Agilent 16534A Help Volume

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Instrument: HP 16533/34A Digitizing Oscilloscope

HP 16533/34A Digitizing Oscilloscope

The HP 16533A and HP 16534A Digitizing Oscilloscopes offer basic oscilloscope functionality. The oscilloscope can be easily correlated with other instruments in the HP 16600A-series or HP 16700A logic analysis system.

Getting Started

• “Calibrating the Oscilloscope” on page 10

• “Probing” on page 14

• “Acquiring a Waveform” on page 31

• “Combining the Oscilloscope with a Logic Analyzer” on page 36

Refining Your Measurement

• “Triggering” on page 39

• “Vertical and Horizontal Scaling” on page 53

• “Changing the Sample Rate” on page 55

• “Comparing Channels” on page 57

• “Using Markers” on page 75

Tip s

• “What Do the Display Symbols Mean?” on page 58

• “Changing Waveform Display and Grid” on page 47

• “Automatic Measurements and Algorithms” on page 62

• “Differences from a Standard Digitizing Oscilloscope” on page 77

• “Using Waveform Memories” on page 78

• “Loading and Saving Oscilloscope Configurations” on page 79

•“When Something Goes Wrong” on page 80

“Specifications and Characteristics” on page 85

Main System Help (see the HP 16600A/16700A Logic Analysis System help volume)

Glossary of Terms (see page 97)

HP 16533/34A Digitizing Oscilloscope

1 HP 16533/34A Digitizing Oscilloscope

Calibrating the Oscilloscope 10

Calibration Reference 12

Probing 14

Table of Compatible Probes 14 Selecting the Proper Probe 15 Compensating the Compensated Passive Divider Probe 18 Probe Loading 19 Descriptions of Probe Types 23 Surface Mount Probing 30

Acquiring a Waveform 31

Autoscale 32 Specifying a Measurement 33

Combining the Oscilloscope with a Logic Analyzer 36

Oscilloscope Triggers Logic Analyzer 36 Logic Analyzer Triggers Oscilloscope 37 Logic Analyzer and Oscilloscope Correlate Data 37

Triggering 39

Trigger Concepts 39 Edge Triggering 41 Pattern Triggering 42 Delayed Triggering 43 Getting a Stable Trigger 44 The Trigger Setup Window 45

Contents

Changing Waveform Display and Grid 47

Zooming In 47 Changing the Persistence of the Waveform 47 Viewing Noisy Waveforms with Averaging 49 Changing Display Colors 51 Changing the Grid 51

Vertical and Horizontal Scaling 53

Changing the Sample Rate 55

Comparing Channels 57

What Do the Display Symbols Mean? 58

Display Setup Window 60

Contents

Automatic Measurements and Algorithms 62

How the Scope Makes Measurements 63 Average Voltage (Vavg) 64 Period 64 Rise Time 64 Fall Time 65 Negative and Positive Pulse Width (±Width) 65 Frequency 66 Base Voltage (Vbase) 67 Top Voltage (Vtop) 67 Preshoot 68 Overshoot 69 Peak-to-Peak Voltage (Vpp) 69 Minimum Voltage (Vmin) 70 Maximum Voltage (Vmax) 70 Time of Minimum Voltage (Tmin) 71 Time of Maximum Voltage (Tmax) 71 Voltage Amplitude (Vamp) 71 Vdcrms (Root Mean Square Voltage, DC) 71 About the Measurements 72 Increasing the Accuracy of Your Measurements 74

Using Markers 75

About Automatic Time Markers 76

Differences from a Standard Digitizing Oscilloscope 77

Using Waveform Memories 78

Loading and Saving Oscilloscope Configurations 79

When Something Goes Wrong 80

Error Messages 80 Calibration Problems 80 Triggering Problems 80 Other Problems 81

Contents

Specifications and Characteristics 85

What is a Specification 89 What is a Characteristic 89 What is a Calibration Procedure 90 What is a Function Test 90

Help - How to Navigate Quickly 91

Run/Group Run Function 92

Setting a tool for independent or Group Run 93 Setting Single or Repetitive Run 94 Checking Run Status 94 Demand Driven Data 95

Glossary

Index

HP 16533/34A Digitizing Oscilloscope

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Calibrating the Oscilloscope

The oscilloscope requires a full operational accuracy calibration by you or a service department whenever

• it has been 6 months or 1,000 hours of use since last full calibration.

• the ambient temperature changes more than 10 degrees C from the

temperature at the time of the last full calibration.

• the frame configuration changes.

• you need to optimize measurement accuracy.

You will get more accurate measurements from the oscilloscope if you perform the operational accuracy calibration at least once a year.

NOTE: Channel skew calibration requires a multi-board oscilloscope. The procedure

cannot be performed on single-board (2-channel) oscilloscopes.

To calibrate the oscilloscope

This is also covered in the Logic Analysis System Installation Guide. Since this procedure requires you to turn off the system, print this information if you do not have access to the Installation Guide.

1. If your oscilloscope has more than two channels, disconnect the short cables on the back of the module that connect the boards.

2. Unprotect the memory.

a. Turn off the HP 16600A or HP 16700A frame.

b. Take the oscilloscope module out of the frame. See the Logic Analysis

System Installation Guide.

c. Set the PROTECT/UNPROTECT switch to UNPROTECT.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Calibrating the Oscilloscope

d. Put the oscilloscope back in the frame.

3. Turn on the HP 16600A or HP 16700A and wait for it to finish booting. You will get a more accurate calibration if you warm up the system for 30 minutes before calibrating the oscilloscope.

4. Select the oscilloscope icon with the right mouse button, and drag the cursor to Calibration...

5. Select the procedure ADC through Logic Trigger. The calibration software will tell you what cables need to be attached.

6. Click Run.

7. Select the procedure Ext Trig Skew and connect the cables as directed.

8. Click Run.

9. Optional - Calibrate the oscilloscope as a multi-board module.

a. Perform the ADC through Logic Trigger and Ext Trig Skew calibrations

on each oscilloscope board first.

b. Click Exit in the system window.

c. Connect the oscilloscopes together with the short board interconnect

cables. Connect the first board’s TRIG OUT to the next board’s TRIG IN until all boards are connected.

d. Start a session.

e. Select the oscilloscope icon with the right mouse button, and drag the

cursor to Calibration.

f. Select the procedure Channel Skew and connect the cables as

directed.

10. After you have finished calibrating, protect the memory. Follow the steps given above for unprotecting, setting the switch to PROTECT instead.

See Also Logic Analysis System Installation Guide

“Calibration Reference” on page 12

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Calibrating the Oscilloscope

Calibration Reference

ADC

The ADC calibration procedure produces a linearization table which is applied to the data out of the analog-to-digital converters (ADC) to undo the effects of a non-linear, analog-to-digital conversion.

Gain

The Gain calibration procedure measures the actual attenuation of the attenuators and measures the actual gain of the preamps.

Offset

The Offset calibration procedure determines the actual offset value that places a null signal in center screen.

Hysteresis

The Hysteresis calibration procedure determines the hardware setting which is closest to achieving a hysteresis of 0.28 screen divisions.

Trigger Level

The Trigger Level calibration procedure determines the actual trigger level values for all possible voltage levels across the screen.

Trigger Delay

The Trigger Delay calibration procedure determines a time delay which correctly lines up the point at which a trace crosses the trigger level with the trigger time.

Logic Trigger

The Logic Trigger calibration procedure determines settings which affect the accuracy of duration trigger measurements.

Ext Trig Skew

The Ext Trig Skew calibration procedure lines up the external trigger edge with the trigger time when triggering on the external channel.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Calibrating the Oscilloscope

Channel Skew

The Channel Skew calibration procedure is only available for multiboard oscilloscope modules. It deskews the trigger channel and data channels which are on different boards.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

The probes covered in the topics below are 1:1 Passive Probes, Active Probes, Current Probes, Compensated Passive Divider Probes, Differential Probes, and Resistive Divider Probes.

•“Table of Compatible Probes” on page 14

•“Selecting the Proper Probe” on page 15

•“Compensating the Compensated Passive Divider Probe” on page 18

•“Probe Loading” on page 19

•“Descriptions of Probe Types” on page 23

•“Surface Mount Probing” on page 30

Table of Compatible Probes

* Most frequently used

Model Probe Type Band- Input Div Input R Input C Numbers width Z ratio

COMPENSATED DIVIDER

HP 10441A Compensated 500 1 Mohm 10:1 1 Mohm 9 pF

*HP 1160A Compensated 500 1 Mohm 10:1 10 Mohm 9 pF Passive Divider MHz

HP 1161A Compensated 500 1 Mohm 10:1 10 Mohm 10 pF Passive Divider MHz

HP 1162A High Impedance 25 1 Mohm 1:1 1 Mohm 50 pF + Passive MHz scope C

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

RESISTIVE DIVIDER

HP 1163A Resistive 1.5 50 ohm 10:1 500 ohm

1.5 pF

Divider GHz

HP 54006A Resistive 6 50 ohm 10:1 500 ohm

0.25 pF

Divider GHz 20:1 or 1Kohm

ACTIVE

*HP 1144A Active 800 50 ohm 10:1 1 Mohm 2 pF MHz

*HP 1145A Dual Channel 750 50 ohm 10:1 1 Mohm 2 pF Small Geometry MHz Active

HP 1141A Differential 200 50 ohm 1:1 1 Mohm 7 pF MHz 10:1 9 Mohm

3.5 pF

100:1 10 Mohm

2.0 pF

HP 54701A Active 2.5 50 ohm 10:1 100 Kohm

0.6 pF

GHz

CURRENT

HP 1146A Current 100 1 Mohm n/a n/a n/a kHz

See Also “Descriptions of Probe Types” on page 23

“Channel Setup Window” on page 34 for setting input impedance and

coupling

Selecting the Proper Probe

Use the flowchart below for selecting the proper type of probe. A

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

comparison of features, tradeoffs, and applications of the probes are available after the flowchart.

1:1 Passive Probe

Features

Tradeoffs High capacitive loading and low bandwidth.

Applications Measuring small, low-bandwidth waveforms when no

No attenuation of waveform.

attenuation can be tolerated such as power supply ripple.

Active Probe

Features

Best overall combination of low resistive and capacitive

loading. High bandwidth.

Tradeoffs Higher cost, limited dynamic range, requires power.

Applications ECL, CMOS, GaAs probing, analog circuit probing,

transmission line probing, source resistance Š10 kohm, op amp probing, most accurate for general measurements of circuits of unknown impedance.

Compensated Passive Divider Probe

Features

Very low resistive loading, accurate amplitude measurements,

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

large dynamic range, and low cost.

Tradeoffs Capacitive loading <10 pF, lower bandwidth than active or

50-ohm resistive divider probes.

Applications General purpose probing, probing high-impedance nodes

(Š10 Kohm), op amp probing, CMOS probing (if bandwidth is adequate), TTL probing (if bandwidth is adequate)

Current Probe

Features

Measures both ac and dc currents on a scope, with minimal

circuit loading.

Tradeoffs Large size.

Applications Power measurements, automotive measurements,

industrial measurements, motors, dynamoes, and alternators.

Differential Probe

Features

High common mode rejection ratio, easy viewing of small waveforms with large dc offsets, more accurate than subtracting one channel from another.

Tradeoffs Bigger than a passive probe, high cost, requires power, and

lower bandwidth than other probes.

Applications Measuring waveforms not referenced to the scope ground,

troubleshooting power supplies, and differential amplifier probing.

Resistive Divider Probe

Features

Highest bandwidth, lowest capacitive load, lower cost than active probes, flat pulse response, good timing measurement accuracy.

Tradeoffs Relatively heavy resistive loading.

Applications ECL probing, GaAs probing, and transmission line probing.

See Also “Descriptions of Probe Types” on page 23

“Table of Compatible Probes” on page 14

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

Compensating the Compensated Passive Divider Probe

Before you can have a flat frequency response when using a Compensated Passive Divider Probe, the probe’s cable capacitance and scope input capacitance must be compensated. One of the compensating capacitors in the probe is adjustable so you can optimize the step response for flatness.

1. Connect the probe to the BNC Output, labeled AC/DC CAL, on the back of the oscilloscope.

2. Connect the probe ground lead to ground.

3. Click the oscilloscope icon and select Calibration...

4. At the bottom of the calibration window, set BNC Output to Probe Comp and close the window.

5. Click the oscilloscope icon and select Setup/Display...

6. Click Autoscale.

7. You should see a waveform similar to one of the following.

8. If necessary, adjust the probe’s compensating capacitor. Set the scope to keep running by right-clicking Run, selecting repetitive, then clicking Run.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

Probe Loading

There are two major factors influencing probe selection: the load the probe imposes on your circuit and the required bandwidth of your circuit with the probe. This is discussed in three sections, below.

Probe Resistance and Capacitance Characteristics (see page 19)

Probe Ground Lead Characteristics (see page 20)

Understanding System Bandwidth at the Probe Tip (see page 21)

Probe Resistance and Capacitance Characteristics

The probe load has both resistive and capacitive components. In addition, the inductance in the probe ground lead causes ringing.

The probe resistance to ground forms a voltage divider network with the source resistance of your circuit. This reduces the waveform amplitude and the dc offset. For example, if the probe’s resistance is 9 times the Thevenin equivalent resistance of your circuit, the waveform amplitude is reduced by about 10 percent. Therefore, if your waveform has a +5 V to 0.8 V range, the scope probe system shows a 4.5 V to 0.72 V range.

NOTE: At high frequencies, the probe reactance dominates the resistance.

The probe capacitive loading (Cin) to ground forms an RC circuit with the resistance of your circuit (R the probe and scope (R

). The time constant of this RC circuit slows

) and the resistance looking into

source

the rise time of any transitions, increases the slew rate, and introduces delay in the actual transition time. The approximate rise time of a simple RC circuit is: t

Tot al

= 2.2R

= [RinR

Tot alCin

source

where

]/[Rin + R

source

]

Thus, for circuit resistance of 100 ohm, a scope probe system resistance of 1 Mohm, and a probe capacitance of 8 pF, the real rise

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

time due to probe loading is:

= [1 Mohm (100 ohm)]/[1 Mohm + 100 ohm], approximately 100

Tot al

ohm.

= 2.2(100 ohm)(8 pF), approximately 1.8 ns.

Therefore, the rise time of your circuit cannot be faster than approximately 1.8 ns, even though it might be faster without the probe.

If the output of the circuit under test is current-limited (as is often the case for CMOS), the slew rate is limited by the relationship dV/dT = I/C.

Perhaps you have connected a scope to a circuit for troubleshooting only to have the circuit operate correctly after connecting the probe. The capacitive loading of the probe can attenuate a glitch, reduce ringing or overshoot of your waveform, or slow an edge just enough that a setup or hold time violation no longer occurs.

Probe Ground Lead Characteristics

NOTE: If you print this page, subscripts and superscripts appear on the main line of

text. If a number seems to be in an odd place in the printed copy, it is probably a superscript.

The inductance of the probe’s ground lead forms an LC circuit with the probe’s capacitance and the output capacitance of the circuit under test, including any parasitic capacitance of PC board traces, and so on. The ringing frequency (F) of this circuit is:

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

Understanding System Bandwidth at the Probe Tip

F = (2 (3.14) (LC)

1/2)-1

If the rise time of the waveform is sufficient to stimulate this ringing, the ringing can appear as part of your captured waveform. To calculate the ringing frequency, you can assume that the probe’s ground lead has an inductance of approximately 25 nH per inch. So, a probe with a capacitance of 8 pF and a 4-inch ground lead has a ringing frequency of approximately:

1/2)-1

F = (2 (3.14) [(25 nH) (4 inches) (8 pF)]

= 178 MHz

The 178 MHz does not include your circuit capacitance. Therefore, a waveform with a rise time of less than 1.9 ns can stimulate ringing.

= 0.35/178 MHz = 1.9 ns

rise

To minimize the ringing effect, you should use a probe ground lead that is as short as possible. Some probes add a ferrite bead to the ground lead to reduce ringing. However, adding the ferrite bead also increases the ground impedance which reduces the common mode rejection of the probe.

System bandwidth is the bandwidth of the scope probe system. System bandwidth affects measurements because the probe becomes part of the circuit being measured. The rise time that is measured depends on the actual rise time, the rise time of the scope probe system, and the rise time of the RC circuit formed by the source resistance and the scope probe system resistance and capacitance.

meas

= [t

act

+ t

sys

1/2

]

where

= the measured rise time.

meas

= the actual rise time of the waveform being measured.

act

= the rise time of the RC circuit formed by the source resistance

and the scope probe system resistance and capacitance.

= the rise time of the scope probe system.

sys

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

NOTE: Often the bandwidth of the scope probe system is specified. The rise time is

calculated using the following equation.

= 0.35/SystemBW

sys

If the rise time of the scope probe system is not specified, it can be calculated using the following formula.

probe

+ t

= [t

sys

scope

1/2

]

For example, if the scope probe system rise time is 600 ps, the probe loading rise time (t

) is 600 ps, and the waveform has a 1-ns rise time,

then the measured rise time is:

= [(1 ns)2 + (600 ps)2 + (600 ps)2]

meas

1/2

= 1.3 ns

The answer is in error by 30%.

However, if the scope probe system rise time is 190 ps, the probe loading rise time is 190 ps, and the waveform has a 1-ns rise time, then the measured rise time is:

= [(1 ns)2 + (190 ps)2 + (190 ps)2]

meas

1/2

= 1.03 ns

Now the error is only 3%.

You may find it useful to memorize three system bandwidth rules:

1. The combined rise time of the scope probe system and the probe loading should be less than 1/3 of the rise time of the waveform you are measuring to keep errors below 5%, and less than 1/7 of the rise time of the waveform you are measuring to keep errors below 1%.

2. Rise time and bandwidth are related by the following approximations: rise time = 0.35/bandwidth and bandwidth = 0.35/rise time.

3. Rise times add approximately as the square root of the sum of the squares (for systems with minimal peaking).

NOTE: Because every scope probe has a different loading effect on your circuit, you

should use the equation given for the type of scope probe you are using.

See Also “Descriptions of Probe Types” on page 23

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

Descriptions of Probe Types

For each of the probe types listed below, the description gives a summary of features and tradeoffs and a short text description. Most of the probe types also give a sample rise time calculation.

•“1:1 Passive Probes” on page 23

•“Active Probes” on page 24

•“Compensated Passive Divider Probes” on page 26

•“Current Probes” on page 27

•“Differential Probes” on page 28

•“Resistive Divider Probes” on page 28

1:1 Passive Probes

Example Rise Time Calculation

Features No attenuation of waveform.

Tradeoffs High capacitive loading and low bandwidth.

Applications Measuring small, low-bandwidth waveforms when no

attenuation can be tolerated such as power supply ripple.

The 1:1 passive probes provide a way to connect the input impedance of the scope directly to your circuit with minimum attenuation due to the resistive loading of the probe. However, 1:1 probes do have very high capacitive loading which is much larger than that of the scope.

There are two types of 1:1 passive probes. One type is designed to work with the scope’s input set to high impedance (1 Mohm) and uses a lossy cable to keep the probe from ringing. The other type is designed to work with the scope’s input set to low impedance (50 ohm) and uses a 50-ohm coaxial cable.

Given the following circuit using the HP 1162A probe,

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

the input resistance is:

= R

= 1 Mohm

scope

The total resisitance is:

= (RinR

Tot al

= 1 Mohm(50 ohm)/(1 Mohm + 50 ohm) = 50 ohm

Tot al

source

)/(Rin + R

source

)

From the Table of Compatible Probes, the probe capacitance is 50 pF. Therefore, the capacitive load is:

= C

probe

+ C

= 50 pF + 7 pF = 57 pF

scope

The rise time due to circuit loading is:

= 2.2R

Tot alCin

tRC = 2.2(50 ohm)(57 pF) = 6.2 ns

From the Table of Compatible Probes, the scope probe system has a bandwidth of 25 MHz. Therefore, the rise time of the scope probe system is: t

= 0.35/25 MHz = 14 ns

Sys

The measured rise time is: t

ns)

+ (6.2 ns)2 + (14 ns)2]

= 0.35/SystemBW

Sys

= [t

meas

1/2

= 140.8 ns

act

+ t

sys

1/2

]

= [(140

meas

Active Probes

Features Best overall combination of low resistive and capacitive

loading. High bandwidth.

Tradeoffs Higher cost, limited dynamic range, requires power.

Applications ECL, CMOS, GaAs probing, analog circuit probing,

transmission line probing, source resistance Š10 kohm, op amp probing, most accurate for general measurements of circuits of

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

unknown impedance.

An active probe has a buffer amplifier at the probe tip. This buffer amplifier drives a 50-ohm cable terminated in 50 ohms at the scope input. Active probes offer the best overall combination of resistive loading, capacitive loading, and bandwidth.

Example Rise Time Calculation

Given the following circuit using the HP 1152A probe,

the input resistance is: R

= 100 kohm. The total input resistance is:

= (RinR

Tot al

= 100 ohm(50 ohm)/(100 ohm + 50 ohm) = 50 ohm

Tot al

source

)/(Rin + R

source

)

The rise time due to circuit loading is:

= 2.2R

Tot alCtip

tRC = 2.2(50 ohm)(0.6 pF) = 66 ps

Because the rise time of the scope probe system is not given in the Table of Compatible Probes, we will have to calculate it using the bandwidth of the probe (2.5 GHz) and the bandwidth of the scope (500 MHz). Therefore, the rise time of the scope probe system is:

= 0.35/ProbeBW = 0.35/2.5 GHz = 140 ps

probe

= 0.35/ScopeBW = 0.35/500 MHz = 700 ps

scope

= [t

sys

= [(140 ps)2 + (700 ps)2]

sys

probe

+ t

scope

1/2

]

1/2

= 714 ps

The measured rise time is:

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

meas

= [t

act

+ t

sys

1/2

]

= [(2 ns)2 + (66 ps)2 + (714 ps)2]

meas

1/2

= 2.12 ns

Compensated Passive Divider Probes

Features Very low resistive loading, accurate amplitude measurements,

large dynamic range, and low cost.

Tradeoffs Capacitive loading <10 pF, lower bandwidth than active or

50-ohm resistive divider probes.

Applications General purpose probing, probing high-impedance nodes

(Š10 Kohm), op amp probing, CMOS probing (if bandwidth is adequate), TTL probing (if bandwidth is adequate).

The compensated passive divider probe is the most common type of scope probe. The 9-Mohm resistor in the tip forms a 10:1 voltage divider with the 1-Mohm input resistance of the scope.

To have a flat frequency response, the probe tip capacitance is compensated by the probe's cable capacitance, a compensating capacitor, and the scope input capacitance. The compensating capacitor is adjustable so you can optimize the step response for flatness.

Example Rise Time Calculation

Not all 9-Mohm divider probes work with all 1-Mohm scope inputs. The probe data sheet shows the range of scope input capacitance it can accommodate. You must make sure that the input capacitance of the scope is within that range.

Given the following circuit using an HP 1160A probe,

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

the input resistance is:

= R

= 9 Mohm + 1 Mohm = 10 Mohm

probe

+ R

scope

The capacitive load is:

= C

probe+Ccable+Ccomp+Cscope

tip

+ {[C

probe(Ccable+Ccomp+Cscope

]}

)]/

This number is calculated for the scope and scope probe combination, and is shown in the Table of Compatible Probes.

The total resistance is: R

= 10 Mohm(50ohm)/(10 Mohm + 50ohm) = 50 ohm

Tot al

Total

= (RinR

The rise time due to circuit loading is: t

source

)/(Rin + R

= 2.2R

TotalCin

source

)

tRC = 2.2(50 ohm)(7.5 pF) = 825 ps

From the Table of Compatible Probes, the bandwidth of the scope probe system is 500 MHz. Therefore, the rise time of the scope probe system is:

= 0.35/SystemBW

sys

= 0.35/500 MHz = 700 ps

sys

The measured rise time is:

= [(t

meas

= [(2 ns)2 + (825 ps)2 + (700 ps)2]

meas

)2 + (tRC)2 + (t

act

sys

)2]

1/2

= 2.27 ns

Remember that probe input impedance for compensated passive divider probes is complex. A simple RC network serves only as a firstorder approximation.

Current Probes

Features Measures both ac and dc currents on a scope, with minimal

circuit loading.

Tradeoffs Large size.

Applications Power measurements, automotive measurements,

industrial measurements, motors, dynamoes, and alternators.

Scopes are designed to measure voltage, but by using a current probe

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

you can measure current. A current probe measures current in a wire by enclosing the wire. Therefore, no electrical connection is needed.

Current probes generally use one of two technologies. The simplest uses the principle of a transformer, with one winding of the transformer being the measured wire. Because transformers only work with alternating voltages and currents, current probes of this type cannot measure direct current.

The other type of current probe uses the Hall effect principle. The Hall effect produces an electric field in response to an applied magnetic field. While this technique requires a power supply, it measures both alternating and direct current.

Differential Probes

Features High common mode rejection ratio, easy viewing of small

waveforms with large dc offsets, more accurate than subtracting one channel from another.

Tradeoffs Bigger than a passive probe, high cost, requires power, and

lower bandwidth than other probes.

Applications Measuring waveforms not referenced to the scope ground,

troubleshooting power supplies, and differential amplifier probing.

A differential probe is a high-impedance differential amplifier with two probe tips; a non-inverting input and an inverting input. These two inputs feed a differential amplifier which in turn drives the 50-ohm input of the scope. The main advantage of differential probes is their ability to reject waveforms that are common to both inputs. This type of probe is often used in floating ground applications.

You could duplicate a differential probe by using two passive probes and subtracting the two scope channels. However, the electrical paths of the differential probe are carefully matched to give a high common mode rejection ratio (CMRR). The higher the CMRR, the smaller the waveforms you can view in the presence of unwanted noise.

Resistive Divider Probes

Features Highest bandwidth, lowest capacitive load, lower cost than

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

active probes, flat pulse response, good timing measurement accuracy.

Tradeoffs Relatively heavy resistive loading.

Applications ECL probing, GaAs probing, and transmission line

probing.

Resistive divider probes are designed for scopes with a 50-ohm input impedance. The probe tips of the HP 1163A or HP 54006A have either a 450-ohm or 950-ohm series resistor. The probe cable is a 50-ohm transmission line. Because the cable is terminated in 50 ohms at the scope input, it looks like a purely resistive 50-ohm load when viewed from the probe tip. Therefore, the resistive divider probe is flat over a wide range of frequencies, limited primarily by the parasitic capacitance and inductance of the 450-ohm or 950-ohm resistor and the fixture that holds it. The resistive load of the probe to your circuit is either 500 ohm or 1 kohm, depending on the probe.

This type of probe has the smallest capacitive load of any probe. The small capacitance and wide bandwidth make this probe type a good choice for wide bandwidth measurements or time-critical measurements.

Example Rise Time Calculation

Given the following circuit using the HP 1163A probe,

the input resistance is: R

= R

+ R

tip

= 450 ohm + 50 ohm = 500 ohm

scope

The total resistance is: R

Tot al

= (RinR

source

)/(Rin + R

source

)

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Probing

= 500 ohm(50ohm)/(500 ohm + 50ohm) = 45 ohm

Tot al

The rise time due to circuit loading is:

= 2.2R

Tot alCtip

tRC = 2.2(45 ohm)(1.5 pF) = 165 ps

From the Table of Compatible Probes, the bandwidth of the scope probe system is 1.5 GHz. Therefore, the rise time of the scope probe system is:

= 0.35/SystemBW

sys

= 0.35/1.5 GHz = 230 ps

sys

The measured rise time is:

= [(t

meas

= [(2 ns)2 + (165 ps)2 + (230 ps)2]

meas

)2 + (tRC)2 + (t

act

sys

)2]

1/2

= 2.02 ns

Surface Mount Probing

The HP 10467A 0.5 mm MicroGrabber Accessory Kit is designed for using the HP 116x family of probes when you are probing fine-pitch (0.5 mm to 0.8 mm) SMT (Surface Mount Technology) devices. The kit contains enough parts for two probes.

The HP 116x probe tip plugs into the single-lead end of the dual-lead adapter. The MicroGrabber connects to the red lead. You can also use a MicroGrabber on the black lead, which you should connect to your circuit’s ground. You can also connect the dual-lead end to circuit pins that are 0.635 mm (0.025 inch) in diameter.

The kit is intended for use with voltages no greater than ±40 V (dc and ac peak).

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Acquiring a Waveform

The two ways to acquire a waveform with the oscilloscope are Autoscale and Run. When you use Run, you can modify settings to fine-tune your measurement.

You can also save acquired waveforms using waveform memories. (see page 78)

Autoscale

Autoscale automatically adjusts volts per division and offset so that the waveform fits into the display. It also attempts to set the seconds per division so that three periods of the waveform are displayed.

Specifying a Measurement

To set up a measurement, first specify the channel setup then the trigger. Based on your waveform you may need to change the offset and scale to get accurate measurements.

A faster way to set up your measurement is to first autoscale, then adjust only the settings you are interested in.

Running

The default acquisition mode is single-shot. To take another acquisition immediately after the first one, select Run with the right mouse button, then choose Repetitive from the menu. The Run button becomes Run(r).

The scope does not support any modes other than real-time mode. You can turn on averaging or accumulate under the Display tab. However, because of the way the oscilloscope samples, this is not the same as the equivalent time mode of a stand-alone oscilloscope.

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Acquiring a Waveform

NOTE: Clicking Run in an instrument window only runs that instrument. To run all

active instruments, select Run All in the System or Workspace window, or Group Run in the window of any instrument included in a group run. If the

scope is triggered by another instrument, do not change settings while the scope is waiting for its trigger or it may not trigger.

See Also “Run/Group Run Function” on page 92

“Autoscale” on page 32

“Specifying a Measurement” on page 33

“Using Waveform Memories” on page 78

“Differences from a Standard Digitizing Oscilloscope” on page 77

“Combining the Oscilloscope with a Logic Analyzer” on page 36

Autoscale

Autoscale automatically optimizes the waveform display for each channel that is turned on. It sets volts per division and offset so that the waveform fits into the middle of the display, and adjusts the timebase (horizontal axis) to show three periods. When signals have different periods, the signal on the lowest-numbered channel is used to set the horizontal scale. If none of the signals show activity, the timebase is set to 200 ns per division.

Autoscale also changes the trigger settings. The trigger channel is channel 1 unless the signal on channel 1 has no detectable voltage change. Triggering is limited to channels 1 and 2; no higher-numbered channels can be set, but they will be autoscaled. The trigger mode is set to the first rising edge and autotriggered. The trigger level is set to the 60% threshold of the signal. If both channel 1 and channel 2 have flat signals, the trigger source is set to channel 2 and the trigger level is set to channel 2’s offset.

The settings changed by autoscale are:

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Acquiring a Waveform

Setting Default Algorithm

V/div 200 mV/div Waveform fits within the middle (Scale) 6 divisions of the display

Channel Offset 0 Waveform is centered vertically

Sec/div 200 ns/div Fit three periods on screen (Scale)

Time offset 0 Always centers waveform around trigger (Delay)

Trigger mode rising edge Always sets trigger to rising edge

Trigger sweep autotrigger Always sets trigger to autotrigger

Trigger level not applicable Always sets level to near 60% threshold if a non-constant signal is detected

Trigger occurrence 1 Always sets occurrence to 1

Trigger source channel 1 Checks channel 1 for an active signal; if signal is flat, sets to channel 2

Specifying a Measurement

1. Connect probes. (see page 14)

2. Set up the channel. (see page 34)

3. Set the display mode. (see page 60)

4. Specify trigger. (see page 39)

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Acquiring a Waveform

5. Right-click Run, and specify single or repetitive.

6. Click Run to start the acquisition.

7. Save particular waveforms to waveform memory. (see page 78)

The data is automatically displayed in the oscilloscope window. You can also connect it to a display tool in order to correlate the oscilloscope with a logic analyzer.

See Also “Combining the Oscilloscope with a Logic Analyzer” on page 36

“Probing” on page 14

“Channel Setup Window” on page 34

“Display Setup Window” on page 60

“Triggering” on page 39

“Using Waveform Memories” on page 78

Channel Setup Window

To access the Channel Setup window, click Setup... under the Channels tab. Use this window to specify your probe type and probe impedance. After the initial setup, you may want to use this window to adjust channel skew.

On/Off Use this button to turn the channel on or off. You can also do

this from the main oscilloscope window.

Name Channel names can be a maximum of 10 characters long.

Customized names appear anywhere the channel is labeled.

Probe The probe attenuation factor. The arrow keys scroll through the

standard probe attenuation values, or you can enter non-standard values by typing in the field. Probe attenuation affects the display and marker measurements.

Input Z / Coupling Probe input impedance. Incorrect impedance will

cause bad measurements. See the “Table of Compatible Probes” on page 14 for suggested values.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Acquiring a Waveform

Skew Adjust for channel-to-channel skew caused by differing

electrical path lengths of the probes. To deskew the channels for multiboard oscilloscopes, run Channel Skew in the calibration utility.

Preset Select from TTL, ECL, and User. TTL sets the scale to 1 V/div

and the offset to 2.50 V. ECL sets the scale to 250 mV/div and the offset to -1.3 V. User defaults to TTL values, but if you change the Scale or Offset settings, the Preset field changes to User.

Scale Scale affects the vertical axis of the waveform display. You can

change it through either the arrow buttons or by typing in the field. It is the same scale field as in the main oscilloscope window.

Offset Offset moves the waveform vertically in the display window.

Parts of the waveform that go offscreen are clipped, which may affect any automatic measurements you run. The offset field also appears in the main oscilloscope window.

You can also display the Channel Setup window by pointing to a channel in the grid and clicking the right mouse button. Select Channels... from the menu.

See Also “Calibrating the Oscilloscope” on page 10

“Probing” on page 14

“Vertical and Horizontal Scaling” on page 53

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Combining the Oscilloscope with a Logic Analyzer

If you want to make a measurement with a logic analyzer and an oscilloscope, there are three cases:

•“Oscilloscope Triggers Logic Analyzer” on page 36

•“Logic Analyzer Triggers Oscilloscope” on page 37

•“Logic Analyzer and Oscilloscope Correlate Data” on page 37

See Also The Intermodule Window (see the HP 16600A/16700A Logic Analysis

System help volume) for a generic approach.

Oscilloscope Triggers Logic Analyzer

1. Click the Workspace icon.

2. In the workspace window, drag both instruments on to the workspace.

3. In the Correlation Error dialog that appears, select Group Run for the scope, and Oscilloscope for the logic analyzer.

4. Select the purple Group Run or the green Run All button to start the acquisition.

5. To view the waveforms together, open the display tool.

• For a Waveform display, right-click one of the labels and select Insert

before... or Insert after.... In the Label Dialog, click the label you want

to insert, then click Apply.

• For the other tools, the oscilloscope labels are already available.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Combining the Oscilloscope with a Logic Analyzer

Logic Analyzer Triggers Oscilloscope

NOTE: When the logic analyzer triggers the oscilloscope, if you are changing

oscilloscope settings when the trigger occurs it may be missed. The message bar and Run Status window show "Waiting for IMB Arm" when this occurs. When this happens, click Stop and restart the acquisition.

1. Click the Workspace icon.

2. In the Workspace window, drag both instruments on to the workspace.

3. Connect both to the same display tool.

4. In the Correlation Error dialog that appears, select Group Run for the logic analyzer and the logic analyzer description for the oscilloscope.

5. A Trigger Problem dialog box may appear. Select Trigger Immediate.

6. Select the purple Group Run or the green Run All button to start the acquisition.

7. To view the waveforms together, open the display tool.

• For a Waveform display, right-click one of the labels and select Insert

before... or Insert after.... In the Label Dialog, click the label you want

to insert, then click Apply.

• For the other tools, the oscilloscope labels are already available.

Logic Analyzer and Oscilloscope Correlate Data

1. Click the Workspace icon.

2. In the Workspace window, drag both instruments on to the workspace.

3. Connect both into same display tool.

4. In the Correlation Error dialog that appears, select Group Run for both instruments.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Combining the Oscilloscope with a Logic Analyzer

5. Select the purple Group Run or the green Run All button to start the acquisition.

6. To view the waveforms together, open the display tool.

• For a Waveform display, right-click one of the labels and select Insert

before... or Insert after.... In the Label Dialog, click the label you want

to insert, then click Apply.

• For the other tools, the oscilloscope labels are already available.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Trig ge ri ng

Triggering

The default trigger type is auto, which means the oscilloscope will trigger after 100 milliseconds. The trigger appears in the center of the acquisition. You can change where the trigger is in the data set by using the Delay field.

To specify more complicated triggers, click Trigger... at the bottom of the main oscilloscope window. This brings up the Trigger Setup Window.

You can also display the Trigger Setup window by pointing to the trigger marker and clicking the right mouse button. Select Trigge r... from the menu.

The area to the right of the Trigger button indicates the current trigger. It does not show details such as occurence count.

•“Trigger Concepts” on page 39

•“Edge Triggering” on page 41

•“Pattern Triggering” on page 42

•“Delayed Triggering” on page 43

•“Getting a Stable Trigger” on page 44

•“The Trigger Setup Window” on page 45

Trigger Concepts

Trigger B a s i cs

The scope trigger circuitry helps you locate the waveform you want to view. There are several types of triggering, but the one that is used most often is edge triggering. Edge triggering identifies a trigger

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Tr ig ge ri ng

condition by looking for the slope (rising or falling) and voltage level (trigger level) on the source you select. The trigger source is restricted to channel 1, channel 2, and the external trigger. If you have more channels on your oscilloscope, they cannot be used as trigger sources.

This figure shows the trigger circuit diagram.

Your waveform enters the positive input to the trigger comparator where it is compared to the trigger level voltage on the other input. The trigger comparator has a rising edge and a falling edge output. When a rising edge of your waveform crosses the trigger level, the rising edge comparator output goes high and the falling edge output goes low. When a falling edge of your waveform crosses the trigger level, the rising edge output goes low and the falling edge output goes high. The scope uses the output you have selected as the trigger output.

Aliasing and Triggering

While aliasing does not cause unstable triggering, it does make it difficult to tell when the scope is triggered. An aliased waveform can appear as a lower frequency waveform that drifts across the display. To ensure that your waveform is not aliased, you should decrease the horizontal scale to its minimum value (maximum sampling rate), then increase it to view your waveform.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Trig ge ri ng

Edge Triggering

Edge trigger is the default trigger setting. Edge mode sets the oscilloscope to trigger on an edge. You can set the source, trigger level, and slope in the oscilloscope main window. Clicking Trigg e r... brings up the Trigger Setup window, which lets you set the number of edges.

You can also display the Trigger Setup window by pointing to the trigger marker and clicking the right mouse button. Select Trigge r... from the menu.

The oscilloscope identifies an edge trigger by looking for the specified slope (rising edge or falling edge) of your waveform. Once the slope is found, the oscilloscope will trigger when your waveform crosses the trigger level.

If you set the source to External, the trigger level is fixed at -1.30 V.

NOTE: The oscilloscope always fills a certain amount of acquisition memory before

looking for a trigger. When counting edge occurrences, you may see more edges before the trigger than the number you specified. This happens because some edges were already in memory but are not included in the occurrence count.

When you set the trigger level on your waveform, it is usually best to set it to a voltage near the middle of your waveform. The middle range is best because there may be ringing or noise at the high and low ends which can cause false triggers.

When you adjust the arm level control, a horizontal dashed line with a T on the right-hand side appears, showing you where the arm level is with respect to your waveform. After a period of time the dashed line will disappear. You can get the line back by adjusting the arm level control again.

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Tr ig ge ri ng

Pattern Triggering

Pattern triggering is similar to the way that a logic analyzer captures data. This mode is useful when you are looking for a particular set of ones and zeros on a computer bus or control lines. You can use channel 1 and 2 and the external trigger to form the trigger pattern. Because you can set the voltage level that determines a logic 1 or a logic 0, any logic family that you are probing can be captured. Channels 3 through 8, available in multi-board oscilloscopes, cannot be used in the pattern.

You can display the Trigger Setup window by pointing to the trigger marker and clicking the right mouse button. Select Trigger... from the menu.

When Pattern

There are five ways you can use to further qualify the pattern that you want to view. They are:

Entered When the scope finds the pattern, it triggers on the edge of

the pulse that makes the pattern valid.

Exited The scope arms the trigger circuitry when it has found the

pattern and triggers on the edge of the pulse that ends the pattern.

Present > The scope triggers when the pattern is found and is present

for greater than the time value that you specify.

Present < The scope triggers when the pattern is found and is present

for less than the time value that you specify.

Range > The scope triggers when the pattern is present within the

time range that you specify.

NOTE: For Present >, Present <, and Range >, the oscilloscope does not trigger until

the pattern is exited.

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Trig ge ri ng

1. Set up a pattern by clicking the X after each channel name. X means the channel is not part of the pattern. Low and High let you set the threshold voltages for channel 1 and channel

2. Select the When Pattern that you want.

3. If you have selected Present >, Present <, or Range >, set the time values. The minimum is 20 ns, and the maximum is 160 milliseconds.

4. Close the Trigger Setup dialog box.

The area to the right of Trigger.. . shows the pattern you set up.

Delayed Triggering

You can delay the trigger by setting the Delay field. The Delay field changes the acquisiton delay. Acquisition delay is the amount of time between the trigger event and the center of the acquisition. It is the only way to change the pre-trigger and post-trigger amounts in the HP 16533A or HP 16534A Digitizing Oscilloscope.

To Store Mostly PostTrigger Data

The value shown in the Delay field is the sum of the acquisition delay and the display delay. The display delay is controlled by the scrollbar, and indicates which portion of the acquisition is currently being displayed.

1. Calculate 16,350 (about half the acquisition memory) divided by the sample rate. You should get a value in seconds.

2. Enter that value in the delay field. Use n for nanoseconds, u for microseconds, and m for milliseconds.

3. If the value is correct, the scrollbar will move to one end of its range and the current signal will not cross the entire display.

4. Click Run. The scrollbar returns to the middle. If you adjust the scrollbar before clicking Run, the oscilloscope treats the value as a display delay only.

To store mostly pre-trigger data, calculate the same value and enter it

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Tr ig ge ri ng

as a negative number.

To Re-center the Trigger in the Acquisition

See Also “Vertical and Horizontal Scaling” on page 53

1. Drag the scrollbar to the center of the scroll area. There is a slight delay in movement when the bar is at the center.

2. Set Delay at the bottom of the window to 0 seconds, and press enter. The scrollbar may jump away from the center. Do not reset it.

3. Click Run to get a new acquisition.

Getting a Stable Trigger

For most waveforms, the easiest way for you to get a stable trigger is to use Autoscale. Autoscale analyzes your waveform and sets the trigger mode to edge and the vertical scale, horizontal scale, and trigger level to best display your waveform.

Manual Triggering

While Autoscale is the easiest way to obtain a stable trigger, there are times when you may need to set the trigger manually to capture more complex waveforms. To stabilize these waveforms:

• Set the Trigger Level to the proper point on the waveform. The proper point is usually somewhere around 50% to avoid possible ringing and noise at the top and base voltages.

• Increase the sampling rate to avoid aliasing. The sampling rate is controlled by the horizontal scale at the bottom of the screen. The maximum sampling rates are 1 gigasample per second for the HP 16533A and 2 gigasamples per second for the HP 16534A.

• Set the Trigger Sweep to Triggered for low-frequency waveforms. The Trigger Sweep field is in the Trigger Setup dialog.

• Remove noise from your waveform.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

You can display the Trigger Setup window by pointing to the trigger marker and clicking the right mouse button. Select Trigger... from the menu.

See Also “The Trigger Setup Window” on page 45

“Autoscale” on page 32

“Changing the Sample Rate” on page 55

The Trigger Setup Window

The Trigger Setup window is for setting up complex triggers. You access it by clicking Tri g g e r... at the bottom of the main oscilloscope window.

Trig ge ri ng

Edge

Pattern

The two selections that are always availabe in the window are Mode and Sweep. Mode specifies the type of condition you want to trigger on. Sweep indicates whether the oscilloscope should wait for the condition (Tri ggered ) or trigger immediately if the condition doesn’t show up in 100 milliseconds (Auto).

Edge mode sets the oscilloscope to trigger on an edge. You can specify the source, trigger level, slope, and occurrence.

If you set the source to External, the trigger level is fixed at -1.30 V.

Use pattern mode for triggering on glitches or unusually long pulses, or for a trigger involving 2 channels.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Tr ig ge ri ng

To Trigger on a Glitch

1. Click Trigger.. .

2. Set the mode to Pattern and the sweep to Triggered.

3. Specify the glitch source by setting it to high or low. An X means the channel is not part of the pattern.

4. Click the button under When Pattern and choose Present <.

5. Set the duration field to less than your clock’s pulse width.

Immediate

Use immediate mode when the oscilloscope is triggered by another instrument in the measurement, or to acquire data as soon as you click Run. No other levels or settings may be specified for this mode.

You can also display the Trigger Setup window by pointing to the trigger marker and clicking the right mouse button. Select Trigge r... from the menu.

See Also “Edge Triggering” on page 41

“Pattern Triggering” on page 42

“Trigger Concepts” on page 39

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Changing Waveform Display and Grid

•“Zooming In” on page 47

•“Changing the Persistence of the Waveform” on page 47

•“Viewing Noisy Waveforms with Averaging” on page 49

•“Changing Display Colors” on page 51

•“Changing the Grid” on page 51

Zooming In

To zoom in on a particular area of your waveform, move the mouse to one corner of the area, press the left mouse button, drag the mouse to the diagonally opposite corner, and release the button.

To undo zoom, right-click in the display area and select Undo Zoom. You can also select Setup->Undo Zoom from the menu bar.

Zoom may change your vertical scale (V/div), offset value, horizontal scale (timebase or s/div), and scrollbar position to match the current section of the waveform as though you had acquired it in that state. When the new settings exceed limits, the display change does not occur. This is most likely to happen with extreme negative delays and detailed vertical scaling (V/div). You may be able to zoom in if you enclose a larger area in the zoom.

If you Run then Undo Zoom, the original settings will be restored, but your waveform may look wrong. The gaps are due to clipping; the HP 16533A or HP 16534A oscilloscopes treat clipped data by leaving it at the top and bottom edges of the display.

Changing the Persistence of the Waveform

Normally, a waveform is displayed only for one acquisition. When the

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Changing Waveform Display and Grid

next run occurs, the previous waveform is erased and the newly acquired waveform is drawn on the display.

By using accumulate, you can see a visual history of a waveform’s acquisitions over time. For example, you can see the accumulated peak-to-peak noise of a waveform over time which may appear significantly different than in only one acquisition. You can see timing jitter, the variance of the waveform from the trigger event, by accumulating acquisitions on the display. By using accumulate, viewing a waveform’s extremes over time is much easier.

Waveform mode sets the amount of time a waveform sample appears on the display. Automated measurements cannot be performed on accumulated waveforms but will be performed on the most recent waveform in acquisition memory. Waveform accumulation does not occur beyond the display area boundary.

The HP 16533A or HP 16534A Digitizing Oscilloscope have three waveform modes: Normal, Accumulate, and Average.

Normal

In the normal waveform mode, a waveform data point is displayed for at least 10 ms or one trigger cycle then erased. If no further triggers occur, the last acquisition is left on the display. This is the default setting. Use this mode for the fastest display update rate.

Accumulate

Accumulate is most like infinite persistence. In the accumulate waveform mode, a waveform sample point is displayed until settings are changed. All sample points are shown at full intensity. Use accumulate to measure jitter or eye diagrams, see a waveform’s envelope, look for timing violations, and find infrequent events.

Average

When Averaging is enabled, the # Avgs control tells the oscilloscope the number of waveforms you want to use in calculating the average value for each sample point. The HP 16533A or HP 16534A oscilloscopes can average from 2 to 512 waveform acquisitions but the larger the number of acquisitions, the more time it will take to

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Changing Waveform Display and Grid

accumulate all the waveforms you have requested.

NOTE: If you are using Accumulate or Average and you change the vertical or

horizontal scaling, position, offset, trigger source or level, zoom, or drag the waveform then the display is redrawn and any accumulated waveforms are cleared. Only the last acquisition is displayed. Set up markers and any measurements before using accumulate or averaging. Adding markers or clearing measurements later can erase acquired waveforms.

See Also “Viewing Noisy Waveforms with Averaging” on page 49

“Display Setup Window” on page 60

Viewing Noisy Waveforms with Averaging

The Waveform Average mode under Display tells the oscilloscope to acquire waveforms from several acquisitions and average them all together, point by point. The greater the number of averages, the less impact each new waveform has on the composite averaged waveform. The perceived display update rate is slowed down as the number of averages is increased because the averaged waveform doesn’t change as much.

Sometimes, a waveform consists of a signal along with some random or asynchronous noise. By using Waveform Average, these noise sources can average to zero over time while the underlying waveform is preserved. This will improve the accuracy of waveform measurements because measurements are made on a more stable waveform and measurement variances are reduced. The effective resolution of the displayed waveform also improves as more acquisitions are averaged together, providing the input waveform is repetitive and has a stable trigger point.

Incidentally, if Waveform Average is enabled but the scope is not properly triggering (perhaps the scope is set to Auto trigger and the wrong trigger channel is selected), you may not see the waveform you expect on the display. In this case, the input waveform is asynchronous to the scope and will average to zero over time even though a non-zero input waveform is being measured.

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Changing Waveform Display and Grid

When Waveform Average is enabled, the # Avgs control sets the number of waveforms you want to use in calculating the average value for each sample point. The HP 16533A or HP 16534A can average from 2 to 512 waveform acquisitions but the larger the number of acquisitions, the more time it will take to accumulate all the waveforms you have requested.

The following formula is used to calculate the average for each data point:

For n between 1 and M. After terminal count is reached (n greater than or equal to M),

where:

= the average sample value

Ave

n = the current average number M = setting of # Avgs control (terminal count)

= the ith sample.

See Also “Changing the Persistence of the Waveform” on page 47

“Trigger Concepts” on page 39

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Changing Waveform Display and Grid

“Getting a Stable Trigger” on page 44

Changing Display Colors

The display colors which indicate channels, memories, and markers are editable. These colors are also used by the display tools in the rest of the logic analysis system.

To Change Colors

1. In the menu bar, select Setup.

2. Select Display... The Display Setup dialog appears.

3. Under Colors, select the channel to modify.

4. Click the color you want it to be.

5. Click Edit Colors... to change a color's value.

NOTE: If you Close the Color Edit box, the new color values will be used in this

session only. If you Apply the color values, they will be used in this session and following sessions. To restore the factory colors, click Reset Defaults.

Changing the Grid

The HP 16533A or HP 16534A Digitizing Oscilloscope has a 10 by 8 display graticule grid which you can turn on or off. When on, a grid line is place on each vertical and horizontal division. When the grid is off, a frame with tic marks surrounds the graticule edges.

You can dim the grid’s intensity or turn the grid off to better view waveforms which the graticule lines might obscure. Otherwise, you can use the grid to estimate waveform measurements such as amplitude and period. The grid intensity control doesn’t affect printing. You must explicitly turn the grid off to remove the grid from a hardcopy.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Changing Waveform Display and Grid

1. In the menu bar, select Setup.

2. Select Display... The Display Setup dialog appears.

3. Click the Grid Type button to change the grid to axes-only scales, frameonly scale, or a background grid. The intensity field controls the brightness. You cannot change the grid color.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Vertical and Horizontal Scaling

The vertical scale is volts per division (V/div). Changing the vertical scale affects the height of the waveform. Extreme changes to the vertical scale can affect your offset values. If the waveform extends beyond the top or bottom of the display, data will be clipped. You cannot measure clipped data, and when you adjust the offset or vertical scale, clipped data stays at the top or bottom edge with a break in the waveform.

The horizontal scale is seconds per division (s/div). Changing the horizontal scale compresses and expands a waveform, and changes the sampling rate. The automatic measurements only measure what is currently shown in the display window, however.

Compressing the waveform may cause your sample rate to slow down. Similarly, expanding your waveform may cause your sample rate to increase, up to 1 gigasample per second for the HP 16533A or 2 gigasamples per second for the HP 16534A. See the table in “Changing the Sample Rate” on page 55 for timebase and sampling rates.

The vertical (V/div) scale control is located under the Channels tab. The horizontal (s/div) scale control is located at the bottom left corner of the oscilloscope window.

Scrolling

The scrollbar below the display indicates what portion of the current data set you are viewing. Its size shows the percentage of the data you are looking at, and its location indicates the location of the data within the data set.

You can scroll through your data set by dragging the scrollbar. You can also use the Delay field, but this may change your acquisition delay as described in “Delayed Triggering” on page 43.

To scroll short distances, drag the waveforms or trigger reference marker. Individual waveforms can also be dragged vertically. Dragging waveforms does change the delay and offset fields and will affect your next acquisition.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Vertical and Horizontal Scaling

When you click Run after having moved the scrollbar, the display shows the same section of the data set that you were viewing before. For example, if you had the scrollbar at the right end, you were viewing the last part of the data set. When you click Run, the oscilloscope acquires more data and again displays the last portion.

Sometimes you may not be able to move the scrollbar through the entire scrolling area. This is because you have increased the sample rate. The scrolling area indicates the size of the next acquisition, but you can only move the scrollbar through the area filled with the current data set. You can use the Delay arrows to move the scrollbar past its dragging limits.

See Also “Delayed Triggering” on page 43

“Changing the Sample Rate” on page 55

“Channel Setup Window” on page 34

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Changing the Sample Rate

The s/div scale controls the sample rate. The relationship is shown in a table at the end of this topic.

The sample rate is displayed in the bottom left corner of the display area. The maximum sample rate is 1 gigasamples per second for the HP 16533A and 2 gigasamples per second for the HP 16534A. The minimum sample rate is 500 samples per second.

Aliasing

Aliasing occurs when the sample rate is not at least four times as fast as the high frequencies of your waveform. If you cannot see why the oscilloscope triggered, or if the waveform moves around on screen, or if the waveform looks slower than it should, suspect aliasing. To increase your sample rate, set the s/div scale to a higher number, then run again.

See Also “Trigger Concepts” on page 39

s/div Sample Rate

< 200 ns 2 GSa/s

500 ns 1 GSa/s

1 us 500 MSa/s

2 us 250 MSa/s

5 us 100 MSa/s

10 us 50 MSa/s

20 us 25 MSa/s

50 us 10 MSa/s

100 us 5 MSa/s

200 us 2.5 MSa/s

500 us 1 MSa/s

1 ms 500 KSa/s

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Changing the Sample Rate

2 ms 250 KSa/s

5 ms - 20 ms 100 KSa/s

50 ms 50 KSa/s

100 ms 25 KSa/s

200 ms 10 KSa/s

500 ms 5 KSa/s

1 s 2.5 KSa/s

2 s 1 KSa/s

5 s 500 Sa/s

Comparing Channels

The HP 16533A or HP 16534A Digitizing Oscilloscope do not support waveform math (A+B or A-B). However, you can easily overlay

waveforms by putting the 0 V indicators ( ) on top of each other, and making sure the waveforms have the same scale. The automatic measurements are done on only one waveform, however.

Using waveform memories, you can also compare a waveform from a previous acquisition to the current display. The waveform must be loaded into memory when it is captured. The captured waveform can be displayed either with the current scale settings or with the ones used when it was captured.

What Do the Display Symbols Mean?

All the indicators around the edge of the grid are draggable.

Local voltage marker. The color indicates which channel it is measuring.

Local time marker. Time markers are channel independent.

Trigger event indicator.

Global marker. The global markers measure time and retain their position within the total acquisition of all instruments in a Group Run.

Trigger level indicator. The color indicates which channel it is set on.

0 V (ground) indicator. The color indicates which channel it is set on. The 0 V indicator is controlled by the offset setting. When offset is negative, the 0 V indicator is above the center line. When offset is positive, the 0 V indicator is below the center line. Also referred to as offset indicator.

Offscreen indicator. The color indicates which channel it is set on. The offscreen indicator appears when the 0 V indicator moves offscreen.

Display Setup Window

The settings under Display control how waveforms are displayed. Only "Acquisition Memory to Display" affects acquisitions.

Waveform Mode

Normal

Accumulate draws subsequent waveforms in the same area, without

is the default setting. It shows the current acquisition only.

erasing previous waveforms. The accumulated waveforms are erased if any settings are changed, however.

Average averages the current acquisition with the specified number of

prior acquisitions. All acquisitions are equally weighted. The averaged waveforms are replaced with the current acquisition if any settings are changed.

Acquisition Memory to Display

For lower time resolutions, these settings allow you to optimize the oscilloscope for greater detail or longer duration. All gives greater detail by sampling more frequently. Partial stretches the acquisition memory over a longer duration by slowing down the sample rate. These settings do not make a difference when the horizontal scale is finer than 1.00 microsecond/division for an HP 16533A, or 500 nanoseconds/ division for an HP 16534A.

Setup...

The Setup... button opens the Display Setup window. This window contains the same controls under the Display tab, and also lets you change the graticule and waveform colors.

Clear Display

The Clear Display button removes all channels from the graticule. It does not affect waveform memories or markers.

See Also “Changing the Persistence of the Waveform” on page 47

Chapter 1: HP 16533/34A Digitizing Oscilloscope

“Changing Display Colors” on page 51

“Changing the Grid” on page 51

Display Setup Window

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Automatic Measurements and Algorithms

Automatic measurements are simpler and usually more accurate to make than the corresponding measurement done manually. (Manual measurements and simple statistics are done using markers; see “Using Markers” on page 75.) Blank values in the automatic measurement field means that requirements for that measurement were not met. For specific measurements, see the list below.

•“How the Scope Makes Measurements” on page 63

•“Average Voltage (Vavg)” on page 64

•“Base Voltage (Vbase)” on page 67

•“Fall Time” on page 65

•“Frequency” on page 66

•“Maximum Voltage (Vmax)” on page 70

•“Minimum Voltage (Vmin)” on page 70

•“Negative and Positive Pulse Width (±Width)” on page 65

•“Overshoot” on page 69

•“Peak-to-Peak Voltage (Vpp)” on page 69

•“Period” on page 64

•“Preshoot” on page 68

•“Rise Time” on page 64

•“Time of Maximum Voltage (Tmax)” on page 71

•“Time of Minimum Voltage (Tmin)” on page 71

•“Top Voltage (Vtop)” on page 67

•“Voltage Amplitude (Vamp)” on page 71

•“Vdcrms (Root Mean Square Voltage, DC)” on page 71

See Also “About the Measurements” on page 72

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Automatic Measurements and Algorithms

“Increasing the Accuracy of Your Measurements” on page 74

“Autoscale” on page 32

How the Scope Makes Measurements

Automatic parametric measurements are calculated from a histogram. Measurements are done as soon as valid data is available. The absolute minimum and maximum are derived from the histogram.

Next, the statistical top and base values are calculated. The top 40% of the histogram is scanned for the top value and the bottom 40% is scanned for the base value. The center 20% of the histogram is not scanned to prevent selecting the middle of a tri-state waveform.

The measurement algorithm decides whether the absolute maximum and minimum values should be used, as in the case of triangle waveforms, or the statistical top and base should be used, as in the case of square waveforms.

After the top and base are calculated, the IEEE 10%, 50%, and 90% thresholds are calculated. These thresholds determine edges and are used by all timing measurements. For example, rise time is measured from the lower threshold to the 90% threshold of a rising edge. Period, frequency, and pulse width measurements use the 50% threshold.

Once the thresholds have been calculated, the edges can be determined. A rising edge is defined as a transition that passes through the 10%, 50%, and 90% threshold levels. A falling edge is defined as a transition that passes through the 90%, 50%, and 10% threshold levels. For an edge to be detected, it must complete the transition through all

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Automatic Measurements and Algorithms

three threshold levels.

Once the oscilloscope locates rising and falling edges, it calculates rise time, fall time, and frequency. If too few sample points fall along an edge, the measurement is not made. The oscilloscope ignores incomplete transitions.

Average Voltage (Vavg)

Vavg is the average voltage of waveform data over the display. It does not include data that is offscreen. The value is calculated by summing all the data points on the screen and dividing by the number of them.

Period

Period is defined as the time between the 50% threshold crossings of two consecutive, like-polarity edges.

The HP 16533A or HP 16534A Digitizing Oscilloscope starts the measurement at the leftmost edge of the display.

Rise Time

Rise time is defined as the time at the 90% threshold minus the time at the 10% threshold on the edge you are measuring.

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Automatic Measurements and Algorithms

The HP 16533A or HP 16534A Digitizing Oscilloscope starts the measurement at the leftmost edge of the display.

Fall Time

Fall time is defined as the time at the 10% threshold minus the time at the 90% threshold on the edge you are measuring.

The HP 16533A or HP 16534A Digitizing Oscilloscope starts the measurement at the leftmost edge of the display.

Negative and Positive Pulse Width (±Width)

Negative pulse width is defined as the time from the 50% threshold of the first falling edge to the 50% threshold of the next rising edge.

Positive pulse width is defined as the time from the 50% threshold of the first rising edge to the 50% threshold of the next falling edge.

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Automatic Measurements and Algorithms

Negative Pulse Width

Positive Pulse Width

The HP 16533A or HP 16534A Digitizing Oscilloscope starts the measurement at the leftmost edge of the display.

Frequency

Frequency is defined as 1/Period. Period is the time between the 50% threshold crossings of two consecutive, like-polarity edges.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Automatic Measurements and Algorithms

The HP 16533A or HP 16534A Digitizing Oscilloscope starts the measurement on the first edge of the leftmost portion of the display.

Base Voltage (Vbase)

Vbase is the voltage of the statistical minimum level of the waveform display, which is defined as the most frequently occurring voltage in the histogram of the bottom 40% of the waveform.

Vbase may be equal to Vmin for many waveforms, such as triangle waveforms. Similarly, Vtop may be equal to Vmax.

This measurement is position-independent and the entire display is used for the measurement.

Top Voltage (Vtop)

Vtop is the voltage of the statistical maximum level of the waveform display, which is defined as the most frequently occurring voltage in

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Automatic Measurements and Algorithms

the histogram of the top 40% of the waveform.

Vtop may be equal to Vmax for many waveforms, such as triangle waveforms. Similarly, Vbase may be equal to Vmin.

This measurement is position-independent and the entire display is used for the measurement.

Preshoot

Preshoot is a waveform distortion that precedes an edge transition.

If the edge is rising, preshoot will be 100*(base - local minimum)/ (top

- base). The local minimum is found half way from the 10% threshold

level to the 10% threshold level at the previous falling edge.

If the edge is falling, preshoot will be 100*(local maximum - top)/(top base). The local maximum is found half way from the 90% threshold level to the previous 90% threshold level at the previous rising edge.

The HP 16533A or HP 16534A Digitizing Oscilloscope starts the measurement at the first edge of the leftmost portion of the display.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Automatic Measurements and Algorithms

Overshoot

Overshoot is a waveform distortion that follows a major edge transition.

If the edge is rising, the overshoot will be 100*(local maximum - top)/ (top - base). The local maximum is found half way from the 90% threshold level to the next 90% threshold level at the falling edge.

If the edge is falling, the overshoot will be 100*(base - local minimum)/ (top - base). The local minimum is found half way from the 10% threshold level to the next 10% threshold level at the next rising edge.

The HP 16533A or HP 16534A Digitizing Oscilloscope starts the measurement at the first edge on the leftmost portion of the display.

Peak-to-Peak Voltage (Vpp)

Peak-to-peak voltage is defined as Vmax - Vmin. Vmax is the absolute maximum voltage of the display. Vmin is the absolute minimum voltage of the display.

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Automatic Measurements and Algorithms

This measurement is position-independent and the entire display is used for the measurement.

Minimum Voltage (Vmin)

Vmin is the absolute minimum voltage of the waveform display.

This measurement is position-independent and the entire display is used for the measurement.

Maximum Voltage (Vmax)

Vmax is the absolute maximum voltage of the waveform display.

This measurement is position-independent and the entire display is used for the measurement.

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Automatic Measurements and Algorithms

Time of Minimum Voltage (Tmin)

Tmin is the first time that the minimum voltage occurs on the display.

This measurement is position-independent and the entire display is used for the measurement.

Time of Maximum Voltage (Tmax)

Tmax is the first time that the maximum voltage occurs on the display.

This measurement is position-independent and the entire display is used for the measurement.

Voltage Amplitude (Vamp)

Vamp is the amplitude of the waveform display. Vamp = Vtop - Vbase.

This measurement is position-independent and the entire display is used for the measurement.

Vdcrms (Root Mean Square Voltage, DC)

Vdcrms is the root-mean-square voltage of the waveform. The equation

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Automatic Measurements and Algorithms

used is:

This measurement is position-independent and the entire display is used for the measurement. Data points offscreen are not included.

About the Measurements

The HP 16533A or HP 16534A Digitizing Oscilloscope makes measurements after every trigger event, always maintaining continuity between the measurement results and the oscilloscope display. This makes sure that no aberration in the waveform under observation is missed.

If the waveform is clipped, the oscilloscope cannot make some automatic measurements. These measurements will show clipped where a value would normally appear. Other indicators you may see are:

? Value is questionable. This can occur because the signal is

clipped, there are not enough points, or the amplitude is too small.

< The result is less than or equal to the value shown. This can

occur when the waveform is clipped low or not enough points are available.

> The result is greater than or equal to the value shown. This

can occur when the waveform is clipped high or not enough points are available.

(blank) No value could be calculated. The most common reason is

missing edges, such as when the display shows less than a full period of a waveform.

The HP 16533A or HP 16534A will interpolate sample points if necessary to determine pulse parameters for automatic measurements. Excessive interpolation can lead to jitter on measurements; if this

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Automatic Measurements and Algorithms

occurs you may have to increase the sample rate.

By default, the oscilloscope uses the IEEE thresholds of 10, 50, and 90 percent for pulse measurements. A rising or falling edge is only recognized after passing through all three thresholds. These thresholds appear on the example pulse waveform as shown below:

Period and Frequency Measurements

At least one full cycle of the waveform with at least two like edges must be displayed for period and frequency measurements. Automatic waveform measurements use a single pulse and may have significant errors introduced by interpolation and trigger inaccuracies. The leftmost cycle is used for making measurements.

Pulse Width Measurements

For either the -Width or +Width measurements, a complete pulse must be displayed to make a valid measurement. Remember that an edge must pass through all three thresholds to be recognized as an edge. Therefore, it is important that the pulse be positioned so that both pulse edges transition through all three thresholds and are displayed on the screen. Pulse width is measured from the leftmost valid edge to the next valid edge.

Rise Time, Fall Time, Preshoot, and Overshoot Measurements

The leading, rising edge of the waveform must be displayed for rise time and rising edge preshoot and overshoot measurements. The trailing, falling edge of the waveform must be displayed for fall time and falling edge preshoot and overshoot measurements. The leftmost edge is used for measurements.

Remember that an edge must pass through all three thresholds to be

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Automatic Measurements and Algorithms

recognized as an edge. Therefore, it is important that the pulse be positioned so that all three thresholds are displayed on the screen. Rise time, fall time, preshoot, and overshoot measurements will be more accurate if you expand the edge of the waveform by choosing a faster sweep speed. Expanding the waveform will provide more data points on an edge, reduce interpolation, and thus provide a more accurate measurement.

Increasing the Accuracy of Your Measurements

Things you can do to make your measurements more accurate:

• Deskew the oscilloscope channels. To deskew the oscilloscope channels, perform the Channel Skew procedure as part of calibrating the oscilloscope (see page 10).

• Use automatic measurements where possible.

• For positive and negative pulse width, make sure enough top and bottom

voltages are showing to accurately calculate the top and base voltages.

• When using markers, increase the sampling rate.

• Minimize the effect of DC errors on time measurements by

• measuring between identical edges (same slew rate, amplitude and

offset).

• using the same DC level to reference each endpoint of the interval.

• performing the measurement on the fastest-slewing portion of each

edge.

• making the waveform as large as possible.

• Calibrate (see page 10) your oscilloscope after it has warmed up.

See Also “Getting a Stable Trigger” on page 44

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Using Markers

The HP 16533A or HP 16534A Digitizing Oscilloscope has both local and global markers. The local markers can only be used within the oscilloscope window. The global markers retain their position across the data sets of all instruments that are part of the same group run as the oscilloscope.

The global markers are G1 and G2 and only measure time. The local markers consist of four voltage markers, V1 - V4, and two time markers, T1 and T2.

To access the markers, click the Markers tab then click Setup.... The

Marker Setup dialog appears, from which you can turn on any of the markers by clicking on the appropriate button. From this dialog, you can also change the channel of the voltage markers.

The information after this does not apply to automatic time markers. Those are covered in a separate topic listed below.

When the markers are turned on, you can set their values by dragging them. If a marker moves offscreen because of scrolling or from typing in a value in the Marker Setup window, you can return it to the edge of the display by clicking the arrow buttons in the Marker Setup window.

You can also place markers by pointing to the area you want the marker on and clicking the right mouse button. Select Place Marker and the marker you want from the menu. If your cursor is on a marker already, select Markers... to display the Marker Setup dialog.

See Also “What Do the Display Symbols Mean?” on page 58

“About Automatic Time Markers” on page 76

Working with Global Markers in Correlated Displays (see the Markers help volume)

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Using Markers

About Automatic Time Markers

Automatic time markers indicate the time at which a specified voltage crossing occurs. For instance, if you scroll the display, an automatic time marker defined for the third edge will automatically reposition itself on the edge third from the left. A regular time marker would remain placed on the waveform and scroll with it off the display.

When you turn on an automatic time marker, Min T2-T1, Max T2-T1, and Mean T2-T1 appear at the bottom of the Markers area. You can gather statistics as long as both time markers are on, and one is an automatic marker. Changing any part of the display will clear statistics.

To turn on automatic time markers

1. Under Markers, click Setup...

2. Click the time marker.

3. Click Marker [OFF] to turn on the marker.

4. Click Automatic [OFF] to put it in automatic mode.

5. Click Define Automatic Marker... If you did not put the marker in automatic mode, the area to the right of T1 or T2 is a time from trigger setting.

6. Specify the automatic setting. Percentage level is based on the automatically calculated top and base voltage.

Automatic time markers cannot be dragged when they are on their specified edge. If the specified edge does not exist, they can be dragged like regular time markers.

See Also “Top Voltage (Vtop)” on page 67

“Base Voltage (Vbase)” on page 67

“How the Scope Makes Measurements” on page 63

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Differences from a Standard Digitizing Oscilloscope

There are some differences between an HP 16533A or HP 16534A Digitizing Oscilloscope and a standard stand-alone digitizing oscilloscope.

• Clipped data (data that is offscreen at acquisition) stays at the top or bottom edge of the display area when the clipped waveform is resized or has the offset moved. The waveform appears to have a gap in it where the clipped data was.

• Repetitive run is repetitive real-time acquisitions, not what is also referred to as equivalent-time mode.

• When there are not enough data points to map at least one sample to each column of pixels in the display, the sin(x)/x interpolation filter is on. You cannot turn it off.

• There is only one graticule area. All oscilloscope channels are sampled and displayed at the same rate.

• The HP 16533A or HP 16534A oscilloscope is easier to use in conjunction with a logic analyzer because arming is handled by the HP 16600A-series or HP 16700A frame. You do not need to connect any wires between the two modules.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Using Waveform Memories

The four waveform memories store copies of waveforms for display within the oscilloscope tool. The memories cannot be exported to other display tools.

To Use Waveform Memory

This procedure assumes you already have acquired a waveform that you want to store.

1. Under Memories, click Setup...

2. In the Load Waveform area, select the waveform source. The button text depends on your setup, but the default is channel 1.

3. Click Load. Sources can be any channel or another waveform memory. If the source does not contain any data (for example, the channel was off during the last acquisition), "Waveform data is not valid!" appears briefly at the top of the Waveform Memory Setup window. If the display is set to accumulate or average, only the last acquired waveform is loaded.

4. To view the memory, click the Off radio button.

5. To make the memory display independent of the main display controls, click the box to the left of Horizontal. This enables the independent horizontal scale controls.

Waveform memories are erased between sessions. They are not cleared when the display is cleared. In all other ways, waveform memories are treated like channels by the display functions.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Loading and Saving Oscilloscope Configurations

Oscilloscope settings and data can be saved to a configuration file. You can also save any tools connected to the oscilloscope. Later, you can restore your data and settings by loading the configuration file into the oscilloscope.

• Loading Configuration Files (see the HP 16600A/16700A Logic Analysis System help volume)

• Saving Configuration Files (see the HP 16600A/16700A Logic Analysis System help volume)

Chapter 1: HP 16533/34A Digitizing Oscilloscope

When Something Goes Wrong

•“Error Messages” on page 80

•“Calibration Problems” on page 80

•“Triggering Problems” on page 80

•“Other Problems” on page 81

Error Messages

• No valid signals have been found. (see page 82)

• Incorrect Calibration Factors for this software revision. (see page 83)

• Waiting for IMB Arm. (see page 83)

Calibration Problems

Calibration is not possible because NV RAM is protected

Unprotect the NV RAM and try again.

Calibration Procedure did not complete successfully

The Calibration window shows which tests passed and failed. If any test failed and all cables were correctly hooked up, you should contact your Hewlett-Packard Service Center.

Triggering Problems

Scope loses trigger when changes made to offset

The trigger level may be too high or too low to reliably trigger before autotrigger. Sometimes this over-sensitivity to offset is caused by too

Chapter 1: HP 16533/34A Digitizing Oscilloscope

When Something Goes Wrong

high an attenuation factor in the channel setup.

Low frequency waveform appears to have unstable trigger

See “Getting a Stable Trigger” on page 44.

Nothing happening

If the scope is being triggered by another instrument, and you were changing some settings, the scope may have missed its trigger signal.

The other common causes when the trigger is set to Triggered are

• trigger level occurs outside normal signal

• the oscilloscope is waiting for a rare event

You can either stop the oscilloscope or set the trigger to Auto to look for these conditions.

Specifications and Characteristics

NOTE: Specifications are valid after a 30 minute warm-up period, and within 10 °C

from the firmware calibration temperature.

NOTE: Definition of Terms To understand the difference between specifications (see

page 89) and characteristics (see page 89), and what gets a calibration procedure (see page 90) and what gets a function test (see page 90), refer to appropriate links within this note.

• Specifications (see page 85)

• Operating Environment (see page 86)

• Characteristics (see page 86)

Specifications

Note: Specifications refer to the input to the BNC connector.

Bandwidth HP 16533A dc to 250 MHz HP 16534A dc to 500 MHz

dc offset accuracy ±(1% of offset + 2% of full scale)

dc voltage measurement accuracy ±(1.25% of full scale + offset accuracy + 0.016 div)

Time interval measurement accuracy ±[(0.005% of *T) + (2e-6 x delay setting) at maximum sampling rate, on a + 100 ps] single card, on a single acquisition

Trigger sensitivity from 10 mV/div to 10 V/div dc to 50 MHz 0.25 div 50 MHz to 500 MHz 0.5 div

Trigger sensitivity at 4 mV/div dc to 50 MHz 0.63 div

Operating Environment

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Specifications and Characteristics

50 MHz to 500 MHz 1.25 div

Input resistance 1 Mohm ± 1% 50 ohm ± 1%

Power Requirements All power supplies required for operating the oscilloscope are supplied through the backplane connector in the logic analysis system.

Operating Environment Characteristics The oscilloscope module's reliability is enhanced when operating the module within the following ranges:

- Indoor use only.

- Temperature: +20 degrees C to +35 degrees C

(+68 degrees F to +95 degrees F)

- Humidity: 20% to 80% noncondensing

Characteristics

General

Maximum sampling rate HP 16533A 1 GSa/S HP 16534A 2 GSa/S

Number of channels 2 to 8 channels using the same timebase and trigger.

Waveform record length 32768 points

Vertical (Voltage)

(characteristics refer to the input at the BNC connector)

Vertical sensitivity range 4 mV/div to 10 V/div in 1:2:4 steps

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Specifications and Characteristics

Vertical resolution 8 bits over 4 vertical divisions

Rise time (calculated from bandwidth) HP 16533A 1.4 ns HP 16534A 700 ps

dc gain accuracy ±(1.25% of full scale + 0.08% per °C difference from calibration temperature)

dc offset range (1:1 probe) Vertical sensitivity Offset range 4 mV/div - 100 mV/div ±2 V 100 mV/div - 400 mV/div ±10 V 400 mV/div - 2.5 V/div ±50 V

2.5 V/div - 10 V/div ±250 V

Probe attenuation Any ratio from 1:1 to 1000:1 factor

Channel-to-channel isolation (with channel sensitivities equal) dc to 50 MHz 40 dB 50 MHz to 250 MHz (HP 16533A) 30 dB 50 MHz to 500 MHz (HP 16534A) 30 dB

Maximum safe input voltage 1 Mohm ±250 Vdc + peak ac (<10KHz), CAT I 50 ohm 5 Vrms, CAT I

Input coupling 1 Mohm ac, dc 50 ohm dc only

Input C approximately 7 pF

Number of channels: 2,4,6, or 8 simultaneous channels using the same trigger OR up to 10 channels with independent triggers for each pair of channels. Maximum of 20 channels with HP 16701A expansion frame.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Specifications and Characteristics

Horizontal (Time)

Timebase ranges 0.5 ns/div to 5 s/div

Timebase resolution 10 ps

Delay range, pre-trigger 81.8 s, 5 divisions

Delay range, post-trigger 2.5e3 seconds

Time interval measurement accuracy ±[(0.005% of *T) + (2e-6 x delay setting) for sampling rates other than + (0.15/sample rate)] maximum, for bandwidth-limited signals (signal rise time > 1.4/sample rate) on a single card, on a single acquisition

Time interval measurement accuracy ±[(0.005% of *T) + (2e-6 x delay setting) for 2, 3, or 4 cards operation on + 550 ps] a single timebase, for measurements made between channels on different cards, at maximum sampling rate

Tr ig ge r

Trigger level range Within display window (vertical offset ± 2 divisions)

Immediate trigger mode Triggers immediately after arming condition is met

Edge trigger mode Triggers on rising or falling edge on channel 1 or channel 2

Pattern trigger mode Triggers on entering or exiting a specified pattern across both channels

Auto condition trigger mode Self-triggers if trigger is not satisfied within approximately

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Specifications and Characteristics

100 ms after arming

Events delay trigger mode The trigger can be set to occur on the nth occurrence of an edge or pattern, n <= 32000

Intermodule trigger mode Arms another measurement module or acti vates a trigger output on the rear panel BNC connector when the trigger condition is met

What is a Specification

A Specification is a numeric value, or range of values, that bounds the performance of a product parameter. The product warranty covers the performance of parameters described by specifications. Products shipped from the factory meet all specifications. Additionally, the products sent to HP Customer Service Centers for calibration and returned to the customer meet all specifications.

Specifications are verified by Calibration Procedures.

What is a Characteristic

Characteristics describe product performance that is useful in the application of the product, but that is not covered by the product warranty. Characteristics describe performance that is typical of the majority of a given product, but not subject to the same rigor associated with specifications.

Characteristics are verified by Function Tests.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Specifications and Characteristics

What is a Calibration Procedure

Calibration procedures verify that products or systems operate within the specifications. Parameters covered by specifications have a corresponding calibration procedure. Calibration procedures include both performance tests and system verification procedure. Calibration procedures are traceable and must specify adequate calibration standards.

Calibration procedures verify products meet the specifications by comparing measured parameters against a pass-fail limit. The pass-fail limit is the specification less any required guardband.

The term "calibration" refers to the process of measuring parameters and referencing the measurement to a calibration standard rather than the process of adjusting products for optimal performance, which is referred to as an "operational accuracy calibration".

What is a Function Test

Function tests are quick tests designed to verify basic operation of a product. Function tests include operator’s checks and operation verification procedures. An operator’s check is normally a fast test used to verify basic operation of a product. An operation verification procedure verifies some, but not all, specifications, and often at a lower confidence level than a calibration procedure.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Help - How to Navigate Quickly

1. Place mouse cursor anywhere in a help window.

2. Press the right mouse button.

3. Select desired destination.

You can also access all navigation and search commands from the help window menu bar.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Run/Group Run Function

• Setting a tool for independent or Group Run (see page 93)

• Setting Single or Repetitive Run (see page 94)

•“Checking Run Status” on page 94

Understanding Run/Run All/Group Run

The Run/Run All/Group Run buttons initiate data capture in the instrument tools you have configured. When an instrument tool is connected to analysis or display tools, any of the tools can initiate a run. When two or more instrument tools are configured, you can run them independently or as a group. Two or more instruments running as a group is called an Intermodule measurement.

Use the Intermodule Window (see the HP 16600A/16700A Logic Analysis System help volume) to coordinate the run function of multiple instruments as a "Group Run". A common "Group Run" configuration is to run the instrument tools at the same time. A more advanced measurement is to configure one instrument to arm another instrument, each with their own trigger conditions.

• Run appears in the setup dialog and icon menu of an instrument if it is not part of an Intermodule measurement.

• Group Run appears in the setup dialog and icon menu of each tool if two or more instruments are configured for an Intermodule measurement.

• Run All always appears in the System, Workspace and Run Status windows, and initiates a run in all configured instruments, whether they are run independently or are part of a Group Run.

Intermodule measurements are configured between individual instruments. Arming between two machines that belong to one analyzer is configured in the Arming Info... dialog found in the Tri gg e r window of the analyzer.

Understanding Stop/Stop_All/Cancel

• Stop will terminate an individual instrument measurement that is running.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Run/Group Run Function

(perhaps waiting for a trigger condition)

• Stop All, when selected from the Workspace, will terminate running measurements from all instruments currently on the Workspace.

• Cancel will terminate the processing of trace data from an instrument to an analysis or display tool connected to its output.

See Also “Demand Driven Data” on page 95

Setting a tool for independent or Group Run

Use the Intermodule Window to change between Group Run and independent Run.

• Click the Intermodule icon in the System Window, OR

• Use Navigate->System->Intermodule

In the Intermodule window, move instruments between independent Run and Group Run by clicking the icon and selecting the desired arming source. All instruments in "Group Run" will run simultaneously.

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Run/Group Run Function

Setting Single or Repetitive Run

A single measurement will stop after memory is full or a store qualification is met. A repetitive measurement executes successive Single measurements until Stop is selected.

When a single or repetitive measurement is stopped, only data that has been captured to that point is available for viewing.

Select single or repetitive by right-clicking on the Run button in the tool’s setup window.

If you have problems displaying trace data when running Repetitive measurements, see “Demand Driven Data” on page 95.

Checking Run Status

The Run Status dialog provides status information about the currently configured instruments, and the status of the run with respect to the trigger specification.

To access the Run Status dialog:

• The Run Status icon in the System Window, OR

• Navigate->System->Run Status

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Run/Group Run Function

Demand Driven Data

When an analyzer measurement occurs, acquisition memory is filled with data that is then transferred to the display memory of the analysis or display tools you are using, as needed by those tools. In normal use, this demand driven data approach saves time by not transferring unnecessary data.

Since acquisition memory is cleared at the beginning of a measurement, stopping a run may create a discrepancy between acquisition memory and the memory buffer of connected tools. Without a complete trace of acquisition memory, the display memory will appear to have ’holes’ in it which appear as filtered data.

This situation will occur in these cases:

• If you stop a repetitive measurement after analyzer data has been cleared and before the measurement is complete.

• If a trigger is not found by the analyzer and the run must be stopped to regain control.

To make sure all of the data in a repetitive run is available for viewing:

• In the workspace, attach a Filter tool to the output of the analyzer.

• In the Filter, select "Pass Matching Data"

• In the filter terms, assure the default pattern of all "Don't Cares" (Xs).

Chapter 1: HP 16533/34A Digitizing Oscilloscope

Run/Group Run Function

This configuration will always transfer all data from acquisition memory. While this configuration will increase the time of each run, it will guarantee that repetitive run data is available regardless of when it is stopped.

Glossary

absolute Denotes the time period or count of states between a captured state and the trigger state. An absolute count of -10 indicates the state was captured ten states before the trigger state was captured.

acquisition Denotes one complete cycle of data gathering by a measurement module. For example, if you are using an analyzer with 128K memory depth, one complete acquisition will capture and store 128K states in acquisition memory.

analysis probe A probe connected to the target microprocessor. It provides an interface between the signals of the target microprocessor and the inputs of the logic analyzer. Also called a "preprocessor".

analyzer 1 In a logic analyzer with two machines, refers to the machine that is on by default. The default name is Analyzer<N>, where N is the slot letter.

analyzer 2 In a logic analyzer with two machines, refers to the machine that is off by default. The default name is Analyzer<N2>, where N is the slot letter.

instruments are armed immediately when Run or Group Run is selected. You can set up one instrument to arm another using the Intermodule Window. In these setups, the second instrument cannot search for its trigger condition until it receives the arming signal from the first instrument. In some analyzer instruments, you can set up one analyzer machine to arm the other analyzer machine in the Trigger Window.

asterisk (*) See edge terms, glitch, and labels.

bits Bits represent the physical logic analyzer channels. A bit is a channel that has or can be assigned to a label. A bit is also a position in a label.

card This refers to a single instrument intended for use in the HP 16600A-series or HP 16700A mainframe. One card fills one slot in the mainframe. A module may comprise a single card or multiple cards cabled together.

channel The entire signal path from the probe tip, through the cable and module, up to the label grouping.

arming An instrument tool must be armed before it can search for its trigger condition. Typically,

click To click an item, position the cursor over the item. Then quickly press and release the left mouse

Glossary

button.

clock channel A logic analyzer

channel that can be used to carry the clock signal. When it is not needed for clock signals, it can be used as a data channel, except in the HP 16517A.

context record A context record is a small segment of analyzer memory that stores an event of interest along with the states that immediately preceded it and the states that immediately followed it.

context store If your analyzer can perform context store measurements, you will see a button labeled Context Store under the Trigger tab. Typical context store measurements are used to capture writes to a variable or calls to a subroutine, along with the activity preceding and following the events. A context store measurement divides analyzer memory into a series of context records. If you have a 64K analyzer memory and select a 16state context, the analyzer memory is divided into 4K 16-state context records. If you have a 64K analyzer memory and select a 64-state context, the analyzer memory will be divided into 1K 64-state records.

count The count function records

periods of time or numbers of state transactions between states stored in memory. You can set up the analyzer count function to count occurrences of a selected event during the trace, such as counting how many times a variable is read between each of the writes to the variable. The analyzer can also be set up to count elapsed time, such as counting the time spent executing within a particular function during a run of your target program.

cross triggering Using intermodule capabilities to have measurement modules trigger each other. For example, you can have an external instrument arm a logic analyzer, which subsequently triggers an oscilloscope when it finds the trigger state.

data channel A channel that carries data. Data channels cannot be used to clock logic analyzers.

data field A data field in the pattern generator is the data value associated with a single label within a particular data vector.

data set A data set is made up of all labels and data stored in memory of any single analyzer machine or instrument tool. Multiple data sets can be displayed together when sourced into a single display tool. The

Glossary

Filter tool is used to pass on partial data sets to analysis or display tools.

debug mode See monitor.

delay The delay function sets the

horizontal position of the waveform on the screen for the oscilloscope and timing analyzer. Delay time is measured from the trigger point in seconds or states.

demo mode An emulation control session which is not connected to a real target system. All windows can be viewed, but the data displayed is simulated. To start demo mode, select Start User Session from the Emulation Control Interface and enter the demo name in the Processor Probe LAN Name field. Click Help in the Start User Session window for details.

deskewing To cancel or nullify the effects of differences between two different internal delay paths for a signal. Deskewing is normally done by routing a single test signal to the inputs of two different modules, then adjusting the Intermodule Skew so that both modules recognize the signal at the same time.

don’t care For terms, a "don’t care" means that the state of the signal (high or low) is not relevant to the

measurement. The analyzer ignores the state of this signal when determining whether a match occurs on an input label. "Don’t care" signals are still sampled and their values can be displayed with the rest of the data. Don’t cares are represented by the X character in numeric values and the dot (.) in timing edge specifications.

dot (.) See edge terms, glitch, labels, and don’t care.

double-click To double-click an item, position the cursor over the item, and then quickly press and release the left mouse button twice.

drag and drop To drag and drop an item, position the cursor over the item, and then press and hold the left mouse button. While holding the left mouse button down, move the mouse to drag the item to a new location. When the item is positioned where you want it, release the mouse button.

edge mode In an oscilloscope, this is the trigger mode that causes a trigger based on a single channel edge, either rising or falling.

edge terms Logic analyzer trigger resources that allow detection of transitions on a signal. An edge term can be set to detect a rising edge,

Glossary

falling edge, or either edge. Some logic analyzers can also detect no edge or a glitch on an input signal. Edges are specified by selecting arrows. The dot (.) ignores the bit. The asterisk (*) specifies a glitch on the bit.

emulation module A module within the logic analysis system mainframe that provides an emulation connection to the debug port of a microprocessor. An E5901A emulation module is used with a target interface module (TIM) or an analysis probe. An E5901B emulation module is used with an E5900A emulation probe.

emulation probe The stand-alone equivalent of an emulation module. Most of the tasks which can be performed using an emulation module can also be performed using an emulation probe connected to your logic analysis system via a LAN.

emulator An emulation module or an emulation probe.

Ethernet address See link-level address.

events Events are the things you are looking for in your target system. In the logic analyzer interface, they take a single line. Examples of events

are Label1 = XX and Timer 1 > 400 ns.

filter expression The filter expression is the logical OR combination of all of the filter terms. States in your data that match the filter expression can be filtered out or passed through the Pattern Filter.

filter term A variable that you define in order to specify which states to filter out or pass through. Filter terms are logically OR’ed together to create the filter expression.

Format The selections under the logic analyzer Format tab tell the logic analyzer what data you want to collect, such as which channels represent buses (labels) and what logic threshold your signals use.

frame The HP 16600A-series or HP 16700A logic analysis system mainframe. See also logic analysis system.

gateway address An IP address entered in integer dot notation. The default gateway address is 0.0.0.0, which allows all connections on the local network or subnet. If connections are to be made across networks or subnets, this address must be set to the address of the

100

Agilent 16534A Help Volume

Specifications and Main Features

Frequently Asked Questions

User Manual

Contents

Calibrating the Oscilloscope

Calibration Reference

Probing

Table of Compatible Probes

Selecting the Proper Probe

Compensating the Compensated Passive Divider Probe

Probe Loading

Descriptions of Probe Types

1:1 Passive Probes

Active Probes

Compensated Passive Divider Probes

Current Probes

Differential Probes

Resistive Divider Probes

Surface Mount Probing

Acquiring a Waveform

Autoscale

Specifying a Measurement

Channel Setup Window

Combining the Oscilloscope with a Logic Analyzer

Oscilloscope Triggers Logic Analyzer

Logic Analyzer Triggers Oscilloscope

Logic Analyzer and Oscilloscope Correlate Data

Trig ge ri ng

Trigger Concepts

Edge Triggering

Pattern Triggering

Delayed Triggering

Getting a Stable Trigger

The Trigger Setup Window

Changing Waveform Display and Grid

Zooming In

Changing the Persistence of the Waveform

Viewing Noisy Waveforms with Averaging

Changing Display Colors

Changing the Grid

Vertical and Horizontal Scaling

Changing the Sample Rate

Comparing Channels

What Do the Display Symbols Mean?

Display Setup Window

Automatic Measurements and Algorithms

How the Scope Makes Measurements

Average Voltage (Vavg)

Period

Rise Time

Fall Time

Negative and Positive Pulse Width (±Width)

Frequency

Base Voltage (Vbase)

Top Voltage (Vtop)

Preshoot

Overshoot

Peak-to-Peak Voltage (Vpp)

Minimum Voltage (Vmin)

Maximum Voltage (Vmax)

Time of Minimum Voltage (Tmin)

Time of Maximum Voltage (Tmax)

Voltage Amplitude (Vamp)

Vdcrms (Root Mean Square Voltage, DC)

About the Measurements

Increasing the Accuracy of Your Measurements

Using Markers

About Automatic Time Markers

Differences from a Standard Digitizing Oscilloscope

Using Waveform Memories

Loading and Saving Oscilloscope Configurations

When Something Goes Wrong

Error Messages

Calibration Problems

Triggering Problems

Other Problems

Error Message: No Valid Signals

Error Message: Incorrect Calibration Factors

Status Message: Waiting for IMB Arm