\ \(em\ Loss of frame alignment should be assumed to have taken place when
more than three of twelve successive frames have an error in the frame
alignment signal and/or in bit 1 of the 193\(hybit frame. Frame alignement should be assumed to have been recovered when four consecutive correct frame alignment signals have been received.
.nr PS 9
.RT
.ad r
\fBTable 1/G.734 [T1.734], p.\fR
.sp 1P
.RT
.ad b
.RT
.ce
\fBH.T. [T2.734]\fR
.ce
TABLE\ 2/G.734
.ce
\fBAllocation of time slot 24, Method 2\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(60p) | cw(24p) sw(18p) sw(24p) sw(18p) sw(24p) sw(18p) sw(24p) sw(18p) , ^ | c | c | c | c | c | c | c | c.
\ \(em\ Loss of frame alignment should be assumed to have taken place when
seven consecutive pairs of the frame alignment signal (00101, 11010) have been incorrectly received in their predicted positions. Frame alignment should be
assumed to have been recovered when two consecutive correct pairs of frame
alignment signals have been received.
.nr PS 9
.RT
.ad r
\fBTable 2/G.734 [T2.734], p.\fR
.sp 1P
.RT
.ad b
.RT
.sp 1P
.LP
.sp 1
2.4
\fIService digits\fR
.sp 9p
.RT
.PP
The use of service digits in channel time slot 24 is under study.
.PP
\fINote\fR \ \(em\ The first bit could be considered for framing
The digital multiplex equipment should detect the following fault conditions:
.RT
.LP
\(em
failure of power supply,
.LP
\(em
loss of the incoming signal at 1544\ kbit/s,
.LP
\(em
loss of frame alignment,
.LP
\(em
loss of timing signals supplied from the centralized clock,
.LP
\(em
alarm indication received from the remote digital multiplex
equipment.
.PP
Some of the above fault conditions may optionally be detected by auxiliary
equipment normally used in association with the digital multiplex
equipment.
.sp 1P
.LP
3.2
\fIConsequent actions\fR
.sp 9p
.RT
.PP
Further to the detection of a fault condition, appropriate actions should
be taken as specified in Table\ 3/G.734.
.RT
.ce
\fBH.T. [T3.734]\fR
.ce
TABLE\ 3/G.734
.ce
\fBFault conditions and consequent actions for the
.ce
digital multiplex equipment\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(48p) | cw(54p) | cw(42p) sw(42p) sw(42p) , ^ | ^ | c | c | c.
Equipment part Fault conditions {
Consequent action
(see Notes 1 and 2)
}
{
Prompt maintenance alarm indication generated
} {
Alarm indication to the remote end transmitted
(see Note 3)
} {
Multiplex out\(hyof\(hysync signal applied to 64 kbit/s output
(see
Note 4)
}
_
.T&
cw(48p) | cw(54p) | cw(42p) | cw(42p) | cw(42p) .
Multiplexer and demultiplexer Failure of power supply Yes Yes (if practicable) Yes (if practicable)
_
.T&
cw(48p) | lw(54p) | cw(42p) | cw(42p) | cw(42p) , ^ | l | c | c | c
^ | l | c | l | l.
Demultiplexer only {
Loss of incoming signal at 1544 kbit/s
} Yes Yes Yes
Loss of frame alignment Yes Yes Yes {
Alarm indication receive from the remote end
} Yes
.TE
.LP
\fINote\ 1\fR
\ \(em\ A \fIYes\fR
| n the table signifies that an action should be taken as a consequence of the relevant fault condition. An \fIopen space\fR
in the table
signifies that the relevant action should \fInot\fR
be taken as a consequence of
the relevant fault condition, if this condition is the only one present. If
more than one fault condition is simultaneously present, the relevant action
should be taken if, for at least one of the conditions, a \fIYes\fR
is defined in relation to this action.
.LP
\fINote\ 2\fR
\ \(em\ These consequent actions may optionally be taken by auxiliary
equipment normally used in conjunction with the digital multiplex equipment.
.LP
\fINote\ 3\fR
\ \(em\ The alarm indication to the remote end may be generated by changing a service bit of time slot 24 from the state 1 to the state 0, if possible.
.LP
\fINote\ 4\fR
\ \(em\ The binary content of the multiplex out\(hyof\(hysync signal is under
study. One Administration uses
00011010.
.nr PS 9
.RT
.ad r
\fBTable 3/G.734 [T3.734], p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 2P
.LP
\fB4\fR \fBMultiplexing method\fR
.sp 1P
.RT
.PP
Cyclic byte interleaving in the tributary numbering order should be used.
The digital multiplex equipment should translate any incoming byte that
contains only 0s into the zero byte suppression code.
.PP
\fINote\ 1\fR \ \(em\ The content of the zero byte suppression code is under
study.
.PP
\fINote\ 2\fR \ \(em\ Further study is needed for the case when the zero
suppression code must be extracted.
.RT
.sp 2P
.LP
\fB5\fR \fBInput\fR
\fBjitter\fR \fBand\fR
\fBwander\fR
.sp 1P
.RT
.PP
The amount of jitter and wander that should be tolerated at the
input of the demultiplexer should be according to Recommendation\ G.824,
\(sc\ 3.1.1.
.RT
.sp 2P
.LP
\fB6\fR \fBDigital interface\fR
.sp 1P
.RT
.PP
The digital interface at 64\ kbit/s and 1544\ kbit/s should be in
\ \(em\ The six possible 320 kbit/s channels in a 2048\ kbit/s stream are
numbered A to F. Preferably the channel pairs A\(hyB, C\(hyD and E\(hyF should be used for stereophonic transmission.
.LP
\fINote\ 2\fR
\ \(em\ If the channel time slot 16 which is assigned to signalling as
covered in \(sc\ 5 is not needed for signalling, it may be used for purposes other than a voice channel encoded within the PCM multiplex equipment.
.nr PS 9
.RT
.ad r
\fBTable 1/G.738 [T1.738], p. \fR
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
\fB3\fR \fBFrame alignment and CRC procedures\fR
.sp 1P
.RT
.PP
An illustration of the procedure is given in Figure\ 2/G.706.
.RT
.sp 1P
.LP
3.1
\fILoss of frame alignment\fR
.sp 9p
.RT
.PP
Refer to \(sc 4.1.1 of Recommendation\ G.706.
.RT
.sp 1P
.LP
3.2
\fIRecovery of frame alignment\fR
.sp 9p
.RT
.PP
Refer to \(sc 4.1.2 of Recommendation G.706.
.RT
.sp 1P
.LP
3.3
\fICRC multiframe alignment in TSO\fR
.sp 9p
.RT
.PP
Refer to \(sc 4.2 of Recommendation G.706.
.RT
.sp 1P
.LP
3.4
\fICRC bit monitoring\fR
.sp 9p
.RT
.PP
Refer to \(sc 4.3 of Recommendation G.706.
.RT
.sp 2P
.LP
\fB4\fR \fBFault conditions and consequent actions\fR
.sp 1P
.RT
.sp 1P
.LP
4.1
\fIFault conditions\fR
.sp 9p
.RT
.PP
The PCM multiplex equipment should detect the following
conditions:
.RT
.PP
4.1.1
Failure of power supply.
.sp 9p
.RT
.PP
4.1.2
Failure of codec (except when using single channel codecs).
.sp 9p
.RT
.PP
As a minimum requirement, this fault condition should be
recognized when for at least one signal level in the range \(em21 to \(em6\
dBm0, the signal\(hyto\(hyquantizing noise ratio performance of the local
codec is 18\ dB or
more below the level recommended in Recommendation\ G.712.
.bp
.PP
4.1.3
Loss of incoming signals at the 64\ kbit/s and 320\ kbit/s tributary input
ports.
.sp 9p
.RT
.PP
\fINote\ 1\fR \ \(em\ This detection is not mandatory when contradirectional
interfaces are used.
.PP
\fINote\ 2\fR \ \(em\ The detection of this fault condition is not mandatory
for channel time slot\ 16 when channel associated signalling is used and
the
signalling multiplex equipment is situated within a few metres of the PCM
multiplex equipment.
.RT
.PP
4.1.4
Loss of the incoming signal at 2048 kbit/s.
.sp 9p
.RT
.PP
\fINote\ 1\fR \ \(em\ The detection of this fault condition is required
only when it does not result in an indication of loss of frame alignment.
.PP
\fINote\ 2\fR \ \(em\ Where separate circuits are used for the digital
signal and the timing signal, the loss of either or both should constitute
loss of the
incoming signal.
.RT
.PP
4.1.5
Loss of frame alignment.
.sp 9p
.RT
.PP
4.1.6
Excessive bit error ratio detected by monitoring the frame
alignment signal.
.sp 9p
.RT
.PP
4.1.6.1
With a random bit error ratio of \(=\ 10\uD\dlF261\u4\d, the probability
of activating the indication of fault condition within a few seconds should
be
less than 10\uD\dlF261\u6\d.
.sp 9p
.RT
.PP
With a random bit error ratio of \(>="\ 10\uD\dlF261\u3\d, the probability
of activating the indication of fault condition within a few seconds should
be
higher than\ 0.95.
.PP
4.1.6.2
With a random bit error ratio of \(>="\ 10\uD\dlF261\u3\d, the probability
of deactivating the indication of fault condition within a few seconds
should be almost\ 0.
.sp 9p
.RT
.PP
With a random bit error ratio of \(=\ 10\uD\dlF261\u4\d, the probability
of deactivating the indication of fault condition within a few seconds
should be higher than\ 0.95.
.PP
\fINote\fR \ \(em\ The activating and deactivating period specified as \*Qa few
seconds\*U is intended to be in the order of\ 4 to\ 5 seconds.
.RT
.PP
4.1.7
Alarm indication received from the remote PCM multiplex equipment (see\
\(sc\ 4.2.3).
.sp 9p
.RT
.sp 1P
.LP
4.2
\fIConsequent actions\fR
.sp 9p
.RT
.PP
Further to the detection of a fault condition, appropriate actions should
be taken as specified in Table\ 2/G.738. The consequent actions are as
follows:
.RT
.PP
4.2.1
Service alarm indication generated to signify that the service
provided by the PCM multiplex is no longer available. This indication should
be forwarded at least to the switching and/or signalling multiplex equipment
depending upon the arrangements provided. The indication should be given as
soon as possible and not later than\ 2\ ms after detection of the relevant
fault condition.
.sp 9p
.RT
.PP
This specification, taking into account the specification given
in \(sc\ 4.2.5, is equivalent to recommending that the average time to detect a
loss
of frame alignment or a loss of the incoming 2048\ kbit/s signal and to
give the relevant indication should not be greater than\ 3\ ms.
.PP
When using common channel signalling the indication should be
forwarded to the switching equipment by means of separate interface on
the PCM multiplex equipment.
.RT
.PP
4.2.2
Prompt maintenance alarm indication generated to signify that
performance is below acceptable standards and maintenance attention is
required locally. When the AIS at 2048\ kbit/s input is detected (see General
Notes
below to\ \(sc\ 4.2), the prompt maintenance alarm indication associated
with loss of
frame alignement (see \(sc\ 4.1.5) and excessive error ratio (see \(sc\
4.1.6) should be inhibited, while the rest of the consequent actions are
in accordance with those associated in Table\ 2/G.738 with the two fault
conditions.
.sp 9p
.RT
.PP
\fINote\fR \ \(em\ The location and provision of any visual and/or audible
alarm activated by the alarm indications given in\ \(sc\ 4.2.1 and\ \(sc\
4.2.2, is left to the discretion of each Administration.
.PP
4.2.3
Alarm indication to the remote end, transmitted by changing bit\ 3 of channel
time slot\ 0 from the state\ 0 to the state\ 1 in those frames not
containing the frame alignment signal. This should be effected as soon as
possible.
.bp
.sp 9p
.RT
.ce
\fBH.T. [T2.738]\fR
.ce
TABLE\ 2/G.738
.ce
\fBFault conditions and consequent actions for the\fR
.ce
\fBPCM multiplex equipment\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(30p) | cw(36p) | cw(30p) sw(24p) sw(30p) sw(24p) sw(30p) sw(24p) , ^ | ^ | l | l | l | l | l | l.
Equipment part {
Fault conditions
(see \(sc\ 4.1)
} {
Consequent actions (see \(sc\ 4.2)
Service alarm indication generated
Prompt maintenance alarm indication
Alarm indication remote end transmitted
Transmission suppressed at the analogue voice\(hyfrquency
outputs
AIS applied to 64\ kbit/s and 320\ kbit/s outputs
AIS applied to the relevant time slot of the 2048\ kbit/s composite
signal
}
_
.T&
lw(30p) | lw(36p) | cw(30p) | cw(24p) | cw(30p) | cw(24p) | cw(30p) | cw(24p) , ^ | l | c | c | c | c | l | l.
{
Multiplexer and demulti
plexer
} Failure of power supply Yes Yes Yes (if practicable) Yes (if practicable) Yes (if practicable) Yes (if practicable)
Failure of codec Yes Yes Yes Yes
_
.T&
lw(30p) | lw(36p) | cw(30p) | cw(24p) | cw(30p) | cw(24p) | cw(30p) | cw(24p) , ^ | l | c | c | c | c | l | l.
Multiplexer only {
Loss of incoming signal at 64\ kbit/s and/or 320\ kbit/s inputs (see
Notes under \(sc\ 4.1.3)
} Yes Yes
_
.T&
lw(30p) | lw(36p) | cw(30p) | cw(24p) | cw(30p) | cw(24p) | cw(30p) | lw(24p) , ^ | c | c | c | c | c | l | c
^ | c | c | c | c | l | c | l
^ | l | l | l | l | l | l | l.
Demultiplexer only {
Loss of incoming signal at 2048\ kbit/s
} Yes Yes Yes Yes Yes {
Loss of frame alignment (see Note 2
Rec.\ G.706, \(sc\ 4.2)
}
Yes Yes (see \(sc\ 4.2.2) Yes Yes Yes {
Error ratio 1\(mu10\uD\dlF261\u3\d on the frame alignment signal
} Yes Yes (see \(sc\ 4.2.2) Yes Yes Yes {
Alarm indication received from the remote end
} Yes
.TE
.LP
\fINote\fR
\ \(em\ A \fIYes\fR
| in the table signifies that an action should be taken as a
consequence of the relevant fault condition. An \fIopen space\fR
in the table
signifies that the relevant action should not be taken as a consequence of the relevant fault condition, if this condition is the only one present. If more
than one fault condition is simultaneously present, the relevant action should be taken if, for at least one of the conditions, a \fIYes\fR
is defined in relation to this action.
.nr PS 9
.RT
.ad r
\fBTableau 2/G.738 [T2.738], p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.PP
4.2.4
Transmission suppressed at the analogue voice\(hyfrequency outputs.
.sp 9p
.RT
.PP
4.2.5
AIS applied to all 64\ kbit/s and 320\ kbit/s outputs (see General
Notes
below to\ \(sc\ 4.2). For 64\ kbit/s outputs this actions should be taken
as soon as possible and not later than\ 2\ ms after the detection of the
fault condition.
.sp 9p
.RT
.PP
4.2.6
AIS applied to relevant time slots in the composite 2048\ kbit/s
output signal (if suspension of incoming 64\ kbit/s and 320\ kbit/s signals is
provided).
.sp 9p
.RT
.sp 1P
.LP
\fIGeneral Notes to \(sc\ 4.2\fR
.sp 9p
.RT
.PP
\fINote\ 1\fR \ \(em\ The equivalent binary content of the alarm indication
signal (AIS) is a continuous stream of binary\ 1s. The strategy for detecting
the presence of AIS should be such that with a high probability the AIS is
detectable even in the presence of random errors having a mean error rate
of\ 1 in\ 10\u3\d. Nevertheless, a signal in which all the binary elements,
with the
exception of the frame alignment signal, are in the state\ 1, should not be
taken as an AIS.
.PP
\fINote\ 2\fR \ \(em\ All timing requirements quoted apply equally to
restoration, subsequent to the fault condition clearing.
.RT
.sp 2P
.LP
\fB5\fR \fBSignalling\fR
.sp 1P
.RT
.PP
Text as in Recommendation\ G.732.
.RT
.sp 2P
.LP
\fB6\fR \fBInterfaces\fR
.sp 1P
.RT
.sp 1P
.LP
6.1
\fIAudio frequency interface\fR
.sp 9p
.RT
.PP
The analogue audio frequency interfaces should be in accordance
with Recommendations\ G.712, G.713, G.714 and G.715.
.RT
.sp 1P
.LP
6.2
\fIDigital interfaces\fR
.sp 9p
.RT
.PP
The digital interfaces at 2048\ kbit/s should be in accordance with Recommendation\
G.703.
.PP
The digital interfaces at 64\ kbit/s should be of either the
codirectional or the contradirectional type specified in Recommendation\
G.703. The specification for 64\ kbit/s interfaces are not mandatory for
channel\(hyassociated signalling. The interface for external synchronization of
the transmitting timing signal should be in accordance with
Recommendation\ G.703.
.PP
The need to define a digital interface operating at 320\ kbit/s is
under study.
.PP
\fINote\ 1\fR \ \(em\ It should be noted that, according to the principle of
minimizing the number of different types of interfaces, the information
rate of 320\ kbit/s will be offered to customers at the user/network interface
level
using the 2048\ kbit/s interface as defined in Recommendation\ I.431 and
Recommendation\ G.703.
.PP
\fINote\ 2\fR \ \(em\ In the case of the 64\ kbit/s codirectional interface,
the design of the input ports should take into account the need to provide
octet
alignment, to allow controlled slips when the tributary timing and that
of the multiplexer timing source are plesiochronous, and to absorb jitter
and wander up to the limits given in Recommendation\ G.823.
.RT
.LP
\fB7\fR \fBJitter\fR
.sp 1P
.RT
.sp 2P
.LP
7.1
\fIJitter at 2048 kbit/s output\fR
.sp 1P
.RT
.PP
7.1.1
In the case where the transmitting timing signal is derived from an internal
oscillator, the peak\(hyto\(hypeak jitter at the 2048\ kbit/s output should
not exceed 0.05\ UI when it is measured within the frequency range from
\fIf\fR\d1\u\ =\ 20\ Hz to \fIf\fR\d4\u\ =\ 100\ kHz. See Figure\ 2/G.823.
.sp 9p
.RT
.PP
7.1.2
In the case where the transmitting timing signal is derived from an
external source having no jitter, the peak\(hyto\(hypeak jitter at the
2048\ kbit/s
output should not exceed 0.05\ UI when it is measured within the frequency
range from \fIf\fR\d1\u\ =\ 20\ Hz to \fIf\fR\d4\u\ =\ 100\ kHz.
.bp
.PP
7.1.3
In the case where the transmitting timing signal is derived from
the incoming 2048\ kbit/s signal having no jitter, the peak\(hyto\(hypeak
jitter at
the 2048\ kbit/s output should not exceed 0.10\ UI when it is measured
within the frequency range from \fIf\fR\d1\u\ =\ 20\ Hz to \fIf\fR\d4\u\
=\ 100\ kHz. The equivalent
binary content of the test signal applied at the 2048\ kbit/s input shall
be a pseudo\(hyrandom bit sequence of length 2\u1\d\u5\d\(em1 as specified
in
Recommendation\ O.151.
.PP
\fINote\fR \ \(em\ It may be necessary to include a frame alignment signal
in the test signal to enable the measurement to be carried out.
.sp 2P
.LP
7.2
\fIJitter at tributary outputs\fR
.sp 1P
.RT
.sp 1P
.LP
7.2.1
\fIJitter at 64 kbit/s output\fR
.sp 9p
.RT
.PP
In the case where the incoming 2048\ kbit/s signal has no jitter,
the peak\(hyto\(hypeak jitter at the 64\ kbit/s output should not exceed
0.025\ UI when it is measured within the frequency range from \fIf\fR\d1\u\
=\ 20\ Hz to
\fIf\fR\d4\u\ =\ 10\ kHz. The equivalent binary content of the test signal
applied to the 2048\ kbit/s input shall be a pseudo\(hyrandom bit sequence
of length
2\u1\d\u5\d\(em1 as specified in Recommendation\ O.151.
.PP
\fINote\fR \ \(em\ In order to carry out this measurement without invoking
AIS at the 64\ kbit/s output it will normally be necessary to include a frame
alignment signal in the test signal.
.RT
.sp 1P
.LP
7.2.2
\fIJitter at 320 kbit/s output\fR
.sp 9p
.RT
.PP
Since the physical and electrical characteristics of a 320\ kbit/s interface
are identical to those of the 2048\ kbit/s interface, the
specification of this parameter is the same as that given in\ \(sc\ 7.1.3
above.
.RT
.sp 2P
.LP
7.3
\fIJitter transfer functions\fR
.sp 1P
.RT
.PP
7.3.1
The jitter transfer function between the 2048\ kbit/s external
synchronization signal and the 2048\ kbit/s output signal should not exceed
the gain/frequency limits given in Figure\ 2/G.738. The 2048\ kHz signal
shall be
modulated with sinusoidal jitter.
.sp 9p
.RT
.PP
Some Administrations require that equipment be fitted with jitter reducers.
In this case, the jitter transfer functions should not exceed the
gain/frequency limits given in Figure\ 3/G.738.
.PP
7.3.2
In the case where the transmitting timing is derived from the
incoming signal, the jitter transfer function between the 2048\ kbit/s
input and the 2048\ kbit/s output shall be as specified in\ \(sc\ 7.3.1.
.sp 9p
.RT
.PP
\fINote\ 1\fR \ \(em\ The 2048 kbit/s test signal shall be modulated by
sinusoidal jitter. The equivalent binary content of the test signal shall
be\ 1000.
.PP
\fINote\ 2\fR \ \(em\ It may be necessary to include a frame alignment
signal in the test signal to enable the measurement to be carried out.
.RT
.PP
7.3.3
The jitter transfer function between the 2048\ kbit/s input and the 64\
kbit/s output should not exceed \(em29.6\ dB when measured over the frequency
range \fIf\fR\d0\uto\ 10\ kHz. The frequency \fIf\fR\d0\ushould be less
than 20\ Hz and as low as possbile (e.g. 10\ Hz), taking into account the
limitations of measuring equipment.
.sp 9p
.RT
.PP
\fINote\ 1\fR \ \(em\ The 2048 kbit/s test signal shall be modulated by
sinusoidal jitter. The equivalent binary content of the test signal shall
be\ 1000.
.PP
\fINote\ 2\fR \ \(em\ In order to carry out this measurement without invoking
AIS at the 64\ kbit/s output, it will normally be necessary to include
a frame
alignement signal in the test signal.
.PP
\fINote\ 3\fR \ \(em\ The jitter reduction of 1/32 due to demultiplexing is
equivalent to \(em30.1\ dB.
.RT
.PP
7.3.4
Since the physical and electrical characteristics of a 320\ kbit/s interface
are identical to those of 2048\ kbit/s interface, the jitter transfer function
between 2048\ kbit/s input and 320\ kbit/s output is the same as that
cw(30p) | cw(30p) | cw(36p) | cw(36p) | cw(36p) | cw(48p) | cw(42p) | cw(42p) | cw(42p) , ^ | l | l | l | l | l | l | l | l.
{
Loss of incoming signal at 2048\ kbit/s
} Extr.s. (E 1) Yes Yes Yes Ins.s. (I 0) Yes Yes Yes
_
.T&
cw(30p) | cw(30p) | cw(36p) | cw(36p) | cw(36p) | cw(48p) | cw(42p) | cw(42p) | cw(42p) , ^ | l | l | l | l | l | l | l | l.
{
Loss of frame alignment (see Note 2 of Rec.\ G.706, \(sc\ 4.2)
} Extr.s. (E 1) Yes (see \(sc\ 4.2.1) Yes Yes Ins.s. (I 0) Yes (see \(sc\ 4.2.1) Yes Yes
_
.T&
cw(30p) | cw(30p) | cw(36p) | cw(36p) | cw(36p) | cw(48p) | cw(42p) | cw(42p) | cw(42p) , ^ | l | l | l | l | l | l | l | l.
{
Error ratio 1 | (mu | 0\uD\dlF261\u3\d on the frame alignment signal (see Note under
\(sc\ 4.1.5)
} Extr.s. (E 1) Yes (see \(sc\ 4.2.1) Yes Yes Ins.s. (I 0) Yes (see \(sc\ 4.2.1) Yes Yes
.TE
.LP
\fINote\fR
\ \(em\ A \fIYes\fR
| in the table signifies that an action should be taken as a
consequence of the relevant fault condition. An \fIopen space\fR
in the table
signifies that the relevant action should not be taken as a consequence of the relevant fault condition, if this condition is the only one present. If more
than one fault condition is simultaneously present, the relevant action should be taken if, for at least one of the conditions, a \fIYes\fR
is defined in relation to this action.
.nr PS 9
.RT
.ad r
\fBTable 2/G.739 [T2.739], p. \fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 2P
.LP
\fB6\fR \fBJitter\fR
.sp 1P
.RT
.sp 1P
.LP
6.1
\fIJitter at 2048 kbit/s output\fR
.sp 9p
.RT
.PP
When there is no jitter on the 2048\ kbit/s inputs (I\d0\u, E\d1\u)
the peak\(hyto\(hypeak jitter at the 2048\ kbit/s outputs (I\d1\u, E\d0\u)
should not
exceed 0.10\ UI when it is measured within the frequency range from
\fIf\fR\d1\u\ =\ 20\ Hz to \fIf\fR\d4\u\ =100\ kHz. The equivalent binary
content of the test signal applied
at the 2048\ kbit/s input shall be a pseudo\(hyrandom bit sequence of length
2\u1\d\u5\d\(em1 as specified in Recommendation\ 0.151. See Figure\ 2/G.823.
.PP
\fINote\fR \ \(em\ It may be necessary to include a frame alignment signal in
the test signal to enable the measurement to be carried out.
.RT
.sp 2P
.LP
6.2
\fIJitter at E\fI
.sp 1P
.RT
.EF '% \fI2\ and\''
.OF '''\fI2\ and\ %'
.EF '% \fI3\ outputs''
.OF '''\fI3\ outputs %'
.PP
6.2.1
The jitter at the E\d2\u(64\ kbit/s) output when there is no jitter at
the 2048\ kbit/s input (E\d1\u) should not exceed 0.025\ UI when measured
within the frequency range from \fIf\fR\d1\u\ =\ 20\ Hz to \fIf\fR\d4\u\
=\ 100\ kHz. The
equivalent binary content of the test signal applied at the 2048\ kbit/s
input shall be a pseudo\(hyrandom bit sequence of length 2\u1\d\u5\d\(em1
as specified in
Recommendation\ O.151.
.sp 9p
.RT
.PP
\fINote\fR \ \(em\ In order to carry out this measurement without invoking
AIS at the 64\ kbit/s output, it will normally be necessary to include
a frame alignment signal in the test signal.
.PP
6.2.2
Since the physical and electrical characteristics of a 320\ kbit/s interface
are identical to those of the 2048\ kbit/s interface, the jitter at
the E\d3\u(synchronous 320\ kbit/s) output when there is no jitter at the
2048\ kbit/s input (E\d1\u) is according to \(sc\ 6.1 above.
.sp 9p
.RT
.sp 2P
.LP
6.3
\fIJitter transfer functions\fR
.sp 1P
.RT
.PP
6.3.1
The jitter transfer function between the 2048\ kbit/s input (I\d0\u, \d1\u)
and the output (I\d1\u, E\d0\u) should not exceed the gain/frequency
limits given in Figure\ 2/G.739.
.sp 9p
.RT
.PP
Some Administrations require that equipment be fitted with
jitter reducers
. In this case, the jitter transfer function should not exceed the gain/frequency
limits given in Figure\ 3/G.739.
.PP
\fINote\ 1\fR \ \(em\ The 2048 kHz signal shall be modulated with sinusoidal
jitter. The equivalent binary content of the test signal shall be 1000.
.PP
\fINote\ 2\fR \ \(em\ It may be necessary to include a frame alignment
signal in the test signal to enable the measurement to be carried out.
.RT
.PP
6.3.2
The jitter transfer function between the 2048\ kbit/s input (E\d1\u) and
the E\d2\u(64\ kbit/s) output should not exceed \(em29.6\ dB when measured
over the frequency range \fIf\fR\d0\uto 10\ kHz. The frequency \fIf\fR\d0\ushould
be less
than 20\ Hz and as low as possible (e.g. 10\ Hz), taking into account the
limitations of measuring equipment.
.sp 9p
.RT
.PP
\fINote\ 1\fR \ \(em\ The 2048\ kbit/s test signal shall be modulated by
sinusoidal jitter. The equivalent binary content of the test signal shall
be\ 1000.
.PP
\fINote\ 2\fR \ \(em\ In order to carry out this measurement without invoking
AIS at the 64\ kbit/s output, it will normally be necessary to include
a frame
alignment signal in the test signal.
.PP
\fINote\ 3\fR \ \(em\ The jitter reduction of 1/32 due to demultiplexing is
equivalent to \(em30.1\ dB.
.RT
.PP
6.3.3
Since the physical and electrical characteristics of a\ 320\ kbit/s interface
are identical to those of the 2048\ kbit/s interface, the jitter
transfer function between the 2048\ kbit/s input (E\d1\u) and E\d3\u(synchronous
320\ kbit/s) output is according to \(sc\ 6.3.1 above.