USE AND ABUSE OFOSCILLOSCOPES

Featuring the Agilent 54600B

Digital Oscilloscope

Safety Tips

Protect YourselfAvoid contact with Voltage

or Current Sources

Use shrouded test leads and alligator clips.

Connect leads to oscilloscope first.

Connect probe to ground before connecting to high.

Familiarize yourself with the manual.

Introduction

ground

channel inputsexternal trigger

power switch

intensity knob

Power Switch

• This switch turns the oscilloscope onand off.

Intensity Knob• This knob adjusts the brightness of

the display

• If no trace is seen, it may be because theintensity knob is set too low.

Ground Connection

• This connection may be used to groundprobes.

Signal Inputs (1 & 2)

• These connections are used to connectcoaxial cable, probes, etc. to the oscilloscope.

• The outside of the connector is grounded.

External Trigger

• This connector is used to connect an externaltriggering source.

Voltage Indicators

Vrms = Vp · .707 (Sine wave)

VppVrms Vp

f = 1/T = 2f

Frequency and PeriodPeriod, T

f1( )t

DC Offset

V

Duty Cycle

Less than 50% (Pulse Train) Tl = Th

Th

Tl

50 % (Square Wave) Tl = Th

Tl Th

Calibration

Oscilloscope Calibration• To check the oscilloscope calibration, connect

a probe to channel one and to the calibrationprong.

• If the oscilloscope does not read approx. 5Vand 1.2 kHz, notify lab supervisor.

Probe Calibration• With the probe still connected to the

calibration prong, check to see if the wave issquare.

• If the wave is not square, use a smallscrewdriver to adjust the probe until the waveis square.

Properly Calibrated Overcompensated Undercompensated

General Oscilloscope Overview

Connecting a Signal• Make sure the input voltage level 400 V.

• Connect a BNC cable or a probe to a channelinput.

• Connect the other end of the cable or probeto the device to be measured.

Positioning a Signal Vertically• Use the vertical position knob (located above

the channel input connector) to position thesignal vertically on the screen.

Positioning a SignalHorizontally

• Use the delay knob to move the signalhorizontally.

• Note the value displayed on the status line.

Setting the Time Base

• Turn the time/div knob to adjust the sweepspeed (time base).

• The sweep speed has a range from 2ns to 5s.

Triggering the Signal

Using the Level Knob• Use the level knob to set the trigger

voltage.

• The screen will display the trigger level ininverse video and a horizontal linerepresenting the trigger location.

Source Menu

• Use this menu to assign a trigger source.

• The choices are line, CH1, CH2 and external.

Mode Menu

• Use this menu to choose a trigger mode.

• The choices are auto level, auto, normal,single, and TV.

Making AutomaticMeasurements

Voltage Menu• Use this menu to make automatic voltage

measurements.

• Measurements include peak to peak voltage,rms voltage, max voltage, etc. The choice is made using the softkeys below the display.

Time Menu

• Use this menu to measure frequency, period,duty cycle, risetime, etc.

Cursor Menu• This menu brings up a list of cursor

commands and activates the cursor knob.

• The cursors can be used to measure specificvoltages, times, etc.

Vertical Section

addition menu

position knob

volts per division volts per division

position knob

channel menu channel menu

Horizontal Section

delay knob

time per division

main/delayed menu

Trigger Section

trigger level knob

holdoff knob

source menu

slope/coupling menu

mode menu

Miscellaneous Sections

cursor menuvoltage menu

print/utilityautoscale

cursor knobtrace menu

time menusetup menu

display menu

erase keyrun key

stop key autostore

Storage Section

Presentation byTimothy Cameron, Ph.D.

Assistant Professor of Mechanical EngineeringGMI Engineering & Management Institute

Visual Aids and Production Assistance byMark Sawko

Senior, Manufacturing Systems Engineering, GMIJeff Hana

Freshman, Engineering, GMI

Equipment Provided byAgilent Technologies, Electronic Measurement Division

For More Information

• Agilent 54600B User’s Guide

• Agilent 54654A Training Kit

USE AND ABUSE OFOSCILLOSCOPES

Featuring the Agilent 54600B

Digital Oscilloscope

•Safety Tips

• Front & Rear Panel Layout

• Signal Features

Introduction

Protect Yourself: Avoid contact with Voltage or Current Sources• Use shrouded test leads and alligator clips.• Leads: Connect to oscilloscope first;

Connect/disconnect at source so loose lead is dead.• Connect probe to ground before connecting to high.

Protect the Scope:• 400V maximum on input.• Use probes to reduce high voltages.• Be familiar with user’s guide.

Safety Tips

Front Panel Features

Intensity Ground

Power

Inputs External Trigger

Measurement

Vertical Scale

Storage

Triggering

Hortizontal Scale

Save/Recall

Calibration

Autoscale/Display/Print

Voltage Indicators

Vrms = 0.707 Vp (Sine wave)

VppVrms Vp

time

Frequency and PeriodPeriod

( )t

Tf

T 1

Hz

rad/s

time

2 f

DC Offset

V

0

Duty Cycle - Pulse Waveforms

THIGH

TLOW

TLOW

THIGH

50%Duty Cycle

20%Duty Cycle

Duty Cycle = % of Period where signal is high

Square Wave:50% Duty Cycle

Risetime / Falltime - Pulse Waveforms

10%

90%

falltimerisetime

0%

100%

• Autoscale

• Averaging, Vpp

Angular VelocityMagnetic Pickup

• Autoscale

• Main/delay,Risetime, Falltime,Vmax, Vmin, Vtop, Vbase

Cable ImpedancePatch Cords vs. Z-matched Co-ax

• Autoscale

• Roll Mode

Natural FrequencyAccelerometer

• Single Trigger

• Single Triggering,Cursors,Time Reference,Storage

Beam FrequencyStrain-Gaged Beam

Beam Frequency & Damping

x(t)

1

2

-1

-20 0.02 0.10.04 0.06 0.08

12

3 4

x0

Tn

x4

n Tn

2 rad s

LogarithmicDecrement

1 x

2

n xnln

Equation of Motion ( mass normalized )

x t nx t n x t f tm

..( )

.( ) ( ) ( ) 2 2

o

• Autoscale

• Trigger Channel, HF Reject

Voltage Across a CapacitorResistor and Capacitor

• Autoscale

• Averaging, Phase cursors, XY mode

Speed of SoundSpeaker and Microphone

Speed of Sound

c = speed of sound f = frequency (Hz)

c f

distance

wavelength

Phase Relationships

Phase, tT 360

timereferencesignal

variablesignal

Tt

Probe Calibration —Calibration Tab

• Autoscale

• Calibration,Vectors

• Autoscale

• Trigger Holdoff

Triggering a Serial PatternAgilent 54654A Training Kit, pt 3

Detecting Periodic Glitches

Agilent 54654A Training Kit, pt 4

• Autoscale

• Autostore

• Autoscale

• Peak Detect

Detecting Narrow PulsesAgilent 54654A Training Kit, pt 6

• Impedance

• Calibration

• Probe Effects

Impedance and Calibration

• Magnitude and Phase Relationships

• Impedance Notation

• Impedance Examples

• Impedance Measurement

Impedance

Magnitude & Phase Relationships

Magnitude Ratio

GA

AV

R

Phase

t

T360

timereferencesignal

variablesignal

Ar

Av

T

t

Impedance NotationIm(Z)

Re(Z)R

XG

Magnitude/Phase Notation

Z G

G Z R X

XR

›

| |

tan

2 2

1

Complex Notation

Z R jX

R Z G

X Z G

Re( ) cos

Im( ) sin

Impedance Examples

Electrical Curcuits (Ohm’s Law):

Mechanical Impedance:

Acoustic Impedance:

V I Z ZV

I

Force at a PointVelocity at the Point

Z Avg. Sound Pressure over Surface (p)Volume Velocity thru Surface (u)

Measurement Impedance

Without Probe With Probe

f = frequency (Hz)

Z

Rj f C

V

V

Z

R Z

GV

V

in

inin

o

in

in

o in

oo

in

11

2

20

log

Vin

Ro

Rin

Cin

Test instrument

Vo

Vin

Ro

Rp

Rin

Cin

Test instrument

ProbeCp

Vp

Z

Rj f C

V

V

Z

R Z Z

GV

V

p

pp

p

in

in

o in p

pp

in

11

2

20

log

Gain Comparison

Frequency (Hz)

Gai

n (d

B)

with 10:1 probe

without probe

-20

0

106

1010

107

108

109

For Agilent 54600B Digital OscilloscopeAgilent 54600B oscilloscope:

Rin = 1 MCin = 13 pf

Agilent 33120A function generator:R0 = 50

Agilent 10071A X10 probe:Tune to oscilloscope

Oscilloscope Calibration• Connect probe to calibration lead

• If oscilloscope does not read approx. 5V and1.2 kHz, contact Hewlett Packard.

Probe Calibration• Use calibration lead to check wave

squareness

• If wave is not square, use a small screwdriverto adjust the probe until the wave is square.

Properly Calibrated Overcompensated Undercompensated

• Aliasing

• Triggering

• Analog vs. Digital

Digital Issues

Aliasing

No Aliasingfsampling> 2 fsignal

Aliasingfsampling< 2 fsignal

Triggering

Triggering level

+ Slope

- Slope

1Delay

Digital Advantages

• Image Storage - High Intensity• Negative Time• Simultaneous Multichannel Measurement

(No Chop or Alternate)• Automatic Measurements • Hardcopy Output • Export Data to Computer

• Autoscale

• Fast DisplayUpdate

• Self Test

AGILENT 54600B Special Features

Developed and Presented byTimothy Cameron, Ph.D.

Assistant Professor of Mechanical EngineeringGMI Engineering & Management Institute

Visual Aid and Production Assistance by GMI StudentsMark Sawko Jeff HanaSenior, Mfg Systems Freshman, Engrg

Technical AdvisorsMarsh Faber Gary HammondAgilent Technologies Professor, Mech Eng, GMI

Equipment Provided by Agilent Technologies

Produced By

GMI Engineering & Management InstituteVideo & Satellite Operations

References

• Electronic Instrument Handbook, 2nd EditionClyde F. Coombs, EditorMcGraw-Hill, New York, 1995

• Electronic Test Measurements, Theory and ApplicationsRobert A. WittePrentice-Hall, Englewood Cliffs, NJ, 1993

For More Information

• Agilent 54600 Series User and Service Guide

• Call Agilent Direct at 1-800-829-4444, orContact Your Local Agilent Representative