ∆time.

7. Adjust the TDR Skew for the right most waveform until the remaining skew is ≅ 0.

Key Path Channel

Calibrate . . . TDR Skew

3-9

Setup Channel Menu

Calibrate . . .

Cal status

The Cal Status function displays a screen similar to Figure 3-8.

Key Path Channel

Figure 3-8

A typical Cal Status display.

Current Date This is the current date and time. You can compare this to the last plug-in module calibration time. That way you will know how long it has been since the last plug-in module calibration was performed.

Calibrate Cal Status

Current Frame ∆Temp This is the temperature change on the inside of the instrument since the last mainframe calibration was performed. A positive number indicates how many degrees warmer the mainframe is currently as compared to the temperature of the mainframe at the last mainframe calibration.

3-10

Setup Channel Menu

Calibrate . . .

Channel 1 Calibration Status The instrument displays Calibrated when the plug-in module has been calibrated in the current mainframe slot otherwise the instrument displays Uncalibrated. Once a plug-in is calibrated, the temperature difference (∆Temp) between when the plug-in was calibrate and the current temperature is displayed. The plug-in module will met dc accuracy specifications as long as the ∆Temp is within the range of -5 °C to +5 °C. Also displayed, is a list of the plug-in module’s model number, serial number, date of last calibration, and time of last calibration.

A calibration can be invalidated if:

• The mainframe has cycled power.

• The plug-in has been repaired, reprogrammed, or removed from the mainframe.

• The instrument’s operating temperature has changed and remains more than 5°C from the temperature at which the Plug-in calibration was performed.

Calibrate probe

Connect a voltage probe to the plug-in and then press:

Calibrate probe Continue

The instrument calibrates to the tip of the probe by setting the probe attenuation to the actual attenuation ratio of the probe. The instrument also automatically compensates for any offset that the probe may introduce.

Key Path Channel

Calibrate Calibrate probe Continue

3-11

Setup Channel Menu

Calibration Overview

This section describes the calibration of the mainframe and TDR plug-in modules vertical channel accuracy. It is intended to give you, or the calibration laboratory personnel, an understanding of the various calibration procedures available, and how they were intended to be used.

Proper calibration is critical to measurement accuracy and repeatability. The HP 54750A/83480A and their associated modules and accessories require that both factory and user calibrations be implemented at the recommended intervals in order to perform measurements at their published specifications.

The following two sections describe factory and user calibrations. The first section describes factory calibrations. A factory calibration consists of verifying instrument performance to all specifications. If an instrument fails to meet specifications, adjustment or repair may be necessary. For most users, this will mean shipping the instrument back to an authorized service center. Some users may purchase the required instrumentation and perform the factory timebase calibrations themselves using the optional HP 83480A, 54750A Service Guide or the TDR performance verification using the HP 54753A/54A Service Guide.

The second section addresses calibrations that are routinely performed by the end user. In addition, there will be summary tables at the end of each of these sections summarizing the main areas addressed. Both factory and user calibrations must be performed regularly in order to ensure proper measurement accuracy and repeatability.

CAUTION

NOTE

The input circuits can be damaged by electrostatic discharge (ESD). Avoid applying static discharges to the front-panel input connectors. Before connecting a coaxial cable to the connectors, momentarily short the center and outer connectors of the cable together. Avoid touching the front panel input connectors without first touching the frame of the instrument. Be sure that the instrument is properly earth-grounded to prevent buildup of static charge. It is strongly recommended that an antistatic mat and wristband be used when connecting to TDR inputs.

For information about TDR/TDT normalized measurements, refer to "Establishing the Reference Plane and Normalizing" located in Chapter 7. Establishing normalization and a reference plane improves TDR measurement accuracy.

3-12

Setup Channel Menu

Factory Mainframe Calibration

Calibration interval

HP recommends that the factory calibration be performed on a periodic basis. HP designs instruments to meet specifications over the recommended calibration interval provided that the instrument is operated within the specified operating environment. To maintain specifications, periodic recalibrations are necessary. We recommend that the plug-in module be calibrated at an HP service facility every 12 months. Users are encouraged to adjust the calibration cycle based on their particular operating environment or measurement accuracy needs.

Required warm-up time

The instrument requires a 1 hour warm-up period before any of the calibrations mentioned in this chapter are performed. It is not enough for the instrument to be in the standby setting. It must be turned on and running for the entire hour.

Remote operation

Remote programming commands for calibrations are included in the HP 83480A/HP 54750A Programming’s Guide. Performing calibrations remotely is slightly different than the operation of front-panel calibrations.

Factory Mainframe Calibration

Mainframe calibration improves timebase accuracy. All timebase measurements such as rise time, fall time, and so forth are affected by the timebase accuracy. The calibration factors are stored in the nonvolatile RAM of the instrument. There is a switch on the back panel of the instrument that allows the mainframe calibration to be protected or unprotected. Next to the switch there is a drawing that shows each switch’s function and protected position. Refer to the optional HP 83480A, 54750A Service Guide for more details about the mainframe calibration, and the position of the rear-panel memory protect switches.

3-13

Setup Channel Menu

Factory Mainframe Calibration

Factory Calibration Summary

Calibration What is calibrated

Mainframe Calibration Accuracy and continuity

of the timescale

Measurements Affected

All time base measurements.

Recommended Interval

Annually at HP service center or if operating temp has changed and remains 5°C or more from calibration temperature. See service manual.

Softkey Path

Utility

Calibrate Calibrate frame

CAUTION To prevent access to the mainframe calibration switch, place a sticker over the

access hole to this switch.

CAUTION Do not attempt a Mainframe calibration without consulting the HP 83480A,

54750A Service Guide.

A mainframe calibration should be performed on a periodic basis (at least annually), or when the ambient operating has changed by and remains 5°C different than the operating temperature at which the last mainframe calibration was performed. To see how much the operating temperature has changed since the last mainframe calibration and the date of the last mainframe calibration, check the Calibration status by pressing the following key sequence:

Utility,

Calibrate

, and then

Cal status

on.

The temperature change is displayed at the top of the display as shown in the following figure.

3-14

Setup Channel Menu

Factory Mainframe Calibration

Current Frame ∆Temp condition

If the Current Frame ∆Temp listing is greater than ±5°C, then the mainframe should either be calibrated at the current operating temperature or be placed in an ambient air temperature that is within 5°C of the temperature of the current calibration.

3-15

Setup Channel Menu

User Calibrations

The following calibrations can be performed by the user:

• Plug-in Module Vertical Calibration

• Probe Calibration

• Channel Skew

• External Scale

CAUTION

The input circuits can be damaged by electrostatic discharge (ESD). Avoid applying static discharges to the front panel input connectors. Before connecting a coaxial cable to the connectors, momentarily short the center and outer connectors of the cable together. Avoid touching the front panel input connectors without first touching the frame of the instrument. Be sure the instrument is properly earth-grounded to prevent buildup of static charge. An antistatic mat and wristband are strongly recommended, particularly when working with TDR modules.

Channel User Calibration Summary

Calibration What is calibrated

Plug-in Vertical Calibration

Vertical offset and vertical scale accuracy.

Measurements Affected

Any vertical measurement

Recommended Interval

Perform after any power cycle or once every 10 hours during continuous use or if operating temperature changes by more than

2°C.

Key Path

Utility

Calibrate Calibrate Plug-in

3-16

Miscellaneous User Calibration Summary

Setup Channel Menu

User Calibrations

Calibration What is calibrated

Probe calibration Probe Attenuation Any measurement

Channel Skew Calibrates out the small

differences in delay between channels. Useful for looking at timing differences between channels

External Scale Compensates for gain o r

loss associated with external devices (calibrates vertical scale to external device

Measurements Affected

taken with the probe

Multiple channel measurements, such as Differential TDR

Any measurement taken through an external device (component or transducer

Plug-in Module Vertical Calibration

The plug-in module vertical calibration allows the instrument to establish the calibration factors for a specific plug-in when the plug-in is installed in the mainframe. The plug-in calibration factors are valid only for the specific mainframe slot in which it was calibrated. The plug-in vertical calibration establishes vertical accuracy.

A plug-in vertical calibration should be done if:

• the mainframe has cycled power,

• the plug-in has been repaired, reprogrammed, or removed from the mainframe

• the instrument’s operating temperature has changed and remains more than 5°C from the temperature at which the Plug-in calibration was performed.

To obtain the best measurement results, it is recommended that a user vertical calibration be performed after every 10 hours of continuous use or if the temperature has changed by greater than 2°C from the previous vertical calibration.

Recommended Interval

Whenever a probe is connected

Before multiple channel measurements when measuring timing differences between channels.

Whenever using external devices (component or transducer)

Key Path

Channel Setup

Calibrate Calibrate probe

Channel Setup

Calibrate Skew

Channel Setup

External Scale

3-17

Setup Channel Menu

User Calibrations

To view the temperature change

This procedure displays the temperature change that the instrument has

undergone since the last Plug-in Vertical Calibration. 1 Press the front-panel channel SETUP key. 2 Press

1 Remove any front-panel connections from channels. 2 Press Utility, 3 Select the plug-in module to be calibrated, press 4 Press 5 Follow the on-screen instructions.

Probe Calibration

Calibrate

The current plug-in ∆Temp value is listed for each installed module.

To perform a plug-in module vertical calibration

Start cal

No additional equipment is required to perform a plug-in vertical calibration.

Reference signals are both generated and routed internally.

For active probes such as the HP 54701A, which the instrument can identify

through the probe power connector, the instrument automatically adjusts the

channel vertical scale factors to the probe’s nominal attenuation, even if a probe

calibration is not performed.

For passive probes or non-identified probes, the instrument adjusts the vertical

scale factors only if a probe calibration is performed. Probe calibration allows

the instrument to establish the gain and offset of specific probes that are

connected to a channel of the instrument, and then apply those factors to the

calibration of that channel.

The analyzer calibrates to the tip of the probe by setting the probe attenuation

to the actual attenuation ratio of the probe. The CAL signal is internally routed

to the probe tip for HP active probes.

The mainframe’s CAL signal is a voltage source, therefore you can let the

instrument compensate for the actual characteristics of your probe by letting

the instrument calibrate to the tip of the probe. The instrument automatically

calibrates to the tip of the probe, sets the probe attenuation, and compensates

for any probe offset.

If you do not perform a probe calibration but want to use a passive probe, enter

the attenuation factor using the following steps:

and then

Calibrate. . .

to start the calibration.

Cal status on

, and then

Calibrate plug-in. . .

.

1 and 2

or

3 and 4

.

3-18

1 Press the plug-in module’s front-panel channel SETUP key.

Setup Channel Menu

User Calibrations

2 Press 3 You can use the probe calibration to calibrate any network, including probes or

1 Press the plug-in module’s front-panel-channel SETUP key. 2 Press

1 Connect the voltage probe to the plug-in. 2 Attach the probe tip to the CAL hook that is located near the floppy disk drive. 3 Press the plug-in module’s front-panel channel SETUP key. 4 Press

Alternate scale

cable assemblies. The instrument calibrates the voltage at the tip of the probe or the cable input.

To calibrate an HP identifiable probe

Calibrate

To calibrate a non-identifiable probe

Calibrate

If the probe being calibrated has an attenuation factor that allows the instrument to adjust the gain (in hardware) to produce even steps in the vertical scale factors, the instrument will do so. Typically, probes have standard attenuation factors such as divide by 10, divide by 20, or divide by 100.

To calibrate other devices

The information in this section applies to both optical and electrical measurements. Since the mainframe’s CAL signal is a voltage source, it cannot be used to calibrate to the probe tip when the units are set to Ampere, Watt, or Unknown. Instead, set the external gain and external offset to compensate for the actual characteristics of the probe or device. If you do not know the actual characteristics, you can refer to the typical specifications that came with the probe or device.

and then

, and then

Attenuation

Calibrate Probe

Calibrate probe

.

1 Press the plug-in module’s front-panel channel SETUP key. 2 Press 3 Press 4 Press 5 Press

Alternate scale

Atten units Ratio, Attenuation 1:1

Ext gain

Ext offset

.

, and then

, and enter the actual gain characteristics of the probe or device.

, and enter the offset introduced by the probe or device.

Units Ampere

(Watt or Unknown).

3-19

External Scale

Setup Channel Menu

User Calibrations

The channels have a setting which allows the user to enter in an offset value to

compensate for gains or losses not associated with the device under test. This

feature is useful for adjusting out the effects of devices such as test fixtures and

attenuators so that the reading on the display gives the measurement value

associated with only the actual device under test.

To adjust the external scale

1 Press the plug-in module’s front-panel channel SETUP key. 2 Press 3 Press

Alternate Scale

Attenuation

Channel Skew Calibration

The skew calibration changes the horizontal position of a waveform on the

display. The skew calibration has a range of approximately 100 µs. You can use

skew to compensate for the differences in cable or probe lengths. It also allows

you to place the trigger edge at the center of the display when you are using a

power splitter connected between the channel and trigger inputs. Another use

for skew is when you are comparing two waveforms that have a timing

difference. If you are interested in comparing the shapes of two waveforms

rather than the actual timing difference, you can use skew to overlay one

waveform on top of the other waveform.

To skew two channels

1 Turn both channels on and overlay the signals vertically. 2 Expand the time base so that the rising edges are at about a 45° angle. 3 Press the plug-in module’s front-panel channel SETUP key. 4 Press 5 Adjust the skew on one of the channels so that the rising edges overlap at the 50%

Calibrate

points.

, and set the

, and enter the appropriate values.

and then

Skew

Atten units

.

to "decibel".

3-20

4

HP 54753A TDR/TDT Setup Menu

What you’ll find in this chapter

This chapter describes the TDR/TDT Setup menu. A key tree and description of the available functions is included.

CAUTION

The input circuits can be damaged by electrostatic discharge (ESD).

Therefore, avoid applying static discharges to the front-panel input connectors.

Before connecting any coaxial cable to the connectors, momentarily short the

center and outer conductors of the cable together. Avoid touching the front-

panel input connectors without first touching the frame of the instrument. Be

sure the instrument is properly earth-grounded to prevent buildup of static

charge.

The top right key of the plug-in module is the TDR/TDT Setup key. This key gives

you access to the TDR/TDT Setup menu. The TDR/TDT Setup menu is displayed

on the right side of the screen when the TDR/TDT Setup key is pressed. There

are several types of softkeys available.

4-2

Figure 4-1

HP 54753A TDR/TDT Setup Menu

TDR/TDT Setup Stimulus

TDR/TDT help . . .

TDT 1 dest

Normalize response . . .

Off On External Cancel Enter

Single ended TDR/TDT Differential common mode TDR/TDT Done

channel 2 none Cancel Enter

Risetime TDR/TDT

TDR normalize

TDR TDT

off on

TDR/TDT Setup Menus

TDR rate automatic . . . (250 kHz)

Preset TDR/TDT

Establish normalization & ref plane

Done

automatic manual TDR rate

Done

4-3

HP 54753A TDR/TDT Setup Menu

Displaying the TDR/TDT Setup Menu

To display the TDR/TDT Setup menu, press the TDR/TDT Setup key on the TDR

plug-in module.

Stimulus

Pressing the

turn off the TDR step. The HP 54753A is a single-ended TDR plug-in and has

one TDR stimulus channel. The following table contains a list of the available

stimulus menu choices and their descriptions.

Table 4-1

Stimulus Menu Choices

Stimulus Description

off Turns the TDR step off and disables the TDR measurement system.

on Turns the TDR step on and enables the TDR measurement system.

external This setup provides control for and requires an external step

Key Path TDR/TDT Setup

Stimulus

TDT 1 dest

The

TDT 1 dest

Pressing the

channel used as the destination channel for TDT measurements. The choices

available for this pull-down menu depend on the other TDR or electrical plug-

in, if any, in the mainframe.

TDT 1 dest

softkey produces a pull-down menu used to turn on or

generator before measurements can be made.

Stimulus

softkey only appears when the

Stimulus

softkey produces a pull-down menu used to select the

is set to on or external.

Any electrical channel is a valid TDT destination channel. If external stimulus

is selected, the TDT destination may not be set to the currently defined TDR

destination channel.

4-4

HP 54753A TDR/TDT Setup Menu

TDR 1 dest

If no other valid TDT destination channels are available, then "none" is the only choice. If a TDT destination other than none is selected, then the

TDR/TDT

control will turn on and preset the TDT destination channel.

Preset

Key Path TDR/TDT Setup

TDR 1 dest

The

TDR 1 dest

Pressing the channel used as the destination channel for TDR measurements. Any electrical channel is a valid TDR destination channel. The TDR destination may not be set to the currently defined TDT destination.

Key Path TDR/TDT Setup

Normalize response . . .

The

Normalize response

normalized step, to select TDR and TDT normalization, to turn on or off the display of the normalized TDR or TDT trace, to change the scaling of the normalized trace, and to establish the normalization filter values and reference plane.

Risetime

The Risetime function allows you to change the normalized step’s risetime from a minimum of

TDT 1 dest

softkey only appears when the stimulus is set to external.

TDR 1 dest

softkey produces a pull-down menu used to select the

TDR 1 dest

function allows you to change the risetime of the

10 ps

or

time per division (s/div) 10 divisions×

min 8 points

whichever is greater, to a maximum of

max 5 time per division (s/div)×=

---------------------------------------------------------------------------------------------

×=

record length

4-5

HP 54753A TDR/TDT Setup Menu

Normalize response . . .

While the TDR step’s risetime applied to the system under test is fixed, the

measured response has a set of mathematical operations applied to it. These

mathematical operations effectively change the displayed response to the

system just as if a different TDR step risetime had actually been applied. This

allows you to select a risetime for TDR/TDT measurements that is close to the

actual risetime used in your system. This risetime value applies to both TDR

and TDT normalized channels. For more information on normalization, see the

chapter titled Improving Time Domain Network Measurements.

Key Path TDR/TDT Setup

TDR/TDT

The

Both TDR and TDT channels can be normalized. This control selects which

normalized trace is referred to for the following controls. Before TDT

normalization can be done, you must select a TDT destination (

Key Path TDR/TDT Setup

TDR or TDT normalize

The

TDR normalize

previous control; otherwise, the TDT normalize function is available. In either

case, this function turns on or off the display of the normalized trace. The TDR

and TDT normalization functions can be on at the same time.

Key Path TDR/TDT Setup

Normalize scaling . . .

Normalize scaling

The

the normalized response is required that is independent from that of the source

channel. This function only appears when TDR or TDT normalize is set to on.

Key Path TDR/TDT Setup

function is used to select between TDR and TDT for normalization.

Normalize response . . . Risetime

TDT 1 dest

Normalize response . . . TDR/TDT

function is available if the TDR mode is selected by using the

Normalize response . . . TDR normalize

function is used when vertical and horizontal scaling of

Normalize response . . . Normalize scaling . . .

).

Vertical There are two choices for vertical mode:

The track source mode sets the control of the vertical scaling for the

normalized trace to that of the source channel. When manual mode is

selected, the

independently change the vertical scale and offset of the normalized trace.

Key Path TDR/TDT Setup

4-6

track source

Y Scale

and

Y Offset

menus appear allowing you to

Normalize response . . .Normalize scaling . . . Vertical

and

manual

.

HP 54753A TDR/TDT Setup Menu

Normalize response . . .

Horizontal There are two choices for horizontal mode:

manual

. The track source mode sets the control of the horizontal scaling for the normalized trace to that of the source channel. When manual mode is selected, the independently change the horizontal scale and position for the normalized trace.

Key Path TDR/TDT Setup

Establish normalization & ref plane

The

Establish normalization & ref plane

to normalize a channel and to set the reference plane for TDR and TDT measurements. This function must be performed separately for TDR and TDT modes. The normalization and reference plane must be re-established when power is lost or when the instrument is turned off. However, the values used for normalization and reference plane calculations can be stored to and reloaded from disk. (See the User’s Guide for more information.)

The normalization filter values and reference plane become invalidated when the timebase scale, record length or channel bandwidth is changed. Also, the normalization process will not be able to remove small synchronous noise in the channels baseline if the timebase position is changed. For most measurements this error is very small.

track source

Y Scale

and

Y Position

menus appear allowing you to

Normalize response . . .Normalize scaling . . . Horizontal

function establishes the filter values used

Disk Menu

chapter in the HP 83480A, HP 54750

and

The reference plane must be established before ohm, % reflect or gain units are selectable for the channel. Also, the available in the Marker menu.

The function steps you through the normalization and reference plane procedure for the selected measurement type. The procedure steps are displayed at the top of the screen. The items required for calibration are shown in Table 4-2.

Reference

ref plane function is not

4-7

Table 4-2

HP 54753A TDR/TDT Setup Menu

TDR rate automatic . . . (250 kHz)

Establish normalization & ref plane Hardware Requirements

Measurement Requirements

TDR 50 ohm 3.5 mm SMA terminator

3.5 mm SMA short

TDT 1 or 2 each 3.5 mm SMA cables

3.5 mm barrel connector

Key Path TDR/TDT Setup

TDR rate automatic . . . (250 kHz)

The

TDR rate automatic . . . (250 kHz)

automatically select the repetition rate of the TDR step. The range of values for manual mode selection are from 50 Hz to 250 kHz repetition rate using a 1-2-5 sequence. When this function is set to automatic, the TDR step repetition rate varies automatically as the Time base steps off screen. As the TDR rate decreases, TDR measurements can be made on longer transmission lines.

Key Path TDR/TDT Setup

Preset TDR/TDT

The

Preset TDR/TDT

measurements by automatically setting several menu fields. The TDR preset feature appears in the TDR/TDT Setup menu once a stimulus has been selected. The menus that are affect by this feature are shown in Table 4-3.

Normalize response . . . Establish normalization & ref plane . . .

function allows you to manually or

Scale

is changed to keep multiple

TDR rate

automatic

manual

function prepares the oscilloscope for making TDR/TDT

4-8

Table 4-3

HP 54753A TDR/TDT Setup Menu

Preset TDR/TDT

Preset TDR/TDT Configuration

Menu Menu Item Set To

Acquisition Averaging on

Best Flatness

Time Base Scale 500.0 ps/div

Position Set to a value which places the

incident edge on screen.

Channel 1 Setup Display on

Scale 100 mV/div Offset 200.0 mV (for Stimulus on)

0.0 mV (form Stimulus external)

Bandwidth 12.4 GHz (for Stimulus on)

18.0 GHz (for Stimulus external) Attenuation units ratio Attenuation 1.000 : 1

Key Path TDR/TDT Setup

Preset TDR/TDT

4-9

4-10

5

HP 54754A TDR/TDT Setup Menu

What you’ll find in this chapter

This chapter describes the HP 54754A TDR/TDT Setup menu. A key tree and description of the available functions is included.

CAUTION

The input circuits can be damaged by electrostatic discharge (ESD). Therefore, avoid applying static discharges to the front-panel input connectors. Before connecting any coaxial cable to the connectors, momentarily short the center and outer conductors of the cable together. Avoid touching the frontpanel input connectors without first touching the frame of the instrument. Be sure the instrument is properly earth-grounded to prevent buildup of static charge.

The top right key of the plug-in module is the TDR/TDT Setup key. This key gives you access to the TDR/TDT Setup menu. The TDR/TDT Setup menu is displayed on the right side of the screen when the TDR/TDT Setup key is pressed. There are several types of softkeys available.

5-2

Figure 5-1

HP 54754A TDR/TDT Setup Menu

TDR/TDT Setup Stimulus

TDR/TDT help . . .

TDT 1 dest

Off

1 only

2 only

1 and 2

differential

common mode external

Cancel

Enter

Single ended TDR/TDT

Differential common mode TDR/TDT

Done

channel 2

none

Cancel

Enter

TDT 2 dest

TDR 1 dest

channel 1

none

Cancel

Enter

channel 2

none

Cancel

Enter

5-3

HP 54754A TDR/TDT Setup Menu

Normalize response . . .

Normalize 1 response . . .

Normalize 2 response . . .

Risetime

TDR/TDT

TDR normalize

Establish normalization & ref plane

Done

Risetime

TDR/TDT

TDR normalize

Establish normalization & ref plane

Done

Risetime

TDR/TDT

TDR

TDT

off

on

TDR

TDT

off

on

TDR

TDT

5-4

TDR normalize

Establish normalization & ref plane

Done

off

on

TDR response 1 . . . Response off

HP 54754A TDR/TDT Setup Menu

differential common mode Cancel Enter

TDR response 2 . . . Response off

Establish ref plane

Response scaling . . . Vertical

Horizontal

Done

differential common mode Cancel Enter

Response scaling . . . Vertical

Horizontal

Done

track source manual

Y Scale Y Offset

X Scale X Position

Y Scale Y Offset

X Scale X Position

5-5

HP 54754A TDR/TDT Setup Menu

TDR rate automatic . . . (250 kHz)

Preset TDR/TDT

TDR/TDT Setup Menu.

automatic manual Done

TDR rate

5-6

HP 54754A TDR/TDT Setup Menu

Displaying the TDR/TDT Setup Menu

To display the TDR/TDT Setup menu, press the TDR/TDT Setup key on the TDR plug-in module.

Stimulus

Table 5-1

Pressing the

Stimulus

softkey produces a pull-down menu used to turn on or turn off the TDR step. The differential TDR plug-in has two TDR channels. The following table contains a list of the available stimulus menu choices and their descriptions.

Stimulus Menu Choices

Stimulus Description

off Turns the TDR steps off for both TDR channels and the TDR

1 only Turns the TDR step on for channel 1 only and enables the TDR

2 only Turns the TDR step on for channel 2 only and enables the TDR

1 and 2 Turns the TDR steps on for both channels. This mode is used to

differential Turns the differential TDR steps on for both channels. The step for

common mode Turns the common mode TDR steps on for both channels. Both

external This setup provides control for and requires an external step

measurement system off.

measurement system.

make two independent single-ended TDR measurements.

channel 1 is a positive going step while the step for channel 2 is effectively a negative going step. This mode is used to make differential TDR measurements

1 and 2

steps are positive going steps. Unlike the is used to make common mode measurements.

generator before measurements can be made.

mode, this mode

Key Path TDR/TDT Setup

Stimulus

5-7

HP 54754A TDR/TDT Setup Menu

TDT 1 dest

1 Only Stimulus Menus

This section describes the menus that are available when the stimulus is set to

1 only

TDT 1 dest

.

Pressing the channel used as the destination channel for TDT measurements. The choices available for this pull-down menu depend on the other TDR or electrical plugin, if any, in the mainframe.

Any electrical channel is potentially a valid TDT destination channel. The TDT destination may not be assigned to a channel already assigned as a TDT destination.

If no other valid TDT destination channels are available, then "none" is the only choice. If a TDT destination other than none is selected, then the

TDR/TDT

Key Path TDR/TDT Setup

TDT 1 dest

control will turn on and preset the TDT destination channel.

Normalize response . . .

The

Normalize response

differential and common mode. The change the risetime of the normalized step, to select TDR and TDT normalization, to turn on or off the display of the normalized TDR or TDT trace, to change the scaling of the normalized trace, and to establish the normalization filter values and reference plane.

Risetime

The Risetime function allows you to change the normalized step’s risetime from a minimum of

10 ps

or

softkey produces a pull-down menu used to select the

TDT 1 dest

function is available for all the

Normalize response

Preset

Stimulus

function allows you to

types except

min 8 points

5-8

time per division (s/div) 10 divisions×

---------------------------------------------------------------------------------------------

×=

record length

HP 54754A TDR/TDT Setup Menu

Normalize response . . .

which ever is greater, to a maximum of

max 5 time per division (s/div)×=

While the TDR step’s risetime applied to the system under test is fixed, the measured response has a set of mathematical operations applied to it. These mathematical operations effectively change the displayed response to the system just as if a different TDR step risetime had actually been applied. This allows you to select a risetime for TDR/TDT measurements that is close to the actual risetime used in your system. This risetime value applies to both TDR and TDT normalized channels. For more information on normalization, see the chapter titled Improving Time Domain Network Measurements.

Key Path TDR/TDT Setup

TDR/TDT

The

TDR/TDT

Both TDR and TDT channels can be normalized. This control selects which normalized trace is referred to for the following controls. Before TDT normalization can be done, you must select a TDT destination (

Key Path TDR/TDT Setup

TDR or TDT normalize

The TDR normalize function is available if the TDR mode is selected by using the previous menu otherwise the TDT normalize function is available. In either case, this function turns on or off the display of the normalized trace. The TDR and TDT normalization functions can be on at the same time.

Key Path TDR/TDT Setup

Normalize scaling . . .

Normalize scaling

The the normalized response is required that is independent from that of the source channel. This function only appears when TDR or TDT normalize is set to on.

Key Path TDR/TDT Setup

function is used to select between TDR and TDT for normalization.

Normalize response . . . Risetime

Normalize response . . . TDR/TDT

Normalize response . . . TDR normalize

function is used when vertical and horizontal scaling of

Normalize response . . . Normalize scaling . . .

TDT 1 dest

).

5-9

HP 54754A TDR/TDT Setup Menu

Normalize response . . .

Vertical There are two choices for vertical mode: The track source mode sets the control of the vertical scaling for the normalized trace to that of the source channel. When manual mode is selected, the independently change the vertical scale and offset of the normalized trace.

Key Path TDR/TDT Setup

Horizontal There are two choices for horizontal mode:

. The track source mode sets the control of the horizontal scaling

manual

for the normalized trace to that of the source channel. When manual mode is selected, the independently change the horizontal scale and position for the normalized trace.

Key Path TDR/TDT Setup

Establish normalization & ref plane

The

Establish normalization & ref plane

to normalize a channel and to set the reference plane for TDR and TDT measurements. This function must be performed separately for TDR and TDT modes. The normalization and reference plane must be re-established when power is lost or when the instrument is turned off. However, the values used for normalization and reference plane calculations can be stored to and reloaded from disk. (See the User’s Guide for more information.)

Y Scale

and

Y Offset

track source

menus appear allowing you to

and

Normalize response . . .Normalize scaling . . . Vertical

track source

Y Scale

and

Y Position

menus appear allowing you to

Normalize response . . .Normalize scaling . . . Horizontal

function establishes the filter values used

Disk Menu

chapter in the HP 83480A, HP 54750

manual

.

and

The normalization filter values and reference plane are invalidated when the timebase scale, record length or channel bandwidth is changed. Also, the normalization process will not be able to remove small synchronous noise in the channels baseline if the timebase position is changed. For most measurements this error is very small.

The reference plane must be established before ohm, % reflect or gain units are selectable for the channel. Also, the available in the Marker menu.

The function steps you through the normalization and reference plane procedure for the selected measurement type. The procedure steps are displayed at the top of the screen. The items required for calibration are shown in Table 5-2.

5-10

Reference

ref plane function is not

Table 5-2

HP 54754A TDR/TDT Setup Menu

TDR rate automatic . . . (250 kHz)

Establish normalization & ref plane Hardware Requirements

Measurement Requirements

TDR 50 ohm 3.5 mm SMA terminator

3.5 mm SMA short

TDT 1 or 2 each 3.5 mm SMA cables

3.5 mm barrel connector

Key Path TDR/TDT Setup

TDR rate automatic . . . (250 kHz)

The

TDR rate automatic . . . (250 kHz)

automatically select the repetition rate of the TDR step. The range of values for manual mode selection are from 50 Hz to 250 kHz repetition rate using a 1-2-5 sequence. When this function is set to automatic, the TDR step repetition rate varies automatically as the Time base steps off screen. As the TDR rate decreases, TDR measurements can be made on longer transmission lines.

Key Path TDR/TDT Setup

Normalize response . . . Establish normalization & ref plane . . .

function allows you to manually or

Scale

is changed to keep multiple

TDR rate

automatic

manual

5-11

Table 5-3

HP 54754A TDR/TDT Setup Menu

Preset TDR/TDT

The Preset TDR/TDT function prepares the oscilloscope for making TDR/TDT measurements by automatically setting several menu fields. The TDR preset feature appears in the TDR/TDT Setup menu once a stimulus has been selected. The menus that are affect by this feature are shown in Table 5-3.

Preset TDR/TDT Configuration

Menu Menu Item Set To

Acquisition Averaging on

Best Flatness

Time Base Scale 500.0 ps/div

Position Set to a value which places the

incident edge on screen.

Channel 1 Setup Display on

Scale 100 mV/div Offset 200.0 mV Bandwidth 12.4 GHz Attenuation units ratio Attenuation 1.000 : 1

Key Path TDR/TDT Setup

5-12

Preset TDR/TDT

2 Only Stimulus Menus

This section describes the menus that are available when the stimulus is set to

2 only

TDT 2 dest

.

Pressing the channel used as the destination channel for TDT measurements. The choices available for this pull-down menu depend on the other TDR or electrical plugin, if any, in the mainframe.

Any electrical channel is potentially a valid TDT destination channel. The TDT destination may not be assigned to a channel already assigned as a TDT destination.

If no other valid TDT destination channels are available then "none" is the only choice. If a TDT destination other than none is selected then the preset TDR/ TDT control will turn on and preset the TDT destination channel.

Key Path TDR/TDT Setup

Normalize response . . .

The

Normalize response

differential and common mode. The change the risetime of the normalized step, to select TDR and TDT normalization, to turn on or off the display of the normalized TDR or TDT trace, to change the scaling of the normalized trace, and to establish the normalization filter values and reference plane.

Risetime

The Risetime function allows you to change the normalized step’s risetime from a minimum of

10 ps

or

TDT 2 dest

softkey produces a pull-down menu used to select the

function is available for all the

Normalize response

Stimulus

function allows you to

types except

time per division (s/div) 10 divisions×

min 8 points

which ever is greater, to a maximum of

max 5 time per division (s/div)×=

While the TDR step’s risetime applied to the system under test is fixed, the measured response has a set of mathematical operations applied to it. These mathematical operations effectively change the displayed response to the

---------------------------------------------------------------------------------------------

×=

record length

5-13

HP 54754A TDR/TDT Setup Menu

Normalize response . . .

system just as if a different TDR step risetime had actually been applied. This allows you to select a risetime for TDR/TDT measurements that is close to the actual risetime used in your system. This risetime value applies to both TDR and TDT normalized channels. For more information on normalization, see the chapter titled Improving Time Domain Network Measurements.

Key Path TDR/TDT Setup

TDR/TDT

The

TDR/TDT

Both TDR and TDT channels can be normalized. This control selects which normalized trace is referred to for the following controls. Before TDT normalization can be done, you must select a TDT destination (

Key Path TDR/TDT Setup

TDR or TDT normalize

The TDR normalize function is available if the TDR mode is selected by using the previous menu otherwise the TDT normalize function is available. In either case, this function turns on or off the display of the normalized trace. The TDR and TDT normalization functions can be on at the same time.

Key Path TDR/TDT Setup

Normalize scaling . . .

Normalize scaling

The the normalized response is required that is independent from that of the source channel. This function only appears when TDR or TDT normalize is set to on.

Key Path TDR/TDT Setup

Vertical There are two choices for vertical mode: The track source mode sets the control of the vertical scaling for the normalized trace to that of the source channel. When manual mode is selected, the change the vertical scale and offset of the normalized trace.

function is used to select between TDR and TDT for normalization.

Normalize response . . . Risetime

Normalize response . . . TDR/TDT

Normalize response . . . TDR normalize

function is used when vertical and horizontal scaling of

Normalize response . . . Normalize scaling . . .

track source

Scale

and

Offset

menus appear allowing you to independently

TDT 2 dest

and

manual

).

.

Key Path TDR/TDT Setup

Horizontal There are two choices for horizontal mode:

manual

. The track source mode sets the control of the horizontal scaling for the normalized trace to that of the source channel. When manual mode is selected, the

5-14

Normalize response . . .Normalize scaling . . . Vertical

track source

Scale

and

Position

menus appear allowing you to

and

HP 54754A TDR/TDT Setup Menu

Normalize response . . .

independently change the horizontal scale and position for the normalized trace.

Key Path TDR/TDT Setup

Establish normalization & ref plane

The to normalize a channel and to set the reference plane for TDR and TDT measurements. This function must be performed separately for TDR and TDT modes. The normalization and reference plane must be re-established when power is lost or when the instrument is turned off. However, the values used for normalization and reference plane calculations can be stored to and reloaded from disk. (See the User’s Guide for more information.)

The normalization filter values and reference plane are invalidate when the timebase scale, record length or channel bandwidth is changed. Also, the normalization process will not be able to remove small synchronous noise in the channels baseline if the timebase position is changed. For most measurements this error is very small.

The reference plane must be established before ohm, % reflect or gain units are selectable for the channel. Also, the available in the Marker menu.

Normalize response . . .Normalize scaling . . . Horizontal

function establishes the filter values used

Disk Menu

chapter in the HP 83480A, HP 54750

Reference

ref plane function is not

5-15

Table 5-4

HP 54754A TDR/TDT Setup Menu

TDR rate automatic . . . (250 kHz)

The function steps you through the normalization and reference plane procedure for the selected measurement type. The procedure steps are displayed at the top of the screen. The items required for calibration are shown in Table 5-4.

Establish normalization & ref plane Hardware Requirements

Measurement Requirements

TDR 50 ohm 3.5 mm SMA terminator

3.5 mm SMA short

TDT 1 or 2 each 3.5 mm SMA cables

3.5 mm barrel connector

Key Path TDR/TDT Setup

TDR rate automatic . . . (250 kHz)

The

TDR rate automatic . . . (250 kHz)

automatically select the repetition rate of the TDR step. The range of values for manual mode selection are from 50 Hz to 250 kHz repetition rate using a 1-2-5 sequence. When this function is set to automatic, the TDR step repetition rate varies automatically as the Time base steps off screen. As the TDR rate decreases, TDR measurements can be made on longer transmission lines.

Key Path TDR/TDT Setup

Normalize response . . . Establish normalization & ref plane . . .

function allows you to manually or

Scale

is changed to keep multiple

TDR rate

automatic

manual

5-16

Table 5-5

HP 54754A TDR/TDT Setup Menu

Preset TDR/TDT

The Preset TDR/TDT function prepares the oscilloscope for making TDR/TDT measurements by automatically setting several menu fields. The TDR preset feature appears in the TDR/TDT Setup menu once a stimulus has been selected. The menus that are affect by this feature are shown in Table 5-5.

Preset TDR/TDT Configuration

Menu Menu Item Set To

Acquisition Averaging on

Best Flatness

Time Base Scale 500.0 ps/div

Position Set to a value which places the

incident edge on screen.

Channel 2 Setup Display on

Scale 100 mV/div Offset 200.0 mV Bandwidth 12.4 GHz Attenuation units ratio Attenuation 1.000 : 1

Key Path TDR/TDT Setup

Preset TDR/TDT

5-17

1 and 2 Stimulus Menus

This section describes the menus that are available when the stimulus is set to

1 and 2

TDT 1 dest

.

Pressing the channel used as the destination channel for channel 1 TDT measurements. The choices available for this pull-down menu depend on the other TDR or electrical plug-in, if any, in the mainframe.

Any electrical channel is potentially a valid TDT destination channel. The TDT destination may not be assigned to a channel already assigned as a TDT destination.

If no other valid TDT destination channels are available then "none" is the only choice. If a TDT destination other than none is selected then the preset TDR/ TDT control will turn on and preset the TDT destination channel.

Key Path TDR/TDT Setup

TDT 1 dest

TDT 2 dest

Pressing the channel used as the destination channel for channel 2 TDT measurements. The choices available for this pull-down menu depend on the other TDR or electrical plug-in, if any, in the mainframe.

Any electrical channel is potentially a valid TDT destination channel. The TDT destination may not be assigned to a channel already assigned as a TDT destination.

If no other valid TDT destination channels are available then "none" is the only choice. If a TDT destination other than none is selected then the preset TDR/ TDT control will turn on and preset the TDT destination channel.

TDT 2 dest

softkey produces a pull-down menu used to select the

TDT 1 dest

softkey produces a pull-down menu used to select the

Key Path TDR/TDT Setup

5-18

TDT 2 dest

Normalize 1 response . . . Normalize 2 response . . .

HP 54754A TDR/TDT Setup Menu

When the Stimulus is 1 and 2, there are two menus,

Normalize 2 response

channels separately. The functions allow you to change the risetime of the normalized step, to select TDR and TDT normalization, to turn on or off the display of the normalized TDR or TDT trace, to change the scaling of the normalized trace, and to establish the normalization filter values and reference plane.

Risetime

The Risetime function allows you to change the normalized step’s risetime from a minimum of

10 ps

or

min 8 points

which ever is greater, to a maximum of

While the TDR step’s risetime applied to the system under test is fixed, the measured response has a set of mathematical operations applied to it. These mathematical operations effectively change the displayed response to the system just as if a different TDR step risetime had actually been applied. This allows you to select a risetime for TDR/TDT measurements that is close to the actual risetime used in your system. This risetime value applies to both TDR and TDT normalized channels. For more information on normalization, see the chapter titled Improving Time Domain Network Measurements.

, which are used to normalize the two independent TDR

time per division (s/div) 10 divisions×

---------------------------------------------------------------------------------------------

×=

max 5 time per division (s/div)×=

record length

Normalize 1 response

and

Key Path TDR/TDT Setup

TDR/TDT

The

TDR/TDT

Both TDR and TDT channels can be normalized. This control selects which normalized trace is referred to for the following controls. Before TDT normalization can be done, you must select a TDT destination (

Key Path TDR/TDT Setup

function is used to select between TDR and TDT for normalization.

Normalize response . . . Risetime

Normalize response . . . TDR/TDT

TDT 1 dest

).

5-19

HP 54754A TDR/TDT Setup Menu

Normalize 1 response . . . Normalize 2 response . . .

TDR or TDT normalize

The TDR normalize function is available if the TDR mode is selected by using the previous menu otherwise the TDT normalize function is available. In either case, this function turns on or off the display of the normalized trace. The TDR and TDT normalization functions can be on at the same time.

Key Path TDR/TDT Setup

Normalize scaling . . .

Normalize scaling

The the normalized response is required that is independent from that of the source channel. This function only appears when TDR or TDT normalize is set to on.

Key Path TDR/TDT Setup

Vertical There are two choices for vertical mode: The track source mode sets the control of the vertical scaling for the normalized trace to that of the source channel. When manual mode is selected, the change the vertical scale and offset of the normalized trace.

Key Path TDR/TDT Setup

Horizontal There are two choices for horizontal mode:

manual

. The track source mode sets the control of the horizontal scaling for the normalized trace to that of the source channel. When manual mode is selected, the independently change the horizontal scale and position for the normalized trace.

Key Path TDR/TDT Setup

Establish normalization & ref plane

The to normalize a channel and to set the reference plane for TDR and TDT measurements. This function must be performed separately for TDR and TDT modes. The normalization and reference plane must be re-established when power is lost or when the instrument is turned off. However, the values used

Normalize response . . . TDR normalize

function is used when vertical and horizontal scaling of

Normalize response . . . Normalize scaling . . .

track source

Scale

and

Offset

menus appear allowing you to independently

Normalize response . . .Normalize scaling . . . Vertical

track source

Scale

and

Position

menus appear allowing you to

Normalize response . . .Normalize scaling . . . Horizontal

function establishes the filter values used

and

manual

.

and

5-20

HP 54754A TDR/TDT Setup Menu

TDR rate automatic . . . (250 kHz)

for normalization and reference plane calculations can be stored to and reloaded from disk. (See the User’s Guide for more information.)

The normalization filter values and reference plane are invalidate when the timebase scale, record length or channel bandwidth is changed. Also, the normalization process will not be able to remove small synchronous noise in the channels baseline if the timebase position is changed. For most measurements this error is very small..

The reference plane must be established before ohm, % reflect or gain units are selectable for the channel. Also, the available in the Marker menu.

The function steps you through the normalization and reference plane procedure for the selected measurement type. The procedure steps are displayed at the top of the screen. The items required for calibration are shown in Table 5-6.

Disk Menu

chapter in the HP 83480A, HP 54750

Reference

ref plane function is not

Table 5-6

Establish normalization & ref plane Hardware Requirements

Measurement Requirements

TDR 50 ohm 3.5 mm SMA terminator

TDT 1 or 2 each 3.5 mm SMA cables

Key Path TDR/TDT Setup

TDR rate automatic . . . (250 kHz)

The

TDR rate automatic . . . (250 kHz)

automatically select the repetition rate of the TDR step. The range of values for manual mode selection are from 50 Hz to 250 kHz repetition rate using a 1-2-5 sequence. When this function is set to automatic, the TDR step repetition

3.5 mm SMA short

3.5 mm barrel connector

Normalize response . . . Establish normalization & ref plane . . .

function allows you to manually or

5-21

HP 54754A TDR/TDT Setup Menu

Preset TDR/TDT

Scale

rate varies automatically as the Time base

is changed to keep multiple steps off screen. As the TDR rate decreases, TDR measurements can be made on longer transmission lines.

Key Path TDR/TDT Setup

Preset TDR/TDT

The Preset TDR/TDT function prepares the oscilloscope for making TDR/TDT measurements by automatically setting several menu fields. The TDR preset feature appears in the TDR/TDT Setup menu once a stimulus has been selected. The menus that are affect by this feature are shown in Table 5-7.

Table 5-7

Preset TDR/TDT Configuration

Menu Menu Item Set To

Acquisition Averaging on

Time Base Scale 500.0 ps/div

Channel 1 Setup and Display on Channel 2 Setup Scale 100 mV/div

TDR rate

automatic

manual

Best Flatness

Position Set to a value which places the

Offset 200.0 mV Bandwidth 12.4 GHz Attenuation units ratio Attenuation 1.000 : 1

incident edge on screen.

Key Path TDR/TDT Setup

5-22

Preset TDR/TDT

Differential and Common Mode Stimulus Menus

This section describes the menus that are available when the stimulus is set to

differential

TDR/TDT

This TDR/TDT function allows you to select either TDR measurements or TDT measurements. The TDT measurement capability requires that an additional TDR or electrical plug-in module be installed in the mainframe.

or common mode.

Key Path TDR/TDT Setup

TDR response 1

The

TDR response 1

differential or common mode TDR response 1. The choices available are off, differential, or common mode.

Key Path TDR/TDT Setup

Response scaling . . .

Response scaling

The the normalized response is required that is independent from that of the source channel. This function only appears when TDR response 1 is set to differential or common mode.

Key Path TDR/TDT Setup

Vertical There are two choices for vertical mode: The track source mode sets the control of the vertical scaling for the normalized trace to that of the source channel. When manual mode is selected, the change the vertical scale and offset of the normalized trace.

Key Path TDR/TDT Setup

TDR/TDT

function is used to enable or disable the display of the

TDR response 1

function is used when vertical and horizontal scaling of

TDR response 1 Response scaling . . .

Scale

and

Offset

menus appear allowing you to independently

TDR response 1 . . .Response scaling . . . Vertical

track source

and

manual

.

5-23

HP 54754A TDR/TDT Setup Menu

TDR response 2

Horizontal There are two choices for horizontal mode:

manual

. The track source mode sets the control of the horizontal scaling for the normalized trace to that of the source channel. When manual mode is selected, the independently change the horizontal scale and position for the normalized trace.

Key Path TDR/TDT Setup

TDR response 2

The

TDR response 2

differential or common mode TDT response 2. The choices available are off, differential, or common mode.

Key Path TDR/TDT Setup

Response scaling . . .

Response scaling

The the normalized response is required that is independent from that of the source channel. This function only appears when TDR response 2 is set to differential or common mode.

Key Path TDR/TDT Setup

track source

and

Scale

Position

TDR response 1 . . .Response scaling . . . Horizontal

function is used to enable or disable the display of the

menus appear allowing you to

TDR response 2

function is used when vertical and horizontal scaling of

TDR response 2 Response scaling . . .

and

Vertical There are two choices for vertical mode: The track source mode sets the control of the vertical scaling for the normalized trace to that of the source channel. When manual mode is selected, the change the vertical scale and offset of the normalized trace.

Key Path TDR/TDT Setup

Horizontal There are two choices for horizontal mode:

manual

. The track source mode sets the control of the horizontal scaling for the normalized trace to that of the source channel. When manual mode is selected, the independently change the horizontal scale and position for the normalized trace.

Key Path TDR/TDT Setup

5-24

track source

Scale

and

Offset

menus appear allowing you to independently

TDR response 2 . . .Response scaling . . . Vertical

Scale

and

Position

menus appear allowing you to

TDR response 2 . . .Response scaling . . . Horizontal

and

manual

track source

.

and

HP 54754A TDR/TDT Setup Menu

TDT response 1

The

TDT response 1

differential or common mode response 1. The choices available are off, differential, or common mode.

function is used to enable or disable the display of the

Key Path TDR/TDT Setup

Response scaling . . .

Response scaling

The the normalized response is required that is independent from that of the source channel. This function only appears when TDT response 1 is set to differential or common mode.

Key Path TDR/TDT Setup

Vertical There are two choices for vertical mode: The track source mode sets the control of the vertical scaling for the normalized trace to that of the source channel. When manual mode is selected, the change the vertical scale and offset of the normalized trace.

Key Path TDR/TDT Setup

Horizontal There are two choices for horizontal mode:

manual

. The track source mode sets the control of the horizontal scaling

for the normalized trace to that of the source channel. When manual mode is selected, the independently change the horizontal scale and position for the normalized trace.

Key Path TDR/TDT Setup

TDT response 1

function is used when vertical and horizontal scaling of

TDT response 1 Response scaling . . .

track source

Scale

and

Offset

menus appear allowing you to independently

TDT response 1 . . .Response scaling . . . Vertical

Scale

and

Position

menus appear allowing you to

TDT response 1 . . .Response scaling . . . Horizontal

and

manual

track source

.

and

TDT response 2

The

TDT response 2

differential or common mode response 2. The choices available are off, differential, or common mode.

Key Path TDR/TDT Setup

function is used to enable or disable the display of the

TDT response 2

5-25

HP 54754A TDR/TDT Setup Menu

Establish ref plane

Response scaling . . .

Response scaling

The the normalized response is required that is independent from that of the source channel. This function only appears when TDT response 2 is set to differential or common mode.

function is used when vertical and horizontal scaling of

Key Path TDR/TDT Setup

Vertical There are two choices for vertical mode: The track source mode sets the control of the vertical scaling for the normalized trace to that of the source channel. When manual mode is selected, the change the vertical scale and offset of the normalized trace.

Key Path TDR/TDT Setup

Horizontal There are two choices for horizontal mode:

manual

. The track source mode sets the control of the horizontal scaling for the normalized trace to that of the source channel. When manual mode is selected, the independently change the horizontal scale and position for the normalized trace.

Key Path TDR/TDT Setup

Establish ref plane

The

Establish ref plane

TDT measurements for differential or common mode stimulus. The function steps you through the calibration procedure for the selected measurement type. The steps are displayed at the top of the screen. The items required for calibration are shown in Table 5-8.

TDT response 2 Response scaling . . .

track source

Scale

and

menus appear allowing you to independently

Offset

TDT response 2 . . .Response scaling . . . Vertical

Scale

and

Position

menus appear allowing you to

TDT response 2 . . .Response scaling . . . Horizontal

function is used to set the reference plane for TDR and

and

manual

track source

.

and

5-26

Table 5-8

HP 54754A TDR/TDT Setup Menu

TDR rate automatic . . . (250 kHz)

Establish ref plane Hardware Requirements

Measurement Requirements

TDR 50 ohm 3.5 mm SMA terminator

3.5 mm SMA short

TDT 1 or 2 each 3.5 mm SMA cables

3.5 mm barrel connector

The reference plane is invalidated when the timebase scale, record length or channel bandwidth is changed.

Before establishing a reference plane for common mode and differential TDR, the test setup must be deskewed. See chapter 8 for information on how to deskew a test setup.

The reference plane must be established before ohm, % reflect or gain units are selectable for the channel. Also, the available in the Marker menu.

Key Path TDR/TDT Setup

TDR rate automatic . . . (250 kHz)

The

TDR rate automatic . . . (250 kHz)

automatically select the repetition rate of the TDR step. The range of values for manual mode selection are from 50 Hz to 250 kHz repetition rate using a 1-2-5 sequence. When this function is set to automatic, the TDR step repetition rate varies automatically as the Time base steps off screen. As the TDR rate decreases, TDR measurements can be made on longer transmission lines.

Key Path TDR/TDT Setup

Reference

ref plane function is not

Normalize response . . . Establish ref plane . . .

function allows you to manually or

Scale

is changed to keep multiple

TDR rate

automatic

manual

5-27

Table 5-9

HP 54754A TDR/TDT Setup Menu

Preset TDR/TDT

The Preset TDR/TDT function prepares the oscilloscope for making TDR/TDT measurements by automatically setting several menu fields. The TDR preset feature appears in the TDR/TDT Setup menu once a stimulus has been selected. The menus that are affect by this feature are shown in Table 5-9 and Table 5-10.

Differential Stimulus Preset TDR/TDT Configuration

Menu Menu Item Set To

Acquisition Averaging on

Best Flatness

Time Base Scale 500.0 ps/div

Position Set to a value which places the

incident edge on screen.

Channel 1 Setup Display on

Scale 100 mV/div Offset 200.0 mV Bandwidth 12.4 GHz Attenuation units ratio Attenuation 1.000 : 1

Channel 2 Setup Scale 100 mV/div

Offset -200 mV

5-28

Table 5-10

HP 54754A TDR/TDT Setup Menu

Preset TDR/TDT

Common Mode Stimulus Preset TDR/TDT Configuration

Menu Menu Item Set To

Acquisition Averaging on

Best Flatness

Time Base Scale 500.0 ps/div

Position Set to a value which places the

incident edge on screen.

Channel 1 Setup Display on

Scale 100 mV/div Offset 200.0 mV Bandwidth 12.4 GHz (for Stimulus on)

18.0 GHz (for Stimulus external) Attenuation units ratio Attenuation 1.000 : 1

Channel 2 Setup Scale 100 mV/div

Offset 200.0 mV

Key Path TDR/TDT Setup

Preset TDR/TDT

5-29

External Stimulus Menus

This section describes the menus that are available when the stimulus is set to

external

TDT 1 dest

.

Pressing the channel used as the destination channel for TDT measurements. The choices available for this pull-down menu depend on the other TDR or electrical plugin, if any, in the mainframe.

Any electrical channel is potentially a valid TDT destination channel. The TDT destination may not be assigned to a channel already assigned as a TDT destination. The TDT destination may not be set to the currently defined TDR destination channel.

If no other valid TDT destination channels are available then "none" is the only choice. If a TDT destination other than none is selected then the preset TDR/ TDT control will turn on and preset the TDT destination channel.

Key Path TDR/TDT Setup

TDT 1 dest

TDR 1 dest

Pressing the channel used as the destination channel for TDR measurements. Any electrical channel is a valid TDR destination channel. The TDR destination may not be set to the currently defined TDT destination.

Key Path TDR/TDT Setup

TDR 1 dest

softkey produces a pull-down menu used to select the

TDT 1 dest

softkey produces a pull-down menu used to select the

TDR 1 dest

5-30

HP 54754A TDR/TDT Setup Menu

Normalize response . . .

The

Normalize response

normalized step, to select TDR and TDT normalization, to turn on or off the display of the normalized TDR or TDT trace, to change the scaling of the normalized trace, and to establish the normalization filter values and reference plane.

Risetime

The Risetime function allows you to change the normalized step’s risetime from a minimum of

10 ps

or

min 8 points

which ever is greater, to a maximum of

max 5 time per division (s/div)×=

function allows you to change the risetime of the

time per division (s/div) 10 divisions×

---------------------------------------------------------------------------------------------

×=

record length

While the TDR step’s risetime applied to the system under test is fixed, the measured response has a set of mathematical operations applied to it that effectively displays the response to the system as if a different TDR step risetime had actually been applied. This allows you to select a risetime for TDR/TDT measurements that is close to the actual risetime used in your system. This risetime value applies to both TDR and TDT normalized channels. For more information on normalization, see the chapter titled Improving Time Domain Network Measurements.

Key Path TDR/TDT Setup

TDR/TDT

The

TDR/TDT

function is used to select between TDR and TDT for normalization. Both TDR and TDT channels can be normalized. This control selects which normalized trace is referred to for the following controls. Before TDT normalization can be done, you must select a TDT destination (

Key Path TDR/TDT Setup

Normalize response . . . Risetime

Normalize response . . . TDR/TDT

TDT 1 dest

).

5-31

HP 54754A TDR/TDT Setup Menu

Normalize response . . .

TDR or TDT normalize

The TDR normalize function is available if the TDR mode is selected by using the previous menu otherwise the TDT normalize function is available. In either case, this function turns on or off the display of the normalized trace. The TDR and TDT normalization functions can be on at the same time.

Key Path TDR/TDT Setup

Normalize scaling . . .

Normalize scaling

The the normalized response is required that is independent from that of the source channel. This function only appears when TDR or TDT normalize is set to on.

Key Path TDR/TDT Setup

Vertical There are two choices for vertical mode: The track source mode sets the control of the vertical scaling for the normalized trace to that of the source channel. When manual mode is selected, the change the vertical scale and offset of the normalized trace.

Key Path TDR/TDT Setup

Horizontal There are two choices for horizontal mode:

manual

. The track source mode sets the control of the horizontal scaling for the normalized trace to that of the source channel. When manual mode is selected, the independently change the horizontal scale and position for the normalized trace.

Key Path TDR/TDT Setup

Establish normalization & ref plane

The to normalize a channel and to set the reference plane for TDR and TDT measurements. This function must be performed separately for TDR and TDT modes. The normalization and reference plane must be re-established when power is lost or when the instrument is turned off. However, the values used

Normalize response . . . TDR normalize

function is used when vertical and horizontal scaling of

Normalize response . . . Normalize scaling . . .

track source

Scale

and

Offset

menus appear allowing you to independently

Normalize response . . .Normalize scaling . . . Vertical

track source

Scale

and

Position

menus appear allowing you to

Normalize response . . .Normalize scaling . . . Horizontal

function establishes the filter values used

and

manual

.

and

5-32

HP 54754A TDR/TDT Setup Menu

Normalize response . . .

for normalization and reference plane calculations can be stored to and reloaded from disk. (See the

Disk Menu

chapter in the HP 83480A, HP 54750

User’s Guide for more information.)

The normalization filter values and reference plane are invalidate when the timebase scale, record length or channel bandwidth is changed. Also, the normalization process will not be able to fully remove step non-flatness if the timebase position is changed since the filter values have been established.

The reference plane must be established before ohm, % reflect or gain units are selectable for the channel. Also, the

Reference

ref plane function is not

available in the Marker menu.

The function steps you through the normalization and reference plane procedure for the selected measurement type. The procedure steps are displayed at the top of the screen. The items required for calibration are shown in Table 5-11.

Table 5-11

Establish normalization & ref plane Hardware Requirements

Measurement Requirements

TDR 50 ohm 3.5 mm SMA terminator

TDT 1 or 2 each 3.5 mm SMA cables

Key Path TDR/TDT Setup

3.5 mm SMA short

3.5 mm barrel connector

Normalize response . . . Establish normalization & ref plane . . .

5-33

HP 54754A TDR/TDT Setup Menu

TDR rate automatic . . . (250 kHz)

The

TDR rate automatic . . . (250 kHz)

automatically select the repetition rate of the TDR step. The range of values for manual mode selection are from 50 Hz to 250 kHz repetition rate using a 1-2-5 sequence. When this function is set to automatic, the TDR step repetition rate varies automatically as the Time base steps off screen. As the TDR rate decreases, TDR measurements can be made on longer transmission lines.

function allows you to manually or

Scale

is changed to keep multiple

Key Path TDR/TDT Setup

Preset TDR/TDT

The Preset TDR/TDT function prepares the oscilloscope for making TDR/TDT measurements by automatically setting several menu fields. The TDR preset feature appears in the TDR/TDT Setup menu once a stimulus has been selected. The menus that are affect by this feature are shown in Table 5-12.

Table 5-12

Preset TDR/TDT Configuration

Menu Menu Item Set To

Acquisition Averaging on

Time Base Scale 500.0 ps/div

Channel 1 Setup Display on

TDR rate

automatic

manual

Best Flatness

Position Set to a value which places the incident

Scale 100 mV/div Offset 0.0 mV Bandwidth 18.0 GHz Attenuation units ratio Attenuation 1.000 : 1

edge on screen.

Key Path TDR/TDT Setup

5-34

Preset TDR/TDT

6

Measure and Other TDR Specific Menus

What you’ll find in this chapter

This chapter describes the Measure menu and the mainframe menu changes that occur when a TDR plug-in module is in the mainframe.

CAUTION

The input circuits can be damaged by electrostatic discharge (ESD). Therefore, avoid appl ying static discharges to the front-pane l input connectors. Before connecting any coaxial cable to the connectors, momentarily short the center and outer conductors of the cable together. Avoid touching the frontpanel input connectors without first touching the frame of the instrument. Be sure the instrument is properly earth-grounded to prevent buildup of static charge.

There are several mainframe menus which change when a TDR plug-in module is inserted into the mainframe menus. This chapter will cover only the changes that occur to the mainframe menus and will not discuss the menu functions which are already documented in the 83480A, 54750A User’s Guide.

6-2

HP 54753A, 54754A User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

The Instrument at a Glance

Menu and Key Conventions

The HP 54753A, 54754A TDR Plug-In Modules

Plug-in Module Purpose

Front Panel of the Plug-in Module

Getting the Best Performance

Installing a Plug-in Module

Trigger

Care and Handling of Precision Connectors

3.5 mm Connector Care

Connector Wear

Operator Skill

Device Specifications

Accuracy Considerations

Visual Inspection

Mechanical Inspection

Connecting the Devices

Setup Channel Menu

Displaying the Setup Channel menu

Display

Scale

Offset

Bandwidth. . .

Alternate scale. . .

Calibrate . . .

Calibration Overview

Factory Mainframe Calibration

User Calibrations

HP 54753A TDR/TDT Setup Menu

Displaying the TDR/TDT Setup Menu

Stimulus

TDT 1 dest

TDR 1 dest

Normalize response . . .

TDR rate automatic . . . (250 kHz)

Preset TDR/TDT

HP 54754A TDR/TDT Setup Menu

Displaying the TDR/TDT Setup Menu

Stimulus

TDT 1 dest

Normalize response . . .

TDR rate automatic . . . (250 kHz)

Preset TDR/TDT

TDT 2 dest

Normalize response . . .

TDR rate automatic . . . (250 kHz)

Preset TDR/TDT

TDT 1 dest

TDT 2 dest

Normalize 1 response . . . Normalize 2 response . . .

TDR rate automatic . . . (250 kHz)

Preset TDR/TDT

TDR/TDT

TDR response 1

TDR response 2

TDT response 1

TDT response 2

Establish ref plane

TDR rate automatic . . . (250 kHz)

Preset TDR/TDT

TDT 1 dest

TDR 1 dest

Normalize response . . .

TDR rate automatic . . . (250 kHz)

Preset TDR/TDT

Measure and Other TDR Specific Menus