IEC PAS 60679-6:2008

IEC/PAS 60679-6
Edition 1.0 2008-02
PUBLICLY AVAILABLE
SPECIFICATION
PRE-STANDARD
Quartz crystal controlled oscillators of assessed quality –

Part 6: Phase jitter measurement method for quartz crystal oscillators
and SAW oscillators – Application guide

IEC/PAS 60679-6:2008(E)
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IEC/PAS 60679-6
Edition 1.0 2008-02
PUBLICLY AVAILABLE
SPECIFICATION
PRE-STANDARD
Quartz crystal controlled oscillators of assessed quality –

Part 6: Phase jitter measurement method for quartz crystal oscillators
and SAW oscillators – Application guide

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
S
ICS 31.140 ISBN 2-8318-9627-4
– 2 – PAS 60679-6 © IEC:2008(E)

CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references .7
3 Terms, definitions, glossary and general terms.7
4 Measurement method .7
4.1 Frequency range and the measurement method .8
4.2 Method of using the phase noise measurement value.8
4.3 Measurement method for the use of the specially designed measurement
equipment .8
4.4 Block diagram of the measurement.9
4.5 Input and output impedance of the measurement system.9
4.6 Measurement equipment .10
4.7 Test fixture .10
4.8 Cable, tools and instruments, etc. .10
5 Measurement and the measurement environment.10
5.1 Set-up before taking measurements. .10
5.2 Points to be considered and noted at the time of measurement .11
5.3 Treatment after the measurement.11
6 Measurement .11
6.1 Reference temperature.11
6.2 Measurement of temperature characteristics .11
6.3 Measurement under vibration .11
6.4 Measurement at the time of impact.11
6.5 Measurement in accelerated ageing .11
7 Other points to be noted .11
8 Miscellaneous .12
Bibliography.21
Annex A (normative) Calculation method for the amount of phase jitter.13
A.1 Explanation .13
A.2 Relations between phase noise and phase jitter .13
A.3 Commentary.15
A.3.1 History of establishment and points to note .15
A.3.2 Theoretical positioning of phase jitter .15
A.4 Description .16
A.4.1 RMS jitter .17
A.4.2 Peak-to-peak jitter .17
A.4.3 Random jitter.17
A.4.4 Deterministic jitter .17
A.4.5 Period (periodic) jitter.18
A.4.6 Data-dependent jitter.18
A.4.7 Total jitter.18
A.5 Points to be considered for measurement.18
A.5.1 Measurement equipment .18
A.5.2 Factors of measurement errors.19

PAS 60679-6 © IEC:2008(E) – 3 –

Figure 1 – Equivalent block diagram .9
Figure A.1 – Concept diagram of SSB phase noise .14
Figure A.2 – Voltage versus time .16
Figure A.3 – Explanatory diagram of the amount of jitter applied to r.m.s. jitter .18
Figure A.4 – Explanatory diagrams of random jitter, deterministic jitter, and total jitter .19

– 4 – PAS 60679-6 © IEC:2008(E)

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
QUARTZ CRYSTAL CONTROLLED OSCILLATORS
OF ASSESSED QUALITY –
Part 6: Phase jitter measurement method for quartz crystal oscillators
and SAW oscillators – Application guide

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
A PAS is a technical specification not fulfilling the requirements for a standard but made
available to the public.
IEC-PAS 60679-6 was submitted by the Japanese Institute of Electronics, Information and
Communication Engineers and has been processed by IEC technical committee 49:
Piezoelectric and dielectric devices for frequency control and selection.
The text of this PAS is based on the This PAS was approved for
following document: publication by the P-members of the
committee concerned as indicated in
the following document
Draft PAS Report on voting
49/784/NP 49/793A/RVN
Following publication of this PAS, which is a pre-standard publication, the technical committee
or subcommittee concerned will transform it into an International Standard.

PAS 60679-6 © IEC:2008(E) – 5 –
This PAS shall remain valid for an initial maximum period of three years starting from the
publication date. The validity may be extended for a single three-year period, following which
it shall be revised to become another type of normative document or shall be withdrawn.

– 6 – PAS 60679-6 © IEC:2008(E)

INTRODUCTION
With the advance of information and telecommunication technologies, such information and
telecommunication devices as measuring instruments and computers have played important
roles in society. Recently, these devices have been digitized and proliferated on a worldwide
basis. For these devices, crystal oscillators with low phase noise are necessary. This
standard deals with the phase jitter measurement method.
International standardization of industrial standards regarding electronic devices is conducted
by many technical committees in the International Electrotechnical Commission (IEC), located
in Geneva. TC 49 works on standardization of international trade regarding piezoelectric and
dielectric devices for frequency control and selection. There are 10 working groups (WG) in
TC49, and WG6 formulates and deliberates international standards regarding measurement
methods.
The special committee for piezoelectric and dielectric devices for frequency control and
selection in the standard investigatory panel of the electronic information communication
society has been working as a domestic deliberative body of IEC/TC49. The activities of the
domestic committee for TC49/WG6 are conducted in the measurement method committee of
the technical committee in the Quartz Industry Association of Japan (QIAJ) which consists of
crystal device manufacturers.
This PAS was formulated as QIAJ technical standard QIAJ-B-011. Phase jitter is a kind of
electronic noise. Other major electronic noise is phase noise. Therefore, the IEC document
should cover both phase jitter and phase noise. However, the phase noise measurement
method has not yet been organized completely. Taking into account the fact that the phase
jitter measurement method is increasingly important due to the advance in digitization, we
considered that we should proceed with the standardization without waiting for the completion
of the study of the phase noise measurement method so that the phase jitter measurement
method can be used in as wide a range as possible. In this context, we requested the
technical committee of the QIAJ to formulate a standard. As a result, the guideline for phase
jitter measurement method of crystal oscillators and SAW oscillators was prepared and this
will be issued as a standard of the Standard Investigatory Panel of the Electronic Information
Communication Society.
This standard is the result of collected wisdom in the field of advanced technology in Japan,
and it is open to the public as a standard of the Institute of Electronics, Information and
Communication Engineers. It is expected that this standard will contribute to the development
of technology in this fast-growing field.

PAS 60679-6 © IEC:2008(E) – 7 –
QUARTZ CRYSTAL CONTROLLED OSCILLATORS
OF ASSESSED QUALITY –
Part 6: Phase jitter measurement method for quartz crystal oscillators
and SAW oscillators – Application guide

1 Scope
This PAS applies to the phase jitter measurement of quartz crystal oscillators and SAW
oscillators used for electronic devices and gives guidance for phase jitter that allows the
accurate measurement of r.m.s. jitter.
In the measurement method, phase noise measurement equipment or a phase noise
measurement system is used.
The measuring frequency range is from 10 MHz to 700 MHz.
This PAS applies to quartz crystal oscillators and SAW oscillators used in electronic devices
and modules that have the multiplication or division functions based on these oscillators. The
type of phase jitter applied to these oscillators is the r.m.s. jitter. In the following text, these
oscillators and modules will be referred to as “oscillator(s)” for simplicity.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60679-1, Quartz crystal controlled oscillators of assessed quality – Part 1: Generic
specification
3 Terms, definitions, glossary and general terms
In the event of contradictory/inconsistent descriptions in the specification that arise due to
certain reasons, the following priority applies.
– Specific standard
– IEC 60679-1
– General rule by product type
– General rule by item
– Other quoted international standard criteria (for example, IEC)
The same prioritization also applies to the equivalent domestic standard.
Annex A gives a description of the terms with regard to phase jitter.
Unit, drawing, codes, and characters are based on IEC 60679-1.
4 Measurement method
The measurement method applied to oscillators is based on the following.

– 8 – PAS 60679-6 © IEC:2008(E)

4.1 Frequency range and the measurement method
The measurement range shall be 10 MHz to 700 MHz. As the measurement method, the
phase noise measurement equipment (system) or the specially designed phase jitter
measurement equipment shall be used.
4.2 Method of using the phase noise measurement value
The recommended method of measuring phase jitter using phase noise measurements is as
given in 4.2.1 to 4.2.4.
4.2.1 Measurement equipment/system
The measurement equipment and system shall be the phase noise measurement equipment
or the phase noise measurement system.
4.2.2 Measurement item
RMS jitter
NOTE Only random jitter. No period jitter.
4.2.3 Range of detuning frequency
The range of detuning frequency should be determined through a prearrangement and
contract between a customer and a supplier. The formula to calculate phase jitter from the
phase noise is described in Annex A.
4.2.4 Phase noise measurement method
The range of detuned frequency shall be determined by contracts between customers and
suppliers after discussion between them. The formula for calculating the r.m.s. jitter from a
phase noise is based on the calculation method for the amount of phase jitter shown in
Annex A.
As the phase noise measurement method, an orthogonal phase detection method (referred to
also as an orthogonal comparison method or a PLL method) shall be used, or the
measurement equipment having built-in electronic circuits for cancelling a noise in the
measurement system (for example, circuits adopting a cross-correlation method) shall be
used.
4.3 Measurement method for the use of the specially designed measurement
equipment
The specification of the method using the specially designed measurement equipment is
based on the following.
4.3.1 Measurement equipment and system
The measurement equipment and system shall be the specially designed SONET/SDH
measurement equipment using a time interval analyser.
4.3.2 Measurement items
The measurement items shall be the r.m.s jitter and the period (periodic) jitter.
4.3.3 Number of measurements
The measurement times shall be determined by contracts between customers and suppliers
after discussion between them. The target measurement times shall be 20 000 times or more.

PAS 60679-6 © IEC:2008(E) – 9 –
NOTE Attention is needed because this device may not meet the requirements of oscillators for the following
reasons.
a) The measurable range of the measurement equipment may not meet the frequency of the oscillators to be
measured.
b) The output voltage of the oscillators is lower as compared with this device. For this reason, an amplifier is
required, and the necessity of evaluating the phase jitter of the amplifier arises.
c) The realization of square waves, such as CMOS, LVDS, and LVPECL, is difficult because harmonics
components decrease in the frequency bands exceeding 300 MHz. For this reason, the signal waveforms
become sine waves, clipped-sine waves and the like. It is difficult to analyse them by the specially
designed SONET/SDH measurement equipment, and thus a decrease in measurement accuracy is
possible.
4.4 Block diagram of the measurement
A representative block diagram is shown in Figure 1. A practical block diagram is utilized as
modified forms of Figure 1.
Measurement
Test fixture
equipment load
Sample
Power supply
oscillator
Figure 1 – Equivalent block diagram

4.5 Input and output impedance of the measurement system
The load impedance of oscillators widely ranges from 5 Ω to 100 MΩ. The parts to be applied
are the types shown below. However, since numerous demands are made by customers, the
values of this load impedance are infinite.
a) Capacitor only
b) Resistor only
c) Both capacitor and resistor
d) Compliment output with bias

Here, since the measurement system is unified into 50 Ω, the input-output impedance of
measurement systems shall be 50 Ω. For this reason, the load impedance of oscillators shall
also be 50 Ω.
The oscillation output voltage changes depend on the load impedance of oscillators. For this
reason, the thermal noise of load circuits also changes.
As a result, since the amount of phase jitter changes, a recommendation is presented to
suppliers and customers, when adopting any load impedance other than 50 Ω, to conduct a
detailed study and examination and to determine the impedance by contract.

– 10 – PAS 60679-6 © IEC:2008(E)

4.6 Measurement equipment
The specification required for the measurement equipment is described in the following
subclauses without any necessity of adhering to this specification. The adoption of
measurement equipment which satisfies sufficiently the requirements of oscillators is
important.
4.6.1 Jitter floor
The jitter floor shall take values of 0,05 ps or less as the random jitter or values smaller by
one digit as compared with the phase jitter demanded for the oscillators.
4.6.2 Frequency range
The frequency range shall be 10 MHz to 700 MHz. Several items of measurement equipment
may be used according to each frequency band.
4.6.3 Output wave form
The output waveforms shall be CMOS, LVDS, LVPECL, clipped-sine waves, sine waves, etc.
NOTE CMOS, LVDS, and LVPECL originally refer to the type of devices and not a waveform per se. However,
they are also used as the terms showing the waveforms and are, therefore, described as the type of output
waveforms in this PAS.
4.6.4 Output voltage
The output voltage shall be 500 mV or more.
4.7 Test fixture
The specification demanded for measurement implements is shown below.
a) Connection between oscillators to be measured and measurement implements
The application of sockets, connectors, screws, clips, and the like may be allowed. In
addition, the oscillators to be measured and the measurement implements shall be
ensured to be mechanically and electrically connectable.
b) Compatibilization of oscillators to be measured and measurement implements
The oscillators to be measured and the measurement implements shall be capable of
being earthed.
c) Although the load impedance may not be built in, a recommendation is presented to use
measurement implements having the load impedance built therein in order to reduce
influences on the phase jitter of the oscillators to be measured from a thermal noise or the
like from the load impedance.
4.8 Cable, tools and instruments, etc.
As for a cable, the double-shield type of a 50 Ω system shall be used. The cable shall be as
short as possible. As connectors, the 50 Ω system shall be used. It is recommended that SMA
or N-type connectors be used.
5 Measurement and the measurement environment
5.1 Set-up before taking measurements
Attention should be paid to the following matters.
a) The entire measurement system and the oscillators to be measured shall be installed in a
measurement chamber at least 2 h previously.

PAS 60679-6 © IEC:2008(E) – 11 –
b) The measurement equipment shall be set to operate for 2 h or more.
c) The frequency stability of clock signals in the measurement equipment shall be verified to
be smaller than, or equivalent to, the frequency stability of the oscillators to be measured.
d) T
...