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.rs
\v | 5i'
.IP
\fB2.2\ Lining\(hyup and monitoring of an international television
connection\fR 
.sp 1P
.RT
.PP
It is assumed that the international television connection is
as shown in Figures\ 2/N.51,\ 5/N.51 and\ 6/N.51 and that such a connection is
provided by the interconnection of permanently and/or occasionally established 
television circuits. 
.sp 1P
.RT
.sp 2P
.LP
\fBRecommendation\ N.60\fR 
.RT
.sp 2P
.ce 1000
\fBNOMINAL\ AMPLITUDE\ OF\ VIDEO\ SIGNALS\ AT\ VIDEO\fR 
.EF '%	Fascicle\ IV.3\ \(em\ Rec.\ N.60''
.OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.60	%'
.ce 0
.sp 1P
.ce 1000
\fBINTERCONNECTION\ POINTS\fR 
.ce 0
.sp 1P
.PP
At video interconnection points, the nominal amplitude of the
picture signal, measured from the blanking level to the white level should
be 0.7\ V (0.714\ V for system\ M\ signals), while the nominal amplitude of the
synchronizing pulses should be 0.3\ V (0.286\ V for system\ M\ signals), 
so that 
the nominal peak\(hyto\(hypeak amplitude of a 
monochrome video signal
should be\ 1.0\ V. The addition of colour information results in an increase 
in the 
overall amplitude of the video signal. The magnitude of this increase depends 
upon the colour system employed, but should not exceed\ 25% (i.e. nominal 
amplitude of 
composite colour video signal
\ \(= | .25\ V). Figure\ 1/N.60
shows the waveform of a video signal.
.sp 1P
.RT
.LP
.rs
.sp 22P
.ad r
\fBFigure 1/N.60 p.\fR 
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
\fBRecommendation\ N.61\fR 
.RT
.sp 2P
.ce 1000
\fBMEASUREMENTS\ TO\ BE\ MADE\ BEFORE\ THE\ LINE\(hyUP\ PERIOD\fR 
.EF '%	Fascicle\ IV.3\ \(em\ Rec.\ N.61''
.OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.61	%'
.ce 0
.sp 1P
.ce 1000
\fBTHAT\ PRECEDES\ A\ TELEVISION\ TRANSMISSION\fR 
.ce 0
.sp 1P
.PP
The national television circuits should be so adjusted that,
when they are connected to the international television link, the amplitude 
of the video signals at the video interconnection points is in accordance 
with 
Recommendation\ N.60.
.bp
.sp 1P
.RT
.sp 2P
.LP
\fBRecommendation\ N.62\fR 
.RT
.sp 2P
.ce 1000
\fBTESTS\ TO\ BE\ MADE\ DURING\ THE\ LINE\(hyUP\ PERIOD\fR 
.EF '%	Fascicle\ IV.3\ \(em\ Rec.\ N.62''
.OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.62	%'
.ce 0
.sp 1P
.ce 1000
\fBTHAT\ PRECEDES\ A\ TELEVISION\ TRANSMISSION\fR 
.ce 0
.sp 1P
.LP
\fB1\fR 	\fBIntroduction\fR 
.sp 1P
.RT
.PP
International television circuits
or national sections of
such circuits may be provided either by Administrations or broadcasting
organizations; both types of entities establish ITCs to carry out the functions 
given in Recommendation\ N.55. One of those functions is to test the 
international television circuits/links before they are handed over to the
broadcasting organizations for programme transmission.
.PP
International television circuits are:
.RT
.LP
	\(em
	circuits with terrestrial sections only
.LP
	\(em
	 circuits comprising a satellite section with national circuit sections 
between each earth station and the ITC in the same country. 
.PP
Figure\ 1/N.62 shows an example of an IMDTC (International
Multiple Destination Television Connection), using circuits of both
types.
.sp 2P
.LP
\fB2\fR 	\fBTest signal source identification\fR 
.sp 1P
.RT
.PP
All full field test signals as described in this Recommendation
should be superimposed with an identification which includes the point of
origin and the name of the sending authority. It may be transmitted either 
in monochrome or in colour according to preference or to suit the technical 
requirements of the particular test signal being transmitted. If the local
language of the originating station is not an internationally recognized
language then the idendification should be displayed not only in the local
language of the station concerned but also in one of the internationally
recognized languages.
.RT
.sp 2P
.LP
\fB3\fR 	\fBTest procedure\fR 
.sp 1P
.RT
.PP
In accordance with Recommendation N.54, lining\(hyup and testing of
the national and international circuit sections should take place between 
\fIH\fR \(em 30 and \fIH\fR \(em 15 min, where \fIH\fR is the time at which 
the circuit should be 
handed over to the broadcasting organization. In practice, these tests 
normally take place: 
.RT
.LP
	\(em
	between ITCs and earth stations
.LP
	\(em
	between earth stations
.LP
	\(em
	between ITCs in adjacent countries linked by terrestrial
circuits.
.PP
The use of insertion test signals (ITS) has been demonstrated to expedite 
the pre\(hytransmission line\(hyup testing of terrestrial and satellite 
circuit sections. Therefore, whenever possible, insertion test signals in
accordance with CCIR Recommendations\ 567\ [1] and 569\ [2] should be used
together with appropriate automatic measuring equipment during the line\(hyup
period. 
Insertion test signals
from the sending broadcasting
organization should also be used during the 
preparatory period
and
subsequent transmission for monitoring and fault location purposes.
.PP
An example of the circuits and circuit sections to be tested during
the first half of the 
line\(hyup period
is shown in Figure\ 1/N.62.
.PP
Priority should be given to verifying the continuity and that the send 
and receive levels are correct. 
.PP
Table 1/N.62 gives a suitable timetable of the sequence of
measurements to be made during the line\(hyup period.
.RT
.PP
At \fIH\fR \(em 15 min precisely, the circuit sections are interconnected 
to form international circuits and the international circuits interconnected 
to 
form international links which could be multiple destination. Tests are 
carried out from the sending ITC for each international link or international 
multiple destination circuit. (See the example given in Figure\ 1/N.62.) 
Again, priority is given to the continuity of each international circuit 
or link and the send and received levels. 
.bp
.RT
.LP
.rs
.sp 32P
.ad r
\fBFigure 1/N.62, p.\fR 
.sp 1P
.RT
.ad b
.RT
.PP
At \fIH\fR precisely, or a few minutes beforehand if the pre\(hytransmission 
tests have been completed, the ITCs extend the international circuits/links 
to the broadcasting organization so that the international television connection 
from the sending broadcasting organization to the receiving broadcasting 
organization(s) can be verified. Any interconnections required in the premises 
of the broadcasting organizations will also be made at this time. International 
television connections should be made available to the broadcasting 
organizations on time, even if all tests have not been completed, provided 
that the continuity and levels have been verified. 
.PP
There is a need for broadcasting organizations to assess subjectively the 
quality of the television picture as per Table\ 1/N.64. If colour bar 
signals
.FS
As defined in [3].
.FE
are used for this purpose, the composite
signal (colour bars plus captions, etc.) must not exceed 1 volt (peak\(hyto\(hypeak) 
in order to preclude interference with adjacent video channels, particularly 
on half transponder satellite operation. 
.RT
.LP
.sp 1
.bp
.ce
\fBH.T. [T1.62]\fR 
.ce
TABLE\ 1/N.62
.ce
\fBSequence of measurements\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(18p) | cw(36p) | cw(54p) | cw(120p) .
Items	Timing	Signal | ua\d\u)\d	Measurement
_
.T&
lw(18p) | lw(36p) | cw(54p) | lw(120p) .
1a 1b	 {
\fIH\fR
\(em30 to \fIH\fR
\(em25
\fIH\fR
\(em15 to \fIH\fR
\(em10
 }	 {
B2 or B3 and B1
(pulse and bar) or insertion test signal | ub\d\u)\d
 }	 {
Luminance bar amplitude error and short period variations (1\ s)
Bar tilt or base line distortion | uc\d\u)\d
2T pulse\(hyto\(hybar ratio
 }
_
.T&
lw(18p) | lw(36p) | cw(54p) | lw(120p) .
2a 2b	 {
\fIH\fR
\(em25 to \fIH\fR
\(em23
\fIH\fR
\(em10 to \fIH\fR
\(em8
 }	 {
No input signal 
or \*Qquiet line\*U
 }	 {
Signal\(hyto\(hyweighted\(hyrandom\(hynoise ratio | ud\d\u)\d
 }
_
.T&
lw(18p) | lw(36p) | cw(54p) | lw(120p) .
3a 3b	 {
\fIH\fR
\(em23 to \fIH\fR
\(em21
\fIH\fR
\(em8\ 
to \fIH\fR
\(em6
 }	A  (field bar)	 {
Field\(hytime waveform distortion
 }
_
.T&
lw(18p) | lw(36p) | cw(54p) | lw(120p) .
4a 4b	 {
\fIH\fR
\(em21 to \fIH\fR
\(em19
\fIH\fR
\(em6\ 
to \fIH\fR
\(em4
 }	 {
Insertion test signals | ub\d\u)\d
 }	 {
Chrominance\(hyluminance gain inequality
Peak differential gain
Peak differential phase
 }
_
.T&
lw(18p) | lw(36p) | cw(54p) | lw(120p) .
5a 5b	 {
\fIH\fR
\(em19 to \fIH\fR
\(em15
\fIH\fR
\(em4\ 
to \fIH\fR
 | ue\d\u)\d
 }	 {
B2 or B3 and B1 or insertion test signals | ub\d\u)\d
 }	 {
Verification of continuity and line\(hyup
 }
.TE
.LP
\ua\d\u)\d
Signals A, B1, B2 and B3 are defined in CCIR Recommendation
567 | 1].
.LP
\ub\d\u)\d
To be inserted in appropriate lines of a video signal with a mean average picture level (APL).
.LP
\uc\d\u)\d
Bar tilt or base line distortion may be measured by mutual
agreement of the Administrations concerned.
.LP
\ud\d\u)\d
Where an ITC has equipment for measuring the
signal\(hyto\(hyweighted\(hynoise ratio on the \*Qquiet\*U line it should take that
measurement during the first five minutes of the test sequence if insertion
test signals are received.
.LP
\ue\d\u)\d
In accordance with Recommendation N.54 connection may be made to the broadcaster by an ITC during this period. Connection may also be made to
the sending broadcaster provided the sending ITC is receiving a
video signal from the broadcaster originating the transmission.
.nr PS 9
.RT
.ad r
\fBTable 1/N.62 [T1.62], p.\fR 
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
\fB4\fR 	\fBTests to be made by the ITCs\fR 
.sp 1P
.RT
.PP
Only 15 minutes is allowed for each of the series of tests
referred to in \(sc\ 2. This period is more than adequate if modern test 
equipment is used. The measurements to be carried out are defined in CCIR 
Recommendations\ 567\ [1] or 569\ [2].
.PP
Before the commencement of the line\(hyup period the staff of the ITCs
should ensure that the test generator(s) and measuring equipment are in good
working order. It is particularly important that impeccable test signals 
should be sent so as to prevent receiving ITCs from concluding, on the 
basis of their measurements, that a circuit is faulty when that is not 
the case. 
.PP
If difficulty is experienced in performing the required tests, as a
minimum, the circuit continuity should be established and the send and 
received levels checked, with the assistance of the sending broadcasting 
organization. If colour bar signals are used for this continuity check, 
the amplitude should be checked and application must be in accordance with 
\(sc\ 3. 
.PP
Table 2/N.62 lists the parameters and test objectives for
international television circuits/links.
.RT
.LP
.sp 1
.bp
.ce
\fBH.T. [T2.62]\fR 
.ce
TABLE\ 2/N.62
.ce
\fBTest\ objectives\fR 
.ce
 | ua\d\u)\d
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(66p) | cw(36p) sw(30p) sw(24p) | cw(18p) sw(18p) sw(18p) sw(18p) , ^  | c | c s | c | c s 
^  | ^  | c | c | c | c | l | l.
Circuit sections	 {
International circuits
ITC/earth station
 }	 {
Earth station/
earth station | ub\d\u)\d
 }
	Terrestrial only	 {
Terrestrial plus satellite | ub\d\u)\d
 }	Half transponder	Full transponder	525\(hyline	625\(hyline	525\(hyline	625\(hyline		
_
.T&
cw(66p) | cw(36p) | cw(30p) | cw(24p) | cw(36p) | cw(36p) .
(1)	(2)	(3a)	(3b)	(4)	(5) 
_
.T&
lw(66p) | cw(36p) | cw(30p) | cw(24p) | cw(36p) | cw(36p) .
Luminance bar amplitude error	 {
\(+- 0.5 dB
or 5 | 
or 5 IRE units
 }	 {
\(+- 0.25 dB
or 2.5 |  or
2.5 IRE units
 }	 {
\(+- 0.25 dB
or 2.5 |  or
2.5 IRE units
 }	 {
\(+- 1 dB
or 11 | 
or 11 IRE units
 }	 {
\(+- 1 dB
or 11 | 
or 11 IRE units
 }
_
.T&
lw(66p) | cw(36p) | cw(30p) | cw(24p) | cw(36p) | cw(36p) .
 {
Short period variations of luminance bar error (1 s)
 }	 {
\(+- 0.3 dB
or 3 | 
or 3 IRE units
 }	 {
\(+- 0.1 dB or
1 |  or
1 IRE unit
 }	 {
\(+- 0.1 dB or
1 |  or
1 IRE unit
 }	 {
\(+- 0.3 dB
or 3 | 
or 3 IRE units
 }	 {
\(+- 0.4 dB
or 4 | 
or 4 IRE units
 }
_
.T&
lw(66p) | cw(36p) | cw(30p) | cw(24p) | cw(18p) | cw(18p) | cw(18p) | cw(18p) .
Bar tilt	\(+- 1 | 	\(+- 1.5 | 	\(+- 1 | 	\(+- 1 |  	\(+- 3 | 	\(+- 2 |  	\(+- 4 |  
_
.T&
lw(66p) | cw(36p) | cw(30p) | cw(24p) | cw(18p) | cw(18p) | cw(36p) .
Base ligne distortion	\(+- 1 | 	Note	Note	\(+- 1 | 	\(+- 3 | 	Note
_
.T&
lw(66p) | cw(36p) | cw(30p) | cw(24p) | cw(18p) | cw(18p) | cw(18p) | cw(18p) .
2T pulse\(hyto\(hybar ratio	\(+- 6 | 	\(+- 6 | 	\(+- 6 | 	\(+- 6 |  	\(+- 8 | 	\(+- 12 |  	\(+- 10 |  
_
.T&
lw(66p) | cw(36p) | cw(30p) | cw(24p) | cw(36p) | cw(36p) .
 {
Signal\(hyto\(hyweighted\(hyrandom\(hynoise ratio
 }	56 dB	49 dB	54 dB	56 dB	48 dB 
_
.T&
lw(66p) | cw(36p) | cw(30p) | cw(24p) | cw(18p) | cw(18p) | cw(18p) | cw(18p) .
 {
Field time waveform distortion
 }	\(+- 2 | 	\(+- 2 | 	\(+- 1 | 	\(+- 2 | 	\(+- 6 | 	\(+- 4 | 	\(+- 6 | 
_
.T&
lw(66p) | cw(36p) | cw(30p) | cw(24p) | cw(18p) | cw(18p) | cw(18p) | cw(18p) .
 {
Chrominance\(hyluminance gain inequality
 }	\(+- 10 | 	\(+- 10 | 	\(+- 10 | 	+ \ 8 |  \(em 11 | 	\(+- 10 | 	+ 12 |  \(em 20 | 	\(+- 15 | 
_
.T&
lw(66p) | cw(36p) | cw(30p) | cw(24p) | cw(18p) | cw(18p) | cw(36p) .
Peak differential gain	\(+- 10 | 	\(+- 10 | 	\(+- 10 | 	\(+- 10 |  	\(+- 8 | 	\(+- 15 |  
_
.T&
lw(66p) | cw(36p) | cw(30p) | cw(24p) | cw(18p) | cw(18p) | cw(18p) | cw(18p) .
Peak differential phase	\(+- 3\(de	\(+- 4\(de	\(+- 3\(de	\(+- 3\(de	\(+- 5\(de	\(+- 6\(de	 {
\(+- 8\(de
\ua\d\u)\d
In principle, the test objectives for terrestrial circuits/links apply to those having a length of about 1250\ km.
 }
.TE
.LP
\ub\d\u)\d
Test objectives given in columns 3a, 3b and 5 refer to temporary circuit sections and circuits
provided by INTELSAT satellites and relate to expected performance in global
beam utilizing earth stations having G/T of 40.7\ dB/K and elevation angles
of\ 10\(de. Different figures may be appropriate when other satellites, earth
station sizes and elevation angles are employed.
.LP
\fINote\fR
\ \(em\ Under study.
.nr PS 9
.RT
.ad r
\fBTable 2/N.62 [T2.62], p.\fR 
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
	\fBReferences\fR 
.sp 1P
.RT
.LP
[1]
	CCIR Recommendation \fITelevision performance of television circuits\fR 
\fIdesigned for use in international connections\fR , Rec.\ 567, Vol.\ 
XII, ITU, 
Geneva,\ 1986.
.LP
[2]
	CCIR Recommendation \fIDefinitions of parameters simplified for\fR 
\fIautomatic measurement of television insertion test signals\fR , Rec.\ 569,
Vol.\ XII, ITU, Geneva,\ 1986.
.LP
[3]
	EBU (European Broadcasting Union) \fIVideo measurement and the\fR 
\fIcorrection of video circuits\fR , Technical Monograph 3116 (L.E. Weaver,\ 
1978), Appendix\ 3, Sections\ 5, 6, 7 and\ 8. 
.bp
.sp 2P
.LP
\fBRecommendation\ N.63\fR 
.RT
.sp 2P
.ce 1000
\fBTEST\ SIGNALS\ TO\ BE\ USED\ BY\ THE\ BROADCASTING\ ORGANIZATIONS\fR 
.EF '%	Fascicle\ IV.3\ \(em\ Rec.\ N.63''
.OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.63	%'
.ce 0
.sp 1P
.ce 1000
\fBDURING\ THE\ PREPARATORY\ PERIOD\fR 
.ce 0
.sp 1P
.PP
After the broadcasting organizations have taken over the
international television connection, they may decide to make measurements on
the complete connection from the point where the television programme is
produced to the point or points where it is to be received.
.sp 1P
.RT
.PP
The broadcasting organizations often use live pictures for testing during 
the preparatory period, especially when a 
standards convertor
is involved. If for any reason they should need to send test signals then it is
desirable that the telecommunication Administrations should recommend the
broadcasting organizations in their countries to send signals that are in
accordance with those recommended in Recommendation\ N.67 (at levels in
accordance with Recommendation\ N.60), so that the staff at intermediate 
video interconnection points can, if necessary, compare the results of 
the 
measurements made by the broadcasting organizations with those obtained 
by the telecommunication Administrations during the line\(hyup period. 
There is no 
occasion to readjust the output levels of the station equipment since these
have already been set during the line\(hyup period.
.PP
All test signals transmitted prior to the actual television
transmission, being full field or otherwise, should be superimposed with the
identification of the broadcaster and location from where the test signal is
originating. This identification may be transmitted either in monochrome, or
in colour, according to preference or to suit the technical requirements of
the particular test signal being transmitted. If the local language of the
.PP
originating source is not an internationally recognized language then the
identification signal should be displayed not only in the local language 
of the country concerned but also in one of the internationally recognized 
languages. 
.PP
When a full field signal is transmitted simply as a means to check
link or tandem connection continuity, it may comprise any suitable composite
video signal (such as test pattern, pulse/bar or other suitable picture or
pattern) provided that it contains specific signal components that include 
Peak White, synchronizing pulses and the identification signal (as previously 
described) of the station or broadcaster transmitting the signal. The composite 
signal (colour bars plus captions,\ etc.) must not exceed 1\ volt (peak\(hyto\(hypeak) 
in order to preclude interference with adjacent video channels, particularly 
on half transponder satellite operation. 
.PP
When television pictures which contain electronically generated
components, e.g.\ captions, are used, the out\(hyof\(hyband\(hyspectral 
power in any 
4\ kHz band above 1.2\ times the nominal video bandwidth shall not exceed
\(em50\ dB.
.RT
.sp 2P
.LP
\fBRecommendation\ N.64\fR 
.RT
.sp 2P
.sp 1P
.ce 1000
\fBQUALITY\ AND\ IMPAIRMENT\ ASSESSMENT\fR 
.EF '%	Fascicle\ IV.3\ \(em\ Rec.\ N.64''
.OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.64	%'
.ce 0
.sp 1P
.LP
\fB1\fR 	\fB5\(hygrade scale for quality and impairment assessment\fR 
.sp 1P
.RT
.PP
The 5\(hygrade scale, applicable to both quality and impairment
assessments in Table\ 1/N.64 should be used.
.RT
.ce
\fBH.T. [T1.64]\fR 
.ce
TABLE\ 1/N.64
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(18p) | cw(36p) | cw(72p) .
Grade	Quality	Impairment
_
.T&
cw(18p) | lw(36p) | lw(72p) .
5	Excellent	Imperceptible
.T&
cw(18p) | lw(36p) | lw(72p) .
4	Good	Perceptible but not annoying
.T&
cw(18p) | lw(36p) | lw(72p) .
3	Fair	Slightly annoying
.T&
cw(18p) | lw(36p) | lw(72p) .
2	Poor	Annoying
.T&
cw(18p) | lw(36p) | lw(72p) .
1	Bad	Very annoying
_
.TE
.nr PS 9
.RT
.ad r
\fBTable 1/N.64 [T1.64], p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.PP
Although the scale is intended, in connection with television, to apply 
to \fIoverall\fR picture assessment, it should be noted that the same scale 
could be used for a critical assessment of particular picture characteristics. 
Moreover, the number of the grade can be taken as either a quality assessment 
or an impairment assessment. Depending on the context, for example, a Grade\ 
3 picture is of \fIfair\fR quality, having \fIslightly annoying\fR impairments. 
The same scale can be used in the case of types of transmission other than 
television. 
.PP
\fINote\ 1\fR \ \(em\ It is implicit that before a circuit is handed over to a
broadcasting organization all reasonable steps will have been taken to 
ensure that the circuit quality from the point of view of transmission 
is the best 
that can be achieved at the beginning of the preparatory period.
.PP
\fINote\ 2\fR \ \(em\ Grade\ 1 should be applied only to a transmission 
considered to be unusable by the broadcasting organization concerned. If, 
under 
exceptional circumstances, the broadcasting organization decides to use a
transmission so graded, because of the interest in the information to be
transmitted, this should not constitute a precedent for changing the grade 
or for changing the significance of Grade\ 1. 
.PP
\fINote\ 3\fR \ \(em\ This Recommendation does not apply to the assessment of
speech transmission quality in telephony.
.RT
.sp 2P
.LP
\fBRecommendation\ N.67\fR 
.RT
.sp 2P
.ce 1000
\fBMONITORING\ TELEVISION\ TRANSMISSIONS\fR .
.EF '%	Fascicle\ IV.3\ \(em\ Rec.\ N.67''
.OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.67	%'
.ce 0
.sp 1P
.ce 1000
\fBUSE\ OF\ THE\ FIELD\ BLANKING\ INTERVAL\fR 
.ce 0
.sp 1P
.LP
\fB1\fR 	\fBMonitoring points\fR 
.sp 1P
.RT
.PP
Technical control by the telecommunication Administrations of a
television transmission in progress should be possible at any time:
.RT
.LP
	\(em
	at national and international television centres in the
connection;
.LP
	\(em
	at the last staffed\(hystation immediately preceding the
frontier of each country and at a point in the station which will include as
much as possible of the station equipment in the direction of transmission
concerned (by providing monitoring\(hydemodulators if necessary).
.PP
These centres and stations should be equipped with an oscilloscope (the 
horizontal sweep frequency of which is synchronized to the line 
frequency) for monitoring the electrical signal and a picture\(hymonitor for
monitoring the complete picture.
.sp 2P
.LP
\fB2\fR 	\fBNumbering of lines in a television field\fR 
.sp 1P
.RT
.PP
For 625\(hyline systems the numbering of the lines is as follows:
.PP
Line\ 1 starts at the instant indicated by 0\dv\uin Figure\ 2\(hy1 of
CCIR\ Report\ 624\ [1]; at this instant, the leading edge of the line
synchronization pulse coincides with the beginning of the sequence of field
synchronization pulses. The lines are numbered according to their sequence 
in time, so that the first field comprises lines\ 1 to 312 as well as the 
first 
half of line\ 313, whereas the second field comprises the second half of
line\ 313 and lines\ 314 to\ 625.
.PP
For 525\(hyline systems the numbering of the lines is as follows:
.PP
Line\ 1 of field\ 1 is the line starting with the first equalizing pulse 
at the instant indicated by 0\dE\\d1\uin Figure\ 2\(hy3a of CCIR\ Report\ 
624\ [2], 
line\ 1 of field\ 2 is the line starting with the second equalizing pulse 
at one half\(hyline period after the instant indicated by 0\dE\\d2\uin 
Figure\ 2\(hy3b of 
this report\ [3].
.RT
.sp 2P
.LP
\fB3\fR 	\fB625\(hyline insertion test signals (ITS)\fR 
.sp 1P
.RT
.PP
The advent of colour has caused the CCIR to recommend a
comprehensive set of test signals which may be inserted on lines\ 17, 18, 330
and\ 331 for international monochrome or colour transmissions
.FS
As an interim measure some organizations may decide to omit some of the 
waveforms, but in 
this case care must be taken not to alter the mean values appreciably.
.FE
.
This signal is illustrated in Figure\ 1/N.67
.FS
A colour burst is
present in the line blanking period during colour transmissions. In the 
case of PAL colour transmissions the chrominance subcarrier of the insertion 
signals is locked at 60\(de from the (B\(hyY) axis. 
.FE
and is made up as follows:
.RT
.LP
.bp
.LP
	\fILine 17\fR 
.LP
	A 10\ \(*ms white bar\ (B\d2\u), a 2\ T sine\(hysquared pulse\ (B\d1\u), a
20\ T composite pulse\ (F) and a 5\(hyriser staircase\ (D\d1\u).
.LP
	\fILine 18\fR 
.LP
	A multiburst\ (C\d2\u) preceded by a reference bar signal\ (C\d1\u)
.LP
	\fILine 330\fR 
.LP
	 A 10\ \(*ms white bar\ (B\d2\u), a 2\ T sine\(hysquared pulse\ (B\d1\u) 
and a 5\(hyriser staircase with superimposed colour subcarrier\ (D\d2\u). 
.LP
	\fILine 331\fR 
.LP
	A chrominance bar signal\ (G\d1\u) or a three\(hylevel chrominance
signal\ (G\d2\u), followed by a sub\(hycarrier reference bar\ (E).
.LP
.rs
.sp 30P
.ad r
\fBFigure 1/N.67 p.\fR 
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
\fB4\fR 	\fB525\(hyline insertion test signal (ITS)\fR 
.sp 1P
.RT
.PP
\fI\fR For colour the CCIR has recommended a comprehensive set of test
signals which may be inserted on lines\ 17 of both fields (lines\ 17 and\ 
280 if numbered consecutively) for international monochrome or colour transmissions. 
These signals are illustrated in Figure\ 2/N.67,\ \fIc\fR ) and\ \fId\fR 
) and are made up as follows: 
.RT
.LP
	\fIFigure 2/N.67, c):\fR  | a luminance bar (reference white
level)\ (B\d2\u), a 2\ T sine\(hysquared pulse\ (B\d1\u), a modulated\ 12.5\ T
sine\(hysquared pulse\ (F) and a superimposed 5\(hyriser staircase\ (D\d2\u);
.bp
.LP
	 \fIFigure 2/N.67, d):\fR  | a reference bar signal\ (C\d1\u), a luminance 
pedestal, a multiburst signal superimposed on the pedestal\ (C\d2\u) 
and a superimposed 3\(hylevel chrominance signal\ (G).
.PP
A detailed description of these signals is given in
CCIR Recommendation\ 473\ [4].
.LP
.rs
.sp 39P
.ad r
\fBFIGURE 2/N.67 p.\fR 
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
\fB5\fR 	\fBMeasurements on insertion test signals (ITS)\fR 
.sp 1P
.RT
.PP
In order to carry out measurements on an insertion test signal,
stations and centres should also be equipped with a line selector which 
enables only the test signal line (or lines) to be displayed on the oscilloscope. 
.bp
.PP
Measurements which can be made with the above signals are given in
Tables\ 1/N.67 and 2/N.67.
.RT
.ce
\fBH.T. [T1.67]\fR 
.ce
TABLE\ 1/N.67
.ce
\fB625\(hyline monochrome or colour signal (Figure 1/N.67)\fR 
.ce
\fB(CCIR Recommendation 473 | 4])\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(126p) | cw(48p) | cw(42p) .
Characteristics measured	Waveform used	Line number
_
.T&
lw(126p) | cw(48p) | cw(42p) .
\fILinear distortions\fR		
.T&
lw(126p) | cw(48p) | cw(42p) .
Insertion gain	B 2	17 and 330
.T&
lw(126p) | cw(48p) | cw(42p) .
Amplitude/frequency response	C 2 and C 1	18
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
Line\(hytime waveform distortion
 }	B 2	17 and 330
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
Short\(hytime waveform distortion
 }		
.T&
lw(126p) | cw(48p) | cw(42p) .
\(em\ step response	B 2	17 and 330
.T&
lw(126p) | cw(48p) | cw(42p) .
\(em\ pulse response	B 1	17 and 330
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
Chrominance\(hyluminance gain inequality
 }	B 2 and G 1 or G 2	17 and 330, 331
.T&
lw(126p) | cw(48p) | cw(42p) .
\fB.\fR	B 2 and F	17
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
Chrominance luminance delay inequality
 }	F	17
_
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
\fINonlinear distortions\fR
 }		
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
Luminance line\(hytime nonlinearity
 }	D 1	17
.T&
lw(126p) | cw(48p) | cw(42p) .
Chrominance nonlinearity	G 2	331
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
Luminance chrominance intermodulation
 }		
.T&
lw(126p) | cw(48p) | cw(42p) .
\(em\ differential gain	D 2	330
.T&
lw(126p) | cw(48p) | cw(42p) .
\(em\ differential phase	D 2 and E	330, 331
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
Chrominance luminance intermodulation
 }	B 2 and G 1 or G 2	17, 331
_
.TE
.nr PS 9
.RT
.ad r
\fBTABLE 1/N.67 [T1.67], p.\fR 
.sp 1P
.RT
.ad b
.RT
.ce
\fBH.T. [T2.67]\fR 
.ce
TABLE\ 2/N.67
.ce
\fB525\(hyline monochrome or colour signal (Figure 2/N.67)\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(126p) | cw(48p) | cw(42p) .
Characteristics measured	Waveform used	Line number
_
.T&
lw(126p) | cw(48p) | cw(42p) .
\fILinear distortions\fR		
.T&
lw(126p) | cw(48p) | cw(42p) .
Insertion gain	B 2	17/field 1
.T&
lw(126p) | cw(48p) | cw(42p) .
Amplitude/frequency response	B 2 | ua\d\u)\d and C 2	17 fields 1 and 2
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
Line\(hytime waveform distortion
 }	B 2	17/field 1
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
Short\(hytime waveform distortion
 }		
.T&
lw(126p) | cw(48p) | cw(42p) .
\(em\ step response	B 2	17/field 1
.T&
lw(126p) | cw(48p) | cw(42p) .
\(em\ pulse response	B 1	17/field 1
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
Chrominance/luminance gain inequality
 }	B 2 and F	17/field 1
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
Chrominance/luminance delay inequality
 }	F	17/field 1
_
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
\fINonlinear distortions\fR
 }		
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
Line\(hytime luminance nonlinearity
 }	D 1 | ub\d\u)\d	17/field 1
.T&
lw(126p) | cw(48p) | cw(42p) .
Chrominance nonlinearity	G	17/field 2
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
Luminance/chrominance intermodulation
 }		
.T&
lw(126p) | cw(48p) | cw(42p) .
\(em\ differential gain	D 2	17/field 1
.T&
lw(126p) | cw(48p) | cw(42p) .
\(em\ differential phase	D 2	17/field 1
.T&
lw(126p) | cw(48p) | cw(42p) .
 {
Chrominance/luminance intermodulation
 }	G	17/field 2
.TE
.LP
\ua\d\u)\d
C
1 (line 17/field 2) may be used in place of B
2, when
line\(hytime distortion is suitably small.
.LP
\ub\d\u)\d
D
2 may be used when the chrominance/luminance intermodulation is suitably small.
.nr PS 9
.RT
.ad r
\fBTABLE 2/N.67 [T2.67], p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 2P
.LP
\fB6\fR 	\fBInsertion and removal of\fR 
\fBtest signals in the field\fR 
\fBblanking period\fR 
.sp 1P
.RT
.sp 1P
.LP
6.1
	\fIInternational signals\fR 
.sp 9p
.RT
.PP
The appropriate international signals inserted by the originating broadcasting 
organization should be transmitted to the point of destination of the television 
connection. Exceptionally, if the connection includes a 
standards or colour systems convertor which does not pass signals occurring
during the field blanking period, then the signals should be monitored 
at the upstream video point nearest to the convertor and new international 
signals, to the appropriate standard, should be inserted at the downstream 
point nearest to the convertor. The test signals should be available at 
any video connection 
point in order to facilitate assessment of performance. They may also be 
of use in carrying out any necessary readjustment of correctors at the 
final 
destination.
.RT
.sp 1P
.LP
6.2
	\fINational signals\fR 
.sp 9p
.RT
.PP
Any test signals inserted in lines\ 18 to 20 (525\(hyline systems), or 
19 to 21 (625\(hyline systems) and the corresponding lines in the second 
field in either standard, should be regarded as national signals and should 
be removed at a suitable video point within the national frontier so that 
downstream 
countries on the circuit may use these lines for their own needs.
Exceptionally, and subject to agreement between all the countries concerned,
national signals may be transmitted across international frontiers.
.RT
.sp 2P
.LP
\fB7\fR 	\fBGeneral implementation\fR 
.sp 1P
.RT
.PP
It is requested that Administrations of countries where national
broadcasting organizations have the sole right of transmitting television
signals should approach those organizations in order that the principles of
this Recommendation may be applied as widely as possible.
.PP
Attention is drawn to the comments in Annex III to Part C of CCIR
Recommendation\ 567\ [5]. Particular attention is drawn to the unrepresentative 
result of measurements made on a single test line per field when 
.PP
half\(hyfield\(hyrate dispersal waveforms are applied to the signal, e.g.,\ on
satellite circuits. Comment is also made in this reference to the difference
between measurements made with full field test signals in accordance with 
CCIR Recommendation\ 567\ [5] and measurements made automatically in accordance 
with CCIR Recommendation\ 569\ [6]. 
.RT
.sp 2P
.LP
	\fBReferences\fR 
.sp 1P
.RT
.LP
[1]
	CCIR Report \fICharacteristics of television systems\fR , Vol.\ XI,
Report\ 624, p.\ 5, Figure\ 2\(hy1, ITU, Geneva,\ 1986.
.LP
[2]
	\fIIbid.\fR , p.\ 7, Figure\ 2\(hy3a.
.LP
[3]
	\fIIbid.\fR , p.\ 7, Figure\ 2\(hy3b.
.LP
[4]
	 CCIR Recommendation \fIInsertion of test signals in the field\(hyblanking 
\fR \fIinterval of monochrome and colour television\fR , Vol.\ XII, Rec.\ 
473, ITU, 
Geneva,\ 1986.
.LP
[5]
	CCIR Recommendation \fITelevision performance of television circuits\fR 
\fIdesigned for use in international connections\fR , Vol.\ XII, Rec.\ 
567, ITU, 
Geneva,\ 1986.
.LP
[6]
	 CCIR Recommendation \fIDefinitions of parameters simplified for automatic\fR 
\fImeasurement of television insertion test signals\fR , Vol.\ XII, Rec.\ 
569, ITU, 
Geneva,\ 1986.
.LP
.rs
.sp 5P
.ad r
BLANC
.ad b
.RT
.LP
.bp
.IP
\fB2.3\ Maintenance of leased circuits for television transmission\fR 
.sp 1P
.RT
.sp 2P
.LP
\fBRecommendation\ N.73\fR 
.RT
.sp 2P
.ce 1000
\fBMAINTENANCE\ OF\ PERMANENT\ INTERNATIONAL\fR 
.EF '%	Fascicle\ IV.3\ \(em\ Rec.\ N.73''
.OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.73	%'
.ce 0
.sp 1P
.ce 1000
\fBTELEVISION\ CIRCUITS,\ LINKS\ AND\ CONNECTIONS\fR 
.ce 0
.sp 1P
.LP
\fB1\fR 	\fBIntroduction\fR 
.sp 1P
.RT
.PP
In most cases, circuits used for television transmissions are
provided by the Administrations, although in some countries broadcasting
organizations own all or part of the circuits within national boundaries.
.PP
\fR 
The routine maintenance of circuits used for transmissions between two 
or more countries requires the closest cooperation between the 
Administrations/broadcasting organizations that provide the circuit sections.
.PP
It is recommended that routine maintenance measurements be carried out 
each month on permanently installed terrestrial circuits. 
.PP
This Recommendation applies also for routine test transmission over
leased satellite circuits for television transmissions directed to TVROs not
related to an ITC.
.RT
.sp 2P
.LP
\fB2\fR 	\fBTest signal elements\fR 
.sp 1P
.RT
.PP
Diagrams of the different test\(hysignal elements as defined in CCIR Recommendation\ 
567\ [1] are given in Annex\ A; the titles of those test\(hysignal 
elements with the reference designations are given below:
.RT
.LP
Field\ bar
	Signal\ A
	Figures\ A\(hy1/N.73 and A\(hy2/N.73
.LP
	Sine\(hysquared\ pulse
	Signal\ B1
	Figures\ A\(hy3/N.73 and A\(hy4/N.73
.LP
	
Luminance\ bar
	Signal\ B2\ or, B3
	Figures\ A\(hy3/N.73 and A\(hy4/N.73
.LP
	
Multiburst
	Signal\ C
	Figures\ A\(hy5/N.73 and A\(hy6/N.73
.LP
	Staircase
	Signal\ D1 and D2
	Figures\ A\(hy7/N.73 and A\(hy8/N.73
.LP
	
Composite pulse
	Signal\ F
	Figures\ A\(hy9/N.73 and A\(hy10/N.73
.LP
	
Chrominance\ bar
	Signal\ G1\ (625\(hylines only)
	Figure\ A\(hy11/N.73
.LP
	
Three\ level\ chrominance\ bar
	Signal\ G2\ (625\(hylines
only)
	Figure\ A\(hy11/N.73
.LP
	Three\ level\ chrominance\ bar
	Signal\ G\ (525\(hylines
only)
	Figure\ A\(hy12/N.73
.sp 2P
.LP
\fB3\fR 	\fBTest equipment\fR 
.sp 1P
.RT
.sp 1P
.LP
3.1
	\fIGenerators\fR 
.sp 9p
.RT
.PP
CCIR Recommendation\ 473\ [2] defines the insertion test signals
required for measurement purposes. The assembly of test signal elements 
in test lines is also referred to in Recommendation\ N.67 and most modern 
test 
signal generators can originate the test signals, either as insertion test
signals or as full\(hyfield test signals. In the latter mode measurements 
can be carried out at standard values of average picture level (APL). 
.PP
The assembly of test signal elements in the test lines is sufficient for 
the measurement of the large majority of television circuit parameters, 
that is, distortions occurring at line frequency and above. However, additional 
test\ signals are needed for low and very low\(hyfrequency measurements. A
field bar
is required for the measurement of 
field time
distortions
and, for the measure
ment\ of long\(hytime waveform distortion,   a signal is required 
which\ is switched at intervals of a few seconds
between low and high APLs. (For further details see CCIR
Report\ 636\ [3].)
.RT
.sp 1P
.LP
3.2
	\fIMeasurement equipment\fR 
.sp 9p
.RT
.PP
The measurement equipment may consist of:
.RT
.LP
	\(em
	an oscilloscope or television waveform monitor with
additional equipment for making nonlinearity
\fR measurements
.FS
A line selector for selecting insertion
test lines for display with older type waveform monitors or
oscilloscopes is commercially available.
.FE
;
.LP
.bp
.LP
	\(em
	modern television waveform monitors equipped with
line\(hyselection and means for measuring nonlinearity
distortion;
.LP
	\(em
	automatic measurement equipment.
.sp 2P
.LP
\fB4\fR 	\fBMeasurement definitions\fR 
.sp 1P
.RT
.PP
CCIR Recommendations 567 [1] and 569 [4] define the
measurements that may be made on television circuits. There are slight
differences in the way certain similar parameters are defined, for example,
insertion gain and luminance bar amplitude, and differences in the way the
results are expressed, for example, luminance bar amplitude and luminance 
bar amplitude error. To standardize routine maintenance measurements, it 
is 
recommended that the definitions given in Recommendation\ 569 [4] be used for
maintenance purposes whenever possible. The results are then easier to 
analyze because the result of a measurement is zero for an undistorted 
parameter. 
.RT
.sp 2P
.LP
\fB5\fR 	\fBAccess points\fR 
.sp 1P
.RT
.PP
Measurements are taken at television signal access points which are well\(hydefined 
points associated with the input and output of a television 
circuit. To suit the characteristics of the measurement equipment, the 
standard level/impedance at the access point should be 1 volt peak\(hyto\(hypeak 
into 75\ ohms. The return loss at the access point shall be better than 
30\ dB. 
.PP
The access point may be the point of interconnection or may be
connected to it by a distortion\(hyfree circuit having zero loss or gain.
.PP
For flexibility, and to ensure that measured parameters are comparable 
to transmission parameters, it is necessary that the interconnection system 
in the ITC should handle programme and test signals in the same way. Figure\ 
1/N.73 shows one method of realizing that objective. 
.RT
.LP
.rs
.sp 18P
.ad r
\fBFigure 1/N.73, p.\fR 
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
\fB6\fR 	\fBRoutine verification of test equipment\fR 
.sp 1P
.RT
.PP
To ensure that test equipment errors will not lead to incorrect
adjustment of a television circuit, the test equipment should be verified
regularly.
.PP
The connection between the test signal generator and the measurement equipment, 
via the interconnection system, should be verified at intervals of, say, 
three months and the results should be within the limits given in 
Table\ 1/N.73.
.RT
.LP
.sp 2
.bp
.ce
\fBH.T. [T1.73]\fR 
.ce
TABLE\ 1/N.73
.ce
\fBLimits for measurement chains\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(120p) | cw(36p) .
Parameter	Limits
_
.T&
lw(120p) | lw(36p) .
Luminance bar amplitude error	\(+- 1 | 
_
.T&
lw(120p) | lw(36p) .
Bar tilt/Base line distortion	\(+- 1 | 
_
.T&
lw(120p) | lw(36p) .
2T pulse/bar ratio error	\(+- 2 | 
_
.T&
lw(120p) | lw(36p) .
Peak differential gain	\(+- 1 | 
_
.T&
lw(120p) | lw(36p) .
Peak differential phase	\(+- 1\(de
_
.T&
lw(120p) | lw(36p) .
 {
Chrominance/luminance gain inequality
 }	\(+- 2 | 
_
.T&
lw(120p) | lw(36p) .
 {
Chrominance/luminance delay inequality
 }	\(+- 5 ns
_
.T&
lw(120p) | lw(36p) .
 {
Signal\(hyto\(hycontinuous\(hynoise ratio (unified weighted)
 }	\(>=" 65 dB
_
.TE
.nr PS 9
.RT
.ad r
\fBTable 1/N.73 [T1.73], p.\fR 
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
.sp 2
\fB7\fR 	\fBMaintenance limits\fR 
.sp 1P
.RT
.PP
The figures given in Table 2/N.73 showing the maintenance limits
are based on the design objectives for hypothetical reference circuits 
given in CCIR Recommendation\ 567\ [1] but refer to international television 
circuits, 
nominally one\(hythird of the length of the hypothetical reference circuit,
between terminal ITCs which are normally in adjacent countries. These limits
are expected to apply for most of the time but may be exceeded for part 
of the time. Hence, maintenance staff must exercise judgement on the action 
to be 
taken when a circuit is outside the maintenance limits for any parameter. If
the results are well outside the limits, for example, if the error is greater 
than twice the limit value or the signal\(hyto\(hynoise ratio is 3\ dB 
worse than the limit value, the fault should be located and corrected. 
On the other hand, if the limits are only exceeded by a relatively small 
amount, corrective action 
should not be carried out unless a given parameter exceeds the maintenance
limits in two successive months.
.PP
Maintenance limits for circuit sections which are different in length and 
construction from the circuit section equal to one third of the 
hypothetical reference circuit may be derived by the application of the 
Laws of Addition specified in CCIR Recommendation\ 567\ [1] to the limits 
quoted in 
Table\ 2/N.73, but the precautions in \(sc\ 10 should be noted.
.RT
.LP
.rs
.sp 5P
.ad r
BLANC
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [1T2.73]\fR 
.ce
TABLE\ 2/N.73
.ce
\fBMaintenance limits for permanent international television circuits\fR 
.ce

.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(24p) | cw(96p) | cw(54p) | cw(54p) .
Item (Note 12)	Parameter	Test waveform(s)	Maintenance limits
_
.T&
lw(24p) | lw(96p) | cw(54p) | cw(30p) | lw(24p) .
		525	625	
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
\ 1	 {
Luminance bar\(hyerror
(Note 1)
 }	B2 or B3	\(+- 11  IRE units	\(+- 11 |   (\(+- 1 dB)
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
\ 2	 {
Variation of luminance bar\(hyerror
(e.g. 1 s)
 }	B2 or B3	\(+- 3  IRE units	\(+- 2 |   (\(+- 0.2 dB)
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
\ 3	 {
Variation of luminance bar\(hyerror
(e.g. 1 hour)
 }	B2 ou B3	\(+- 8  IRE units	\(+- 11 |   (\(+- 1 dB)
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
\ 4	 {
Signal\(hyto\(hycontinuous\(hyweighted\(hynoise ratio
 }	 {
No input signal
(Notes 1, 3)
or
\*Qquiet\*U line
(Notes 2, 4)
 }	\(>=" 56 dB	\(>=" 52 dB (Note 10)
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(54p) .
\ 5	 {
Signal\(hyto\(hyperiodic\(hynoise ratio (power supply frequency
\(em0.1 kHz) 
(Note 2)
 }	No input signal	\(>=" 35 dB  (Note 5)
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(54p) .
\ 6	 {
Signal\(hyto\(hyperiodic\(hynoise ratio (1 kHz \(em \fIf\fI
)
(Note 2)
 }	No input signal	\(>=" 55 dB
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(54p) .
\ 7	 {
Signal to impulsive noise ratio
(Note 2)
 }	No input signal	\(>=" 25 dB
_
.T&
cw(24p) | cw(96p) | cw(54p) | lw(30p) | lw(24p) , ^  | ^  | ^  | l s.
3 | 	10 | 	 {
(Note 6)
\ 9
Chrominance gain non\(hylinearity
(Note 2)
G ou G2
 }		
			
_
.T&
cw(24p) | cw(96p) | cw(54p) | lw(30p) | lw(24p) , ^  | ^  | ^  | l s.
4 | 	7 | 	 {
(Note 6)
10
Chrominance phase non\(hylinearity
(Note 2)
G ou G2
 }		
			
_
.T&
cw(24p) | cw(96p) | cw(54p) | lw(30p) | lw(24p) , ^  | ^  | ^  | l s.
4\(de	5\(de	 {
(Note 6)
11
Peak differential gain
(Note 1)
D2
 }		
			
_
.T&
cw(24p) | cw(96p) | cw(54p) | lw(30p) | lw(24p) , ^  | ^  | ^  | l s.
\(+- 10 | 	\(+- 8 | 	 {
(Note 6)
12
Peak differential phase
(Note 1)
D2
 }		
			
_
.T&
cw(24p) | cw(96p) | cw(54p) | lw(30p) | lw(24p) , ^  | ^  | ^  | l s.
\(+- 3\(de	\(+- 5\(de	(Note 6)		
			
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(54p) .
13	 {
Chrominance\(hyluminance intermodulation
(Notes 1, 2)
 }	G or G2	\(+- 3 |   (Note 6)
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(54p) .
14	 {
Sync. amplitude error
(Note 1)
 }	(Note 7)	\(+- 10 |   (Note 6)
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(54p) .
15	 {
Long\(hytime waveform distortion
(Note 2)
 }	\*QBump\*U signal	 {
40 | 
(Notes 13, 14)
\fBH.T. [2T2.73]\fR
 }
_
.T&
rw(24p) | lw(96p) | cw(54p) | cw(54p) .
 {
TABLE\ 2/N.73\ \fI(cont.)\fR
 }			
.T&
cw(24p) | cw(96p) | cw(54p) | cw(54p) .
Item (Note 12)	Parameter	Test waveform(s)	Maintenance limits
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
16	 {
Field\(hytime waveform distortion
(Note 2)
 }	A  (Note 11)	\(+- 2 | 	\(+- 6 | 
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
17	 {
Line\(hytime waveform distortion (Note\ 2)
Bar tilt (Note\ 1)
 }	B2 or B3	\(+- 1 | 	\(+- 3 | 
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
18	 {
Base line distortion (Note\ 1)
 }	B2 or B3	\(+- 1%	\(+- 3%
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
19	 {
2T pulse/bar ratio error (Note\ 1)
 }	B1 and B2 or B3	\(+- 6 | 	\(+- 8 | 
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(54p) .
20	 {
Short\(hytime waveform distortion
(Note 2)
 }	B1	 {
1\us\d\ut\d adjacent lobe
6 | 
2\un\d\ud\d adjacent lobe
3 | 
 }
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
21	 {
Gain/frequency characteristic
(Note 2)
 }	C  (Note 8)	\(+- 1 dB	+1.5 dB to \(em1 dB
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
22	 {
Chrominance\(hyluminance gain inequality
(Note 1)
 }	B2 or B3  and G, G 2 or F	\(+- 10 | 	\(+- 10 | 
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(54p) .
23	 {
Chrominance\(hyluminance delay inequality
(Note 1)
 }	F	\(+- 80 ns (Note 9)
.TE
.LP
\fINote 1\fR
\ \(em\ As defined in CCIR Recommendation 569 [4].
.LP
\fINote 2\fR
\ \(em\ As defined in CCIR Recommendation 567 [1].
.LP
\fINote 3\fR
\ \(em\ Noise measured via unified weighting filter and low and
high pass filters specified in Annex II to Part C of CCIR
Recommendation\ 567 [1].
.LP
\fINote 4\fR
\ \(em\ Noise measured on line(s) allocated for noise measurement
with weighting network and filters as given in Note\ 3 plus a chrominance
frequency notch filter as specified in CCIR Recommendation\ 569 [4].
.LP
\fINote 5\fR
\ \(em\ The maintenance limits refer to circuits without clamps.
When clamps are used the maintenance limits are \(>="\ 50\ dB.
.LP
\fINote 6\fR
\ \(em\ Measured at APLs of 10% and 90%.
.LP
\fINote 7\fR
\ \(em\ Video signal containing synchronizing signals with normal
amplitude.
.LP
\fINote 8\fR
\ \(em\ Measurements on C2 may be referred to C1 taking account of
any difference in the amplitude of the two elements. The results of this test may conflict with those obtained with test waveforms. If this occurs the
waveform results should be considered to be definitive.
.LP
\fINote 9\fR
\ \(em\ The value is positive if the luminance component leads the
chrominance component.
.LP
\fINote 10\fR
\ \(em\ Further data is required to consider amendment to this
figure.
.LP
\fINote 11\fR
\ \(em\ A window signal is specified in CCIR Recommendation\ 567 [1]
for use on 525\(hyline systems. Test results are required before limits for this signal can be included. Use of this signal should be noted in the measurement results.
.LP
\fINote 12\fR
\ \(em\ Routine measurements made at regular intervals may be limited to
less than the complete list of items given in Table\ 2/N.73 by agreement between the Administrations concerned.
.LP
\fINote 13\fR
\ \(em\ The value is provisional and for further study.
.LP
\fINote 14\fR
\ \(em\ The maintenance limit applies to testing a circuit without
clamping. This is the preferred method of measurement. When clamps are used,
the maintenance limit is 6%.
.nr PS 9
.RT
.ad r
\fBTable 2/N.73 [1T2.73], p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [2T2.73]\fR 
.ce
TABLE\ 2/N.73\ \fI(cont.)\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(24p) | cw(96p) | cw(54p) | cw(54p) .
Item (Note 12)	Parameter	Test waveform(s)	Maintenance limits
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
16	 {
Field\(hytime waveform distortion
(Note 2)
 }	A  (Note 11)	\(+- 2 | 	\(+- 6 | 
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
17	 {
Line\(hytime waveform distortion (Note\ 2)
Bar tilt (Note\ 1)
 }	B2 or B3	\(+- 1 | 	\(+- 3 | 
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
18	 {
Base line distortion (Note\ 1)
 }	B2 or B3	\(+- 1%	\(+- 3%
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
19	 {
2T pulse/bar ratio error (Note\ 1)
 }	B1 and B2 or B3	\(+- 6 | 	\(+- 8 | 
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(54p) .
20	 {
Short\(hytime waveform distortion
(Note 2)
 }	B1	 {
1\us\d\ut\d adjacent lobe
6 | 
2\un\d\ud\d adjacent lobe
3 | 
 }
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
21	 {
Gain/frequency characteristic
(Note 2)
 }	C  (Note 8)	\(+- 1 dB	+1.5 dB to \(em1 dB
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(30p) | cw(24p) .
22	 {
Chrominance\(hyluminance gain inequality
(Note 1)
 }	B2 or B3  and G, G 2 or F	\(+- 10 | 	\(+- 10 | 
_
.T&
cw(24p) | lw(96p) | cw(54p) | cw(54p) .
23	 {
Chrominance\(hyluminance delay inequality
(Note 1)
 }	F	\(+- 80 ns (Note 9)
.TE
.LP
\fINote 1\fR
\ \(em\ As defined in CCIR Recommendation 569 [4].
.LP
\fINote 2\fR
\ \(em\ As defined in CCIR Recommendation 567 [1].
.LP
\fINote 3\fR
\ \(em\ Noise measured via unified weighting filter and low and
high pass filters specified in Annex II to Part C of CCIR
Recommendation\ 567 [1].
.LP
\fINote 4\fR
\ \(em\ Noise measured on line(s) allocated for noise measurement
with weighting network and filters as given in Note\ 3 plus a chrominance
frequency notch filter as specified in CCIR Recommendation\ 569 [4].
.LP
\fINote 5\fR
\ \(em\ The maintenance limits refer to circuits without clamps.
When clamps are used the maintenance limits are \(>="\ 50\ dB.
.LP
\fINote 6\fR
\ \(em\ Measured at APLs of 10% and 90%.
.LP
\fINote 7\fR
\ \(em\ Video signal containing synchronizing signals with normal
amplitude.
.LP
\fINote 8\fR
\ \(em\ Measurements on C2 may be referred to C1 taking account of
any difference in the amplitude of the two elements. The results of this test may conflict with those obtained with test waveforms. If this occurs the
waveform results should be considered to be definitive.
.LP
\fINote 9\fR
\ \(em\ The value is positive if the luminance component leads the
chrominance component.
.LP
\fINote 10\fR
\ \(em\ Further data is required to consider amendment to this
figure.
.LP
\fINote 11\fR
\ \(em\ A window signal is specified in CCIR Recommendation\ 567 [1]
for use on 525\(hyline systems. Test results are required before limits for this signal can be included. Use of this signal should be noted in the measurement results.
.LP
\fINote 12\fR
\ \(em\ Routine measurements made at regular intervals may be limited to
less than the complete list of items given in Table\ 2/N.73 by agreement between the Administrations concerned.
.LP
\fINote 13\fR
\ \(em\ The value is provisional and for further study.
.LP
\fINote 14\fR
\ \(em\ The maintenance limit applies to testing a circuit without
clamping. This is the preferred method of measurement. When clamps are used,
the maintenance limit is 6%.
.nr PS 9
.RT
.ad r
\fBTable 2/N.73 (cont.) [2T2.73], p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 2P
.LP
\fB8\fR 	\fBSchedule for routine maintenance measurements\fR 
.sp 1P
.RT
.PP
\fR The performance of routine maintenance measurements between two
ITCs requires adherence to routine procedures and a due regard to the allocated 
time. Tests (Table\ 3/N.73) should start at a scheduled time (\fIZ\fR ) 
which has 
been agreed between the Administrations/broadcasting organizations concerned
and should progress in accordance with the fixed timetable. This will give
adequate time for measurements to be repeated if there is a possibility that
one or more circuit parameters are outside tolerance limits.
.PP
It is necessary for the maintenance staff to book the routine
maintenance period with the programme booking centre (PBC) on a regular 
basis so that the PBC can intervene when bookings are made for programme 
transmissions at the same time, and propose a different period for the 
routine maintenance measurements. 
.PP
The test schedule shown in Table\ 3/N.73 should be used by the
sub\(hycontrol station at the sending end of the circuit unless there is a
specific agreement between the Administrations/broadcasting organizations
concerned to use a different test schedule.
.RT
.ce
\fBH.T. [T3.73]\fR 
.ce
TABLE 3/N.73
.ce
\fBSchedule for routine maintenance measurements\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(60p) | cw(90p) | cw(48p) .
Duration	Operation	Signal
_
.T&
lw(60p) | lw(90p) | cw(48p) .
 {
\fIZ\fR
to \fIZ\fR
+ 5 min
 }	Check level	B2 or B3
_
.T&
lw(60p) | lw(90p) | cw(48p) .
 {
\fIZ\fR
+ 5 to \fIZ\fR
+ 10 min
 }	 {
Measurement of linear distortions (APL\ low)
 }	Test lines
_
.T&
lw(60p) | lw(90p) | cw(48p) .
 {
\fIZ\fR
+ 10 to \fIZ\fR
+ 15 min
 }	 {
Measurement of nonlinear distortions (APL\ low)
 }	Test lines
_
.T&
lw(60p) | lw(90p) | cw(48p) .
 {
\fIZ\fR
+ 15 to \fIZ\fR
+ 20 min
 }	 {
Measurement of nonlinear distortions (APL\ high)
 }	Test lines
_
.T&
lw(60p) | lw(90p) | cw(48p) .
 {
\fIZ\fR
+ 20 to \fIZ\fR
+ 25 min
 }	Measurement of noise	None
_
.T&
lw(60p) | lw(90p) | cw(48p) .
 {
\fIZ\fR
+ 25 to \fIZ\fR
+ 30 min
 }	 {
Measurement of field\(hytime waveform distortion
 }	A
_
.T&
lw(60p) | lw(90p) | cw(48p) .
 {
\fIZ\fR
+ 30 to \fIZ\fR
+ 35 min
 }	 {
Measurement of long\(hytime waveform distortion
 }	\*QBump\*U
_
.T&
lw(60p) | lw(90p) | cw(48p) .
 {
\fIZ\fR
+ 35 to \fIZ\fR
+ 95 min
 }	 {
Variation of luminance bar amplitude
 }	B2 or B3
.TE
.LP
\fINote\fR
\ \(em\ \fIZ\fR
\ is the agreed time to commence the tests.
.nr PS 9
.RT
.ad r
\fBTable 3/N.73 [T3.73], p.\fR 
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
\fB9\fR 	\fBMaintenance of international television circuits\fR 
.sp 1P
.RT
.PP
In general the programme booking centre (PBC) will not know when
permanent connections are in use for programme transmissions and the agreement 
of the customer must be obtained before such connections are interrupted 
in 
ITCs to carry out maintenance on a circuit.
.RT
.sp 2P
.LP
\fB10\fR 	\fBMaintenance of international television circuits, links and
connections\fR 
.sp 1P
.RT
.PP
International television circuits, links and connections will
comprise chains of circuit sections, both national and international, connected 
in tandem, which are maintained and may be leased as separate entities. 
Each of these circuit sections may have suitable maintenance limits derived 
as quoted in \(sc\ 7. 
.bp
.PP
The 
Laws of Addition
may also be used to derive expected
performance limits for such chains but precautions are necessary in the 
use of such limits for maintenance purposes. It is possible that the overall 
response of the circuit, link or connection may fail to meet the calculated 
performance expected, even though the response of each circuit section 
comprising the 
chain meets the individual maintenance limits used for the calculation 
of the overall response. In such cases the calculated response of the chain 
can only be used as a guide to the expected overall response on the initial 
lining up, unless additional overall equalizers are employed. 
.PP
There is also the possibility that the difference between the actual and 
the calculated overall response of the chain can vary with time, even 
though the responses of the individual circuit sections remain within their
respective maintenance limits.
.RT
.ce 1000
ANNEX\ A
.ce 0
.ce 1000
(to Recommendation N.73)
.sp 9p
.RT
.ce 0
.ce 1000
\fBTest signal elements\fR 
.sp 1P
.RT
.ce 0
.PP
An indication of the signal elements required to carry out the tests mentioned 
in this Recommendation is given below in the form of figures. Preferred 
assemblies for insertion test signals are given in 
Recommendation\ N.67.
.sp 1P
.RT
.LP
.rs
.sp 16P
.ad r
\fBFigure A\(hy1/N.73, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 16P
.ad r
\fBFigure A\(hy2/N.73, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 26P
.ad r
\fBFigure A\(hy3/N.73, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 23P
.ad r
\fBFigure A\(hy4/N.73, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 20P
.ad r
\fBFigure A\(hy5/N.73, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 21P
.ad r
\fBFigure A\(hy6/N.73, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure\ A\(hy7/N.73, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure A\(hy8/N.73, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 17P
.ad r
\fBFigure A\(hy9/N.73, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 17P
.ad r
\fBFigure A\(hy10/N.73, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 21P
.ad r
\fBFigure A\(hy11/N.73, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 19P
.ad r
\fBFigure\ A\(hy12/N.73, p.\fR 
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
	\fBReferences\fR 
.sp 1P
.RT
.LP
[1]
	CCIR Recommendation \fITelevision performance of television circuits\fR 
\fIdesigned for use in international connections,\fR Vol.\ XII, Rec.\ 567, ITU,
Geneva,\ 1986.
.LP
[2]
	 CCIR Recommendation \fIInsertion of test signals in the field blanking\fR 
\fIinterval of monochrome and colour television signals,\fR Vol.\ XII, 
Rec.\ 473, ITU, Geneva,\ 1986.
.LP
[3]
	 CCIR Report \fILong\(hytime waveform distortion in long distance television\fR 
\fIcircuits,\fR Vol.\ XII, Rec.\ 636, ITU, Geneva,\ 1986. 
.LP
[4]
	 CCIR Recommendation \fIDefinitions of parameters simplified for automatic\fR 
\fImeasurement of televison insertion test signals,\fR Vol.\ XII, 
Rec.\ 569, ITU, Geneva,\ 1986.
.bp
.LP
\fBMONTAGE: PAGE 84 = PAGE BLANCHE\fR 
.sp 1P
.RT
.LP
.bp
.sp 1P
.ce 1000
\v'3P'
SECTION\ 3
.ce 0
.sp 1P
.ce 1000
\fBINTERNATIONAL\ VIDEOCONFERENCE\ TRANSMISSIONS\fR 
.ce 0
.sp 1P
.IP
\fB3.1\ International videoconference transmissions\ \(em\ Definitions\fR 
.sp 1P
.RT
.sp 2P
.LP
\fBRecommendation\ N.81\fR 
.RT
.sp 2P
.sp 1P
.ce 1000
\fBDEFINITION\ FOR\ APPLICATION\ TO\ INTERNATIONAL\ VIDEOCONFERENCE\fR  |
\fBTRANSMISSIONS\fR 
.EF '%	Fascicle\ VI.3\ \(em\ Rec.\ N.81''
.OF '''Fascicle\ VI.3\ \(em\ Rec.\ N.81	%'
.ce 0
.sp 1P
.ce 1000
(under study)
.sp 9p
.RT
.ce 0
.sp 1P
.IP
\fB3.2\ Line\(hyup, service commissioning and maintenance of videoconference
systems\fR 
.sp 1P
.RT
.sp 2P
.LP
\fBRecommendation\ N.86\fR 
.RT
.sp 2P
.ce 1000
\fBLINE\(hyUP\ AND\ SERVICE\ COMMISSIONING\ OF\ INTERNATIONAL\fR 
.EF '%	Fascicle\ VI.3\ \(em\ Rec.\ N.86''
.OF '''Fascicle\ VI.3\ \(em\ Rec.\ N.86	%'
.ce 0
.ce 1000
\fBVIDEOCONFERENCE\ SYSTEMS\ OPERATING\ AT\ TRANSMISSION\ BIT\ RATES\fR 
.ce 0
.sp 1P
.ce 1000
\fBOF\ 1544\ AND\ 2048\ kbit/s\fR 
.ce 0
.sp 1P
.LP
\fB1\fR 	\fBGeneral\fR 
.sp 1P
.RT
.PP
This Recommendation deals with the line\(hyup and service
commissioning of international videoconference systems routed over transmission 
paths operating at transmission bit rates of 2048\ and 1544\ kbit/s. In 
this 
context an international videoconference system comprises the international
videoconference connection and the videoconference rooms which are
interconnected.
.PP
Figure 1/N.86 shows the constituent parts of an international
videoconference connection. Recommendation\ H.110\ [1] describes hypothetical
reference connections for videoconferencing.
.RT
.PP
The video codecs are normally located within the videoconference studios 
but in some circumstances are located elsewhere so that the local tail 
serving the videoconference studio may be provided on wideband analogue 
(e.g.\ 5.5\ MHz) or higher order digital transmission systems (e.g.\ 140\ 
Mbit/s). Codecs are described in Recommendation\ H.120\ [2]. 
.PP
The location of any 2048/1544 kbit/s remultiplexers which may be
involved will be as agreed between the Administrations.
.bp
.RT
.LP
.rs
.sp 12P
.ad r
\fBFigure 1/N.86, p.\fR 
.sp 1P
.RT
.ad b
.RT
.PP
Supplement No.\ 5.2 gives guidance on the setting up and testing
arrangements for videoconference studios.
.PP
The international videoconference centre provides the interconnection point 
of the national videoconference circuit and the international link. This 
interconnection may be made manually or by automatic means. 
.PP
Normally the international videoconference link will be common for all 
videoconference calls between the two Administrations concerned, whereas 
the 
national videoconference circuits will vary from call to call. Thus, in
addition to the setting up and lining up of the constituent parts of the
international videoconference connection, service commissioning tests are 
made between videoconference studios prior to the opening of an international 
videoconference service to ensure that a service can be satisfactorily
sustained.
.RT
.sp 2P
.LP
\fB2\fR \fBSetting up and lining up the constituent parts of the connection\fR 
.sp 1P
.RT
.sp 1P
.LP
2.1
	\fINational videoconference circuits\fR 
.sp 9p
.RT
.PP
The national videoconference circuits should be set up and tested in accordance 
with the national procedures of the Administrations concerned. 
This will include the line up of any sections which may not be provided as
2048\ or 1544\ kbit/s digital paths. The 2048 and 1544\ kbit/s data performance
limits to be met are given in Table\ 1/N.86 and it is recommended that 
two data tests should be made, each of one hour's duration, on different 
days and at 
times that cover the peak traffic periods on the route concerned.
.RT
.sp 1P
.LP
2.2
	\fIInternational link\fR 
.sp 9p
.RT
.PP
The international videoconference link will only need to be set up and 
tested when establishing the first service between two Administrations. 
The procedures of Recommendation\ 555\ [3] should apply. 
.PP
A data test should be made of five hours duration and should be
scheduled so as to include the peak traffic period on the route concerned. 
The test results should meet the data performance limits given in 
Table\ 1/N.86.
.RT
.sp 2P
.LP
\fB3\fR 	\fBPerformance check codec\(hyto\(hycodec\fR 
.sp 1P
.RT
.PP
The constituent parts of the connection having been satisfactorily lined 
up and connected together at the international videoconference centres, 
three data tests (each of one hour's duration) should be made between the 
codecs. The tests should be made on different days and at times to cover the
peak traffic periods for the route. The testers should be connected at the
digital line side of the codecs, as close to the codecs as possible. Each 
test should meet the data performance limits given in Table\ 1/N.86. 
.PP
Where loop facilities exist, loop measurements may be made in order to 
obtain reference measurements for subsequent maintenance. Care must be 
taken to avoid simultaneous operation of loop facilities. 
.bp
.RT
.ce
\fBH.T. [T1.86]\fR 
.ce
TABLE\ 1/N.86
.ce
\fBPath performance test limits\fR 
.ce
 | ua\d\u)\d
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(78p) | cw(38p) | cw(22p) | cw(30p) | cw(30p) | cw(30p) .
\fB.\fR	 {
Nominal data rate | ub\d\u)\d
(kbit/s)
 }	Bit error ratio  (BER)	Max. errors  in 1\ hour	 {
Severely errored events | uc\d\u)\d
in 1\ hour
 }	 {
Error\(hyfree seconds 
(EFS) 
(%)
 }
_
.T&
lw(78p) | cw(38p) | cw(22p) | cw(30p) | cw(30p) | cw(30p) , ^  | c | c | c | c | c.
 {
National videoconference circuit
 }	2048	1 \(mu 10\uD\dlF261\u6\d	\ 7 | 42	0	92
	1544	1 \(mu 10\uD\dlF261\u6\d	\ 5 | 30	0	92
_
.T&
lw(78p) | cw(38p) | cw(22p) | cw(30p) | cw(30p) | cw(30p) , ^  | c | c | c | c | c.
 {
International videoconference link
 }	2048	1 \(mu 10\uD\dlF261\u6\d	\ 7 | 42	2	92
	1544	1 \(mu 10\uD\dlF261\u6\d	\ 5 | 30	2	92
_
.T&
lw(78p) | cw(38p) | cw(22p) | cw(30p) | cw(30p) | cw(30p) , ^  | c | c | c | c | c.
 {
International videoconference link
 }	2048	1 \(mu 10\uD\dlF261\u6\d	\ 7 | 42	2	92
	1544	1 \(mu 10\uD\dlF261\u6\d	\ 5 | 30	2	92
_
.T&
lw(78p) | cw(38p) | cw(22p) | cw(30p) | cw(30p) | cw(30p) , ^  | c | c | c | c | c.
 {
International videoconference connection
 }	2048	3 \(mu 10\uD\dlF261\u6\d	21 | 27	2	92
	1544	3 \(mu 10\uD\dlF261\u6\d	16 | 89	2	92
.TE
.LP
\ua\d\u)\d
The limits are provisional and subject to further
study.
.LP
\ub\d\u)\d
Structured formatting required with a consequent reduction
in actual test data rate as follows:
At 2048 kbit/s, test data rate = 1984 kbit/s (time slots
1 to 31 only);
At 1544 kbit/s, test data rate = 1536 kbit/s (8 bits used for
frame alignment).
.LP
\uc\d\u)\d
Severely errored events are defined by the particular data
tester used, e.g. 20 | 00\ errors in 100 | 00\ bits. A continuous period of up
to 10\ seconds, during which severely errored transmission persists,
will be considered as a single severely errored event.
.LP
\fINote\ 1\fR
\ \(em\ In addition to the above limits the BER shall be no worse than
1 \(mu 10\uD\dlF261\u5\d over any 5\(hyminute period during the tests
(5952\ errors at 2048\ kbit/s and 4608\ errors at 1544\ kbit/s). If this
test fails, then corrective action shall be taken on the
offending section.
.LP
\fINote\ 2\fR
\ \(em\ For loop\(hytests, the above limits should be doubled
(92% EFS becoming 84%\ EFS).
.nr PS 9
.RT
.ad r
\fBTable 1/N.86 [T1.86], p.\fR 
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
\fB4\fR 	\fBDigital test equipment\fR 
.sp 1P
.RT
.PP
The data tester required for the above tests shall be capable of
transmitting and receiving a test pattern within a signal structured in
accordance with Recommendation\ G.732\ [4] for 2048\ kbit/s interfaces or
Recommendation\ G.733\ [5] for 1544\ kbit/s interfaces. The nature of the test
pattern is undefined but should be the subject of further study.
.PP
When working through a 2048/1544 kbit/s remultiplexer, the test signal 
should be restricted to time slots\ 1\(hy24 with time slots\ 25\(hy31 being 
vacant. 
.PP
If compatible testers are not available at both ends of the link or
connection under test, then one tester should be used to transmit and receive 
with a loop being provided at the other end. 
.RT
.sp 2P
.LP
\fB5\fR 	\fBVideoconference studios\fR 
.sp 1P
.RT
.PP
All videoconference studios that will be used for international
videoconference calls should comply with agreed design standards. Providers 
and operators of such studios are encouraged to adopt the provisions of 
Supplement\ No.\ 5.2 until CCITT Recommendations are specified. The adoption 
of common standards facilitates the interworking between any pair of studios 
in 
different countries with pre\(hycall adjustments reduced to a minimum.
.bp
.RT
.sp 2P
.LP
\fB6\fR 	\fBService commissioning tests\fR 
.sp 1P
.RT
.sp 1P
.LP
6.1
	\fIGeneral\fR 
.sp 9p
.RT
.PP
The international videoconference connection having been
satisfactorily tested, functional video and audio service commissioning 
tests should be undertaken between the videoconference studios. 
.RT
.sp 1P
.LP
6.2
	\fITest videoconference studios\fR 
.sp 9p
.RT
.PP
The videoconference studio chosen by an Administration for
commissioning tests should be typical (with regard to the parameters of
Supplement\ 5.2) of all the other studios to be used fo the service. This 
studio should then serve as a reference studio for any future tests between 
videoconference studios with other Administrations.
.PP
The reference studio for each Administration should be identified to all 
other Administrations. The parameters of this studio should also be shared 
with all other Administrations. 
.RT
.sp 1P
.LP
6.3
	\fICommissioning test\fR 
.sp 9p
.RT
.PP
The end\(hyto\(hyend commissioning tests between videoconference studios 
are described in Supplement\ 5.2. The purpose of the tests is to demonstrate 
that the international videoconference system performs adequately when the
constituent parts are connected together. The tests include a subjective
assessment of the main functions of each videoconference studio and selected
objective tests. The tests are not intended to be exhaustive, but should 
serve as sample checks in compliance with the standards and as a confident 
indicator to both Administrations before the opening of an internatinal 
videoconference service. 
.RT
.sp 2P
.LP
	\fBReferences\fR 
.sp 1P
.RT
.LP
[1]
	CCITT Recommendation \fIHypothetical Reference Connections for\fR 
\fIVideoconferencing using primary digital group transmission\fR , Vol.\ III,
Rec.\ H.110.
.LP
[2]
	CCITT Recommendation \fICodecs for videoconferencing using primary\fR 
\fIdigital group transmission\fR , Vol.\ III, Rec.\ H.120.
.LP
[3]
	CCITT Recommendation \fIBringing international digital blocks, paths\fR 
\fIand sections into service\fR , Vol.\ IV, Rec.\ M555.
.LP
[4]
	CCITT Recommendation \fICharacteristics of primary PCM multiplex\fR 
\fIequipment operating at 2048\ kbit/s\fR , Vol.\ III, Rec.\ G.732.
.LP
[5]
	CCITT Recommendation \fICharacteristics of primary PCM multiplex\fR 
\fIequipment operating at 1544 kbit/s\fR , Vol.\ III, Rec.\ G.733.
.sp 2P
.LP
\fBRecommendation\ N.90\fR 
.RT
.sp 2P
.ce 1000
\fBMAINTENANCE\ OF\ INTERNATIONAL\ VIDEOCONFERENCE\ SYSTEMS\fR 
.EF '%	Fascicle\ IV.3\ \(em\ Rec.\ N.90''
.OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.90	%'
.ce 0
.sp 1P
.ce 1000
\fBOPERATING\ AT\ TRANSMISSION\ BIT\ RATES\ OF\ 1544\ AND\ 2048\ kbit/s\fR 
.ce 0
.sp 1P
.LP
\fB1\fR 	\fBScope\fR 
.sp 1P
.RT
.PP
This Recommendation deals with the maintenance procedures to be
applied to international videoconferencing systems operating at transmission
bit rates of 1544\ and 2048\ kbit/s.
.RT
.sp 2P
.LP
\fB2\fR 	\fBGeneral\fR 
.sp 1P
.RT
.PP
2.1
The configuration shown in Figure\ 1/N.90 is a simplified
description of a typical connection.
.sp 9p
.RT
.PP
2.2
Each participating Administration shall establish an
international videoconference centre (IVC) with the same general
responsibilities and functions as those set out in Recommendation\ N.55 
for an international television centre\ (ITC) in respect of international 
television connections. However, as a videoconference connection is a bidirectional 
transmission path, the choice of control and sub\(hycontrol IVCs shall 
always be established by mutual agreement. This choice should hold for 
all the 
international videoconference connections serving two
Administrations.
.bp
.LP
.rs
.sp 14P
.ad r
\fBFigura 1/N.90, p.\fR 
.sp 1P
.RT
.ad b
.RT
.PP
2.3
The maintenance procedures are designed to facilitate restoration of service 
when a videoconference connection is broken, or unacceptably 
degraded, during a videoconference call. At this time it is essential that
close cooperation is maintained between control and sub\(hycontrol IVCs 
in order to minimize disruption to the call. 
.PP
2.4
The IVCs will require to be provided with equipment such as
codecs, monitors and cameras so as to be able to make limited functional 
checks (visual and audio) for confirmation of call establishment and rapid 
fault 
sectionization.
.PP
Additionally, testers should be available for 1544 and 2048 kbit/s data 
performance tests. The testers should be able to send a structured test 
signal in accordance with either the Recommendation\ G.732\ [1] or H.733\ [2]
structures. The test pattern should be a pseudo random test signal of sequence 
length 2\u1\d\u5\d\uD\dlF261\u1\d as described in Recommendation\ O.151\ 
[3]. 
.PP
The tester conforming to Recommendation G.733\ [2] should be able to
work at 1536\ kbit/s information rate, sending the test signal in time 
slots\ 1 to\ 24. 
.PP
The tester conforming to Recommendation G.732\ [1] should be able to
work at 1536\ or 1984\ kbit/s information rates. When switched to 1536\ 
kbit/s it should send the test signal in time slots\ 1 to\ 15 and\ 17 to\ 
25. When switched to 1984\ kbit/s it should use time slots\ 1 to\ 31. 
.RT
.sp 2P
.LP
\fB3\fR 	\fBPre\(hycall tests\fR 
.sp 1P
.RT
.PP
It is essential that pre\(hycall tests are made to confirm that a
scheduled call will be satisfactory. All equipments and all parts of the
international videoconference connection to be used in a call should be 
checked beforehand on the day of the call. For this purpose tests should 
be made of the complete transmission path between the appropriate videoconference 
studio(s) 
and frontier station(s) by each Administration and between the frontier
stations\ (EF's).
.PP
These pre\(hycall tests are intended to be simple checks to establish
that the transmission paths are acceptable, for example, that the transmitted 
and received radio frequency carrier levels at each earth station are within 
their prescribed limits.
.PP
Additionally, where the international videoconference connection is
new or where previous, similar calls have suffered problems a complete
studio\(hyto\(hystudio functional test should be made. This should take 
the form of a visual and, if appropriate, audio subjective assessment of 
the end\(hyto\(hyend 
performance. Such tests should be sufficiently in advance of the start 
of the call (15\ to 30\ minutes) to give some opportunity for clearing 
any problem which may be found. As experienced and confidence is gained, 
the time required for 
pre\(hycall testing should reduce.
.RT
.sp 2P
.LP
\fB4\fR 	\fBFault localization\fR 
.sp 1P
.RT
.PP
4.1
A general outline of the fault localization procedure for
international videoconference connections is given below. This approach 
aims to rapidly localize a fault to a circuit section. 
.bp
.sp 9p
.RT
.PP
4.2
Fault reports may be received by either IVC on a connection but
shall only be accepted from points within their own country.
.PP
4.3
On receipt of a fault report the IVC shall monitor the connection where 
possible to broadly localize the fault unless this is obvious from the 
fault report or from other information, e.g.\ system alarms. The IVC should
then immediately advise the distant IVC of the reported fault and any
information which may assist to determine the course of action to be taken.
.PP
4.4
If the source of the problem is not known then both IVCs shall
work together to determine in which circuit section the fault lies, e.g.\ by
means of loopback. Preferably this should be in accordance with an agreed
planned procedure. If these procedures do not localize the fault then the 
IVCs shall agree the further action to be taken. 
.PP
4.5
If at any stage the fault is localized then the appropriate
clearance procedures should be put in hand.
.PP
4.6
Both IVCs should be in constant telephone contact during these
procedures. The IVCs should report to their respective videoconference
studios\ (VSs) no longer than 10\ minutes after receipt of the fault report
advising on localization progress and estimated time to restore service. A
second status report should be given after a further maximum period of
10\ minutes. If, at 20\ minutes following the fault report, the time to 
restore service has not been determined then the customers should be so 
advised and a decision made as to whether or not to abort the call. 
.PP
4.7
If, during localization, the overall connection is found to be
satisfactory, the problem may be caused by the interworking of the studio
equipment (e.g.\ codecs). In this case it may prove necessary to monitor and
test the connection VS to\ VS.
.PP
4.8
Minor problems that are reported for correction but which do not make a 
call unusable, shall be accepted for clearance and entered in the fault 
record but shall not count against the service availability of the connection. 
Action to deal with such problems should not interrupt an ongoing call, 
except at the direction of the control\ IVC. 
.PP
4.9
Where a videoconference call transmission is encrypted, the VSs
shall be required to remove the encryption for fault localization and clearance 
purposes when requested by the IVCs. 
.sp 2P
.LP
\fB5\fR 	\fBMaintenance parameters\fR 
.sp 1P
.RT
.PP
5.1
The maintenance limits for 1544 and 2048 kbit/s transmission paths are 
given in Table\ 1/N.90. Where the national videoconference circuit includes 
wideband analogue or higher order digital system sections then the national 
maintenance standards should apply to these sections.
.sp 9p
.RT
.PP
5.2
Because of the need to restrict the time taken for dealing with
faults during scheduled videoconference calls, any assessment of the 1544\ 
and 2048\ Kbit/s performance that may be required should be based on bit 
error 
ratio (BER) measurements only. The measuring time should be kept to the
minimum necessary for the investigation in hand.
.PP
5.3
Where maintenance activities do not risk the establishment or
completion of a scheduled videoconference call then any assessment of the 
1544 and 2048\ kbit/s performance should be against all the parameters 
shown in 
Table\ 1/N.90. Such measurements should be made over a minimum period of
15\ minutes.
.LP
.rs
.sp 9P
.ad r
BLANC
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [T1.90]\fR 
.ce
TABLE\ 1/N.90
.ce
\fBMaintenance limits\fR 
.ce
 | ua\d\u)\d
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(78p) | cw(38p) | cw(22p) | cw(30p) | cw(30p) | cw(30p) .
\fB.\fR	 {
Nominal data rate | ub\d\u)\d
(kbit/s)
 }	Bit error ratio  (BER)	Max. errors  in   15\ minutes	 {
Severely errored events | uc\d\u)\d
in 15\ minutes
 }	 {
Error\(hyfree seconds 
(EFS) 
(%)
 }
_
.T&
lw(78p) | cw(38p) | cw(22p) | cw(30p) | cw(30p) | cw(30p) , ^  | c | c | c | c | c.
 {
National videoconference circuit
 }	1544	1 \(mu 10\uD\dlF261\u6\d	1382	0	92
	2048	1 \(mu 10\uD\dlF261\u6\d	1785	0	92
_
.T&
lw(78p) | cw(38p) | cw(22p) | cw(30p) | cw(30p) | cw(30p) , ^  | c | c | c | c | c.
 {
International videoconference link
 }	1544	1 \(mu 10\uD\dlF261\u6\d	1382	0	92
	2048	1 \(mu 10\uD\dlF261\u6\d	1785	0	92
_
.T&
lw(78p) | cw(38p) | cw(22p) | cw(30p) | cw(30p) | cw(30p) , ^  | c | c | c | c | c.
 {
International videoconference connection
 }	1544	3 \(mu 10\uD\dlF261\u6\d	4147	0	92
	2048	3 \(mu 10\uD\dlF261\u6\d	5357	0	92
.TE
.LP
\ua\d\u)\d
The limits are provisional and subject to further
study.
.LP
\ub\d\u)\d
Structured formatting required with a consequent reduction
in actual test data rate as follows:
At 2048 kbit/s, test data rate = 1984 kbit/s (time slots
1 to 31 only);
At 1544 kbit/s, test data rate = 1536 kbit/s (8 bits used for
frame alignments).
.LP
\uc\d\u)\d
Severely errored events are defined by the particular data
tester used, e.g. 20 | 00\ errors in 100 | 00\ bits. A continuous period of up
to 10\ seconds, during which severely errored transmission persists,
will be considered as a single severely errored event.
.nr PS 9
.RT
.ad r
\fBTable 1/N.90 [T1.90], p.\fR 
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
.sp 2
	\fBReferences\fR 
.sp 1P
.RT
.LP
[1]
	CCITT Recommendation \fICharacteristics of primary PCM multiplex\fR 
\fIequipment operating at 2048\ kbit/s\fR , Vol.\ III, Rec.\ G.732.
.LP
[2]
	CCITT Recommendation \fICharacteristics of primary PCM multiplex\fR 
\fIequipment operating at 1544\ kbit/s\fR , Vol.\ III, Rec.\ G.733.
.LP
[3]
	CCITT Recommendation \fIError performance measuring equipment for\fR 
\fIdigital systems at the primary bit rate and above\fR , Vol.\ IV, Rec.\ 
O.151. 
.LP
.rs
.sp 11P
.ad r
BLANC
.ad b
.RT
.LP
.bp
.LP
\fBMONTAGE: PAGE 92 = PAGE BLANCHE\fR 
.sp 1P
.RT
.LP
.bp