I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n

ITU-T O.174
TELECOMMUNICATION (11/2009)
STANDARDIZATION SECTOR
OF ITU

SERIES O: SPECIFICATIONS OF MEASURING

EQUIPMENT
Equipment for the measurement of digital and
analogue/digital parameters

Jitter and wander measuring equipment for

digital systems which are based on
synchronous Ethernet technology

Recommendation ITU-T O.174

 ITU-T O-SERIES RECOMMENDATIONS
SPECIFICATIONS OF MEASURING EQUIPMENT

General O.1–O.9
Maintenance access O.10–O.19
Automatic and semi-automatic measuring systems O.20–O.39
Equipment for the measurement of analogue parameters O.40–O.129
Equipment for the measurement of digital and analogue/digital parameters O.130–O.199
Equipment for the measurement of optical channel parameters O.200–O.209
Equipment to perform measurements on IP networks O.210–O.219
Equipment to perform measurements on leased-circuit services O.220–O.229

For further details, please refer to the list of ITU-T Recommendations.

Recommendation ITU-T O.174

Jitter and wander measuring equipment for digital systems

which are based on synchronous Ethernet technology

Summary
Recommendation ITU-T O.174 specifies test equipment used to generate and measure timing jitter
and synchronization wander in digital systems based on synchronous Ethernet technology.

History
Edition Recommendation Approval Study Group
1.0 ITU-T O.174 2009-11-13 15

Rec. ITU-T O.174 (11/2009) i

 FOREWORD
The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of
telecommunications, information and communication technologies (ICTs). The ITU Telecommunication
Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical,
operating and tariff questions and issuing Recommendations on them with a view to standardizing
telecommunications on a worldwide basis.
The World Telecommunication Standardization Assembly (WTSA), which meets every four years,
establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on
these topics.
The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.
In some areas of information technology which fall within ITU-T's purview, the necessary standards are
prepared on a collaborative basis with ISO and IEC.

NOTE
In this Recommendation, the expression "Administration" is used for conciseness to indicate both a
telecommunication administration and a recognized operating agency.
Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain
mandatory provisions (to ensure e.g., interoperability or applicability) and compliance with the
Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some
other obligatory language such as "must" and the negative equivalents are used to express requirements. The
use of such words does not suggest that compliance with the Recommendation is required of any party.

INTELLECTUAL PROPERTY RIGHTS

ITU draws attention to the possibility that the practice or implementation of this Recommendation may
involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence,
validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others
outside of the Recommendation development process.
As of the date of approval of this Recommendation, ITU had not received notice of intellectual property,
protected by patents, which may be required to implement this Recommendation. However, implementers
are cautioned that this may not represent the latest information and are therefore strongly urged to consult the
TSB patent database at http://www.itu.int/ITU-T/ipr/.

 ITU 2010
All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the
prior written permission of ITU.

ii Rec. ITU-T O.174 (11/2009)

 CONTENTS
Page
1 Scope ............................................................................................................................ 1
2 References..................................................................................................................... 1
3 Definitions .................................................................................................................... 2
4 Abbreviations and acronyms ........................................................................................ 3
5 Conventions .................................................................................................................. 4
6 Functional block diagram ............................................................................................. 4
7 Interfaces....................................................................................................................... 5
7.1 Synchronous Ethernet interfaces .................................................................... 5
7.2 External reference clock input ........................................................................ 5
8 Jitter/wander generation function ................................................................................. 5
8.1 Modulation source .......................................................................................... 5
8.2 Clock generator .............................................................................................. 5
8.3 Digital test pattern generator .......................................................................... 6
8.4 Sinusoidal jitter/wander generation function.................................................. 6
8.5 TDEV wander generation function ................................................................ 7
8.6 MTIE wander generation function ................................................................. 7
9 Jitter measurement function.......................................................................................... 8
10 Wander measurement function ..................................................................................... 8
10.1 Measurement of maximum relative time interval error (MRTIE).................. 8
11 Operating environment ................................................................................................. 9
Appendix I – Measurement guidelines for wander measurement............................................ 10
I.1 TDEV/MTIE wander tolerance ...................................................................... 10
I.2 TDEV wander transfer ................................................................................... 12

Rec. ITU-T O.174 (11/2009) iii

Recommendation ITU-T O.174

Jitter and wander measuring equipment for digital systems

which are based on synchronous Ethernet technology

1 Scope
The test equipment specified in this Recommendation consists principally of a jitter/wander
measurement function and a jitter/wander generation function. Measurements can be performed at
the physical layer of synchronous Ethernet systems. A bit error rate test set may be part of the same
equipment or may be physically separate.
[ITU-T O.172] specifies the test equipment for generation and measurement of jitter and wander in
digital systems based on the synchronous digital hierarchy (SDH).
[ITU-T G.8261], [ITU-T G.8262] and [ITU-T G.8264] should be read in conjunction with this
Recommendation.

2 References
The following ITU-T Recommendations and other references contain provisions which, through
reference in this text, constitute provisions of this Recommendation. At the time of publication, the
editions indicated were valid. All Recommendations and other references are subject to revision;
users of this Recommendation are therefore encouraged to investigate the possibility of applying the
most recent edition of the Recommendations and other references listed below. A list of the
currently valid ITU-T Recommendations is regularly published. The reference to a document within
this Recommendation does not give it, as a stand-alone document, the status of a Recommendation.
[ITU-T G.691] Recommendation ITU-T G.691 (2006), Optical interfaces for single channel
STM-64 and other SDH systems with optical amplifiers.
[ITU-T G.703] Recommendation ITU-T G.703 (2001), Physical/electrical characteristics of
hierarchical digital interfaces.
[ITU-T G.705] Recommendation ITU-T G.705 (2000), Characteristics of plesiochronous
digital hierarchy (PDH) equipment functional blocks.
[ITU-T G.781] Recommendation ITU-T G.781 (1999), Synchronization layer functions.
[ITU-T G.783] Recommendation ITU-T G.783 (2006), Characteristics of synchronous digital
hierarchy (SDH) equipment functional blocks.
[ITU-T G.810] Recommendation ITU-T G.810 (1996), Definitions and terminology for
synchronization networks.
[ITU-T G.811] Recommendation ITU-T G.811 (1997), Timing characteristics of primary
reference clocks.
[ITU-T G.812] Recommendation ITU-T G.812 (2004), Timing requirements of slave clocks
suitable for use as node clocks in synchronization networks.
[ITU-T G.813] Recommendation ITU-T G.813 (2003), Timing characteristics of SDH
equipment slave clocks (SEC).
[ITU-T G.822] Recommendation ITU-T G.822 (1988), Controlled slip rate objectives on an
international digital connection.
[ITU-T G.823] Recommendation ITU-T G.823 (2000), The control of jitter and wander within
digital networks which are based on the 2048 kbit/s hierarchy.

Rec. ITU-T O.174 (11/2009) 1

[ITU-T G.824] Recommendation ITU-T G.824 (2000), The control of jitter and wander within
digital networks which are based on the 1544 kbit/s hierarchy.
[ITU-T G.825] Recommendation ITU-T G.825 (2000), The control of jitter and wander within
digital networks which are based on the synchronous digital hierarchy (SDH).
[ITU-T G.957] Recommendation ITU-T G.957 (1999), Optical interfaces for equipments and
systems relating to the synchronous digital hierarchy.
[ITU-T G.959.1] Recommendation ITU-T G.959.1 (2008), Optical transport network physical
layer interfaces.
[ITU-T G.8010] Recommendation ITU-T G.8010/Y.1306 (2004), Architecture of Ethernet layer
networks.
[ITU-T G.8110.1] Recommendation ITU-T G.8110.1/Y.1370.1 (2006), Architecture of Transport
MPLS (T-MPLS) layer network.
[ITU-T G.8261] Recommendation ITU-T G.8261/Y.1361 (2008), Timing and synchronization
aspects in packet networks.
[ITU-T G.8262] Recommendation ITU-T G.8262/Y.1362 (2007), Timing characteristics of
synchronous Ethernet equipment slave clock (EEC).
[ITU-T G.8264] Recommendation ITU-T G.8264/Y.1364 (2008), Distribution of timing
information through packet networks.
[ITU-T O.3] Recommendation ITU-T O.3 (1992), Climatic conditions and relevant tests for
measuring equipment.
[ITU-T O.150] Recommendation ITU-T O.150 (1996), General requirements for
instrumentation for performance measurements on digital transmission
equipment.
[ITU-T O.171] Recommendation ITU-T O.171 (1997), Timing jitter and wander measuring
equipment for digital systems which are based on the plesiochronous digital
hierarchy (PDH).
[ITU-T O.172] Recommendation ITU-T O.172 (2005), Jitter and wander measuring
equipment for digital systems which are based on the synchronous digital
hierarchy (SDH).
[IEEE 802.3] IEEE Standard 802.3-2008, Information technology – Telecommunications and
information exchange between systems – Local and metropolitan area
networks – Specific requirements – Part 3: Carrier Sense Multiple Access with
Collision Detection (CSMA/CD) Access Method and Physical Layer
Specifications.

3 Definitions
This Recommendation uses the following terms defined elsewhere:
3.1 Ethernet synchronization message channel: [ITU-T G.8264].
3.2 non-sync operation mode: [ITU-T G.8264].
3.3 synchronization network clock: [ITU-T G.8261].
3.4 synchronous operation mode: [ITU-T G.8264].
3.5 time interval error function: [ITU-T G.810].
3.6 (timing) jitter: [ITU-T G.810].

2 Rec. ITU-T O.174 (11/2009)

3.7 wander: [ITU-T G.810].
Note that [ITU-T G.810] and [ITU-T G.8261] provide additional definitions and abbreviations used
in timing and synchronization Recommendations. They also provide background information on the
need to limit phase variation and impairments on digital systems.

4 Abbreviations and acronyms

This Recommendation uses the following abbreviations and acronyms:
EEC synchronous Ethernet Equipment Clock
ESMC Ethernet Synchronization Messaging Channel
ETH Ethernet MAC layer network
ETY Ethernet PHY layer network
GE Gigabit Ethernet
IP Internet Protocol
IWF InterWorking Function
LPF Low-Pass Filter
MTIE Maximum Time Interval Error
MRTIE Maximum Relative Time Interval Error
NE Network Element
NRZ Non Return to Zero
PDH Plesiochronous Digital Hierarchy
PDU Protocol Data Unit
PLL Phase-Locked Loop
ppm parts per million
PRBS Pseudo Random Binary Sequence
PRC Primary Reference Clock
QL Quality Level
RTIE Relative Time Interval Error
SDH Synchronous Digital Hierarchy
SEC Synchronous digital hierarchy Equipment Clock
SSM Synchronization Status Message
SSU Synchronization Supply Unit
STM-N Synchronous Transport Module, level N
TDEV Time DEViation
TIE Time Interval Error
UI Unit Interval
UIpp Unit Interval, peak-to-peak

Rec. ITU-T O.174 (11/2009) 3

5 Conventions
The jitter/wander measurement function in this Recommendation applies to synchronous Ethernet
interfaces. Jitter measurement functions for legacy Ethernet are defined partly in [IEEE 802.3].

6 Functional block diagram

Figure 1 shows the general block diagram of the equipment and identifies the main functions
covered in this Recommendation. The figure does not describe a specific implementation.

Jitter/wander
Wander Jitter generation
modulation modulation function
source source

External
Clock Clock
reference
generator generator
clock input

Test signal
Digital test output
pattern Interfaces
generator Reference timing
signal output

Jitter
Reference measurement
timing function
signal

Jitter
Phase Measurement result
Test
detector filter
signal
input*2
Interfaces
TIE/RTIE
result
Measurement
*2 Jitter measurement function
in this figure is applicable to filter
Synchronous Ethernet MTIE/MRTIE
interfaces. MTIE/MRTIE result
calculation
Phase
detector
TDEV
TDEV result
External Reference calculation
Wander
reference timing measurement
clock input signal function

Figure 1 – Functional block diagram for jitter and wander test set

4 Rec. ITU-T O.174 (11/2009)

7 Interfaces

7.1 Synchronous Ethernet interfaces

The equipment shall be capable of operating at one or more of the following Ethernet interfaces.
Table III.1 of [ITU-T G.8262] lists the interfaces supporting synchronous Ethernet.

7.2 External reference clock input

The measuring equipment shall support reference data signals at bit rates of 1 544 kbit/s or
2 048 kbit/s. If 2 048 kbit/s can be accepted, the equipment shall also accept a clock signal at
2 048 kHz as a reference. The characteristics of clock signals shall be in accordance with
[ITU-T G.703].

8 Jitter/wander generation function

Tests of digital equipment may be made with either a jittered, wandered or a non-jittered/wandered
digital signal. This will require the digital test pattern generator, clock generator and modulation
source shown in Figure 1.

8.1 Modulation source

The modulation source, required to perform tests conforming to relevant Recommendations may be
provided within the clock generator and/or digital test pattern generator, or may be provided
separately. This Recommendation defines a sinusoidal modulation source for jitter generation. The
modulation source for wander generation is defined as one of the following three signals.
– Sinusoidal.
– Time deviation (TDEV) wander (noise): White Gaussian noise filtered to obtain required
TDEV characteristic.
– Maximum time interval error (MTIE) wander: Test signal to obtain required MTIE or
maximum relative time interval error (MRTIE) characteristic.
The sinusoidal jitter/wander, TDEV wander and MTIE wander generation functions are defined in
clauses 8.4, 8.5 and 8.6, respectively.

8.2 Clock generator

It shall be possible to phase-modulate the clock generator from the modulation source and to
indicate the peak-to-peak phase deviation of the modulated signal.
The generated peak-to-peak wander and the modulating frequencies shall meet the minimum
requirements of Figure 2. The generated peak-to-peak jitter and the modulating frequencies for
EEC options 1 and 2 shall meet [IEEE 802.3]. The Ethernet measurement methodology is defined
in [IEEE 802.3]. The applicability to jitter measurement in a synchronization network environment
is for further study.
8.2.1 Accuracy of clock generator
The frequency deviation of the internal clock signal from its nominal value shall be less than
±4.6 ppm excluding locked operation.
As an option, the clock generator may provide adjustable frequency offset of sufficient magnitude
to facilitate tests across the clock tolerance range of the equipment under test, e.g., ±10 ppm to
±100 ppm as defined for the various bit rates listed in Table III.1 of [ITU-T G.8262].
It shall be possible to phase-lock the generation function to an external reference clock source of
arbitrary accuracy; refer to clause 7.2.

Rec. ITU-T O.174 (11/2009) 5

8.3 Digital test pattern generator
The jitter/wander measurement function will normally be used in conjunction with any suitable
digital test pattern generator supporting the following facilities.
a) Ethernet signal in accordance with [IEEE 802.3].
b) Ethernet synchronous messaging channel protocol data unit (ESMC PDU) format signal in
accordance with [ITU-T G.8264].

8.4 Sinusoidal jitter/wander generation function

The ability to generate sinusoidal wander for wander tolerance (MTIE) measurements as described
in [ITU-T G.8262] may be provided. The following requirements shall be met to ensure sufficiently
accurate, robust and consistent measurements.
8.4.1 Minimum sinusoidal jitter/wander generation capability
The jitter/wander amplitude/frequency characteristics of the generation function shall meet the
minimum requirements of Figure 2 for EEC signals.

Peak-to-peak
Wander amplitude
(log scale)

A0

A1

A2

f5 f4 f3 f2 f1 f0
Frequency (log scale)

Minimum peak-to-peak
Wander frequency breakpoints (Hz)
Signal wander amplitude (µs)
A0 A1 A2 f5 f4 f3 f2 f1 f0
EEC 23.15 2.5 0.3 12µ 178µ 0.8m 16m 0.13 10
NOTE 1 – Values based on requirements of Table 8 of [ITU-T G.8262] for option 1.
NOTE 2 – Jitter value is for further study.

Figure 2 – Minimum amplitude of adjustable generated sinusoidal

wander amplitude versus wander frequency for EEC signals
8.4.2 Generation accuracy
The sinusoidal test signal source shall be compatible with the jitter/wander measurement function
so that the overall measuring accuracy is not substantially deteriorated. The generation accuracy
may be increased by measuring the jitter/wander applied to the unit under test using a
corresponding jitter/wander measuring device.
The generating accuracy of the sinusoidal jitter/wander generation function depends on several
factors, such as fixed intrinsic error, setting resolution, distortion and frequency response error. In
addition, some error is a function of the actual setting.

6 Rec. ITU-T O.174 (11/2009)

8.4.2.1 Phase amplitude error
The amplitude error of sinusoidal jitter/wander generation shall be less than:
Q% of setting ±0.02 UIpp
Where Q is a variable error specified in Table 1 for EEC signals. The frequencies f0 and f5 used in
Table 1 are defined in Figure 2.
NOTE – This Recommendation excludes any wideband intrinsic jitter/wander components.

Table 1 – Variable error (Q) of EEC signal jitter/wander generation

Signal Error, Q Frequency range
EEC ±10% f5 to f0
NOTE – Value of jitter range is for further study.

8.4.2.2 Intrinsic jitter/wander of generation function

The intrinsic wander of the jitter/wander generation function measured in the bandwidth f0–f5, as
defined in Figure 2 with the amplitude set to zero, shall be less than:
0.04 UIpp for test signal defined in clause 8.3.

8.5 TDEV wander generation function

The ability to generate TDEV wander (noise) for wander tolerance and wander transfer
measurements as described in [ITU-T G.8262] may be provided. The following requirements shall
be met to ensure sufficiently accurate, robust and consistent measurements:
a) Wander generation function shall produce a test signal with TDEV within ±20% of the
applicable TDEV input tolerance mask. This accuracy shall be met when the measurement
period T ≥ 12τmax, where τmax is the largest value of τ for the mask.
b) The MTIE of the test signal shall not be greater than the upper limit defined in Annex C of
[ITU-T O.172].
c) The test signal shall be deterministic and repeatable, implying that the signal can start at the
same point of the signal time function.
Clause II.2 of [ITU-T G.812] shows an example of an adequate implementation algorithm for
generating a TDEV wander noise.
Clause II.1 of [ITU-T G.812] has additional information on application of TDEV wander noise.
NOTE – The signal may exceed the corresponding MTIE tolerance mask limits. Since both TDEV and
MTIE requirements must be met for an input interface, the TDEV limits may be more stringent and therefore
may exceed the MTIE values.

8.6 MTIE wander generation function

The ability to generate an MTIE wander signal for wander tolerance measurements as described in
[ITU-T G.8262] may be provided. The following requirements shall be met to ensure sufficiently
accurate, robust and consistent measurements:
a) The wander generation function shall produce a test signal or set of test signals with MTIE
within ±5% of the applicable MTIE input tolerance mask. For a set of test signals, the
MTIE will be considered to be the upper envelope of the set of corresponding MTIE
curves.
b) The jitter generated by the wander generation function shall not exceed the limits for the
applicable network interface output jitter.

Rec. ITU-T O.174 (11/2009) 7

NOTE – When a test set is evaluated for compliance with these requirements, the generated wander must be
measured using a low-pass filter (LPF) with adequate bandwidth so that its effect on the measured MTIE is
less than 1%. See Appendix VI of [ITU-T O.172] for guidance on evaluating MTIE wander signal
generation.

9 Jitter measurement function

The jitter measurement methodology for Ethernet interfaces is defined in [IEEE 802.3]. Ethernet
assumes that there are essentially two jitter mechanisms: deterministic jitter and random jitter.
Separate requirements are specified for transmitters and receivers. The jitter measurement for
synchronous Ethernet according to [ITU-T O.172] is for further study.

10 Wander measurement function

The following measurement definitions, also applicable for synchronous Ethernet, are defined in
clause 10 of [ITU-T O.172].
– Reference timing signal.
– Measurement of TIE.
– Measurement of transient TIE.
– Measurement of MTIE.
– Measurement of TDEV.
– Measurement of frequency offset.
– Measurement of frequency drift rate.
Appendices II, V and VI of [ITU-T O.172] provide further information about test configurations for
measuring wander.
The MRTIE measurement function is defined in clause 10.1.

10.1 Measurement of maximum relative time interval error (MRTIE)

The ability to measure maximum relative time interval error (MRTIE), as defined in [ITU-T G.810]
and [ITU-T G.823], may be provided.
MRTIE is a measure of wander that characterizes phase transients. It is a function of the
parameter τ called the observation interval. MRTIE(τ) is the largest peak-to-peak relative TIE
(RTIE), described in clause I.2.2.2 of [ITU-T G.823], in any observation interval of length τ.
The MRTIE network limits of packet networks are specified in [ITU-T G.8261].
10.1.1 Measurement and observation interval ranges
To support the MRTIE specifications of various ITU-T Recommendations, it shall be possible to
measure MRTIE over a range of observation intervals from at least:
0.05 s to 1000 s for TIE as described in 10.2 of [ITU-T O.172].
The maximum range of calculated MRTIE results shall be at least:
100 000 ns
(corresponding to five times the maximum specification defined in [ITU-T G.823], for example).
NOTE – The minimum measurement period T for MRTIE(τ) is the observation interval (i.e., T = τ).

8 Rec. ITU-T O.174 (11/2009)

10.1.2 Calculation algorithm accuracy
In some cases, the MRTIE calculation algorithm can be separated functionally from the TIE
measurement, when the following accuracy requirements apply to the stand-alone algorithm.
When provided with a given set of TIE measurement data, an algorithm used to calculate RTIE and
MRTIE shall yield results within a certain error of the values calculated in accordance with the
standard estimator formulas given in clauses II.2.2.2 of [ITU-T G.823] and II.5 of [ITU-T G.810].
The total MRTIE calculation error shall be less than:
±2% of MRTIE value ±Z1 (τ)
where Z1 (τ) is specified in Table 2 and τ is the observation interval.

Table 2 – Fixed error (Z1) of MRTIE calculation algorithm

Z1 (τ) (ns) Observation interval, τ (s)

0.5 + 0.0055 τ 0.05 ≤ τ ≤ 1000
NOTE – These requirements are based on [ITU-T G.823] and [ITU-T G.8261].

10.1.3 Measurement result accuracy

The total measurement error (i.e., including error from TIE measurement and error from MRTIE
calculation algorithm) shall be less than:
±7% of MRTIE value ±Z3 (τ)
where Z3 (τ) is specified in Table 3 and τ is the observation interval.

Table 3 – Fixed error (Z3) of MRTIE measurement result

Z3 (τ) (ns) Observation interval, τ (s)

3 + 0.033 τ 0.05 ≤ τ ≤ 1000
NOTE – These requirements are based on [ITU-T G.823] and [ITU-T G.8261].

11 Operating environment
The performance requirements shall be met when operating within the climate conditions specified
in clause 2.1 of [ITU-T O.3].

Rec. ITU-T O.174 (11/2009) 9

 Appendix I

Measurement guidelines for wander measurement

(This appendix does not form an integral part of this Recommendation)

I.1 TDEV/MTIE wander tolerance

I.1.1 Intent
The intent of this test procedure is to measure wander tolerance in terms of the TDEV/MTIE
wander amplitude that, when applied to an equipment input, causes a designated degradation of
error performance. TDEV/MTIE wander tolerance is a function of the amplitude and observation
interval, τ, of the applied TDEV/MTIE (τ) mask.
I.1.2 Apparatus
The following apparatus is required:
– External reference clock source.
– TDEV/MTIE wander modulation source.
– Clock generator.
– Digital signal generator.
– TDEV/MTIE wander measurement function (option).
I.1.3 Basic technique
The errors criterion for TDEV/MTIE wander tolerance measurements is defined as the largest
amplitude of TDEV/MTIE mask that causes a cumulative total bit error rate of less than 10–12,
where this total bit error rate has been summed over the measurement period of twelve times the
observation interval.
I.1.4 Equipment connection
Clauses I.1.5 and I.1.6 provide information on test configurations for TDEV/MTIE wander
tolerance measurements that are in accordance with [ITU-T G.8262].
I.1.5 Measurement for EEC signal
Figure I.1 shows the test configuration for the input data signal of the EEC basic technique. The
optional TDEV/MTIE wander measurement function is used to verify the amplitude of generated
TDEV/MTIE wander on the input data signal.

10 Rec. ITU-T O.174 (11/2009)

 Ref.
TDEV/MTIE
External input wander
reference measurement
clock function (option)

TDEV/MTIE Digital
EEC
wander Clock Digital signal
under test signal
modulation generator generator
EEC EEC receiver
source
signal Output

Figure I.1 – TDEV/MTIE wander tolerance measurement configuration for EEC

I.1.6 Measurement for timing reference
Figure I.2 shows the test configuration for the input timing reference of the EEC basic technique.
The optional TDEV/MTIE wander measurement function is used to verify the amplitude of
generated TDEV/MTIE wander on the input timing reference signal.
TDEV/MTIE
wander
modulation Clock
source generator

Timing
reference

TDEV/MTIE
External Ref. Input wander EEC
measurement Digital
reference under test
function signal
clock
(option) receiver

Figure I.2 – TDEV/MTIE wander tolerance measurement

configuration for timing reference
I.1.7 Equipment settings
This technique involves setting a measurement period for TDEV/MTIE and determining the
TDEV/MTIE wander amplitude of the data signal that satisfies the errors criterion. Specifically, this
technique requires:
1) isolation of the TDEV/MTIE wander amplitude "transition region" (where error-free
operation ceases);
2) performance of total bit error rate measurement, the measurement period of 12 times the
observation interval in duration, for each incrementally added TDEV/MTIE wander
amplitude from the beginning of this region;
3) determination of the largest TDEV/MTIE mask for which the cumulative total bit error rate
is less than 10–12.

Rec. ITU-T O.174 (11/2009) 11

I.1.8 Measurement procedure
1) Connect the equipment as shown in Figure I.1 or I.2. Verify proper continuity and error-
free operation.
2) Set the initial TDEV/MTIE wander amplitude to 0 ns peak to peak.
3) Set the TDEV/MTIE wander amplitude for the desired TDEV/MTIE mask specified in the
applicable standard.
4) Record the number of errors occurring during twelve times the TDEV/MTIE observation
interval. Note that the initial measurement must be 0 errors.
5) Record the indicated TDEV/MTIE wander to characterize the TDEV/MTIE wander
tolerance curve.

I.2 TDEV wander transfer

Appendix II of [ITU-T G.812] describes how to measure noise transfer.

12 Rec. ITU-T O.174 (11/2009)

 SERIES OF ITU-T RECOMMENDATIONS

Series A Organization of the work of ITU-T

Series D General tariff principles

Series E Overall network operation, telephone service, service operation and human factors

Series F Non-telephone telecommunication services

Series G Transmission systems and media, digital systems and networks

Series H Audiovisual and multimedia systems

Series I Integrated services digital network

Series J Cable networks and transmission of television, sound programme and other multimedia signals

Series K Protection against interference

Series L Construction, installation and protection of cables and other elements of outside plant

Series M Telecommunication management, including TMN and network maintenance

Series N Maintenance: international sound programme and television transmission circuits

Series O Specifications of measuring equipment

Series P Terminals and subjective and objective assessment methods

Series Q Switching and signalling

Series R Telegraph transmission

Series S Telegraph services terminal equipment

Series T Terminals for telematic services

Series U Telegraph switching

Series V Data communication over the telephone network

Series X Data networks, open system communications and security

Series Y Global information infrastructure, Internet protocol aspects and next-generation networks

Series Z Languages and general software aspects for telecommunication systems

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