optix sdh test principles and common specifications-20080528-a

7/28/2019 OptiX SDH Test Principles and Common Specifications-20080528-A

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HUAWEI TECHNOLOGIES CO., LTD.

www.huawei.com

Huawei Confidential

Security Level: Internal Use Only

OptiX SDH Test Principles

and Common Specifications


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HUAWEI TECHNOLOGIES CO., LTD. All rights reserved Page 2

After this course, you will get familiar with:

The test specifications, principles, and methods ofoptical interfaces and electrical ports.

The test specification, principles, and methods of bit

error performance.

The concepts, test principles, and methods of jitter andwander.

Objectives


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Principles of Testing Equipment

Principles and Methods for Testing theSpecifications of an Optical Interfaces

Test Principles and Methods of Electrical

Ports Index

Contents


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Principles of Testing Equipment Optical Interface Types

Application

Scenario

Intra-

office

Inter-office

Short-distance Long-distance

Operating

wavelength (nm)1310 1310 1550 1310 1550

Fiber Type G.652 G.652 G.652 G.652G.652/

G.654G.653

Transmission

Distance (km)2 15 40 80

Rate

level

STM-1I-1 S-1.1 S-1.2 L-1.1 L-1.2 L-1.3

STM-4 I-4 S-4.1 S-4.2 L-4.1 L-4.2 L-4.3

STM-16 I-16 S-16.1 S-16.2 L-16.1 L-16.2 L-16.3


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The Purposes of Defining the Operating Wavelength Range:

1. Ensuring sufficient flexibility in transverse compatibility.

2. When the wavelength division multiplexing (WDM) is

applied, more choices of operating lengths can be provided.

Constraints for Choosing Operating Wavelength:

Modal noise-affects the transmission quality

Fiber attenuation-decreases the powerFiber dispersioncauses intersymbol interference


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1. 850 nm: for multi-mode transmission

2. 1310 nm: for single-mode transmission. The dispersion is the

lowest in fiber transmission (0 dispersion)

3. 1550 nm: for single-mode transmission. The attenuation is the

lowest in fiber transmission

Three Windows of Fiber Transmission:


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1. G.652 fiber (dispersion-unshifted fiber): The fiber has the

best dispersion performance in the 1310nm window. It can

transmit the optical signals of 1310nm and 1550nm.

2. G.653 fiber (dispersion-shifted fiber): The fiber has the best

dispersion performance in the 1550nm window. It can transmitthe optical signals with a wavelength of 1550 nm and thus it is

suitable for transmitting single-wavelength and high-speed

optical signals.

3. G.655 fiber: The fiber has the best annenuation

performance in the 1550 nm window. It has little dispersionand thus it can transmit the optical signals and DWDM optical

signals with a wavelength of 1550 nm.

Fiber Types


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Optical transmit

end

Optical

receive end

Optical

Cable

CTX CRX

S R

Three types of optical parameters: Optical transmit parameters of the point S.Optical receive parameters of point R

Optical parameters between point S and point R.

The criteria for defining the specification of the parameters:

When the attenuation and dispersion are the worst, the regenerator

sectionBER110 -10

Principles of Testing equipment

Definitions of Optical Interface Parameters


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The energy of single-longitudinal mode lasers focuses on the dominant mode. Hence, the

spectral width is defined according to the maximum width when the maximum peak power

falls to -20dB. The features of the spectrum are shown in the following figure.

P

AA2

A1

-20dB

Maximum -20dB bandwidth is A2-A1

Principles of Testing equipment

Parameters of Point SLaser Emitter Parameters

1 Maximum20 dB Bandwidth


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The ITU-T recommends EX10dB in long distance and 8.2dB in other cases.



2. Minimum Side-Mode Suppression Ratio (SMSR)

The minimum ratio of the mean optical power (P1) of major

longitudinal mode to the optical power (P2) of the most obvious

side mode in full modulation under the worst reflection condition.

SMSR10lg(P1/P2)>30dB3 Extinction Ratio

The minimum of the ratio between the mean launched optical power

(A) of the optical signals that are defined as 1s and the mean

launched optical power (B) of the optical signals that are defined as

0s. EX10lg(A/B).


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4 Nominal Source Type

The types of the optical components used by the optical

transmitter:

Light Emitting Diode (LED)

Multi-longitudinal mode laser

Single-longitudinal mode laser

5 The wave form of transmitting signals (eye pattern)

To prevent the receiver sensitivity from getting severely

degraded, the waveform of transmitting signals must be

controlled by using eye pattern mask to control the pulse

shaping of optical signals.


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BER

Received optical power

A B

110-10

Point A is the receiver sensitivity point.

Point B is the overload point of optical power


Parameters of Point ROptical Parameters of Receivers


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Parameters of optical channel between point S and point R

1AttenuationDecrease the optical power

2 Dispersion1dBthe power penalty of optical channel

3 ReflectionBrings interference noise


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Test Principles and Methods of Optical

Interfaces Index

Test Principles and Methods of Electrical Ports

Index

Contents


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Test Principles and Methods of

Optical Interfaces Index

Mean Launched Optical Power

Concept: The index refers to the test value at reference point

S (OUT port of the optical board) of the mean power of the

pseudorandom binary sequence that is coupled to the fiber by

the transmitter.

Note: The optical power of the transmitter is relevant to the

proportion of 1s in the transmitted signals. The optical power

is higher when more 1 signals are contained. When the

transmitted data signals are pseudorandom binary sequence,

the proportion of 1s and 0s are approximately same. The

optical power in this case is defined as the mean launchedoptical power.


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Interfaces Index

Mean Launched Optical Power Schematic drawing of the test

Test procedure:

Connect the circuit following the schematic drawing.

The optical power meter is set to the desired wavelength. Wait unitll theoutput power is stable and then read the mean launched optical power. To

achieve high accuracy of test results, more tests for a mean value is

recommended. ).

Caution:

a) To do this test, you have to keep the fiber connector clean and well connected,and also keep the board front panel well connected and clean.

b) Test the attenuation of the fiber jumper to ensure proper optical transmit power.

c) Identify the optical module for choosing proper wavelength.

Optical power meter

Optical interface board

Tested optical interface

OUT

IN

Fiber jumper

-


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Interfaces Index

Actual received optical power

Concept: The actual received optical power refers to the mean optical power that is actually

received in the R reference point (the IN port of the optical board).

Test Procedure:

Set the optical power meter to the wavelength of the board under test.

Choose the fiber jumper that connects with the IN port of the optical interface board in

this site. Connect the fiber jumper to the IN port of the optical power meter, as shown in thefollowing figure.

Read the optical power after

the receive optical power is stable.

This is the actual received optical

power of the optical board.

Caution:

a) To do this test, you have to keep the fiber connector clean and well connected.

b) The test value of the optical power must be 3dB higher than the sensitivity index of the

optical interface board. Otherwise, you need to check the fiber connections.

c) The obtained value must be 5dB lower than the overload index value of this optical interface

board. Otherwise, add another attenuator at the ODF side.


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Receiver sensitivity Definition: Receiver sensitivity is the minimum mean optical

power that a receiver can receive within the allowable bit error

range (BER=110-10).Test Configuration:

SDHanalyzer

Transmitterside

Receiverside

Powermeter

R

Tributary

Tributary

SDH equipment

Optical

attenuator

f


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Optical Interfaces Index Receiver sensitivity

Configure the NE test: Use the network management system to configure

the cross service of the desired circuit and tributary card. (Legend: take slot

2 as PQ1, and slot 6 as SL16 to configure a bidirectional 2M service. You

can also configure the service of other rate as required).


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Receiver sensitivity

Test Procedure:

Connect the circuit following the configuration diagram.

According to the level of the channel monitoring the error codes,

the SDH analyzer transmits the PRBS and transmits test signals to the

IN port of the 2 Mbit/s tributary (or the circuit IN port).

Adjust the optical attenuator by increasing the attenuation value.

As a result, the SDH analyzer generates error code. Decrease the

attenuation value until the error code disappears, the receive optical

power of the SDH equipment is the sensitivity.

Disconnect point R, connect the optical attenuator to the optical

power meter, and read the receiver optical power, namely the receiver

sensitivity.

T t P i i l d M th d f


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Receiver overload optical power

Definition: Receiver overload optical power is the maximum mean

optical power that a receiver can receive within the allowable bit error

range (BER=10-10)in the R reference point (the IN port of the optical

board).

Test Configuration:

SDHanalyzer

Transmitterside

Receiverside

Powermeter

R

Tributary

Tributary

SDH equipment

Optical

attenuator

T P i i l d M h d f


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Optical Interfaces Index Receiver overload optical power

Configure the NE test: Use the network management system to configurethe cross service of the desired circuit and tributary card. (Legend: take

slot 2 as PQ1, and slot 6 as SL16 to configure a bidirectional 2M service.

You can also configure the service of other rate as required).



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Optical Interfaces Index Receiver overload optical power

Test Procedure:

a Connect the circuit following the configuration diagram. According to the level of the channel monitoring the error codes, the SDH

analyzer transmits the PRBS and transmits test signals to the 2M tributary IN

port (or the circuit IN port).

c) Adjust the optical attenuator by decreasing the attenuation value. Ensurethe bit error tested by the SDH analyzer close to but not more than the

specified BER (in general BER=10-10), and observe the test for 10 minutes.

Disconnect point R, connect the optical attenuator to the optical power

meter and read the receiver optical power, namely the receiver overload

optical power.

Summary: If the power is too strong, bit errors may occur or even damage thereceiving optical module; if the optical power is too low, bit errors may occur

or receive no optical signals. The signals received by the optical board cannot

be too strong or poor. The receive optical power must be within the specified

range to ensure stability of the optical board. The overload point of the APD is

-9DB, and thus easy to be broken down. Test with caution.



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Permitted frequency deviation at the optical input interface

Definition: This index refers to the permitted frequency deviation when the

received signals at the optical input interface are normal.

Requirements: The accuracy of the internal oscillator of the repeater in the

free-run mode should not be worse than 2010-6 . The downstream SDH

equipment should be able to tolerate this kind of signals.

Test configuration

Receiver

Transmitter

20 ppm

SDH

analyzer

T t P i i l d M th d f O ti l


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Interfaces Index Permitted frequency deviation at the optical input interface

Configure the NE test: Configure the NE test: Use the network managementsystem to configure the cross service of the desired circuit and tributary

card . (Legend: take slot 2 as PQ1, and slot 6 as SL16 to configure a

bidirectional 2M service. You can also configure the service of other rate as

required).


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Permitted frequency deviation at the optical input interface

Test Procedure:

Connect the circuit following the configuration diagram (Loop

back the tributary channel that requires bit error monitoring; in the

synchronization source, trace the circuit clock).

The SDH analyzer transmits proper test signals (without

frequency deviation and jitter) according to the rate level of the test

interface.

Use the SDH analyzer to receive the test signals and detect bit

errors at the output port of the tested equipment. The instrumentgives no alarms and bit errors.

The SDH analyzer transmits signals with positive (+) or negative(-)

frequency deviation (the range is 20ppm).No bit errors should occur

in the tested equipment during the test.


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Jitter and Wander Definition:

The jitter and wander are relevant with the schedule

feature of the system. Scheduled jitter (jitter) refers to the

short-time deviation from the ideal time place in the

specific time (for example, best sampling time). The short-

time deviation refers to the change of the phase higher

than 10Hz. The wander refers to the long-term deviation

from the ideal time place in the specific time. The long-

term refers to the change of the phase lower than 10 Hz.



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SDH Input Jitter Tolerance at the SDH port

Definition: For STM-N optical interface the input jitter tolerance is the peak-

to-peak amplitude of sinusoidal jitter in case of 1dB power penalty. The

parameter defines that when the SDH NEs are interconnected to transmit

STM-N signals, the input jitter tolerance of the current NE should contain the

output jitter generated by the upper NEs.

Test configuration



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Interfaces Index

Input jitter tolerance at the SDH port

Configure the NE test: Configure the NE test: Use the network management system to

configure the cross service of the desired circuit and tributary card . (Legend: take

slot 2 as PQ1, and slot 6 as SL16 to configure a bidirectional 2M service. You can also

configure the service of other rate as required).



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Interface Indexes Input jitter tolerance at the SDH port

Test ProcedureConnect the circuit following the configuration diagram (Loop back the tributary

channel to be monitored and ensure that the path is accessible for the service on the

equipment and the SDH analyzer ).

The SDH analyzer transmits test signals to the tested interface according to the rate

level of the interface.

Start the auto test for the jitter tolerance of the SDH analyzer and record the jitter

tolerance limits of each frequency. The values should comply with the test standards.

It is recommended that you start the print function of the SDH analyzer. The test curve

should be higher than the template curve.

The index and template of the G.958 type A are as follows:

STM levelUIp-p Frequency (kHz

A2 A1 f0 ft

STM-1 (electrical

interface)

1.5 0.15 6.5 65

STM-1 (optical

interface)

1.5 0.15 6.5 65

STM-4 1.5 0.15 25 250

STM-16 1.5 0.15 100 1000



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Interfaces Index Output jitter at the SDH port

Definition: The output jitter at the SDH port refers to the jitter occurred at the output portof the NE. The purpose of the test is to measure the jitter of the desired entity (SDH NE or

network interface), to ensure the output jitter of the port does not exceed the limit

specified in the NE input port.

Note: The SDH output jitter indexes are classified into the index in the case of the whole

frequency band (B1 index) and the index in the case of the high frequency band (B2 index)

The output jitter amplitude varies in different frequency bands. The jitter has more power

in the low frequency part. Use a band-pass filter or high-pass filter to test the jitter. If thefilter is shut down, the jitter value of the whole frequency band is tested, namely, the jitter

value of the frequency with the maximum jitter in the whole frequency band is displayed.

Technical specifications:Interface Rate Measurement Filter Peak jitter rate

STM-1500Hz1.3MHz 0.5UIpp65kHz1.3MHz 0.1UIpp

STM-4

1000Hz5MHz 0.5UIpp250kHz5MHz 0.1UIpp

STM-16

5kHz20MHz 0.5UIpp1MHz20MHz 0.1UIpp

STM-6410kHz80MHz 0.5UIpp4MHz80MHz 0.1UIpp



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Optical Interfaces Index Output jitter at the SDH port

Configuring a service by using the single station: Use the T2000 toconfigure the cross-connect service of the desired line board and

tributary board. (Legend: In the following figure, a bidirectional 2 Mbit/s

add/drop service is configured between the PQ1 in slot 2 and the SL16 in

slot 6. You can also configure the service of other rate as required).



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Output jitter at the SDH port

Test configuration:

Test Procedure:

Connect the circuit following the configuration diagram (Loop back the

tributary channel to be monitored and ensure that the path is accessible for

the service on the equipment and the SDH analyzer ).

The SDH analyzer transmits proper test signals (transmits signals without

jitter to the input port corresponding to the tested output port) according to

the rate of the tested interface.

Set proper test filter for the jitter tester as required. (Select B1, HP1+LP, B2,

and HP2+LP).

Perform tests not less than 60s continuously and read the maximum peak-

peak jitter value.

Tributary

board

Cross-connect

board

Lineboard

Cable

loopback

TX

RX

RX

TX

TX

RX

SDH

analyzer


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Interfaces Index

Test Principles and Methods of Electrical

Ports Index



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Electrical Ports Index Allowed Frequency Deviation at Input Interface of PDH

Definition: This index refers to the permitted maximum frequency deviation when the

received signals at the optical input interface are normal.

Technical specifications:

Test Configuration:

Bit Rate (kbit/s Tolerance Code pattern PRBS for test1544VC-11 3210-6

154400050bit/sB8ZSAMI 220-1

2048VC-12 5010-62048000103bit/s

HDB3 215-1

34368VC-3 2010-634368000688bit/s

HDB3 223-1

44736VC-3 20 10-644736000895bit/s

B3ZS 220-1

155520 2010-51555200003111bit/s

CMI 223-1

Test configuration

Pattern

generator

BER tester

PDH/SDH analyzer

SDH

transmitter

side

SDH

receiver

side


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Electrical Ports Index

Allowed Frequency Deviation at the PDH Input Interface Test Procedure:

a) Connect the circuit following the previous diagram (Configure the tested system

using the NMS system; configure the service at the tested port, Perform a selfloop

in the monitored optical port by using a fiber jumper to ensure that the path is

accessible for the service on the equipment and SDH analyzer);

b) The pattern generator or SDH/PDH analyzer transmits proper test signals to the

tested input interface according to the interface type and rate level. Adjust the

system to the normal work state, no bit errors occur.

c )Adjust the frequency deviation to the required range. The whole equipment works

normally and no bit errors occur.

d) When you need to test the actual frequency deviation tolerance, you can increase

the positive and negative frequency deviations until bit errors disappear. Record

the relevant frequency deviations.



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Input jitter tolerance at the PDH port

Definition: To ensure the stability of the telecommunication equipment, the

transmission equipment must tolerate the maximum jitter occurred in the

transmission process.

Test configuration

Tributaryboard

Cross-connect

board

Lineboard

Clock tracing

SDHanalyzer



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Electrical Ports Index Input jitter tolerance at the PDH port

Test Procedure:

a) Connect the circuit according to the previous diagram (Configure the test

system using the NMS system. Configure the service in the tested ports).

b) Transmit test signals to the tested tributary input port according to the rate

level.

c) Set the auto test function of the jitter tolerance and then start the test.

d) Wait for a while and you can obtain complete input jitter tolerance from the

meter. Print the results. The test curve must be over the template curve.



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SDH

analyzer

Cross-connect

board

Tributary

board

Lineboard

Cable/Fiber

loopback


Electrical Ports Index PDH Port Output Jitter

Definition: To ensure the stability of telecommunication equipment, the jitter ofthe output signals should not be greater than the maximum jitter tolerance at the

receive side.

Technical specifications:

Test configuration

Interface bit rate Filter bandwidth Requirement

1544kbit/s

B110Hz40kHz


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PDH Optical Port Output Jitter

Test Procedure:

Connect the circuit following the previous diagram (Configure the

tested system using the NMS system; configure the service at the

tested port,

Self-loop the optical interface to be monitored using the fiber jumper

to ensure that the path is accessible for the service on theequipment and SDH analyzer);

The SDH analyzer transmits proper test signals (transmits signals

without jitter to the input port corresponding to the tested output port)

according to the rate of the tested interface.

Set proper test filter for the jitter tester as required. (Select B1,

HP1+LP, B2, and HP2+LP).

Perform tests not less than 60s continuously and read the maximum

peak-peak jitter value.



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Mapping jitter at the PDH tributary port

Definition: When PDH signals with different frequency deviations are input at a PDH

tributary port of the SDH equipment, in the absence of pointer justifications in STM-N

signals, the maximum jitter of the output PDH tributary signals at the PDH tributary

port is the mapping jitter.

Test configuration

Tributaryboard

Cross-connect

board

Lineboard

TXRX

TX RX

SDHanalyzer



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Mapping jitter at the PDH tributary port

Test Procedure:

Connect the circuit following the test diagram (configure the tested NE using the NMS system.

Configure the service at the tributary port to be tested. Observe the SDH analyzer, if no alarms and bit

errors occur, perform the test).

The SDH analyzer selects proper PRBS according to the rate level of the PDH tributary output port. Set

the nominal value (without frequency deviation) for the bit rate, and insert the value into the relevant

VC of the tested PDH tributary. The STM-N signals have no pointer justification.

Set proper filters (select HP1+LP and HP2+LP) for the jitter tester according to the rate level of the PDH

tributary port and the requirements.

At the PDH tributary output port, use the jitter tester to test for more than 60s continuously and read

the peak-peak value of the jitter generated by the mapping.



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Test Principles and Methods ofElectrical Ports Index Mapping jitter at the PDH tributary port

The SDH analyzer changes the bit rate of the PRBS, namely, adds a certain

frequency deviation f,f=5,1015ppm. Repeat this step, and you willobtain some mapping jitter data of different frequency deviations.

In the data, the jitter in the case of a certain frequency deviation is obvious.

Change the bit rate of the PRBS with smaller frequency deviation step (for

example, 1 ppm) close to the specific frequency deviation. Repeat the operation

in step E to find out the maximum mapping jitter.

Note: The frequency deviation in the test refers to that of the PDH service, namely,

the frequency deviation of VC-12 in the STM-N signals, not the frequency

deviation of line signals. Normally, STM-1 frequency deviation index is 20ppm.

The 50ppm frequency deviation is not allowed.

The indexes of the mapping jitter are as follows:

PDH Rate

(kbit/s)

Tolerance

range of bit

rate

Mapping Jitter Filter characteristics

F1-F4UI

F3-F4UI

F1

High

pass

F3

High pass

F4

Low pass

2,048 50 0.4 0.075 20Hz 18kHz 100kHz34,368 20 0.4 0.075 200Hz 10kHz 800kHz139,264 15 0.4 0.075 200Hz 10kHz 3500kHz



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Electrical Ports Index Combined Jitter at PDH Tributary interface

Definition: At the SDH line port, input the signals of pointer testsequence that comply with the G.783 specifications, in this case, the

pointer justification occurs on the SDH equipment. Change the

frequency deviation of the input signal, the PDH tributary port outputs

signals and the tested maximum jitter is the combined jitter of the

equipment.

Test configuration:

Tributaryboard

Cross-connect

board

Lineboard

TXRX

TX RX

SDH

analyzer


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Combined jitter at PDH Tributary interface

Test Procedure:

Connect the circuit following the test diagram (configure the tested NE using

the NMS system. Configure the service at the tributary port to be tested.

Observe the SDH analyzer. If no alarms and bit errors occur, perform the test).)

The SDH analyzer selects the test signal according to the level of the PDH

tributary output interface and transmits the G.783-compliant pointer test

sequence.

At the output port of the PDH tributary, set proper filters (select HP1+LP and

HP2+LP ) for the jitter tester, and test for not less than 60s.

Change the frequency deviation of the input signal and find the maximum

output jitter value, namely the combined jitter.


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Bit Error Performance Indexes


Definition: A bit error means that an error occurs on some bits in the code stream afterthe bits are received, judged and regenerated, and the error impairs the quality of

information transmitted.

Measuring the Performance of Bit Errors:

Traditional measurement (G.821) is to measure the performance of bit errors in the

digital reference circuit of the 27500 km end-end in the 64kbit/s channel. The

measurement is based on the bit errors. Using bits to measure the performance of bit

errors is limited when the transmission rate increases.

Currently, the performance of bit errors in the channels with high bit rates (2M or 2M

higher) is defined in ITU-T G.826 and M.2100, and the measurement unit is blocks (B1,

B2, and B3 monitors bit error blocks). As a result, a group of parameters based on

blocks are generated. The meanings of the parameters are described as follows:


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Block Error

The block with error bits in the transmission is called error block.

Errored Second (ES) and Error Second Ratio (ESR)

The errored second (ES) indicates a one-second period thatcontains one or more errored blocks. The ratio between the total

errored second (occurred in the specified test time) and the total

available time is called errored second ratio.


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Serious Errored Second (SES) and Serious Errored

Second Ratio (SESR) The serious errored second (SES) refers to a one-second period that

contains more than 30% errored blocks or at least one SDP. The SDP

is a period of at least four consecutive blocks or 1 ms (taking the

longer one) where the error ratios of all the consecutive blocks are

more than or equal to 10-2 or loss of signal occurs. The SESR refers to

the ratio between the SES total (occurred in the test period) and the

total available time.

The SES is generally burst error block generated by pulse interference.

Hence, the SESR reflects the anti-interference capability of the

equipment.


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Background Block Error (BBE) and BackgroundBlock Error Ratio (BBER)

The BBE refers to the block errors occurred out of the unavailable time

and SSE period. The BBER refers to the ratio between the BBE and the

block total subtracting blocks in the unavailable time and SES period.

If the test lasts for long, the BBER reflects the bit errors in the

equipment and is relevant with performance stability of the

components adopted.

Bi E P f I d


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Test configuration:

Test Procedure

1) Connect the circuit following the previous diagram (Configure the NE to be

tested using the NMS system. Configure the service at the tributary port of

the NE to be tested. Set the loopback at the port).

2)The SDH analyzer selects proper PRBS to transmit test signals to the inputport according to the rate level of the desired system interface.3) 24After 24

hours, read (or print) the test result from the test instrument.

NE

NE

NE

NESDH analyzer

PDHInterface

Inloop

Bit Error Performance Indexes (Instances)


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Bit error performance indexes Test (example)

Following the test diagram, connect the SDH analyzer to the NE3

service port, at the DDF side, self-loop all 2Mbit/s services of NE1.



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Bit error performance indexes Test (example)

Assume that 63X2Mbit/s services are configured

between NE1 and NE3.Connect the 63x2Mbit/s services of NE3 in

series following the diagram,

and connect the services to the SDH analyzer.

Perform an inloop for all service ports in the DDF.

Set the meter into the Print state and perform the 24-hour BER test. Print the test result

24 hours later. The test result must show that no bit error occurs. A small number of

pointer justifications are allowed. The number of justifications must be less than 6.

Note: In the case of an MSP ring, perform a 24-hour BER test for the working channel and

a 12-hour BER test for the protection channel. The test result must show that no bit error

occurs. The number of pointer justifications must be less than 6. If the first 24-hour BER

test shows that bit errors occur, rectify the fault and perform another 24-hour BER test.

Continually perform the test until no bit error occurs.

NoticeDuring the test, unrelated personnel are forbidden to enter the test

environment. It is forbidden to touch optical fibers, wires, and cables

randomly.

Do not perform swapping operations to the power supply equipment within

the test area.


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Quiz

What items are included in the optical interface

test?

What items are included in the electrical interface

test?

What are the cautions in the optical interface test?


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Conclusion

The mean launched optical power, actual received optical

power, and bit error are mandatory items. You need to master

the concepts, test principles, and test methods of these items.

The receiver sensitivity, receiver overload optical power,allowed frequency deviation at optical input port, input jitter

tolerance at the SDH port, output jitter tolerance at the SDH

port, permitted frequency deviation at the PDH input port, Input

jitter tolerance at the PDH port, output jitter and mapping jitter

at the PDH port, and combined jitter are optional items. You

need to know the concepts, test principles, and test methods.


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Thanks!

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optix sdh test principles and common specifications-20080528-a

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