ASTM E1324-21

Standard Guide for Measuring Some Electronic Characteristics of Ultrasonic Testing Instruments

SIGNIFICANCE AND USE
4.1 The recommended measurement procedures described in this guide are intended to provide performance-related measurements that can be reproduced under the specified test conditions using commercially available test instrumentation. These measurements indicate capabilities of sections of the ultrasonic testing instrument independent of specific transducers or examination conditions. Measurements are made from normally available connectors or test points so that no access to internal circuitry is required. Further, this guide is not intended for service, calibration, or maintenance of circuitry for which the manufacturer's instructions are available. It is intended primarily for pulse echo flaw detection instruments operating in the nominal frequency range of 100 kHz to 25 MHz, but the procedures are applicable to measurements on instruments utilizing significantly higher frequency components.  
4.2 These procedures can be applied to the evaluation of any pulse-echo ultrasonic testing instrument which can be described as a combination of the electronic sections discussed in this guide.
Note 2: These procedures are not intended to preclude the use or application of equipment for which some or all of the measurement techniques of this document are not applicable.  
4.3 An ultrasonic testing instrument that cannot be completely described as a combination of the electronic sections discussed in this practice can be partially evaluated. Each portion of the ultrasonic testing instrument that is evaluated must fit the description for the corresponding section.  
4.4 This guide is meant to be used by electronic personnel to evaluate the electronic system components and not the ultrasonic system characteristics.
SCOPE
1.1 This guide describes procedures for electronically measuring the following performance-related characteristics of some sections of ultrasonic instruments:  
1.1.1 Power Supply Section:  
line regulation,
battery discharge time, and
battery charge time.  
1.1.2 Pulser Section:
pulse shape,
pulse amplitude,
pulse rise time, pulse length, and
pulse frequency spectrum.  
1.1.3 Receiver Section:
vertical linearity,
frequency response,
noise and sensitivity, and
dB controls.  
1.1.4 Time Base Section:
horizontal linearity, and
clock (pulse repetition rate).  
1.1.5 Gate/Alarm Section:
delay and width,
resolution,
alarm level,
gain uniformity,
analog output, and
back echo gate.  
1.2 This guide complements Practice E317 and is not intended for evaluating the performance characteristics of ultrasonic testing instruments on the inspection/production line.  
Note 1: No access to internal circuitry is required.  
1.3 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-May-2021
• ICS: 19.100 - Non-destructive testing
• Technical Committee: E07 - Nondestructive Testing
• Drafting Committee: E07.06 - Ultrasonic Method

Relations

• Refers: ASTM E1316-24 - Standard Terminology for <?Pub Dtl?>Nondestructive Examinations
• Effective Date: 01-Feb-2024
• Refers: ASTM E1316-19b - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Dec-2019
• Refers: ASTM E1316-19 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Mar-2019
• Refers: ASTM E1316-18 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Jan-2018
• Refers: ASTM E1316-17a - Standard Terminology for Nondestructive Examinations
• Effective Date: 15-Jun-2017
• Refers: ASTM E1316-17 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Feb-2017
• Refers: ASTM E1316-16a - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Aug-2016
• Refers: ASTM E1316-16 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Feb-2016
• Refers: ASTM E1316-15a - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Dec-2015
• Refers: ASTM E1316-15 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Sep-2015
• Refers: ASTM E1316-14e1 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Jun-2014
• Refers: ASTM E1316-14 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Jun-2014
• Refers: ASTM E1316-13d - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Dec-2013
• Refers: ASTM E1316-13c - Standard Terminology for Nondestructive Examinations
• Effective Date: 15-Jun-2013
• Refers: ASTM E1316-13b - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Jun-2013

Overview

ASTM E1324-21, titled Standard Guide for Measuring Some Electronic Characteristics of Ultrasonic Testing Instruments, provides a comprehensive framework for evaluating the electronic performance of ultrasonic testing (UT) instruments. Developed by ASTM International, this standard guides electronic personnel in performing reproducible, performance-related electronic measurements of UT systems. Its target applications are primarily pulse-echo flaw detection instruments operating in the 100 kHz to 25 MHz frequency range, although the procedures may be applicable to higher frequencies.

ASTM E1324-21 is designed to assess instrument capabilities independently of transducers or specific test conditions. All measurements are made using standard connectors or test points, ensuring no access to internal circuitry is required. The guide is not intended for service, calibration, or maintenance requiring manufacturer-specific instructions.

Key Topics

The standard is organized by the main electronic sections of ultrasonic testing instruments:

• Power Supply Section
  • Evaluates line regulation, battery discharge time, and battery charge time
• Pulser Section
  • Measures pulse shape, amplitude, rise time, duration (length), and frequency spectrum
• Receiver Section
  • Assesses vertical linearity, frequency response, noise and sensitivity, and dB controls
• Time Base Section
  • Checks horizontal linearity and clock (pulse repetition rate)
• Gate/Alarm Section
  • Investigates delay and width, resolution, alarm level, gain uniformity, analog output, and back echo gate

The guide clearly outlines that each section of an instrument can be independently tested, making it suitable even for partial evaluations. Additionally, all procedures use commercially available test equipment, supporting widespread applicability.

Applications

ASTM E1324-21 is primarily used in laboratory environments to:

• Perform comparative evaluations of electronic sections within ultrasonic testing instruments
• Establish baseline performance metrics for new instruments or post-maintenance verification
• Support quality control initiatives where consistent instrument performance is critical
• Assist in product comparisons for procurement or specification development
• Facilitate regulatory compliance by referencing an internationally recognized measurement methodology

This guide is not intended for in-process production line evaluations or as a replacement for the manufacturer’s recommended maintenance procedures. It is best suited for trained electronic personnel who possess competence in the use of measurement and calibration equipment.

Related Standards

ASTM E1324-21 complements and references several important standards, including:

• ASTM E317 - Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-Echo Testing Instruments and Systems
• ASTM E1316 - Terminology for Nondestructive Examinations
• ISO 10012 - Measurement Management Systems-Requirements for Measurement Processes and Measuring Equipment
• ISO 17025 - General Requirements for the Competence of Testing and Calibration Laboratories
• IEEE Std. 100 - IEEE Standard Dictionary of Electrical and Electronics Terms

These standards collectively provide a solid foundation for measurement consistency, terminology, and lab competence, further supporting the effective application of ASTM E1324-21 in the field of nondestructive testing.

---

By following ASTM E1324-21, organizations ensure that the electronic characteristics of their ultrasonic testing equipment are accurately measured and documented, promoting instrument reliability and data integrity in critical inspection processes.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E1324 − 21
Standard Guide for
Measuring Some Electronic Characteristics of Ultrasonic
Testing Instruments
This standard is issued under the fixed designation E1324; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* mathematical conversions to SI units that are provided for
information only and are not considered standard.
1.1 This guide describes procedures for electronically mea-
1.4 This standard does not purport to address all of the
suring the following performance-related characteristics of
safety concerns, if any, associated with its use. It is the
some sections of ultrasonic instruments:
responsibility of the user of this standard to establish appro-
1.1.1 Power Supply Section:
priate safety, health, and environmental practices and deter-
line regulation,
mine the applicability of regulatory limitations prior to use.
battery discharge time, and
1.5 This international standard was developed in accor-
battery charge time.
dance with internationally recognized principles on standard-
1.1.2 Pulser Section:
ization established in the Decision on Principles for the
pulse shape,
Development of International Standards, Guides and Recom-
pulse amplitude,
mendations issued by the World Trade Organization Technical
pulse rise time, pulse length, and
Barriers to Trade (TBT) Committee.
pulse frequency spectrum.
1.1.3 Receiver Section:
2. Referenced Documents
vertical linearity,
frequency response,
2.1 ASTM Standards:
noise and sensitivity, and
E317PracticeforEvaluatingPerformanceCharacteristicsof
dB controls.
Ultrasonic Pulse-Echo Testing Instruments and Systems
1.1.4 Time Base Section:
without the Use of Electronic Measurement Instruments
horizontal linearity, and
E1316Terminology for Nondestructive Examinations
clock (pulse repetition rate).
2.2 ISO Standards:
1.1.5 Gate/Alarm Section:
ISO 10012 Measurement Management Systems—
delay and width,
Requirements for Measurement Processes and Measuring
resolution,
Equipment
alarm level,
ISO 17025General Requirements for the Competence of
gain uniformity,
Testing and Calibration Laboratories
analog output, and
2.3 Other Standard:
back echo gate.
IEEE Std. 100,IEEE Standard Dictionary of Electrical and
1.2 This guide complements Practice E317 and is not
Electronics Terms
intended for evaluating the performance characteristics of
ultrasonic testing instruments on the inspection/production
3. Summary of Guide
line.
3.1 The electronic performance of each section is measured
NOTE 1—No access to internal circuitry is required.
by identifying that portion of the electrical circuit of the
1.3 Units—The values stated in inch-pound units are to be
regarded as standard. The values given in parentheses are
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
This guide is under the jurisdiction ofASTM Committee E07 on Nondestruc- Standards volume information, refer to the standard’s Document Summary page on
tive Testing and is the direct responsibility of Subcommittee E07.06 on Ultrasonic the ASTM website.
Method. Available from International Organization for Standardization (ISO), 1, ch. de
Current edition approved June 1, 2021. Published June 2021. Originally la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org.
approved in 1990. Last previous edition approved in 2016 as E1324–16. DOI: Available from Institute of Electrical and Electronics Engineers, Inc. (IEEE),
10.1520/E1324-21. 445 Hoes Ln., P.O. Box 1331, Piscataway, NJ 08854-1331
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1324 − 21
instrument which comprises the section, applying the recom- primarily for pulse echo flaw detection instruments operating
mended stimulus or load, or both, and performing the required in the nominal frequency range of 100 kHz to 25 MHz, but the
measurements using commercially available electronic test procedures are applicable to measurements on instruments
equipment. These data are then summarized in tabular or utilizing significantly higher frequency components.
graphical form as performance-related values which can be
4.2 Theseprocedurescanbeappliedtotheevaluationofany
comparedwithcorrespondingvaluesofotherultrasonictesting
pulse-echo ultrasonic testing instrument which can be de-
instruments or of values for the same instrument obtained
scribedasacombinationoftheelectronicsectionsdiscussedin
earlier (see Section 12 for a suggested reporting format).
this guide.
3.2 The following describes the sections of the ultrasonic
NOTE 2—These procedures are not intended to preclude the use or
instrument and their interrelations during measurement:
application of equipment for which some or all of the measurement
3.2.1 Power Supply Section—The power supply section is
techniques of this document are not applicable.
that portion of the total instrument circuitry which supplies the
4.3 An ultrasonic testing instrument that cannot be com-
regulated DC voltages required to power all other sections of
pletely described as a combination of the electronic sections
the ultrasonic instrument, including the high voltage (that is,
discussed in this practice can be partially evaluated. Each
pulser and display voltage) circuitry.
portion of the ultrasonic testing instrument that is evaluated
3.2.2 Pulser Section—The pulser section is that portion of
must fit the description for the corresponding section.
the total instrument circuitry which generates the electrical
4.4 Thisguideismeanttobeusedbyelectronicpersonnelto
pulse used to energize the ultrasonic search unit. The pulser
evaluate the electronic system components and not the ultra-
section may also include the pulse-shape modification controls
sonic system characteristics.
such as pulse length, damping, or tuning controls.
3.2.3 Receiver Section—The receiver section is that portion
5. Apparatus
ofthetotalinstrumentcircuitrywhichamplifies,ormodifies,or
5.1 Ultrasonic Instrument—Anyelectronicinstrumentcom-
both, the radio frequency (RF) pulses received from the
prised of a power supply, pulser, clock, receiver, and a sweep
ultrasonic search unit. This includes the RF amplifiers,
and display section to generate, receive, and display electrical
detectors, video amplifiers, suppression and filtering, and the
signals related to ultrasonic waves for examination purposes.
display vertical deflection circuits. Some instruments may not
contain all of these circuits.
NOTE3—Someultrasonicinstrumentsdonotincludeacathoderaytube
3.2.3.1 Time Variable Gain (TVG), (alternatively referred to
display. Some sections of this guide may not apply to these instruments,
as Distance Amplitude Correction (DAC), Time Controlled or may be applicable only with modifications. Such modifications should
be made only by personnel competent in electronics.
Gain (TCG), etc.) and reject or threshold, while part of the
receiver section, should be turned off while making measure-
5.2 Voltmeter—Any instrument(s) capable of measuring the
ments unless otherwise specified by the user. AC line and DC battery voltages required for 7.1 or 7.2.
3.2.4 Gate/Alarm Section—This section monitors the sig-
5.3 Variable Transformer—An autotransformer or other de-
nalsinthereceiversectiontodetectthepresenceorabsenceof
vice capable of supplying variableAC power to the ultrasonic
significant indications. The gate may include attenuation or
instrument over the full range of voltages and waveforms
gain controls. This section is considered separate from the
specified by the manufacturer.
receiversectionforthepurposesofthisguide.Thealarmsignal
5.4 Pulser Load—Unless otherwise requested by the using
may be audible, a voltage proportional to the indication
parties, the pulser load should be a 50Ω noninductive resistor,
amplitude, or a mark on voltage or current sensitive paper or
preferablymountedinashieldedcoaxialassembly.Theresistor
some combination of these.
must be able to withstand the maximum peak pulser voltage.
3.2.5 Time Base Section—The time base section provides
The impedance of the resistor should be checked at the
the linear horizontal sweep, or baseline. It includes the hori-
anticipated operating frequency to ensure that it is noninduc-
zontal deflection circuits and the clock and delay circuits that
tive. Other impedances may be used if specified.
control repetition rate and positioning of signals on the
baseline.
5.5 Spectrum Analyzer—Any spectrum analyzer (and probe
assembly,ifrequired)thatiscapableofanalyzingtheelectrical
4. Significance and Use pulse from the pulser module and displaying the frequency
componentsofthepulseasdescribedin8.3.Arecordingofthe
4.1 The recommended measurement procedures described
display (photograph or chart recorder) is desirable.
in this guide are intended to provide performance-related
measurements that can be reproduced under the specified test 5.6 Probe—A wide band high input impedance (≥10 kΩ)
conditions using commercially available test instrumentation. attenuating(100×or50×)probetoreducethepulseamplitude,
These measurements indicate capabilities of sections of the asdeliveredtotheoscilloscopeandthespectrumanalyzer,toa
ultrasonic testing instrument independent of specific transduc- levelthat(a)willnotharmtheequipmentand(b)willallowfor
ers or examination conditions. Measurements are made from frequency and time analysis without significantly altering the
normallyavailableconnectorsortestpointssothatnoaccessto pulse shape. The probe output impedance should match the
internalcircuitryisrequired.Further,thisguideisnotintended input impedance of the measurement instrument. (If the im-
for service, calibration, or maintenance of circuitry for which pedanceishigh,aterminatingresistancemayberequiredatthe
the manufacturer’s instructions are available. It is intended input to match the output impedance of the probe.) The
E1324 − 21
frequency bandwidth should be at least as wide as that of the 6. Precautions and Limitations
measuring instruments. The probe must be able to withstand
6.1 This guide describes procedures that are applicable to
the pulser output voltage.
laboratory measurement conditions using, in most instances,
commercially available electronic test equipment.
NOTE4—Morethanoneprobemaybeneededtomatchthevarioustest
instruments used.
6.2 This guide is not intended, nor is it applicable, as a
specification defining the performance of ultrasonic testing
5.7 Function Generator—The function generator should be
systems.Ifsuchperformancecriteriaarerequired,theymustbe
capable of producing a single-cycle sine wave or a five-cycle
agreed upon by the using parties.
sine wave burst (as required in 9.1.3, 9.2.3, 9.3.1, 10.1.1, and
11.1), the frequency of which is variable over the range of the 6.3 Implementation of this guide may require more detailed
frequency capabilities of the ultrasonic instrument. The fre-
procedural instructions. Competence in the use of the elec-
quency read-out should be accurate to 1.0%. It must be tronic measurement instrumentation specified is a prerequisite
capable of being triggered from a signal derived from the for effective use of these procedures.
instrument clock to provide wave trains coherent with the
6.4 Careful selection of the specific measurements to be
display. An adjustable delay of at least 10 µs is required.
made is recommended. If the related parameter is not relevant
5.7.1 A free-running (that is, non-triggered) single-cycle
to the intended application, its measurement may be unneces-
sine wave may not be used for receiver evaluation.
sary. For example, vertical linearity may be irrelevant for an
application using a single-level flaw alarm, while horizontal
5.8 Calibrated Oscilloscope—The oscilloscope should be
linearity might be required only for accurate flaw-depth or
capable of displaying all portions of the pulser output with
thickness measurement from the instrument screen.
sufficient timebase expansion, triggering capability, and fre-
6.5 Nominimumintervalbetweeninstrumentevaluationsis
quency response to enable measurement of the pulse rise time,
recommended or implied.
amplitude, and duration, as well as fulfilling the requirements
of other measurements.
6.6 The accuracy of each measurement is dependent upon
the combined accuracies of each of the electronic measuring
5.9 Calibrated Attenuator—Theattenuatorshouldprovidea
instruments (which should be described in the specifications
measuring range of 60 dB in 1 dB steps with an accuracy
and calibrations for these instruments), and the precisions
within 60.5 dB and have a frequency bandwidth at least as
associatedwithreadingthevaluesofeachpartofthemeasure-
wide as the highest frequency of interest. Most attenuators
ment system. It is assumed that the precision of measuring the
have a nominal input and output impedance of 50Ω, but other
vertical and horizontal values from the ultrasonic instrument
impedancesmaybespecified.Properterminationrulesmustbe
screen is 60.04 in. (61 mm).
observed. An impedance matching probe should be used to
6.7 All measuring instrumentation should have current cali-
protect the attenuator if it is to be used to reduce pulse output.
bration certificates. A calibration control system, such as that
5.10 Terminators—Terminators are used to match the im-
described in ISO10012 or ISO 17025, is suggested.
pedances of instruments and cables used (see 5.4.). They
should be non-inductive, feed-through style.
7. Power-Supply Section Measurements
5.11 Cables—Cables should be coaxial, with maximum 7.1 AC-Powered Instrument Line Regulation:
7.1.1 Connect the variable transformer, the voltmeter and a
lengthof6ft(2m)anda50Ωcharacteristicimpedance.Other
lengths,orimpedances,orboth,maybeusedifauthorized,but search unit which matches the nominal frequency of the
instrument, to the ultrasonic instrument as shown in Fig. 1.
lengths should be kept as short as possible to minimize the
WhileFig.1showsanimmersionset-up,theevaluationmaybe
effects of cable capacitance on measurements.
performed by either the contact or immersion method. The
5.12 Search Unit—An ultrasonic search unit of the desired
type, size, and frequency required for the procedures and test
block selected for 5.14, 7.1.1, 7.2.1, 10.2,or 10.3.
5.13 Immersion Tank (Optional)—An ultrasonic immersion
system that will enable continuous variation of the distance
between the ultrasonic search unit and a reflector over a water
pathrangethatwillprovideatimerangecomparabletotheend
use of the ultrasonic instrument.Adistance (position) scale of
precision needed for the procedure in 10.2 must be incorpo-
rated.
5.14 Test Block—Ablockofanysuitablematerialwhichcan
be used to provide ultrasonic echo signals.
5.15 Camera or Recorder—This is particularly helpful in
measuring pulse characteristics, and is useful in making other
measurements. FIG. 1 Setup for Voltage Regulation Measurements
E1324 − 21
primary requirement is that the signal from the reference 7.2.1.4 Thedatarecordingmaybeminimizedbymakingan
reflector does not vary due to coupling or position variations initialreadingandthenbeginningtheperiodicmeasurementsat
during the evaluation. Contact tests may require clamping of a later time near the anticipated discharge time.
the search unit to the test piece. A block with permanently 7.2.2 Charge Time:
bonded search unit(s) is quite useful. 7.2.2.1 With the instrument battery discharged in accor-
7.1.2 Adjust the variable transformer for 100% nominal dance with 7.2.1, turn the instrument power switch to the OFF
line voltage and obtain a 50% full-scale indication from the or CHARGE position, connect the battery charger to the
reference block. Decrease the variable transformer output battery, and begin charging the battery.
voltage until the reference reflector indication changes its 7.2.2.2 At time intervals ≤15 min, disconnect the charger,
amplitude, width, or horizontal position by 10%. connect the DC voltmeter to the battery terminals, and record
the battery voltage versus time as shown in Fig. 3.The battery
NOTE 5—Damage may result from going beyond the manufacturer’s
charge curve shown in Fig. 3 is typical for NiCd and sealed
line voltage specifications in either direction.
lead batteries used in most ultrasonic instruments. The fully
7.1.3 The ultrasonic instrument display may turn off before
charged condition corresponds to the maximum voltage value
any significant signal change is noted.
shown in Fig. 3. Record this value in minutes.
7.1.4 Record the variable transformer output voltage(s) at
7.2.2.3 Thedatarecordingmaybeminimizedbymakingan
which the 10% change or turn-off occurs. These are the input
initialreadingandthenbeginningtheperiodicmeasurementsat
voltage limits.
a later time near the anticipated charge time. Enough data
NOTE 6—If a regulating transformer is always used to supply power to should be acquired to reliably indicate the shape of the charge
the instrument, the procedures in 7.1 may not be needed.
curve (see Fig. 3) in the region of full charge.
7.2 Battery-Powered Instruments
8. Pulser Section Measurements
7.2.1 Discharge Time:
7.2.1.1 With the battery in the full charged condition, 8.1 Pulse Shape—Pulses are generally classed in two types,
Tuned and Untuned, or Narrow Band and Broad Band.
connect a search unit to the instrument and obtain a 50%
full-scale indication from a suitable reference block. This 8.1.1 Tuned pulsers are tuned to match the frequency of the
evaluation may be performed by either the contact or immer- search unit to be used. The output of a tuned pulser (without
sion method. The primary requirement is that the signal from search unit) will be a damped sinusoid as is shown in Fig. 4a.
thereferencereflectordoesnotvaryduetocouplingorposition If the pulse is highly damped, only a half or one and a half
changes during the battery discharge time period. cycle may appear. At minimum damping (Pulse Length
maximum), there may be many cycles.
7.2.1.2 Instrument controls that affect power drain, such as
pulse repetition rate, display brightness, sweep range, etc., 8.1.2 Untuned pulsers generally produce negative spikes,
such as is shown in Fig. 4b. If highly damped (Pulse Length
should be set to the maximum levels corresponding to good
examinationpracticestoprovidethemaximumpracticalpower minimum), the exponential tail will be quite short. Another
supply loading condition. type of untuned pulse used in some instruments is a “rectan-
gular” pulse (sometimes square), shown in Fig. 4c.
7.2.1.3 At time intervals ≤15 min, record the amplitude of
8.1.3 With the instrument turned on and no load connected
the signal from the reference block and graph these values
to the pulser section output, connect the oscilloscope to the
versustimeasshowninFig.2untilthehorizontalsweeplength
pulser section using a 100× or 50× probe if needed.Adjust the
or position or amplitude of the indication changes 10%, or
oscilloscope gain and triggering controls to obtain a display of
until the instrument display turns off.The discharge time is the
a pulser-module output pulse. Fig. 5 shows the set-up. The
time required for a change of the stated amount or until the
Early SyncTrigger should be used, but if it is not available, an
display turns off, whichever occurs first. Record this value.
FIG. 3 NiCd and Lead Acid Battery Charge Characteristics—
FIG. 2 Battery Discharge Characteristics—Typical Typical
E1324 − 21
a. Tuned (narrow band) b. Spike (broad band)
c. Square (broad band)
FIG. 4 Pulse Shapes (Slopes Exaggerated)
8.2.1 Start with the set-up of Fig. 5 with the 50 Ω load
connected. Obtain a display on the oscilloscope screen that
clearly shows the leading edge of the pulse.
8.2.2 Pulse Rise Time:
8.2.2.1 The rise time of the broadband pulse is the time
interval T (innanoseconds)betweenthe10%and90%points
r
(relative to peak amplitude) on the leading edge of the pulse
(Fig. 4a). Note that “rise time” and “fall time” refer,
respectively, to the leading and trailing edges of the pulse,
NOTE 1—Signal leads must be kept as short as possible.
whether the deflection is positive or negative.
NOTE 2—Probe needs 50 Ω output to match input to attenuator or
spectrum analyzer, or both.
NOTE 9—The measured rise time includes the inherent rise times of the
FIG. 5 Instrumentation for Pulse Measurements
oscilloscope and probe if used. The actual rise time is given by
2 2 2 2
T 5 T 2 T 2 T (1)
r m s p
where:
T = measured rise time,
m
oscilloscope with built-in vertical signal delay will be needed
T = oscilloscope rise time, and
s
in order to observe the leading edge of the pulse.
T = probe rise time.
p
Ifonlythebandwidthsoftheoscilloscopeandprobeareknown,aclose
NOTE 7—Pulses involve very high frequency components. It is impor-
approximation to their rise times in nanoseconds can be obtained by
tant to keep ground connections of probes short and close to the point of
5,6
dividing 350 by their bandwidths in MHz.
contact. Verify that probe frequency compensation is properly adjusted.
NOTE 8—In some commercial instruments, the pulse repetition rate is
under microprocessor control and not accessible to the operator. In such
Terman, F. E., and Pettit, J. M., Electronic Measurements, McGraw-Hill, 2nd
instruments the repetition rate does not necessarily follow a clock
Ed., 1952, pg. 327.
schedule and the oscilloscope display may appear unstable.
Matick, R. E., Transmission Lines for Digital and Communications Networks,
8.2 Pulse Rise Time, Duration, and Amplitude McGraw-Hill, 1969, pg. 191.
E1324 − 21
Some manufacturers provide a combined rise time for their own
8.3.3 Peak Frequency—On the spectrum analyzer display,
oscilloscope/probecombinations.Thisrisetime,whethergivenassuchor
the peak frequency is the frequency corresponding to the
calculatedfromthebandwidth,isusedfor T intheequation,for T above,
s r
highest amplitude. Record this frequency with and without the
and T is omitted.
p
50 Ω load.
NOTE 10—It is a general rule for measurement of transients, that the
8.3.4 The Pulse Upper Frequency Limit is the highest
bandwidth of an oscilloscope be at least twice the highest frequency
component of the signal to be displayed. Put in other terms, the
frequency that corresponds to 70.7% of the amplitude at peak
oscilloscope should have an inherent rise time no more than half that of
frequency. Measure pulse upper frequency limits F and
UMAX
the signal (pulse) to be measured.
F with pulse length controls at MAX and MIN, respec-
UMIN
Amplitude and shape (width) will also be affected because the ampli-
tively.
tude response of the amplifier begins to drop off and phase shifts become
8.3.5 The Lower Pulse Frequency Limit is the lowest
significant about mid-frequency, causing shape distortions.
Because of these considerations, the squared-term formula in Note 9
frequency that corresponds to 70.7% of the amplitude at peak
should be used with caution. Too narrow a bandwidth could cause pulse
frequency. Measure and record F and F at MAX and
LMAX LMIN
shape distortion that would lead to the misreading of pulse characteristics
MIN pulse length controls, respectively.
and cause rejection of a useful pulser.
NOTE 11—In some instruments, the setting of the Pulse-Echo/Thru
8.2.2.2 Measure and record the Pulse Rise Time MIN at
Transmission Switch may affect the results. If so, tests should be made
minimum Pulse Length and Pulse Rate Time MAX at maxi-
with each setting.
mum Pulse Length.
9. Receiver Section Measurements
8.2.2.3 Remove the 50 Ω load and repeat 8.2.2.2.
8.2.2.4 For a tuned pulse, rise time is less meaningful
9.1 Vertical Linearity—The receiver section vertical linear-
because it is basically limited by the tuning Q. However, the
ity should be evaluated first because some other characteristics
measurementmaybemadeasinFig.4a.Measurementmaybe
require vertical linearity for their measurement.
confusing because the first half-oscillation may not be the
9.1.1 Connect the ultrasonic instrument and the measuring
strongest and may indeed be quite weak. Some judgement will
equipment as shown in Fig. 6. If the function generator cannot
be needed.
produce delayed g
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1324 − 16 E1324 − 21
Standard Guide for
Measuring Some Electronic Characteristics of Ultrasonic
Testing Instruments
This standard is issued under the fixed designation E1324; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This guide describes procedures for electronically measuring the following performance-related characteristics of some
sections of ultrasonic instruments:
1.1.1 Power Supply Section:
line regulation,
battery discharge time, and
battery charge time.
1.1.2 Pulser Section:
pulse shape,
pulse amplitude,
pulse rise time, pulse length, and
pulse frequency spectrum.
1.1.3 Receiver Section:
vertical linearity,
frequency response,
noise and sensitivity, and
dB controls.
1.1.4 Time Base Section:
horizontal linearity, and
clock (pulse repetition rate).
1.1.5 Gate/Alarm Section:
delay and width,
resolution,
alarm level,
gain uniformity,
analog output, and
back echo gate.
This guide is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.06 on Ultrasonic Method.
Current edition approved June 1, 2016June 1, 2021. Published June 2016June 2021. Originally approved in 1990. Last previous edition approved in 20112016 as
E1324 - 11.E1324 – 16. DOI: 10.1520/E1324-16.10.1520/E1324-21.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1324 − 21
1.2 This guide complements Practice E317, D2548and is not intended for evaluating the performance characteristics of ultrasonic
testing instruments on the inspection/production line.
NOTE 1—No access to internal circuitry is required.
1.3 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D2548 Method of Test for Analysis of Oil Soluble Petroleum Sulfonates by Liquid Chromatography; Replaced by D 3712
(Withdrawn 1979)
E317 Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-Echo Testing Instruments and Systems without the
Use of Electronic Measurement Instruments
E1316 Terminology for Nondestructive Examinations
2.2 ISO Standards:
ISO 10012 Measurement Management Systems—Requirements for Measurement Processes and Measuring Equipment
ISO 17025 General Requirements for the Competence of Testing and Calibration Laboratories
2.3 Other Standard:
IEEE Std. 100, IEEE Standard Dictionary of Electrical and Electronics Terms
3. Summary of Guide
3.1 The electronic performance of each section is measured by identifying that portion of the electrical circuit of the instrument
which comprises the section, applying the recommended stimulus or load, or both, and performing the required measurements
using commercially available electronic test equipment. These data are then summarized in tabular or graphical form as
performance-related values which can be compared with corresponding values of other ultrasonic testing instruments or of values
for the same instrument obtained earlier (see Section 12 for a suggested reporting format).
3.2 The following describes the sections of the ultrasonic instrument and their interrelations during measurement:
3.2.1 Power Supply Section—The power supply section is that portion of the total instrument circuitry which supplies the regulated
DC voltages required to power all other sections of the ultrasonic instrument, including the high voltage (that is, pulser and display
voltage) circuitry.
3.2.2 Pulser Section—The pulser section is that portion of the total instrument circuitry which generates the electrical pulse used
to energize the ultrasonic search unit. The pulser section may also include the pulse-shape modification controls such as pulse
length, damping, or tuning controls.
3.2.3 Receiver Section—The receiver section is that portion of the total instrument circuitry which amplifies, or modifies, or both,
the radio frequency (RF) pulses received from the ultrasonic search unit. This includes the RF amplifiers, detectors, video
amplifiers, suppression and filtering, and the display vertical deflection circuits. Some instruments may not contain all of these
circuits.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org.
Available from Institute of Electrical and Electronics Engineers, Inc. (IEEE), 445 Hoes Ln., P.O. Box 1331, Piscataway, NJ 08854-1331
E1324 − 21
3.2.3.1 Time Variable Gain (TVG), (alternatively referred to as Distance Amplitude Correction (DAC), Time Controlled Gain
(TCG), etc.) and reject or threshold, while part of the receiver section, should be turned off while making measurements unless
otherwise specified by the user.
3.2.4 Gate/Alarm Section—This section monitors the signals in the receiver section to detect the presence or absence of significant
indications. The gate may include attenuation or gain controls. This section is considered separate from the receiver section for
the purposes of this guide. The alarm signal may be audible, a voltage proportional to the indication amplitude, or a mark on
voltage or current sensitive paper or some combination of these.
3.2.5 Time Base Section—The time base section provides the linear horizontal sweep, or baseline. It includes the horizontal
deflection circuits and the clock and delay circuits that control repetition rate and positioning of signals on the baseline.
4. Significance and Use
4.1 The recommended measurement procedures described in this guide are intended to provide performance-related measurements
that can be reproduced under the specified test conditions using commercially available test instrumentation. These measurements
indicate capabilities of sections of the ultrasonic testing instrument independent of specific transducers or examination conditions.
Measurements are made from normally available connectors or test points so that no access to internal circuitry is required. Further,
this guide is not intended for service, calibration, or maintenance of circuitry for which the manufacturer’s instructions are
available. It is intended primarily for pulse echo flaw detection instruments operating in the nominal frequency range of 100 kHz
to 25 MHz, but the procedures are applicable to measurements on instruments utilizing significantly higher frequency components.
4.2 These procedures can be applied to the evaluation of any pulse-echo ultrasonic testing instrument which can be described as
a combination of the electronic sections discussed in this guide.
NOTE 2—These procedures are not intended to preclude the use or application of equipment for which some or all of the measurement techniques of this
document are not applicable.
4.3 An ultrasonic testing instrument that cannot be completely described as a combination of the electronic sections discussed in
this practice can be partially evaluated. Each portion of the ultrasonic testing instrument that is evaluated must fit the description
for the corresponding section.
4.4 This guide is meant to be used by electronic personnel to evaluate the electronic system components and not the ultrasonic
system characteristics.
5. Apparatus
5.1 Ultrasonic Instrument—Any electronic instrument comprised of a power supply, pulser, clock, receiver, and a sweep and
display section to generate, receive, and display electrical signals related to ultrasonic waves for examination purposes.
NOTE 3—Some ultrasonic instruments do not include a cathode ray tube display. Some sections of this guide may not apply to these instruments, or may
be applicable only with modifications. Such modifications should be made only by personnel competent in electronics.
5.2 Voltmeter—Any instrument(s) capable of measuring the AC line and DC battery voltages required for 7.1 or 7.2.
5.3 Variable Transformer—An autotransformer or other device capable of supplying variable AC power to the ultrasonic
instrument over the full range of voltages and waveforms specified by the manufacturer.
5.4 Pulser Load—Unless otherwise requested by the using parties, the pulser load should be a 50 Ω noninductive resistor,
preferably mounted in a shielded coaxial assembly. The resistor must be able to withstand the maximum peak pulser voltage. The
impedance of the resistor should be checked at the anticipated operating frequency to ensure that it is noninductive. Other
impedances may be used if specified.
E1324 − 21
5.5 Spectrum Analyzer—Any spectrum analyzer (and probe assembly, if required) that is capable of analyzing the electrical pulse
from the pulser module and displaying the frequency components of the pulse as described in 8.3. A recording of the display
(photograph or chart recorder) is desirable.
5.6 Probe—A wide band high input impedance (≥10 kΩ) attenuating (100× or 50×) probe to reduce the pulse amplitude, as
delivered to the oscilloscope and the spectrum analyzer, to a level that (a) will not harm the equipment and (b) will allow for
frequency and time analysis without significantly altering the pulse shape. The probe output impedance should match the input
impedance of the measurement instrument. (If the impedance is high, a terminating resistance may be required at the input to match
the output impedance of the probe.) The frequency bandwidth should be at least as wide as that of the measuring instruments. The
probe must be able to withstand the pulser output voltage.
NOTE 4—More than one probe may be needed to match the various test instruments used.
5.7 Function Generator—The function generator should be capable of producing a single-cycle sine wave or a five-cycle sine
wave burst (as required in 9.1.3, 9.2.3, 9.3.1, 10.1.1, and 11.1), the frequency of which is variable over the range of the frequency
capabilities of the ultrasonic instrument. The frequency read-out should be accurate to 1.0 %. It must be capable of being triggered
from a signal derived from the instrument clock to provide wave trains coherent with the display. An adjustable delay of at least
10 μs is required.
5.7.1 A free-running (that is, non-triggered) single-cycle sine wave may not be used for receiver evaluation.
5.8 Calibrated Oscilloscope—The oscilloscope should be capable of displaying all portions of the pulser output with sufficient
timebase expansion, triggering capability, and frequency response to enable measurement of the pulse rise time, amplitude, and
duration, as well as fulfilling the requirements of other measurements.
5.9 Calibrated Attenuator—The attenuator should provide a measuring range of 60 dB in 1 dB steps with an accuracy within 60.5
dB and have a frequency bandwidth at least as wide as the highest frequency of interest. Most attenuators have a nominal input
and output impedance of 50 Ω, but other impedances may be specified. Proper termination rules must be observed. An impedance
matching probe should be used to protect the attenuator if it is to be used to reduce pulse output.
5.10 Terminators—Terminators are used to match the impedances of instruments and cables used (see 5.4.). They should be
non-inductive, feed-through style.
5.11 Cables—Cables should be coaxial, with maximum length of 6 ft (2 m) and a 50 Ω characteristic impedance. Other lengths,
or impedances, or both, may be used if authorized, but lengths should be kept as short as possible to minimize the effects of cable
capacitance on measurements.
5.12 Search Unit—An ultrasonic search unit of the desired type, size, and frequency required for the procedures and test block
selected for 5.14, 7.1.1, 7.2.1, 10.2, or 10.3.
5.13 Immersion Tank (Optional)—An ultrasonic immersion system that will enable continuous variation of the distance between
the ultrasonic search unit and a reflector over a water path range that will provide a time range comparable to the end use of the
ultrasonic instrument. A distance (position) scale of precision needed for the procedure in 10.2 must be incorporated.
5.14 Test Block—A block of any suitable material which can be used to provide ultrasonic echo signals.
5.15 Camera or Recorder—This is particularly helpful in measuring pulse characteristics, and is useful in making other
measurements.
6. Precautions and Limitations
6.1 This guide describes procedures that are applicable to laboratory measurement conditions using, in most instances,
commercially available electronic test equipment.
E1324 − 21
6.2 This guide is not intended, nor is it applicable, as a specification defining the performance of ultrasonic testing systems. If such
performance criteria are required, they must be agreed upon by the using parties.
6.3 Implementation of this guide may require more detailed procedural instructions. Competence in the use of the electronic
measurement instrumentation specified is a prerequisite for effective use of these procedures.
6.4 Careful selection of the specific measurements to be made is recommended. If the related parameter is not relevant to the
intended application, its measurement may be unnecessary. For example, vertical linearity may be irrelevant for an application
using a single-level flaw alarm, while horizontal linearity might be required only for accurate flaw-depth or thickness measurement
from the instrument screen.
6.5 No minimum interval between instrument evaluations is recommended or implied.
6.6 The accuracy of each measurement is dependent upon the combined accuracies of each of the electronic measuring instruments
(which should be described in the specifications and calibrations for these instruments), and the precisions associated with reading
the values of each part of the measurement system. It is assumed that the precision of measuring the vertical and horizontal values
from the ultrasonic instrument screen is 60.04 in. (61 mm).
6.7 All measuring instrumentation should have current calibration certificates. A calibration control system, such as that described
in ISO 10012 or ISO 17025, is suggested.
7. Power-Supply Section Measurements
7.1 AC-Powered Instrument Line Regulation:
7.1.1 Connect the variable transformer, the voltmeter and a search unit which matches the nominal frequency of the instrument,
to the ultrasonic instrument as shown in Fig. 1. While Fig. 1 shows an immersion set-up, the evaluation may be performed by either
the contact or immersion method. The primary requirement is that the signal from the reference reflector does not vary due to
coupling or position variations during the evaluation. Contact tests may require clamping of the search unit to the test piece. A
block with permanently bonded search unit(s) is quite useful.
7.1.2 Adjust the variable transformer for 100 % nominal line voltage and obtain a 50 % full-scale indication from the reference
block. Decrease the variable transformer output voltage until the reference reflector indication changes its amplitude, width, or
horizontal position by 10 %.
NOTE 5—Damage may result from going beyond the manufacturer’s line voltage specifications in either direction.
7.1.3 The ultrasonic instrument display may turn off before any significant signal change is noted.
FIG. 1 Setup for Voltage Regulation Measurements
E1324 − 21
7.1.4 Record the variable transformer output voltage(s) at which the 10 % change or turn-off occurs. These are the input voltage
limits.
NOTE 6—If a regulating transformer is always used to supply power to the instrument, the procedures in 7.1 may not be needed.
7.2 Battery-Powered Instruments
7.2.1 Discharge Time:
7.2.1.1 With the battery in the full charged condition, connect a search unit to the instrument and obtain a 50 % full-scale
indication from a suitable reference block. This evaluation may be performed by either the contact or immersion method. The
primary requirement is that the signal from the reference reflector does not vary due to coupling or position changes during the
battery discharge time period.
7.2.1.2 Instrument controls that affect power drain, such as pulse repetition rate, display brightness, sweep range, etc., should be
set to the maximum levels corresponding to good examination practices to provide the maximum practical power supply loading
condition.
7.2.1.3 At time intervals ≤15 min, record the amplitude of the signal from the reference block and graph these values versus time
as shown in Fig. 2 until the horizontal sweep length or position or amplitude of the indication changes 10 %, or until the instrument
display turns off. The discharge time is the time required for a change of the stated amount or until the display turns off, whichever
occurs first. Record this value.
7.2.1.4 The data recording may be minimized by making an initial reading and then beginning the periodic measurements at a later
time near the anticipated discharge time.
7.2.2 Charge Time:
7.2.2.1 With the instrument battery discharged in accordance with 7.2.1, turn the instrument power switch to the OFF or CHARGE
position, connect the battery charger to the battery, and begin charging the battery.
7.2.2.2 At time intervals ≤15 min, disconnect the charger, connect the DC voltmeter to the battery terminals, and record the battery
voltage versus time as shown in Fig. 3. The battery charge curve shown in Fig. 3 is typical for NiCd and sealed lead batteries used
in most ultrasonic instruments. The fully charged condition corresponds to the maximum voltage value shown in Fig. 3. Record
this value in minutes.
7.2.2.3 The data recording may be minimized by making an initial reading and then beginning the periodic measurements at a later
time near the anticipated charge time. Enough data should be acquired to reliably indicate the shape of the charge curve (see Fig.
3) in the region of full charge.
FIG. 2 Battery Discharge Characteristics—Typical
E1324 − 21
FIG. 3 NiCd and Lead Acid Battery Charge Characteristics—Typical
8. Pulser Section Measurements
8.1 Pulse Shape—Pulses are generally classed in two types, Tuned and Untuned, or Narrow Band and Broad Band.
8.1.1 Tuned pulsers are tuned to match the frequency of the search unit to be used. The output of a tuned pulser (without search
unit) will be a damped sinusoid as is shown in Fig. 4a. If the pulse is highly damped, only a half or one and a half cycle may appear.
At minimum damping (Pulse Length maximum), there may be many cycles.
a. Tuned (narrow band) b. Spike (broad band)
c. Square (broad band)
FIG. 4 Pulse Shapes (Slopes exaggerated)Exaggerated)
E1324 − 21
8.1.2 Untuned pulsers generally produce negative spikes, such as is shown in Fig. 4b. If highly damped (Pulse Length minimum),
the exponential tail will be quite short. Another type of untuned pulse used in some instruments is a “rectangular” pulse (sometimes
square), shown in Fig. 4c.
8.1.3 With the instrument turned on and no load connected to the pulser section output, connect the oscilloscope to the pulser
section using a 100× or 50× probe if needed. Adjust the oscilloscope gain and triggering controls to obtain a display of a
pulser-module output pulse. Fig. 5 shows the set-up. The Early Sync Trigger should be used, but if it is not available, an
oscilloscope with built-in vertical signal delay will be needed in order to observe the leading edge of the pulse.
NOTE 7—Pulses involve very high frequency components. It is important to keep ground connections of probes short and close to the point of contact.
Verify that probe frequency compensation is properly adjusted.
NOTE 8—In some commercial instruments, the pulse repetition rate is under microprocessor control and not accessible to the operator. In such instruments
the repetition rate does not necessarily follow a clock schedule and the oscilloscope display may appear unstable.
8.2 Pulse Rise Time, Duration, and Amplitude
8.2.1 Start with the set-up of Fig. 5 with the 50 Ω load connected. Obtain a display on the oscilloscope screen that clearly shows
the leading edge of the pulse.
8.2.2 Pulse Rise Time:
8.2.2.1 The rise time of the broadband pulse is the time interval T (in nanoseconds) between the 10 % and 90 % points (relative
r
to peak amplitude) on the leading edge of the pulse (Fig. 4a). Note that “rise time” and “fall time” refer, respectively, to the leading
and trailing edges of the pulse, whether the deflection is positive or negative.
NOTE 9—The measured rise time includes the inherent rise times of the oscilloscope and probe if used. The actual rise time is given by
2 2 2 2
T 5 T 2 T 2 T (1)
r m s p
where:
T = measured rise time,
m
T = oscilloscope rise time, and
s
T = probe rise time.
p
If only the bandwidths of the oscilloscope and probe are known, a close approximation to their rise times in nanoseconds can be obtained by dividing
5,6
350 by their bandwidths in MHz.
Some manufacturers provide a combined rise time for their own oscilloscope/probe combinations. This rise time, whether given as such or calculated
from the bandwidth, is used for T in the equation, for T above, and T is omitted.
s r p
NOTE 10—It is a general rule for measurement of transients, that the bandwidth of an oscilloscope be at least twice the highest frequency component of
the signal to be displayed. Put in other terms, the oscilloscope should have an inherent rise time no more than half that of the signal (pulse) to be measured.
Amplitude and shape (width) will also be affected because the amplitude response of the amplifier begins to drop off and phase shifts become significant
about mid-frequency, causing shape distortions.
Because of these considerations, the squared-term formula in Note 9 should be used with caution. Too narrow a bandwidth could cause pulse shape
NOTE 1—Signal leads must be kept as short as possible.
NOTE 2—Probe needs 50 Ω output to match input to attenuator or spectrum analyzer, or both.
FIG. 5 Instrumentation for Pulse Measurements
Terman, F. E.E., and Pettit, J. M., Electronic Measurements, McGraw-Hill, 2nd Ed., 1952, pg. 327.
Matick, R. E., Transmission Lines for Digital and Communications Networks, McGraw-Hill, 1969, pg. 191.
E1324 − 21
distortion that would lead to the misreading of pulse characteristics and cause rejection of a useful pulser.
8.2.2.2 Measure and record the Pulse Rise Time MIN at minimum Pulse Length and Pulse Rate Time MAX at maximum Pulse
Length.
8.2.2.3 Remove the 50 Ω load and repeat 8.2.2.2.
8.2.2.4 For a tuned pulse, rise time is less meaningful because it is basically limited by the tuning Q. However, the measurement
may be made as in Fig. 4a. Measurement may be confusing because the first half-oscillation may not be the strongest and may
indeed be quite weak. Some judgement will be needed.
8.2.2.5 Repeat 8.2.2.2 and 8.2.2.3 for the tuned pulse.
8.2.3 Pulse Duration:
8.2.3.1 The pulse duration of a tuned pulse is measured from 10 % of the peak amplitude of the first large half cycle to the end
of the last cycle that exceeds the 10 % level. This is illustrated in Fig. 4a.
8.2.3.2 The pulse duration of the untuned pulse is the time between 10 % of peak on the leading edge and 10 % of peak on the
trailing edge as illustrated in Fig. 4b and Fig. 4c.
8.2.3.3 With the 50 Ω load in place, for either pulse, measure and record Pulse Length MIN and Pulse Length MAX.
8.2.3.4 Remove the 50 Ω load and repeat 8.2.3.3.
8.2.4 Pulse Amplitude:
8.2.4.1 The pulse amplitude of a tuned pulse is the amplitude of the strongest half-oscillation as shown in Fig. 4a. (The strongest
half-oscillation may be positive.)
8.2.4.2 The pulse amplitude of an untuned pulse is the peak amplitude as shown in Fig. 4b and Fig. 4c.
8.2.4.3 With the 50 Ω load connected,connected (see Fig. 5)), for either pulse, measure and record the Pulse Amplitude MIN for
minimum pulse length and Pulse Amplitude MAX for maximum pulse length.
8.2.4.4 Remove the 50 Ω load and repeat 8.2.4.3.
8.3 Pulse Frequency
...