ELQ 2+
xDSL LINE QUALIFIER
403-000-000
Operating Manual
Kurth Electronic GmbH
Muehleweg 11
D-72800 Eningen u.A.
Tel. : +49-7121-9755-0
Fax. : +49-7121-9755-56
info@kurthelectronic.de
2007.
OM-403-000-000E
CONTENTS
1
2
3
4
5
6
Introduction .............................................................................................. 1-1
1.1
The Use of This Manual ..................................................................... 1-1
1.2
Application .......................................................................................... 1-1
Main Features ........................................................................................... 2-1
2.1
Measuring Modes ............................................................................... 2-1
2.2
Keyboard and LEDs ........................................................................... 2-4
2.3
Connectors & Measuring Cables........................................................ 2-7
Operating Instructions ............................................................................. 3-1
3.1
Start up and general rules .................................................................. 3-1
3.2
Saving and Recall of Test Results ..................................................... 3-2
Single Manual Tests ................................................................................. 4-1
4.1
Transmitting ....................................................................................... 4-1
4.2
Receiving ........................................................................................... 4-2
4.3
Insertion Loss Measurement .............................................................. 4-3
4.4
Near End Cross Talk (NEXT) Measurement ...................................... 4-4
4.5
Longitudinal Balance Measurement ................................................... 4-5
4.6
Return Loss Measurement ................................................................. 4-6
4.7
Impedance Measurement................................................................... 4-7
4.8
Wideband Noise Measurement .......................................................... 4-8
4.9
Spectrum Analyzer ............................................................................. 4-9
4.10 Impulse Noise Measurement............................................................ 4-10
4.11 Load Coil Detection .......................................................................... 4-12
Automatic Tests ....................................................................................... 5-1
5.1
Mode Selection................................................................................... 5-1
5.2
Pair identification, service telephone.................................................. 5-1
5.3
System Selection ............................................................................... 5-2
5.4
Preparing the Measurement ............................................................... 5-4
5.5
Checking of system and cable parameters ........................................ 5-5
5.6
Running the Program ......................................................................... 5-6
5.7
Test Results ....................................................................................... 5-7
TDR measurements ................................................................................. 6-1
6.1
Principles of Operation ....................................................................... 6-1
6.2
Settings before Measurement ............................................................ 6-2
6.3
Running a Test ................................................................................... 6-2
6.4
Waveform Evaluation ......................................................................... 6-3
6.5
Propagation Velocity .......................................................................... 6-4
6.6
TDR application guide ........................................................................ 6-6
6.6.1
General Hints ............................................................................. 6-6
i
6.6.2
Typical Waveforms .................................................................... 6-6
Micro Interruption Measurement (SW option) ....................................... 7-1
7.1
Principles of Operation ....................................................................... 7-1
7.2
Settings at the transmitter end ........................................................... 7-2
7.3
Settings at the receiver end ............................................................... 7-3
7.4
Measuring process ............................................................................. 7-4
7.5
Storage of test results ........................................................................ 7-7
8
Group Delay Distortion Measurement (SW option) ............................... 8-1
8.1
Introduction ........................................................................................ 8-1
8.2
Operating instructions ........................................................................ 8-1
8.2.1
Settings at the transmitter end ................................................... 8-1
8.2.2
Settings at the receiver end ....................................................... 8-1
9
AC/DC Bridge (Built in panel option)...................................................... 9-1
9.1
Principles of Bridge Tests .................................................................. 9-1
9.2
Cable Parameter Measurements ....................................................... 9-2
9.2.1
Voltage Measurement ................................................................ 9-2
9.2.2
Insulation Resistance Measurement .......................................... 9-3
9.2.3
Loop Resistance Measurement ................................................. 9-6
9.2.4
Resistance 2 Wire & Ground Measurement .............................. 9-8
9.2.5
Search For Short Or Strap ......................................................... 9-9
9.2.6
Resistance Difference Measurement ......................................... 9-9
9.2.7
Mutual Capacitance Measurement .......................................... 9-10
9.2.8
Capacitive Unbalance Measurement ....................................... 9-11
9.2.9
Cable Temperature Measurement ........................................... 9-12
9.3
Fault Location Methods .................................................................... 9-13
9.3.1
MURRAY Method ..................................................................... 9-14
9.3.2
KÜPFMÜLLER Method ............................................................ 9-15
9.3.3
Break Location ......................................................................... 9-16
9.3.4
Break Without Leakage............................................................ 9-16
9.3.5
Break With Leakage................................................................. 9-17
10
Digital Multimeter (Built in panel option) ......................................... 10-1
10.1 Voltage Measurements .................................................................... 10-1
10.2 Insulation Resistance Measurement ................................................ 10-2
10.3 Loop Resistance Measurement ....................................................... 10-4
10.4 Current measurement ...................................................................... 10-5
10.5 Mutual capacitance measurement ................................................... 10-5
11
Battery Manager ................................................................................. 11-1
11.1 Battery Capacity Indication .............................................................. 11-1
11.2 Normal charging ............................................................................... 11-1
11.3 Fast charging ................................................................................... 11-1
11.4 Regenerating charge process .......................................................... 11-2
7
ii
11.5 Initial charging .................................................................................. 11-2
12
Settings, Status. ................................................................................. 12-1
12.1 Settings ............................................................................................ 12-1
12.2 Status & options ............................................................................... 12-2
13
Calibration .......................................................................................... 13-1
14
PC programs ....................................................................................... 14-1
14.1 Software Upgrade.(EL2u.exe) .......................................................... 14-1
14.2 Data Transfer program option (ELQ2c.exe) ..................................... 14-1
14.3 Parameter Set Editor option (ELQ2e.exe) ........................................ 14-1
14.4 Demo Program (ELQ 2d.exe) ........................................................... 14-1
14.5 PC Control Mode .............................................................................. 14-1
15
Specifications ..................................................................................... 15-1
15.1 General specifications ...................................................................... 15-1
15.2 Single Manual Tests ......................................................................... 15-2
15.3 Automatic Measurements................................................................. 15-7
15.4 TDR measurements ......................................................................... 15-8
15.5 Micro Interruption Measurement (SW option) .................................. 15-9
15.6 Group delay distortion measurement (SW option) ......................... 15-10
15.7 AC/DC Bridge (Built in panel option) .............................................. 15-11
15.8 Digital Multimeter (Built in panel option) ......................................... 15-12
16
Ordering Information ............................ Fehler! Textmarke nicht definiert.
16.1 Basic Setup ..................................... Fehler! Textmarke nicht definiert.
16.2 Options ............................................ Fehler! Textmarke nicht definiert.
iii
ELQ 2+
1
1.1
1.1 The Use of This Manual
INTRODUCTION
The Use of This Manual
This Operating Manual is intended to help the user in operating the
ELQ 2+ explaining the operation rules. While following the instructions as
given below, it is recommended to use the demo program found on the
CD inside the back cover of this manual. Running the demo under
WINDOWS will show you the front panel of the instrument with display
and keyboard. By clicking with the mouse on the keyboard, the “virtual”
ELQ 2+ will behave as the real instrument, helping the user to carry out
complete measuring procedures, but of course only “virtually”.
1.2
Application
Numerous Digital Subscriber Line systems (xDSL) appeared on the market to fulfill the need of faster data transfer for fast Internet access, remote LAN access and interactive multimedia etc. The “x” in xDSL indicates the different kinds of subscriber line technologies using the conventional copper local loops for fast data transfer. The xDSL modems using
higher frequencies can achieve higher data rate than the plain old telephone services (POTS) on the same cable pairs. The main benefit of
xDSL is that, there is no cable installation cost. The maximal loop length
and the achievable maximal data rate depend on the cable quality.
Before the installation of xDSL modems we must be sure that the
quality of the cable pair is sufficient for the given system.
ELQ 2+Line Qualifier provides:
Measurement of all analogue parameters required for ADSL2+, ADSL2,
ADSL, READSL, ADSL G.LITE, HDSL, SHDSL, ISDN etc. subscriber line
qualification.
• Automatic test-programs producing immediate PASS/FAIL indication and detailed test results in graphic and numeric forms.
• Automatic achievable bit rate calculation for each xDSL system
• Program editor to create user programs with user defined system
and cable parameters.
• PC interface for data transfer.
• Cable fault location with TDR
• Basic cable tests (with DMM option).
• Basic cable tests and fault location (with Bridge option)
1-1
ELQ 2+
2
2.1 Measuring Modes
MAIN FEATURES
2.1
Measuring Modes
The measuring modes of ELQ 2+can be included into four groups:
• Single tests
• TDR tests
• Automatic tests
• DMM or Bridge tests (option)
Single Tests
The transmitted signal of DSL modem may suffer from impairments due
to noises and the frequency dependence of principal characteristics. The
data transfer capability of subscriber line depends on:
• Insertion loss
• Unbalance about the earth (LCL)
• Return loss
• Characteristic impedance
• Near-end cross talk
• Wideband noise
• Noise spectrum
• Impulse noise
• Micro interruption measurement (optional)
In this test group ELQ 2+provides single manual measurements of these
cable characteristics.
(Details in chapter 4 Single Manual Tests 4-1 and Annex.)
TDR measurements
•
•
•
•
•
Test of a single pair (short, break, tap etc.)
Location of cross talk point (NEXT)
Comparison of two pairs
Comparison with memory
Long time measurement
(Details in chapter 6 TDR measurements 6-1)
2-1
2.1 Measuring Modes
ELQ 2
Automatic Tests
In this test group ELQ 2+ provides automatic bi-directional measurement
of principal characteristics of the subscriber line using two instruments.
They are connected to the ends of the tested pair in MASTER-SLAVE arrangement. The two instruments communicate over the tested pairs.
• The Master initializes the measurements and collects the results.
• The Slave performs the measurements according to the Master’s
commands and sends back the results.
ELQ 2+ can be programmed as MASTER and SLAVE as well.
For SLAVE function a simplified version is available (ELQ 2S)
Numerous short and long standard programs are available containing preprogrammed system parameters and cable parameter limits.
User defined parameter sets can be easily created with the PARAMETER
SET EDITOR.
(Details in chapter 5 Automatic Tests 5-1)
Measurements with the AC/DC Bridge option
• Loop resistance
• Resistance difference
• Insulation resistance
• Cable capacitance
• Cable temperature
• Disturbing AC and DC voltages
• Leakage location
• Break location
(Details in chapter 9 AC/DC Bridge (Built in panel option) 9-1)
Measurements with the DMM option
In this test group ELQ 2+provides five basic measurements:
• Loop resistance (RL)
• Insulation resistance (F)
• DC voltage (U)
• DC current (I)
• Mutual capacitance(C)
(Details in chapter 10 Digital Multimeter (Built in panel option) 10-1)
2-2
ELQ 2+
2.1 Measuring Modes
Power Sources
ELQ 2+can be supplied from rechargeable internal NiMH batteries, which
can be charged from 12V car batteries or mains using external AC adapter. The instrument is equipped with a processor controlled battery manager system providing:
• Battery charging level indication
• Initial charging mode
• Normal charging mode
• Fast charging mode
• Regenerating mode
• Protection against deep discharging
(Details in chapter 11 Battery Manager 11-1)
2-3
2.2 Keyboard and LEDs
2.2
ELQ 2+
Keyboard and LEDs
?
MAINS
1
ABC
2
DEF
3
GHI
4
JKL
5
MNO
6
PQRS
7
TUV
8
WXYZ
9
CHARGE
MEAS
--
0
ELQ 2+
REMOTE
ENTER
F1
F2
xDSL LINE QUALIFIER
F3
F4
F5
ELQ 2+
ESC
F6
ELEKTR
START
STOP
NIKA
microphone
Controls
Switches the ELQ 2+on and off. The instrument has an automatic switch-off feature to save battery life: switch-off takes
place automatically 10 minutes after the latest keystroke. (see
chapter 8.)
F1

The function of the six Function keys depends on the actual measuring mode.
F6
Starts or stops the selected measurement,
program or process.
This key is intended to acknowledge a selected measurement
mode or a new parameter, or to carry out other changes.
2-4
ELQ 2+
2.2 Keyboard and LEDs
These keys are intended to select the required measuring
mode or to change a parameter.
These keys are intended to select the required option and to
adjust the position of vertical line cursor.
By this key negative sign or decimal point can be added to a
number
This key can be used to cancel something.
This key is intended to call the help function.
This key can be used for LCD contrast adjustment.
This key can be used for the control of back light.
This key enters '0'.
This key enters '1'.
This key enters '2' or A B C letters when required.
2-5
2.2 Keyboard and LEDs
This key enters '3' or D E F letters when required.
This key enters '4' or G H I letters when required.
This key enters '5' or J K L letters when required.
This key enters '6' or M N O letters when required.
This key enters '7' or P Q R S letters when required.
This key enters '8' or T U V letters when required.
This key enters '9' or W X Y Z letters when required.
LEDs
Mains indicator
Charge indicator
Measurement indicator
Remote control indicator
2-6
ELQ 2+
ELQ 2+
2.3
2.3 Connectors & Measuring Cables
Connectors & Measuring Cables
1
Speaker
2
TDR balance
3
3 pole CF socket for Line1 connection
4
3 pole CF socket for Line2 connection
5
9 way D connector for connecting a PC (V.24/RS232C)
6
2.1/5.5 mm coaxial connector for mains or 12V car adapter
Connector L1
This connector is used for AUTOMATIC and SINGLE measurements.
In case of automatic End-to-end measurements the two instruments
(Master and Slave) communicate via Line L1. This line is used for service
telephone connection and pair detection too.
Connector L 2
This connector is used for DMM or BRIDGE measurements, and the
connection of the second pair at AUTOMATIC mode.
Measuring Cables
For the connection of the tested pair (pairs) two cables are provided with
a 3pole plug on the first end and colored banana plugs on the other end.
The colors of banana plugs:
• Wire A → A terminal RED
• Wire B → B terminal GREEN
• Earth
→ E terminal BLACK
2-7
2.3 Connectors & Measuring Cables
ELQ 2+
The way of connection depends on the selected measurement mode.
• In bridge modes a simple diagram is displayed, instructing the user
how to connect ELQ 2+ to the cable. If applicable, the diagram
shows the necessity of a strap on the far end of the cable and/or
the grounding of the E terminal.
Warning: the instrument must not be grounded unless specifically required by the displayed connection diagram!
• In other test modes the cable connecting information appears when
the ? key is pressed.
Note: at LCL measurement the E terminal should be grounded.
2-8
ELQ 2+
3
3.1
3.1 Start up and general rules
OPERATING INSTRUCTIONS
Start up and general rules
• Switch the instrument on.
• First the opening display appears showing the name and e-mail
address of the manufacturer ELEKTRONIKA.
• After the percentage of the BATTERY LEVEL will be shown.
• 2 seconds later, self-test indication and the MAIN MENU appears.
The user should now either start the self-calibration program by pressing
the CAL (F6) key or skip it. The choice depends on the accuracy requirement. Normally, no further self-calibration is required if the environmental conditions since the previous self-calibration are unchanged. This
is allowed because the ELQ 2+is a very stable instrument storing the selfcalibration results. Note, however, that the specified accuracy can be
guaranteed only after self-calibration.
(Details in chapter 13 Calibration 13-1)
Basically, the user should follow the instructions appearing at the
bottom of each display in all measurement modes!
• In most cases, the measuring, setting and editing modes are selected by the menu-driven operation system. For selection use the
vertical cursor keys and then press ENTER.
• The various cable and test parameters can be selected with the
function keys: F1 to F6. To facilitate and speed up operation, some
of the measuring modes can be selected directly with them too.
• To return back to the previous display, press ESC.
Measurements can be started or stopped with the START/STOP key.
3-1
3.2 Saving and Recall of the Test Results
3.2
ELQ 2+
Saving and Recall of Test Results
When a test is completed the result can be saved in each measuring
mode under a user given object name. There are four identifiers of each
stored results:
• OBJECT (user given name)
• DATE (automatically added)
• TIME (automatically added)
• MODE (automatically added)
The automatically added identifiers are very comfortable for the user, as
the time is different for each test result, the same object name can be
used repeatedly.
Note: The name of operator should be given in before starting a measurement. Enter SETTINGS/OPERATOR`S NAME and type the name in
as it is usual at mobile phones. A text or a character can be deleted by the
left cursor. A space can be placed by the right cursor. For the user’s comfort test results are stored in groups according to the measuring modes:
• AUTOMATIC TESTS
• SINGLE TESTS
• TDR TEST RESULTS
• DMM or BRIDGE TEST RESULTS
Saving of test results:
Having the test finished:
• Press the SAVE (F1) key
• Type an object name and press ENTER
Recall of test results.
• Enter the MAIN MENU/STORED RESULTS option
• Enter the required group
• Select the required result and press ENTER
Deleting a test result
• Enter the MAIN MENU/STORED RESULTS option
• Enter the required group
• Select the result to be deleted and press DELETE (F4)
• If you are sure press ENTER
Deleting a complete group of test result
• Enter the MAIN MENU/STORED RESULTS option
• Enter the group to be deleted and press EMPTY (F2)
If you are sure press ENTER twice
3-2
ELQ 2+
4
4.1 Transmitting
SINGLE MANUAL TESTS
To call a manual measurement, enter the SINGLE TESTS option of MAIN
MENU. Having the ENTER key pressed the following display appears:
4.1
Transmitting
Frequency range: 200 Hz to 2.2 MHz
Output impedances:
• 10kHz to 2.2 MHz
• 200Hz to 10kHz
100, 120, 135, 150 Ohm
600 Ohm
Two transmitting modes are provided:
• 1 FR (generation of one single frequency)
• 10 FR (generation of 10 frequencies at the same time)
Output level range:
• In 1 FR mode:0 to −24 dBm in 0.1 dB steps
• In 10 FR mode the output level is fixed
−6 dBm / frequency
−12 dBm / frequency
for Z =100, 120, 135, 150 Ohm
for Z = 600 Ohm
Test Procedure
• Enter SINGLE TESTS/TRANSMITTING mode.
1 FR mode settings:
• Press the FREQ (F5) key and enter the required frequency
• Press the Z (F4) key and enter the required impedance
• Press the LEVEL (F1) key and enter the required output level.
4-1
4.2 Receiving
ELQ 2+
10 FR mode settings:
• Press the 10 FR (F6) key.
• Press the ←FR→ (F5) key and enter the required frequency range
• Press the Z (F4) key and enter the required impedance.
The output can be enabled or disabled with the START/STOP key.
4.2
Receiving
In this mode ELQ 2+can be used as a selective level meter with auto
ranging.
Frequency range: 200 Hz to 2.2 MHz
Input impedances:
• 10 kHz to 2.2 MHz
100, 120, 135, 150 Ohm
• 200 Hz to 10 kHz 600 Ohm
• 200 Hz to 2.2 MHz
20 kOhm  50 pF
Two measuring modes are provided:
• 1 FR (measurement on one single frequency)
• 10 FR (measurement on 10 frequencies at the same time)
Test Procedure
• Enter SINGLE TESTS/RECEIVING mode
• Pressing the HIGH/Z (F3) key select the required line termination.
Note:
For the proper dBm calculation the nominal line impedance (Z) should be
given even if HIGH input impedance is set.
1 FR mode settings:
• Press the FREQ (F5) and enter the required frequency.
• Press the Z (F4) key and enter the required impedance.
10 FR mode settings:
• Press the 10 FR (F6) key.
• Press the ←FR→ (F5) key and enter the required frequency range.
• Press the Z (F4) key and enter the required impedance
The measurement can be started or interrupted by the START/STOP key
Test Results
Test results are available both in graphic and numeric forms
• In 1 FR mode they are displayed together
• In 10 FR mode the result is displayed first in graphic form but
pressing the LIST (F2) key it appears in numeric form as well.
4-2
ELQ 2+
4.3
4.3 Insertion Loss Measurement
Insertion Loss Measurement
ELQ 2+ can be used as a generator and a tracking selective receiver by
transmitting on L1 and receiving on L2.
Impedances:
• 10 kHz to 2.2 MHz
100, 120, 135, 150 Ohm
• 200 Hz to 10 kHz 600 Ohm
Two measuring modes are provided:
• FIX FR. (Transmitting and receiving on one single frequency)
• SWEEP (Sweeping on a selected frequency range)
The number of test frequencies in sweep mode:
• 200 Hz to 4 kHz range (with 10 HZ RESOLUTION option) 380
• In other sweep ranges
50
Test Procedure
• Enter SINGLE TESTS/INSERTION LOSS mode
Fix frequency mode settings:
• Press the FREQ (F5) and enter the required frequency.
• Press the Z (F4) key and enter the required line impedance
Sweep mode settings:
• Press the SWEEP (F6) key.
• Press the ←FR→ (F5) key and enter the required frequency range
• Press the Z (F4) key and enter the required line impedance.
The measurement can be started or stopped by the START/STOP key
Test Results
Test results are available both in graphic and numeric forms.
• In FIX FR. mode they are displayed together
• In SWEEP mode the result is displayed first in graphic form but
pressing the LIST (F2) key it appears in numeric form as well.
Note for the 10 HZ RESOLUTION option:
In the 200Hz to 4 kHz sweep range the basic resolution of graphic display
is 20 Hz. To change the horizontal resolution to 10 Hz around the cursor,
press the ZOOM (F3) key.
4-3
4.4 Near End Cross Talk (NEXT) Measurement
4.4
ELQ 2+
Near End Cross Talk (NEXT) Measurement
Near-end cross talk (NEXT) is a major impairment for systems that share
the same frequency band for upstream and downstream transmission.
The most serious problem of two pair HDSL and primary rate ISDN systems is the noise caused by near-end cross talk between the pairs.
NEXT can be tested by transmitting on L1 and receiving on L2.
ELQ 2+ calculates the NEXT value as the ratio of transmitted and received powers. The higher the NEXT the better the cross talk.
In case the NEXT is out of limit it is very likely that the reason is split. The
location of cross talk point can be found by TDR.
(Details in chapter TDR Tests)
Two measuring modes are provided:
• FIX FR. (Transmitting and receiving on one single frequency)
• SWEEP (Sweeping over a selected frequency range)
Test Procedure
• Enter SINGLE TESTS/NEXT mode
Fix frequency mode settings:
• Press the FREQ (F5) and enter the required frequency.
• Press the Z (F4) key and enter the required line impedance
Sweep mode settings:
• Press the SWEEP (F6) key.
• Press the ←FR→ (F5) key and enter the required frequency range
• Press the Z (F4) key and enter the required line impedance.
The measurement can be started or stopped by the START/STOP key
Test Results
Test results are available both in graphic and numeric forms
• In FIX FR mode they are displayed together
• In SWEEP mode the result is displayed first in graphic form but
pressing the LIST (F2) key it appears in numeric form as well.
4-4
ELQ 2+
4.5 Longitudinal Balance Measurement
Note for the 10 HZ RESOLUTION option:
In the 200Hz to 4 kHz sweep range the basic resolution of graphic display
is 20 Hz. To change the horizontal resolution to 10 Hz around the cursor,
press the ZOOM (F3) key.
4.5
Longitudinal Balance Measurement
Longitudinal currents can cause noises on the line if the balance is imperfect. Longitudinal balance ratio (LCL) reflects the ability of line to suppress
the effects of longitudinal currents. (ITU-T Rec. 0.9). ELQ 2+provides LCL
measurement using the test circuit recommended by ITU-T.
LCL=20 log U1/U2 dB
The better the balance of a cable pair the higher is LCL in dB.
Two measuring modes are provided:
• FIX FR. (Transmitting and receiving on one single frequency)
• SWEEP (Selected frequency range with 50 frequencies)
Frequency range: 200 Hz to 2.2 MHz
Impedances:
• 10 kHz to 2.2 MHz………………100, 120, 135, 150 Ohm
• 200 Hz to 10 kHz………………..600 Ohm
Test Procedure
• Enter SINGLE TESTS/BALANCE mode
Fix frequency mode settings:
• Press the FREQ (F5) key and enter the required frequency
• Press the Z (F4) key and enter the required line impedance
Sweep mode settings:
• Select sweep mode by pressing the SWEEP (F6) key.
• Press the ←FR→ (F5) key and enter the required frequency range.
• Press the Z (F4) key and enter the required line impedance
The measurement can be started or stopped by the START/STOP key.
4-5
4.6 Return Loss Measurement
ELQ 2+
Test Results
Test results are available both in graphic and numeric forms
• In FIX FR. mode they are displayed together
• In SWEEP mode the result is displayed first in graphic form but
pressing the LIST (F2) key it appears in numeric form as well.
4.6
Return Loss Measurement
Return loss factor indicates the deviation of line impedance from the nominal value. ELQ 2+ performs a bridge measurement comparing the line
impedance to an internal Rn normal resistor.
Frequency range: 200 Hz to 2.2 MHz
Available normal resistors:
• 10 kHz to 2.2 MHz………...100, 120, 135, 150 Ohm
• 200 Hz to 10 kHz………….600 Ohm
The return loss factor:
The closer the impedance of cable pair to the nominal value (Rn) the
higher is the return loss in dB.
Two measuring modes are provided:
• FIX FR. (Transmitting and receiving on one single frequency)
• SWEEP (Selected frequency range with 50 frequencies)
Test Procedure
• Enter SINGLE TESTS/RETURN LOSS mode
Fix frequency mode settings:
• Press the FREQ (F5) key and enter the required frequency
• Press the Z (F4) key and enter the required line impedance
Sweep mode settings:
• Select sweep mode by pressing the SWEEP (F6) key
• Press the ←FR→ (F5) key and enter the required frequency range
• Press the Z (F4) key and enter the required line impedance
The measurement can be started or stopped by the START/STOP key.
4-6
ELQ 2+
4.7 Impedance Measurement
Test Results
Test results are available both in graphic and numeric forms.
• In FIX FR. mode they are displayed together
• In SWEEP mode the result is displayed first in graphic form but
pressing the LIST (F2) key it appears in numeric form as well.
4.7
Impedance Measurement
In this mode the line impedance can be measured.
Frequency range: 200 Hz to 2.2 MHz
For the sake of better display resolution there are two measuring ranges:
• 400 Ohm range for the test of lines with a nominal impedance of
100, 120, 135 or 150 Ohm. (Test frequency ≥10 kHz).
• 1600 Ohm range for test objects with a nominal impedance of
600 Ohm (Test frequency <10 kHz.)
Two measuring modes are provided:
• FIX FR. (Transmitting and receiving on one single frequency)
• SWEEP (Selected frequency range with 50 frequencies)
The impedance measuring range automatically changes from 400 Ohm to
1600 Ohm if:
• In fix frequency mode f <10kHz is entered or
• In sweep mode the 5 or 10kHz range is selected.
Test Procedure
• Enter SINGLE TESTS/IMPEDANCE mode
Fix frequency mode settings:
• Press the FREQ (F5) key and enter the required frequency
Sweep mode settings:
• Select sweep mode by pressing the SWEEP (F6) key
• Press the ←FR→ (F5) key and enter the required frequency range
To return to fix frequency mode press the FIX FR. key.
The measurement can be started or interrupted by the START/STOP key.
Test Results
Test results are available both in graphic and numeric forms.
• In FIX FR. mode they are displayed together
• In SWEEP mode the result is displayed first in graphic form but
pressing the LIST (F2) key it appears in numeric form as well.
4-7
4.8 Wideband Noise Measurement
4.8
ELQ 2+
Wideband Noise Measurement
Noises reduce the data transfer capability of subscriber lines. The transmitted signal suffers from impairments due to noises. Noise on the telephone line normally occurs because of improper balance, cross talk and
bad splices. The wideband noise can be characterized by power level
(RMS value) and frequency spectrum. The received noise signal is
named wideband noise when its peaks don’t exceed the RMS value more
than 12 dB (UPEAK < 4 URMS)
Noise level measurement should be made using weighting filters specified
in ITU-T recommendations. ELQ 2+provides the following filters:
• P ................................................................................... For POTS
• 1010 Hz Notch (with 10 HZ RESOLUTION option) ..... For VOICE
• E Filter ................................................................... For ISDN BRA
• G2-E Filter .................................................. For ISDN PRA HDB3
• F-E Filter ............................................... For HDSL, 2 PAIR, 2B1Q
• F1-E Filter ............................................. For HDSL, 1 PAIR, 2B1Q
• G Filter ................................................................. For ADSL, DMT
• 3dB at fmin and fmax Filter ................................. For auto modes
The proper measurement time depends on the nature of noise. In case of
a quasi stationer noise 1 to 5 sec is enough. If the noise level is slowly
changing, a longer measurement time provides the proper test result.
Frequency spectrum gives useful information to find the origin of noise.
ELQ 2+ provides the following special noise spectrum analyzer mode:
• Frequency range
....................................... 10 kHz to 2.2 MHz
• Frequency step .................................................................. 10 kHz
• Band width
................................................................... 15 kHz
As the bandwidth is larger than the frequency step no disturbing signal
can remain hidden.
Test Procedure
• Enter SINGLE TESTS/WIDEBAND NOISE mode
Noise level measurement:
• Press the TIME (F2) key and enter the required measurement time
• Press the FILTER (F5) key and enter the required filter option
(The line impedance is automatically set with the filter)
• Press the HIGH/Z (F3) key and select the required termination
• When the NONE filter option is selected press the Z (F4) key and
enter the required line impedance
The measurement can be started or stopped by the START/STOP key
4-8
ELQ 2+
4.9 Spectrum Analyzer
Test results
The test results are available both in numeric and graphic forms.
Noise spectrum measurement
Test Procedure
• To see the frequency spectrum press the SPECTR (F6) key
• Press the INPUT (F3) key and enter the required line termination
• Press the Z (F4) key and enter the required line impedance
• Press the MODE (F5) key and enter the required evaluation mode.
The bandwidth is higher than the frequency step so none of the noise
components can remain hidden.
Three evaluation modes are provided:
• NORM. Measurement of the actual value of input signal
• PEAK Measurement of the peak value of input signal
• AVG Measurement of the average value of input signal
Measuring results
ELQ 2+ performs a sequence of repeated measurements.
Test results are available both in graphic and numeric forms, the default is graphic but pressing the LIST (F2) key the display changes to
numeric form.
4.9
Spectrum Analyzer
In this mode ELQ 2+can be used as a spectrum analyzer with the following receiver bandwidths:
Frequency range
Bandwidth
Zoom OFF
Zoom ON
10 to 2200 kHz
10 kHz
5 kHz
2.5 to 500 kHz
2.5 kHz
1.25 kHz
1 to 200 kHz
1 kHz
0.5 kHz
0.2 to 20 kHz
100 Hz
50 Hz
0.2 to 4 kHz***
20 Hz
10 Hz
****With 10 HZ RESOLUTION option
4-9
4.10 Impulse Noise Measurement
ELQ 2+
Test Procedure
Enter SINGLE TESTS/SPECTRUM ANALIZER mode
• Press the ←FR→ (F5) key and enter the required frequency range
• Press the INPUT (F3) key select the required line termination
• Press the Z (F4) key and enter the required line impedance
Note: For the proper dBm calculation the nominal line impedance (Z)
should be given even if HIGH input impedance is set.
The measurement can be started or interrupted by the START/STOP key.
Three evaluation modes are provided:
• NORM. Measurement of the actual value of input signal
• PEAK Measurement of the peak value of input signal
• AVG Measurement of the average value of input signal
Settings when the measurement is running
• Press the MODE (F4) key select and enter the required evaluation
mode
• Press the F3 key to selected dBm or dBm/Hz evaluation
• Press the ZOOM (F6) key select and enter the required zoom value
Test results
The test results are displayed first in graphic form during the measurement. To get numeric form:
• Interrupt the measurement by the STAR/STOP key,
• Press the LIST (F2) key and the result appears in numeric form.
4.10
Impulse Noise Measurement
Impulse noise is a non-stationary cross talk from electromagnetic events
in the vicinity of phone lines. Examples of impulse noise generators are
as diverse as the opening of refrigerator door (the motor turns on/off),
control voltages to elevators (phone lines in apartment buildings often run
through the elevator shaft) and ringing of phones on lines sharing the
same binder.
Any burst of noise that produces a voltage exceeding the power level of
the background noise by more than 12dB is declared impulse noise.
In impulse noise-measuring mode ELQ 2+ operates as an impulse counter. An impulse is counted when the received noise signal exceeds a preset threshold for more than 500 ns.(The recommended threshold setting
is 14 dB above the measured wideband noise level.)
4-10
ELQ 2+
4.10 Impulse Noise Measurement
Test Procedure
• Enter SINGLE TESTS/IMPULSE NOISE mode
• Pressing the HIGH/Z (F3) key select the required line termination
• Press the Z (F4) key and enter the required line impedance
• Press the TRESH (F5) key and enter the required threshold level
• Press the TIME (F2) key and enter the required measurement time
• Start counting by the START/STOP key
Note: For the proper dBm calculation the nominal line impedance (Z)
should be given even if HIGH input impedance is set.
•
4-11
4.11 Load Coil Detection
ELQ 2+
4.11 Load Coil Detection
It used to be a common practice to install load coils on long local loops.
Load coils with cable capacitances form a low-pass filter improving the
frequency response in the pass-band 0 to 4kHz.
Over 4kHz the load coils cause high attenuation spoiling the frequency
range of xDSL systems therefore all the coils must be removed.
The presence of load coils can be detected by impedance measurement.
Load coils make the monotone impedance characteristics waving in the
voice frequency band.
Test Procedure
• Enter SINGLE TESTS/LOAD COIL DETECTION mode
• Be sure that the other end of the tested pair is open
• Start measurement pressing the START/STOP key
• Wait until the test is completed and the test result appears
Test Results
• NO LOAD COIL DETECTED indication appears if the impedance
characteristic is monotone.
• LOAD COIL DETECTED indication appears if the impedance
characteristic is waving.
4-12
ELQ 2+
5
5.1 Mode Selection
AUTOMATIC TESTS
Test Procedure
5.1 Mode Selection
In automatic tests two instruments are used connected to the ends of the
tested pair (pairs).
Warning! The instruments must be fitted with the same software. (Software version 4.40 or greater.)
On switching on the instrument, the software version number is visible on
the screen for about 2 seconds: "SOFTWARE VERSION: X.XX"
The instruments may be shipped with a software version number lower
than the required, in these cases the instruments must be upgraded from
the supplied CD.
One of them should be programmed to MASTER, the other one to
SLAVE mode. Mode selection is in the MAIN MENU.
5.2
Pair identification, service telephone.
Pair identification
SLAVE end.
Enter the SLAVE mode and connect the pair to be tested. While waiting for the master’s commands the slave ELQ 2+ transmits a 400 Hz
tone on the L1 connector for acoustic pair identification.
MASTER end.
Enter the MASTER mode and connect the pair to be tested to the L1
connector. To be sure that the proper line is connected switch the
acoustic indication on by pressing the TONE (F6) key on the MASTER
MODE MENU display. The 400 Hz tone indicates the proper connection. (The tone generation can be switched on and off from the master
side by remote control using the ON (F3) or OFF (F4) key.)
Service telephone mode
ELQ 2+ is equipped with built-in microphone and loudspeaker providing
half duplex telephone connection between the two ends of the line.
The service telephone mode can be reached from MAIN MENU or from
the MASTER MODE MENU by pressing the TEL (F5) key.
• The TEL (F5) key switches the loudspeaker on and ELQ 2+ is waiting for a call from the other end of the line.
• To send a ringing tone, press the RING (F4) key.
• The user can talk when the MIC (F6) key is pressed.
(Then the microphone is active and the speaker is disabled)
5-1
5.3 System Selection
5.3
ELQ 2+
System Selection
ELQ 2+ measures the analogue parameters of the line to be used for a
specified xDSL system. The system and cable parameters, test frequency
range, the tolerances and the test method depend on the specified system. As the parameters of the used systems are very different the system
should be defined before measurement. During the automatic test sequence ELQ 2+ measures the analog parameters of the line and evaluates the test result according to the requirements of the defined system.
In the MASTER MODE MENU the xDSL systems are included into
groups:
• STANDARD SYSTEMS containing the system and cable parameters of the most popular standard xDSL systems.
• USER DEFINED SYSTEMS containing the non-standard system
and cable parameters, which may be created according to the requirements of a new system or can be a modified version of a
standard system. PARAMETER SET EDITOR is provided for creating or modifying a user defined system.
In addition an automatic SYSTEM INDEPENDENT measuring mode is
provided for trouble shooting
The required system can be selected in two steps:
• System Group selection at the MASTER MENU (Fig. 5.1)
• System and data rate selection (Fig 5.2 and 5.3)
Fig. 5.1 (Select by ↑↓ and press ENTER)
5-2
ELQ 2+
5.3 System Selection
Fig. 5.2 illustrates the selection of ITU-T G.991.2 SHDSL systems.
Fig. 5.2
• Select the data rate by ↑↓ keys.
• Press ENTER
Fig. 5.3 illustrates the selection of ITU-T G.992.5 ADSL2+ systems.
Fig. 5.3
• Select system and data rate with ↑↓ and function keys.
• Press ENTER
5-3
5.4 Preparing the Measurement
ELQ 2+
Note: ITU-T G.992.5 Annex J and M allows the use of more upstream
carriers for the sake of higher data rate. The number of upstream carriers
can be changed with the RATE ↑ key.
Having the data rate and the system selected the AUTOMATIC TEST
PROGRAM display appears. (Fig 5.4)
Fig. 5.4
This display (as in case of all such programs) offers three automatic test
options:
• SHORT test (loss and noise)
• LONG test (all the principal characteristics)
• DISCRETE test (one measurement selected by the user
5.4
Preparing the Measurement
To prepare the automatic test the user has to select:
• One of the three automatic test options pressing the
DISCR. (F1), SHORT (F2) or LONG (F3) key.
• When the tested line is for an ADSL system the place of master
ELQ 2+ should be declared by using the MASTER (F5) key.
5-4
ELQ 2+
5.5
5.5 Checking of system and cable parameters
Checking of system and cable parameters
Before running the test program the system and cable parameters of the
selected system can be studied.
Pressing the PARAM (F6) key the table of SYSTEM PARAMETERS will
be shown.
Fig 5.5 illustrates the main parameters of an 8/1 MBPS ADSL2+ D FDD
system working parallel with an ADSL OVER POTS
Fig. 5.5
• n (min) the multiplier of ∆f subcarrier spacing, determining the lowest tone, of downstream and upstream
• min kHz the lower frequency limit of downstream and upstream
band
• n (max) the multiplier of ∆f subcarrier spacing, determining the
highest tone of downstream and upstream
• max kHz the higher frequency limit of downstream and upstream
band
• RATES kbit/sec the specified data rate (payload) in downstream
and upstream band
• NOISE MARGIN the margin, which will be used to the calculation of
the attainable data rate on the actually measured line
• MAX BITLOAD determined by the used ADSL system
• CODING GAIN when trellis coding is used
• Z LINE the nominal impedance of the line.
5-5
5.6 Running the Program
ELQ 2+
The CABLE PARAMETERS according to the above-mentioned standard
are listed on the next page (See Fig. 5.6), which can be called in by
pressing the PAGE ↑ key. In this table the parameters of the standard
test loop are given, which determines the template used as limit to the
pass/fail decision.
Fig. 5.6
5.6
Running the Program
After selecting the test options the program can be started or aborted by
the START/STOP key. Before starting or restarting the program be sure
that the SLAVE: READY indication is on.
Important note: Before starting the program be sure that the Master
and Slave instruments have the same software version !
5-6
ELQ 2+
5.7
5.7 Test Results
Test Results
Short Form Test Result
When the test program is completed a SHORT FORM TEST RESULT
page appears with immediate PASS/FAIL information and with the list of
detailed result pages.
The reasons of fail indication are marked by asterisks. (See Fig. 5.7)
Fig. 5.7
Detailed Result Pages
• Use the cursor keys to select the required result page
• Press ENTER (To return press ESC).
Selecting for example the marked CABLE LOSS result the display shown
on the Fig. 5.8 appears. On this display the loss/frequency diagram and
the template for pass/fail decision is shown. Moving the cursor line by the
vertical arrow keys, the loss and frequency values belonging to the cursor
position are displayed.
5-7
5.7 Test Results
ELQ 2+
Fig. 5.8
Pressing the LIST (F2) key a table appears with the measured data
Fig. 5.9
5-8
ELQ 2+
5.7 Test Results
Storage of test results
Test results can be saved under the name of the test object when the
SHORT FORM TEST RESULT page is displayed.
• Press the SAVE (F1) key and type in the identifier of the object
• Press ENTER (Date, time and operator’s name is automatically
added)
Recall of Stored Results
The stored results can be recalled from the MAIN MENU.
Enter the STORED RESULTS option, and select one of the result groups
by the cursor as it is shown on the display.
5-9
ELQ 2+
6
6.1
6.1 Principles of Operation
TDR MEASUREMENTS
Principles of Operation
ELQ 2+ in Time Domain Reflectometer (TDR) mode utilizes the radar
principle. A measuring pulse is transmitted down a cable. When that
pulse reaches the end of the cable or a fault along the cable, a certain
part or all the pulse energy is reflected back to the instrument.
ELQ 2+ measures the time taken by the pulse to travel down the cable,
see the problem, and reflect back. Than converts this time to distance
and displays the information as a waveform.
The displayed waveform shows all impedance discontinuities along the
cable.
The amplitude of any reflection is determined by the degree of the impedance change.
Distance to fault is displayed on the screen after the cursor is positioned
to the start of the reflected fault pulse
Measuring Modes
Investigation of a single pair (L 1 or L 2)
Transmission and reception of pulses takes place over the same terminal
(L1 or L2). ELQ 2+ performs a sequence of repeated measurements. The
last result is graphically displayed and the previous ones are cleared.
(The most frequently used basic mode of operation)
Long time measurement of a single pair (L1 LT or L2 LT)
This measuring mode can be used to locate lose contacts. ELQ 2+ performs a sequence of repeated measurements in this mode as well but the
results are not cleared. All the results are displayed together. If the features of the tested pair change during the measurement the waveform
becomes thick at the place of change.
Location of cross talk points (XTALK)
The measuring pulse is transmitted via L1, and the reflected pulses are
received via L2. This mode is typically used for locating splits.
Comparison between two pairs (L1&L2)
Two traces are simultaneously displayed. Even faultless pairs may produce reflections caused by joints or other inherent discontinuities. Comparing the faulty pair to a faultless one, reflections from faults and the
regular reflections can be separated.
6-1
6.2 Settings before Measurement
ELQ 2+
Comparison with memory (L1&M, L1-M)
L1&M. The actual trace and a stored one are displayed together.
L1-M The difference between them is displayed.
A waveform stored in memory can be used for comparison of cable conditions before and after a critical period or a repair job.
6.2
Settings before Measurement
Mode selection
• Enter TDR TESTS MENU and select the required measuring mode
• Press ENTER
Measuring range selection
• Press the RANGE (F5) key and select the measuring range covering the length of cable.
• Press ENTER
Velocity constant (V/2) setting
• Press the F6 key and enter a new value or modify the actual one.
• Press ENTER
Automatic calculation is provided.
(For more details see chapter 6.5 Propagation Velocity 6-4)
6.3
Running a Test
Start
• Connect the cable to the appropriate terminals.
• Start the test by the START/STOP key and obtain a waveform.
Balance adjustment
• Adjust the rotary BALANCE control to minimize the transmit pulse
(In XTALK mode the balance control is not effective.)
Gain adjustment
• To obtain suitable reflected pulse amplitude the gain should be
• Increased until compensates the cable attenuation. Press the
• GAIN (F2) key and set the suitable gain.
• Press ENTER
6-2
ELQ 2+
6.4 Waveform Evaluation
Setting the pulse width
The pulse width is automatically changed with measuring range. In case
of high cable attenuation, better reading may sometimes be obtained by
using wider pulse. Therefore 3 pulse widths are provided for each range.
• Press the PULSE (F3) key and select the best pulse width.
• Press ENTER.
6.4
Waveform Evaluation
Reading distance to fault
After the measurement process is completed, move the vertical line cursor by the ← → keys to the start point of the reflected pulse.
The displayed value of the cursor shows the distance to fault. Remember
to deduct the length of the test leads.
Trace expansion (ZOOM)
The trace can be shown in more detail around the cursor line by using the
ZOOM facility. The amount of horizontal expansion can be selected as
follows:
• Set the vertical cursor line to the critical point of waveform by
the ← → keys.
• Press the ZOOM (F4) key and select the best zoom
• Press ENTER
Use of marker
The marker appears as a vertical dotted line and can be placed to any selected point of the waveform. Displayed are: the position of marker and
the cursor, further the true distance from marker to cursor.
6-3
6.5 Propagation Velocity
ELQ 2+
To measure the distance between any two points, the marker should be
used as follows:
• Move the cursor to the waveform from which the distance is to be
measured (e.g. reflection from a known point or from the change of
the cable type), and set the marker by pressing ENTER.
• Move the cursor to the waveform to which the distance measurement is to be carried out.
The distance between these points is directly shown by the display.
6.5
Propagation Velocity
Propagation Velocity Units
ELQ 2+ calculates the distance to cable problem using the total travel
time and the Propagation Velocity (V) of waves in the tested cable type.
V depends on insulating material, size, etc.
The following units are regularly used to characterize a cable:
• Propagation Velocity
(V)
• Half Propagation Velocity (V/2 )
• Propagation Velocity Factor ( PVF )
By definition, the PVF is the propagation velocity of electromagnetic
waves in the cable, divided by the velocity of light in free space.
The following table gives typical values for some insulating materials:
INSULATION
6-4
V
µs
TYPICAL
V/2
PVF
µs
PVC
160
80
0.53
POLYETHILENE
192
96
0.64
JELLY FILLED
200
100
0.67
PAPER (50nF/km)
216
108
0.72
PAPER (45nF/km)
264
132
0.88
LIGHT IN SPACE
300
150
1
ELQ 2+
6.5 Propagation Velocity
The change of propagation velocity unit
• Press the F6 key
• Press the required unit key: F3 or F4
• Press ENTER
Setting the propagation velocity constant of cable.
• Press the F6 key
• Type in the new value or press the RECALL (F2) key and select
your cable from Cable Library
• Press ENTER
If the propagation velocity constant is not known ELQ 2+ provides automatic calculation methods to obtain it.
Automatic velocity constant calculation
The unknown constant can be determined in the following cases:
• The length of the cable is known
• The distance to a known point is available (e.g. join box, change of
cable-type etc.)
• A sample of the same cable is available with a known length
• The distance between two points is known.
When the cable length or the distance to a known point is available
• Connect the cable to the L1 terminals and obtain a waveform
• Place the cursor to the start point of the pulse reflected from the
known point.
• Press the F6 key
• Press the CURSOR (F5) key
• Type in the known distance
• Pressing the ENTER key, the proper value will be set automatically
When the distance between two points is known
• Connect the cable to the L1 sockets and obtain a waveform
• Place the cursor to the starting point of the pulse reflected from the
first known point, and set the marker by pressing ENTER
• Place the cursor to the starting point of the pulse reflected from the
second known point
• Press the F6 key
• Press the CUR-MAR (F6) key
• Type in the known distance between the two points.
• By pressing the ENTER key, the proper value will be set automatically.
6-5
6.6 TDR application guide
6.6
6.6.1
ELQ 2+
TDR application guide
General Hints
Reflections can be classified to fall into two groups:
• Regular reflections
• Reflections from faults (irregular reflections)
Regular reflections
Even faultless pairs may produce reflections caused by inherent discontinuities such as joints or cable type changes.
Reflections from faults
A faulty pair produces regular reflections and, in addition, reflections from
the fault. Because of the attenuation losses, the reflection from a fault
long way down the cable may be much smaller than a regular reflection
from a nearby discontinuity.
A suitable method to distinguish regular and irregular reflections is to
compare the faulty cable with a good one. By using the L1&L2 method,
the regular reflections caused by the common features of the two pairs
can be separated from reflections caused by faults.
• In telephone cables there are several pairs of conductors. The
physical length of the pairs depends on their position in the cable,
the length increasing with the distance of the layer from the center.
Consequently, the physical length of pairs can be longer than the
cable length, and the propagation velocity (V) may be different for
different layers. Therefore, in case of comparative tests, the two
pairs compared should be in the same layer.
• If there is more than one fault, the first one may reflect so much
from the pulse energy that the subsequent fault may not be seen.
Therefore, having located and eliminated the first fault, the cable
section following the fault should be tested again.
6.6.2
Typical Waveforms
Open circuit (series faults)
The reflection is a positive (upward going) pulse. No reflected pulse from
the far end.
6-6
ELQ 2+
6.6 TDR application guide
Short circuit (shunt fault)
The reflection is a negative (downward going) pulse. No reflected pulse
from the far end.
Change of cable type (mismatch)
The amplitudes of the reflected pulses are determined by the degree of
impedance changes.
Joints (splices)
The joints produce ‘S’ shaped reflections.
6-7
6.6 TDR application guide
ELQ 2+
Taps (tee joints)
A tap produces two pulses, one at the beginning and the other at the end
of the tap.
The troubleshooting may be difficult if the tested pair is tapped at many
points. In this case, moving from tap to tap the test should be progressively done
Splits and resplits
Splits and resplits produce cross talk.
Loading coils
Loading coils produce positive (upward going) reflections. Generally,
TDR’s cannot ‘see’ beyond the first loading coil. For fault location beyond
the loading coil, the ETDR 10 should be connected to another point following the coil.
6-8
ELQ 2+
6.6 TDR application guide
Capacitance network
The reflection is negative (downward going pulse).
Wet section
The presence of water causes a capacitance increase. Therefore, there
are two pulses: one from the beginning, the other from the end of the wet
section.
Open sheath
If the metallic sheath of the cable is broken, the position of the break can
be located by connecting the test leads to the shield and to as many conductors as possible.
6-9
6.6 TDR application guide
ELQ 2+
Lose Contacts
The location of lose contacts can be found with Long Time test.
If the features of the tested pair change during the measurement the
waveform becomes thick at the place of change.
6-10
ELQ 2+
7
7.1
7.1 Principles of Operation
MICRO INTERRUPTION MEASUREMENT (SW OPTION)
Principles of Operation
A micro interruption is a temporary line interruption due to external mechanical action on the copper wires constituting the transmission path, for
example, at a cable splice. Splices can be hand-made wire-to-wire junctions, and during cable life oxidation phenomena and mechanical vibrations can induce micro interruptions at these critical points.
The effect of a micro interruption on the transmission system can be a
failure of the digital transmission link. In the presence of an interruption of
specified maximum length the xDSL modem may reset.
ELQ 2+ Line Qualifier can be upgraded in order to measure micro interruptions. That option is a very useful tool for troubleshooting.
ELQ 2+ detects the micro interruptions according to the ITU O.62 recommendation using 2 kHz test tone. An interruption is detected when the
level of the received test tone drops below a designated threshold for
more than 0.3 ms.
The detected interruptions are divided into five categories by duration:
• 0.3 ms to 3 ms
• 3ms to 30 ms
• 30 ms to 300 ms
• 300 ms to 1min
• >1min
The threshold level is adjustable in steps to the values 3, 6, 10 and 20 dB
below the normal test signal level. The measuring time is adjustable between 4 min and 72 hours.
ELQ 2+provides detailed information about
• Number of interruptions divided into five categories.
• Relative duration of interruptions.
• Error seconds.
• Time distribution of interruptions in 240 time slots.
For the interruption measurement two ELQ 2+ s are necessary connected
to the ends of the tested pair. One of them transmits a test tone the other
one receives and evaluates it.
The measurement can be performed even if the test tone must be over
the frequency range of basic rate ISDN (50 kHz). In this case the measuring frequency is 82 kHz.
7-1
7.2 Settings at the transmitter end
7.2
ELQ 2+
Settings at the transmitter end
To save the battery life ELQ 2+ has a power down facility switching the
instrument off after a preset time. Therefore in case long time interruption
measurement ELQ 2+should be used with mains adapter. If it is not possible then the power off function should be disabled before starting a long
time test like interruption
Disablement of power down function
• Enter the SETTINGS & OPERATOR mode
• Enter the POWER OFF TIME function
• Enter the OFF option
Measuring mode selection
Enter the SINGLE TESTS / TRANSMITTING mode and when the
TRANSMITTING display appears set the frequency, level and output impedance.
7-2
ELQ 2+
7.3 Setting at the receiver end
Test tone frequency setting
Press the FREQ. (F5) key and enter 2 or 82 kHz
Output impedance for 2 kHz
In case 2 kHz test frequency 600 Ohm output impedance is set automatically.
Output impedance for 82 kHz
Press the Z (F4) key and select 100 Ohm output impedance by the vertical cursors and press ENTER.
Output level setting
Press the LEVEL (F1) key and set the needed level and press ENTER.
Having the settings finished start the transmitting by pressing the
START/STOP key.
7.3
Settings at the receiver end
Measuring mode selection
Enter the SINGLE TESTS / MICRO INTERRUPTION mode and when the
MICRO INTERRUPTION display appears set the time, frequency and
threshold level.
Measuring time setting
Press the TIME (F4) key and select the required measuring time by the
vertical cursors and press ENTER.
7-3
7.4 Measuring process
ELQ 2+
Test tone frequency setting
Press the FREQ (F6) key and select the required test frequency by the
vertical cursors and press ENTER. The input impedance is automatically
set with the frequency. (600 Ohm for 2 kHz and 100 Ohm for 82 kHz)
Threshold level setting
Press the THRESH (F5) key and select the required threshold level by the
vertical cursors and press ENTER. (20 dB only for 2 kHz test tone)
Having the settings finished start the measurement by pressing the
START/STOP key.
7.4
Measuring process
The measuring process consists of two parts.
• First when the measurement is started ELQ 2+ measures the level
of the received test tone and stores that value as REFERENCE
LEVEL of the measurement.
• Having the REFERENCE LEVEL stored ELQ 2+ starts to count interruptions.
The following picture is displayed during and after the measurement
keeping the user informed about the actual count of interruptions and the
measuring time left:
7-4
ELQ 2+
7.4 Measuring process
When the measurement is ready the user can get immediate information
about the:
• Number of interruptions divided into five categories.
• Relative duration of interruptions.
• Error seconds.
In addition ELQ 2+ provides detailed information about the time distribution of interruptions. The measuring time is divided into 240 time slots.
Number of interruptions in a time slot
Pressing the GRAPH (F3) key the number of interruptions appears in
graphic form. The displayed picture shows the time distribution for a selected category as a vertical bar graph.
• To see the count of interruptions in a given time slot, use the horizontal cursors.
• To see the count of interruptions in numeric form, press the LIST
(F2) key. The appearing list shows the count for each category and
time slots together.
• To change the category, press the CAT (F4) key select the required category with the vertical cursors and press ENTER
7-5
7.4 Measuring process
ELQ 2+
To return press GRAPH (F2)
Relative duration of interruptions in a time slot
Pressing the DUR (F3) key the test relative duration of interruptions appears in graphic form. The displayed picture shows the time distribution
as a vertical bar graph.
• To see the relative duration in a given time slot, use the horizontal
cursors.
• To see the relative duration of interruptions in numeric form, press
the LIST (F2) key.
7-6
ELQ 2+
7.5 Storage of test results
To return press GRAPH (F2)
7.5 Storage of test results
The measuring results can be stored by pressing the SAVE (F1) key
when the short form test result picture is displayed. For the sake of economical utilization of memory the resolution of stored results depends on
the count of interruptions as it is shown in the next table:
Count range ........................................................................................ Resolution
0 to 15 ................................................................................................. 1
15 to 20 ................................................................................................. 5
20 to 150 .............................................................................................. 10
150 to 200 .............................................................................................. 50
200 to 1500 .......................................................................................... 100
1500 to 2000 .......................................................................................... 500
2000 to 15000 ...................................................................................... 1000
7-7
ELQ 2+
8
8.1 Introduction
GROUP DELAY DISTORTION MEASUREMENT (SW OPTION)
8.1
Introduction
ELQ 2+ applies the multi tone test method described in the recommendation ITU-T O.81 Appendix I (Earlier CCITT Blue Book Fascicle IV.4 Supplement No. 3.7)
Since 1981, instruments using multitone test signals have been used by
various Administrations all over the world.
Measurement results are obtained quickly and unambigously and are
compatible with those obtained with conventional methods.
The user needs two ELQ 2+ instruments (Transmitter and receiver) for
the group delay distortion measurement.
The group delay distortion measuring software SW 370-570-000 includes
the serial number of the instrument to be upgraded with it.
When ordering that software to upgrade your ELQ 2 set please inform us
about the serial number of the two instruments.
The upgrade software will be supplied in CD form. The CD contains all
the necessary instructions for the upgrade process.
8.2
Operating instructions
The group delay distortion measurement can be managed by two ELQ 2+
instruments connected to the ends of the tested pair. One of them transmits a test tone the other one receives and evaluates it.
8.2.1
Settings at the transmitter end
• Connect the tested line to the L1 socket
• Enter SINGLE TESTS/GROUP DELAY DISTORTION mode
• Select the transmitter function by pressing the F2 key.
Pressing F2, the impedance is set to 600 Ohm and the transmitter is
switched on automatically.
8.2.2 Settings at the receiver end
• Connect the tested line to the L1 socket
• Enter SINGLE TESTS/GROUP DELAY DISTORTION mode
• Select the receiver function by pressing the F5 key.
8-1
8.2 Operating instructions
ELQ 2+
Pressing F5, the impedance is set to 600 Ohm and the following display
appears:
Test process
ELQ 2DT measures the loss and group delay distortion simultaneously.
To start the measurement, press the START/STOP key.
Test Results
Test results are available both in graphic and numeric forms. The results
are displayed first in graphic form.
• Pressing the LIST L (F2) the result of loss measurement appears
in numeric form
• Pressing the LIST G (F3) the result of group delay distortion measurement appears in numeric form
The test results can be saved by pressing the SAVE (F1) key.
8-2
ELQ 2+
9
9.1 Principles of Bridge Tests
AC/DC BRIDGE (BUILT IN PANEL OPTION)
All test results can be saved. In order to save your test results do following:
• Having completed the measurement press the SAVE (F1) key
• Give in an identifier for the test results
• Press the ENTER key
In the menu system you can navigate to the saved results on the
MAIN MENU / STORED RESULTS / BRIDGE RESULTS way. The results can also be uploaded to a PC.
9.1
Principles of Bridge Tests
ELQ 2+ in bridge mode is much more than a classical Wheatstone bridge:
it is rather a special measuring network allowing flexible and versatile applications which would practically be impossible with conventional measuring bridges. This is explained by the fact that in the case of conventional
measuring bridges, a single DC or AC generator is used for driving the
network under test, and a single voltmeter is used to measure the network response to this driving signal. On the other hand, the structure of
the ELQ 2+ allows the DC or AC driving signal to be applied at three junctions, even simultaneously, and to measure, even simultaneously by two
meters, the currents in two suitably selected network branches.
The fault location methods of the ELQ 2+ can be applied in place of several well-known classical measurement methods. The equivalent methods
are summarized in the following Table.
Fault location method of a classical bridge
Equivalent fault location
method of the ELQ 2
Murray‘s method and Varley‘s method
Murray‘s method
Hector‘s method and Küpfmüller‘s method
Küpfmüller‘s method
9-1
9.2 Cable Parameter Measurements
9.2
9.2.1
ELQ 2+
Cable Parameter Measurements
Voltage Measurement
The purpose of the test is to measure DC and AC voltages between the
two wires of a pair and between the pair and the ground.
Test Procedure
• Enter BRIDGE TESTS/VOLTAGE mode
Entering the VOLTAGE mode the measurement starts automatically. ELQ 2+ measures continuously until stopping the measurement
by pressing the START/STOP key.
• Connect the cable wires to the ELQ 2+ as shown on the display.
• The test results can be stored by pressing the SAVE (F1) key only
after having stopped the measurement.
Definitions
• Differential mode voltage: AC and DC Voltage (Vab=Va0-Vb0)
measured between the two wires of the pair.
• Common mode voltage: AC and DC Voltage (Vcom=(Va0+Vb0)/2)
measured between the pair and ground.
Test Results
• Vab differential mode DC voltage measured directly between both
wires
• Va0, Vb0 DC voltages between each wire and the ground calculated
from the differential mode and common mode DC voltages
• Vab differential mode AC voltage measured directly between both
wires
• Va0, Vb0 approximate values of the AC voltages between each wire
and the ground calculated from the differential mode and common
mode AC voltages
• Vcom AC part of the common mode voltage
• MAX. Vcom maximum value of the Vcom AC common mode voltage
NOTE: The measurement will be periodically repeated every few seconds
and the result display accordingly refreshed as long as the START/STOP
key is again depressed.
If you want to measure the longitudinal voltages induced by traction power
in a wire pair (Va0, Vb0 ), then first you should connect both wires’ far ends
to the ground.
9-2
ELQ 2+
9.2.2
9.2 Cable Parameter Measurements
Insulation Resistance Measurement
ELQ 2+ provides the measurement of insulation resistance between the
two wires of a pair and between any of the wires and the ground. The
measured insulation resistances are defined as follows:
Rins = Fab || ( Fa0 + Fb0 )
RAE = Fa0 || ( Fab + Fb0 )
RBE = Fb0 || ( Fab + Fa0 )
Fab, Fa0, Fb0 are the so-called physical resistances. Regarding insulation
resistances a pair of wires is like a delta connection of these physical resistors:
Between the wires a and b attached to the connectors A and B you can
measure the insulation resistance Rins i.e. the total resistance between
the points A and B of the delta.
Test procedure
• Enter BRIDGE TESTS / INSULATION RESISTANCE mode
• Connect the wires to be measured and the shield of the cable to
the ELQ 2+ as shown on the display.
• The far ends of the two wires under test are NOT to be shorted during the measurement!
• Start the measurement by pressing the START/STOP key.
• Before the whole measuring procedure and after measuring any individual parameter (Rins, RAE, RBE) the cable will be discharged automatically. The end of the discharging process always has to be
awaited i.e. during discharging the keys (except for the green ones)
are inactive.
• You can stop the measuring procedure by pressing the
START/STOP key.
9-3
9.2 Cable Parameter Measurements
ELQ 2+
• If you do not want to wait for the end of the measurement, you can
jump to the measurement of the next insulation resistance immediately by pressing the ENTER key. In this case the displayed partial
result will be kept as the result of the measurement. An “E” will appear indicating that the measurement of that parameter was accelerated by ENTER. The ELQ 2+ will start the discharging procedure
and then the measuring of the next resistance. If there was no partial result yet, neither a result nor an “E” will appear.
WARNING!
If you force the ELQ 2+ to end the measurement immediately by
pressing ENTER, the measured resistance value can be inaccurate. The accuracy given in the specification is only guaranteed if
you wait until the measurement is fully completed without pressing
the ENTER key.
• The discharging procedures CANNOT be interrupted or skipped by
pressing the START/STOP or the ENTER key!
Test results
• Insulation resistance Rins between the two wires of the pair,
• Insulation resistance RAE between wire a and the ground (shield),
• Insulation resistance RBE between wire b and the ground (shield).
Calculation of GOhm/km values if the cable length is known:
• Press the LENGTH (F5) key
• Enter the known length.
9-4
ELQ 2+
9.2 Cable Parameter Measurements
Instructions for use of filter EFF 51
Using the filter EFF 51 in most cases it is possible to measure insulation
resistances even if there is a longitudinal voltage present in the cable. The
EFF 51 has to be plugged into connector L2, the pair of wires and the
shield of the cable (ground) has to be attached to EFF 51. EFF 51 is a
passive filter also containing serial resistors. These resistors can decrease the accuracy of the measurement. In order to eliminate the effect
of these resistors on the accuracy the user should switch on/off the filter
mode manually by pressing the FILTER (F3) key. I.e. if you measure insulation resistances using EFF 51 then you should switch the filter on: in
this case ELQ 2+ will display “THE FILTER EFF 51 IS ON” and the test
results will be corrected automatically. If you measure without the EFF 51,
you should switch the filter off (“THE FILTER EFF 51 IS OFF”), so the
correction does not happen. Below the test results ELQ 2+ will tell you if
the filter was switched on during the measurement.
NOTE
During the insulation resistance measurement NO wire may be attached
to the L1 connector or else the accuracy of the results will be degraded.
The filter EFF 51 may be used in the insulation resistance mode only.
9-5
9.2 Cable Parameter Measurements
9.2.3
ELQ 2+
Loop Resistance Measurement
Purpose of the test is to measure the loop resistance.
IMPORTANT NOTE
If your test leads have relative high resistances, i.e. the serial resistances
of the test leads have a considerable effect on the result of the measurement, then it is recommended to do the “Bridge Cal. Of Test Leads” before the measurement. If you use the test leads ELQ 2+ had been
shipped with, then in most cases you need not do this calibration. To do
the calibration press the CAL (F6) key in the MAIN MENU and select
BRIDGE CAL OF TEST LEADS in the appearing submenu. You can
learn more about this calibration in chapter Calibration.
Test Procedure
• Enter BRIDGE TESTS /LOOP RESISTANCE mode
• Connect the two wires under test to ELQ 2+ as shown on the display
• During this measurement the far ends of the two wires under test
must be strapped (i.e. shorted)!
• Start measurement pressing the START/STOP key.
Measured Test Results
• Loop resistance RL
Calculation of cable length
For the correct calculation of the cable length (i.e. DTS = Distance To
Strap) from the measured loop resistance (RL) first the user should enter
the temperature of the cable and the cable type:
• To enter the temperature of the cable press the TEMP.(F3) key,
type in the temperature value and press ENTER.
• To enter the cable type either press the CABLE (F4) key, use the
vertical arrow keys to select a cable and press ENTER, or press
the LIBRARY (F6) key and recall a cable from the Cable Library. If
there is no suitable cable in the list, then you can define a new cable in the Cable Library among the User-Defined Cu-Cables.
Note: the Multi-Section Cable cannot be used for calculation of
length in this measurement!
9-6
ELQ 2+
9.2 Cable Parameter Measurements
Calculation of the cable parameters if the cable length is known
• Press the LENGTH (F5) key
• Enter the known cable length and press ENTER
• Now the calculated cable parameters appear on the display i.e.
∅-value (=gauge), m/Ω-value and Ω/m-value
• If the calculated ∅-value is inside the range 0.29 – 1.40 mm, then
the device thinks it for sensible so you can store it in the Cable Library:
∗ Press the STO CAB (F2) key
∗ Select a free place for the new cable using the vertical arrow
keys. If you select an occupied place, the old cable will be
overwritten.
∗ Press the STO CAB (F1) key to store the cable (or press
ESC to cancel the operation). If the selected place has already been occupied, the device asks you for confirmation
before it overwrites the old ∅-, m/Ω- and Ω/m-values. Press
the YES (F1) key to confirm the action or the NO (F3) key to
cancel operation.
∗ A cable cannot be stored without a name. To enter a name
(type) for the cable press the TYPE (F2) key, enter the name
and press ENTER.
∗ If you know the wave velocity in the cable you can enter it
pressing the F6 key, typing in the value and pressing
ENTER.
∗ Press ENTER to accept the new cable.
∗
Press the ESC key to return to the measurement.
9-7
9.2 Cable Parameter Measurements
9.2.4
ELQ 2+
Resistance 2 Wire & Ground Measurement
Purpose of the test is to measure both wire resistances of the pair and the
resistance of the shield (ground) simultaneously.
IMPORTANT NOTE
If your test leads have relative high resistances, i.e. the serial resistances
of the test leads have a considerable effect on the result of the measurement, then it is recommended to do the “Bridge Cal. Of Test Leads” before the measurement. If you use the test leads ELQ 2+ had been
shipped with, then in most cases you need not do this calibration. To do
the calibration press the CAL (F6) key in the MAIN MENU and select
BRIDGE CAL OF TEST LEADS in the appearing submenu. You can
learn more about this calibration in chapter Calibration.
Test Procedure
• Enter BRIDGE TESTS / RESISTANCE 2WIRE&GROUND mode
• Connect the two wires and the shield of the cable to ELQ 2+ as
shown on the display
• During this measurement the far ends of the two wires must be
strapped (i.e. shorted) and connected to the cable’s shield
(ground)!
• Start measurement pressing the START/STOP key.
Measured Test Results
• Wire resistances Ra, Rb
• Resistance of the shield (ground) R0
Calculation of each wire’s length
For the correct calculation of lengths (i.e. La, Lb) from the measured wire
resistances first the user should enter the temperature of the cable and
the cable type:
• To enter the temperature of the cable press the TEMP.(F3) key,
type in the temperature value and press ENTER.
• To enter the cable type either press the CABLE (F4) key, use the
vertical arrow keys to select a cable and press ENTER, or press
the LIBRARY (F6) key and recall a cable from the Cable Library. If
there is no suitable cable in the list, then you can define a new cable in the Cable Library among the User-Defined Cu-Cables.
Note: the Multi-Section Cable cannot be used for calculation of
lengths in this measurement!
9-8
ELQ 2+
9.2.5
9.2 Cable Parameter Measurements
Search For Short Or Strap
Purpose of the test is to find the pair of wires that has a strap or is shorted
(perhaps at its far end). It is a simple resistance measurement between
two points.
Test Procedure
• Enter BRIDGE TESTS / SEARCH FOR SHORT OR STRAP mode
• Connect the two wires of the pair to ELQ 2+ as shown on the display
• You need not start this measurement and need not stop it either. It
will be running until you exit it by the ESC key.
• If the resistance measured between the two points is smaller than
about 10 kOhm, then you will hear a continuous buzzing sound.
• If you cannot find the short or strap, then try measuring the next
pair of wires etc.
• In order to exit the measurement press the ESC key.
9.2.6
Resistance Difference Measurement
The purpose of the test is to measure the difference between the resistances of the two wires of a pair. The measurement is realised as a
Murray-measurement.
IMPORTANT NOTE
If the difference to be measured is too small, i.e. the serial resistance of
the test leads have a considerable effect on the result of the measurement, then it is recommended to do the Bridge Cal. Of Test Leads before
the measurement. Even if you use the test leads that ELQ 2+ had been
shipped with, you may have to do this calibration. To do the calibration
press the CAL (F6) key in the MAIN MENU and select BRIDGE CAL OF
TEST LEADS in the appearing submenu. You can learn more about this
calibration in chapter Calibration.
Test procedure
• Enter BRIDGE TESTS/RESISTANCE DIFFERENCE mode
• Connect the two wires and the shield of the cable to ELQ 2+ as
shown on the display
• During this measurement the far ends of the two wires must be
strapped (i.e. shorted) and connected to the cable’s shield
(ground)!
• Start measurement pressing the START/STOP key.
9-9
9.2 Cable Parameter Measurements
ELQ 2+
Test Results
• Ra+Rb loop resistance
• Ra–Rb approximate value of the resistance difference
NOTE
This is calculated from the measured Lx/L value and the loop resistance. The Lx/L value has an accuracy of up to three decimal
digits. So if you want to measure the small difference of high resistances, Ra–Rb can be inaccurate. That is why we say approximate value.
• Lx/L: The measurement is realized as a Murray-measurement. The
strap to the ground at the far end plays the role of the leakage. Lx/L
has the same meaning as at the Murray-method fault location
measurement.
• the resistance difference referring to the average wire resistance
displayed in percent:
2•
Ra − Rb Ra − Rb Ra − Rb
=
=
RS
Ra + Rb Ra + Rb
2
2
WARNING!
If any of the two wires has a leakage (i.e. the insulation resistance between wire and ground is less than about 1000 times the value of the loop
resistance), then this measurement can be inaccurate!
9.2.7
Mutual Capacitance Measurement
The purpose of the test is to measure the mutual capacitance of a pair of
wires.
Test procedure
• Enter BRIDGE TESTS/MUTUAL CAPACITANCE mode
• Connect the cable wires to the ELQ 2+ as shown on the display.
• During this measurement the far ends of the wires under test must
not be shorted (strapped)!
• Start measurement pressing the START/STOP key.
9-10
ELQ 2+
9.2 Cable Parameter Measurements
Test Results
• Cm calculated mutual capacitance:
Cm = Cab +
Ca 0 • Cb 0
Ca 0 + Cb 0
• Cab capacitance between both wires and its loss angle tanδ.
• Ca0 capacitance between wire a and ground and its loss angle tanδ
• Cb0 capacitance between wire b and ground and its loss angle tanδ
Calculation of nF/km value if the total cable length is known:
• Press the LENGTH (F5) key.
• Enter the known length.
Calculation of cable length if nF/km value is known:
• Press the nF/km (F4) key
• Enter the known nF/km.
9.2.8
Capacitive Unbalance Measurement
The purpose of the test is to measure the capacitive unbalance of a pair
of wires. The measurement is realised as a “Break Without Leakage”measurement.
Test procedure
• Enter BRIDGE TESTS/CAPACITIVE UNBALANCE mode
• Connect the cable wires to the ELQ 2+ as shown on the display.
• During this measurement the far ends of the wires under test
MUST NOT be shorted (strapped)!
• Start measurement pressing the START/STOP key.
Test Results
• Lx/L has the same meaning as at the measurement “Break Without Leakage”, the unbalance will be calculated from this measured
value
• the difference of the two capacitances (measured between wire a
and the ground / wire b and the ground) referring to the average
wire to ground capacitance displayed in percent:
2•
Ca 0 − Cb 0 Ca 0 − Cb 0
=
Ca 0 + Cb 0 Ca 0 + Cb 0
2
9-11
9.2 Cable Parameter Measurements
9.2.9
ELQ 2+
Cable Temperature Measurement
The purpose of the test is to measure the temperature of a cable.
Test Procedure
• Enter BRIDGE TESTS/CABLE TEMPERATURE mode.
• Plug the thermometer probe (supplied as an option) into ELQ 2+ as
shown on the display and put the probe near the cable.
• Wait a few minutes until the surface temperature of the probe
reaches the cable temperature and start the measurement pressing the START/STOP key.
Test Results
• Cable Temperature T
ELQ 2+ is able to measure temperature within –20 Celsius and
+60 Celsius.
The measured temperature can be stored by pressing the →TEMP (F3)
key i.e. the temperature field of the subsequent loop resistant measurement or fault location measurement will be updated to this value.
9-12
ELQ 2+
9.3 Fault Location Methods
9.3 Fault Location Methods
The ELQ 2+ offers two methods for finding the location of leakage, which
is due to the decreased insulation resistance between the wire and the
shield.
• The first is the well-known Murray-method applicable when the
two wires of the pair have the same gauge (∅), the same length,
are made of the same material and only one of them is leaky. To
provide the specified accuracy, the good wire’s insulation resistance between wire and ground must be at least 1000 times
greater than the faulty wire’s insulation resistance between wire
and ground.
• The second method is an improved version of the well-known
Küpfmüller’s method. This method is applicable when the two
wires of the pair have the same gauge (∅), the same length, are
made of the same material and both wires are leaky. The leakage
resistances do not need to be higher than the loop resistance, but
the insulation resistance between the two wires has to be at least
100 times the measured Rx resistance. (Explanation of Rx sea below)
In order to get the correct location of the fault (i.e. DTF Distance To Fault)
and to get the correct cable length (i.e. DTS Distance To Strap) based on
the measured resistances, after the measurement the user should enter
the actual temperature and parameters of the cable under test:
• To enter the temperature of the cable press the TEMP.(F3) key,
type in the temperature value and press ENTER.
• To enter the cable type either press the CABLE (F4) key, use the
vertical arrow keys to select a cable and press ENTER, or press
the LIBRARY (F6) key and recall a cable from the Cable Library. If
there is no suitable cable in the list, then you can define a new cable in the Cable Library among the User-Defined Cu-Cables.
Note: the Multi-Section Cable can also be used for calculation of
DTF, DTS at the fault location measurements!
When the total length of a cable, i.e. the distance from the near end to the
strap at the far end, is known (e.g. from a cable layout plan), the user can
invert the calculation system of the ELQ 2+. This means that the user, instead of selecting the cable type and reading out the DTS, can enter the
length of the cable, and the ELQ 2+ then calculates the DTF based only
on the measured Lx/L value. This method of fault location provides improved accuracy.
9-13
9.3 Fault Location Methods
ELQ 2+
To enter the cable length, do the following after the measurement:
• Press the LENGTH (F5) key.
• Type in the cable length and press ENTER.
• Now the calculated new DTF value appears on the display.
• If you want to enter a new cable length (correction), press the
LENGTH (F5) key and enter the new value. You can repeat this as
many times as you want to.
• If you want to return to the calculation system based on the measured resistances and selected cable type, press the CABLE (F4)
key, select the cable type and press ENTER.
NOTE
If your test leads have relative high resistances, i.e. the serial resistance
of the test leads have a considerable effect on the result of the measurement, then it is recommended to do the Bridge Cal. Of Test Leads before
the measurement. If you use the test leads ELQ 2+ had been shipped
with, then you need not do this calibration. To do the calibration press the
CAL (F6) key in the MAIN MENU and select BRIDGE CAL OF TEST
LEADS in the appearing submenu. You can learn more about this calibration in chapter Calibration.
9.3.1
MURRAY Method
The purpose of the test is to find the location of the wire-to-ground insulation fault. Note that this test is applicable when the two wires of the pair
have the same resistances and only one of them is leaky. The ratio of the
good wire insulation to the leaky wire insulation must be at least 1000.
Test procedure
• Enter BRIDGE TESTS/FAULT LOCATION/MURRAY mode.
• Connect the wires under test and the shield (ground) of the cable to
ELQ 2+ as shown on the display.
• The far ends of the two wires must be strapped (shorted) during
this measurement!
• Start measurement pressing the START/STOP key
Test Results
• Loop resistance RL
• Wire resistance Rx of the faulty wire between the fault and the
ELQ 2+
• The insulation resistance F between the faulty wire and the ground
• The relative distance Lx/L of the fault location
9-14
ELQ 2+
9.3 Fault Location Methods
Parameter needed for calculation of the fault location
• Temperature
• Cable type
You can learn from chapter Fault Location Methods how to enter these
parameters.
9.3.2
KÜPFMÜLLER Method
The purpose of the test is to find the location of the wire-to-ground insulation fault. This method is applicable when the two wires of the pair have
the same resistances and both wires are leaky. The insulation resistance
need not be higher than the loop resistance, but the insulation resistance
between the two wires (Rins) has to be at least 100 times the measured Rx
resistance.
Test procedure
This procedure requires two measurements. During the first measurement, the far endings of the pair are open. During the second measurement they are interconnected.
• Enter BRIDGE TESTS/FAULT LOCATION/KÜPFMÜLLER mode.
• Connect the wires under test and the shield (ground) of the cable to
ELQ 2+ as shown on the display.
• The far ends of the two wires must be open (must NOT be
strapped/shorted) during the first measurement!
• Start the first measurement pressing the START/STOP key.
• When the first measurement is completed the far ends of the two
wires should be strapped (shorted) as shown on the display! Short
them together.
• Start the second measurement pressing the START/STOP key.
• When the second measurement is completed the test result appears.
Test Results
• Loop resistance RL
• Wire resistance Rx of the faulty wire between the fault and the
ELQ 2+
• The insulation resistances Fa0 and Fb0 between each wire and the
ground
• The relative distance Lx/L of the fault location
Parameter needed for calculation of the fault location
• Temperature
• Cable type
9-15
9.3 Fault Location Methods
ELQ 2+
You can learn from chapter Fault Location Methods how to enter these
parameters.
9.3.3
Break Location
The procedure for finding the location of the break of a cable depends on
the number of wires broken in the pair.
If both wires of a pair are broken then the break location can be found by
measuring the capacitance of the faulty pair and of one of the faultless
(good) pairs, as detailed in chapter Mutual Capacitance Measurement. After this measurement the relative distance of the break (Lx/L) can be calculated as
Lx / L =
Cfaulty
Cgood
If only a single wire of a pair is broken then the procedure of finding the
break location depends on whether it is a simple break, i.e. a break without leakage, or a break with leakage.
9.3.4
Break Without Leakage
The purpose of the test is to find the location of the break in a single wire
of a pair.
Test procedure
• Enter BRIDGE TESTS /FAULT LOCATION/BREAK WITHOUT
LEAKAGE mode.
• Connect the two wires of the pair under test and the shield (ground)
of the cable to ELQ 2+ as shown on the display.
• The far ends of the two wires must be strapped (shorted) during
this measurement!
• Start measurement pressing the START/STOP key.
Test Results
• Lx/L relative distance of the break.
• Measured Ca0, Cb0 capacitances of the two wire parts (i.e. capacitance between wire and ground).
Calculation of distance to break when the total length is known:
• Press the LENGTH (F5) key
• Enter the known length.
9-16
ELQ 2+
9.3.5
9.3 Fault Location Methods
Break With Leakage
The purpose of the test is to find the location of the break in a single wire
of a pair when a simultaneous leakage is present.
Test procedure
• Enter BRIDGE TESTS / FAULT LOCATION / BREAK WITH
LEAKAGE mode.
• Connect the two wires of the pair under test and the shield (ground)
of the cable to ELQ 2+ as shown on the display.
• The far ends of the two wires must be strapped (shorted) during
this measurement!
• Start measurement pressing the START/STOP key.
Test Results
• Lx/L relative distance of the break.
• Measured Ca0, Cb0 capacitances of the two wire parts (i.e. capacitance between wire and ground).
• The insulation resistance Fa0 between the wire a and ground,
• The insulation resistance Fb0 between the wire b and ground.
Calculation of distance to break when the total length is known:
• Press the LENGTH (F5) key
• Enter the known length
9-17
ELQ 2+
10
10.1 Voltage Measurements
DIGITAL MULTIMETER (BUILT IN PANEL OPTION)
ELQ 2+ provides the measurements of five further important cable parameters: Voltage, Insulation resistance, Loop resistance, DC current and
Mutual capacitance. For all DMM measurements socket L2 is used.
All test results can be saved. In order to save your test results do following:
• Having completed the measurement press the SAVE (F1) key
• Give in an identifier for the test results
• Press the ENTER key
In the menu system you can navigate to the saved results on the
MAIN MENU / STORED RESULTS / DMM RESULTS way. The results
can also be uploaded to a PC.
10.1
Voltage Measurements
The purpose of the test is to measure DC voltages between the A and B
wires of a pair and between the wires and the ground (E).
Test Procedure
• Enter DMM TESTS/DC VOLTAGE mode
• Connect the cable wires to the L2 connector.
• Start measurement pressing the START/STOP key
When the test is completed the test result appears:
Test Results
• VAB measured between the two wires of the pair.
• VAE measured between the A wire and ground.
• VBE measured between the B wire and ground.
NOTE: The measurement will be periodically repeated every few seconds
and the result display accordingly refreshed as long as the START/STOP
key is again depressed.
10-1
10.2 Insulation Resistance Measurement
10.2
ELQ 2+
Insulation Resistance Measurement
In this mode ELQ 2+ measures the total insulation resistances FAB, FAE,
FBE. Resistance FAB is measured between the two wires a and b closed to
the connectors A and B of terminal L2. Resistances FAE and FBE are
measured between wire a and the shield (ground) of the cable and wire b
and the shield respectively.
The total insulation resistances are defined as follows:
FAB = WAB || ( WAE + WBE )
FAE = WAE || ( WAB + WBE )
FBE = WBE || ( WAB + WAE )
where WAB, WAE and WBE are the so-called physical resistances of the
cable model below:
Test procedure
• Enter DMM TESTS/INSULATION RESISTANCE mode
• Connect the cable wires to the L2 connector.
• The far ends of the wires must not be strapped (shorted) during this
measurement.
• Start measurement pressing the START/STOP key
• Before the whole measuring procedure and after measuring any individual parameter (FAB, FAE, FBE) the cable will be discharged automatically. The end of the discharging process always has to be
awaited i.e. during discharging the keys (except for the green ones)
are inactive.
10-2
ELQ 2+
10.2 Insulation Resistance Measurement
• If you do not want to wait for the end of the measurement, you can
jump to the measurement of the next insulation resistance immediately by pressing the ENTER key. In this case the displayed partial
result will be kept as the result of the measurement. An “E” will appear indicating that the measurement of that parameter was accelerated by ENTER. The ELQ 2+ will start the discharging procedure and
then the measuring of the next resistance. If there was no partial result yet, neither a result nor an “E” will appear.
WARNING!
If you force the ELQ 2+ to end the measurement immediately by
pressing ENTER, the measured resistance value can be inaccurate.
The accuracy given in the specification is only guaranteed if you wait
until the measurement is fully completed without pressing the
ENTER key.
When the measurement is completed, the test results appear
Test Results
• Total insulation resistance FAB between the two wires of the pair,
• Total insulation resistance FAE between the wire a and ground,
• Total insulation resistance FBE between the wire b and ground.
Information about how to measure insulation resistance:
• Every pair of wires has capacitances.
A meaningful and reliable result can be achieved only if the cable
has been properly loaded.
There can be chosen two cable length values:
- press the TSHORT (F3) key for a length of up to about 3 km
- press the TLONG (F4) key for a length of up to about 10 km
• In case of a bedewing of the device it should slowly beheated to
room temperature (in about 1-2 hours).Before the measurement
you should measure insulation resistance without having plugged
anything into the L1 and L2 terminals of the device. All measured
resistance values (FAB, FAE, FBE) must be greater than 1.1 GOhm,
or else the device has to be heated longer.
• The measurement voltage of this measurement is 6.3V.
• If you want to measure resistance values higher than about
100 MOhm or 1 GOhm and there is a high disturbing voltage present, then you should connect a 1 MOhm serial resistor to the test
lead E in order to suppress the disturbing voltage.
10-3
10.3 Loop Resistance Measurement
10.3
ELQ 2+
Loop Resistance Measurement
The purpose of the test is to measure the loop resistance of a pair and
calculate the parameters of the wire. In the loop resistance measurement
mode a strap has to be placed at the far end of the measured cable section, joining together the two wires.
Test Procedure
• Enter DMM TESTS/LOOP RESISTANCE mode
• Connect the cable wires to the L2 connector. Also, call the operator
at the far end site, and ask him to connect a strap on the two wires.
• Start measurement pressing the START/STOP key.
When the test is completed the measured loop resistance value appears
Measured Test Results
• Loop resistance RL,
Calculated Test Results
ELQ 2+ automatically calculates the following parameters of a homogeneous pair from the measured loop resistance and the temperature:
• LENGTH
• ∅ (Gauge)
• Ω/m value
• m/Ω value
Having the loop resistance measured, and any of the mentioned parameters is given, pressing the appropriate key ELQ 2 +automatically calculates the others.
10-4
ELQ 2+
10.4
10.4 Current measurement
Current measurement
The purpose of the test is to measure the DC loop current.
ATTENTION: The max. current to be measured is 150 mA. A higher current can damage the instrument!
Test Procedure
• Enter DMM TESTS/DC CURRENT mode
• Connect the cable wires to the L2 connector.
• Start measurement pressing the START/STOP key.
When the test is completed the test result appears:
Measured Test Results
• Loop current I.
NOTE: The measurement will be periodically repeated every few seconds
and the result display accordingly refreshed as long as the START/STOP
key is again depressed.
10.5
Mutual capacitance measurement
The purpose of this test is to measure the mutual capacitance of wire
pairs.
Test Procedure
• Enter DMM TESTS/MUTUAL CAPACITANCE mode
• Connect the cable wires to the L2 connector.
• Start measurement pressing the START/STOP key.
Note: During the capacitance measurement the far end of the tested pair
must be free.
When the test is completed the test result appears:
Measured Test Results
• Mutual capacitance (C)
10-5
ELQ 2+
11
11 Battery Manager
BATTERY MANAGER
Battery Charging Modes
ELQ 2+ is equipped with a processor controlled automatic chargerdischarger circuit providing the following functions:
• Battery capacity indication
Charging process control:
• Normal charging
• Fast charging
• Battery regeneration
• Battery initialization
• Protection against deep discharging
11.1
Battery Capacity Indication
The battery manager system continuously measures the battery state.
When ELQ 2+ is switched on battery information appears showing the actual state of battery in % form.
11.2
Normal charging
When the mains adapter is connected and the battery level sinks below
60% the automatic circuit starts normal charging with 0.1C (C is the nominal capacity of the built in battery)
When the full charge is reached the control system automatically stops
charging and the BATTERY LEVEL > 95 % indication appears.
The CHARGE indicator LED is lighted while the charging is in progress.
When full charge is reached, the charger is automatically switched off,
and the CHARGE indicator LED goes out.
11.3
Fast charging
When FAST CHARGING or regenerative charging is selected in the
BATTERY MANAGER MENU the battery is charged with a relatively high
current ( 0.5C) for approx. 2 to 3 hours during which the instrument can't
be used. In this mode after a short time the instrument is automatically
switched off. If temperature of the battery exceeds the environment by
o
10 C the charging is automatically finished.
The blinking of CHARGE indicator LED indicates that the process is in
progress.
When the charging is completed the charge indicator goes out, and the
instrument stays switched off.
11-1
11 Battery Manager
ELQ 2+
Switching the instrument on during the process:
• Information can be obtained about the current battery level and the
charging time left.
• The process can be aborted by pressing the ABORT (F3) key.
11.4
Regenerating charge process
In this mode the battery is discharged and fast charged. The instrument
can't be used during this process. To start regenerating process:
• Enter BATTERY MANAGER
• Select the REGENERATING option and press ENTER
In the first phase, discharging message is displayed. In the second phase,
the instrument is automatically switched off, and the charge indicator LED
is blinking.
The process can be interrupted by pressing the ABORT (F3) key.
11.5
Initial charging
The initialization is the first charging of battery. It is necessary when the
INITIAL CHARGING RECOMMENDED warning appears (The same process is required when the battery is replaced.) The process can be started by the START/STOP key
During the 2 to 3 hour process the battery state measuring system will be
calibrated. The initial process can be skipped or interrupted but in these
cases always the BATTERY LEVEL IS UNKNOWN battery charging level
indication appears when the instrument is switched on. Therefore the
skipping or interruption of the process is not recommended.
DO NOT CHARGE THE BATTERIES WHEN THE
TEMPERATURE IS BELOW +5 °C OR OVER +45 °C.
11-2
AMBIENT
ELQ 2+
12
12.1
12 Settings, Status
SETTINGS, STATUS.
Settings
In setting mode some important parameters can be set:
Date and time can be typed in by the number keys.
The name of operator can be typed in like an SMS at mobile phones.
To change the other parameters:
• Select the parameter by the vertical cursors and press ENTER.
• Change parameter by the vertical cursors and press ENTER.
Note: In SLAVE mode the power off system is not active.
12-1
12.2 Status & options
12.2
ELQ 2+
Status & options
STATUS & OPTIONS point of the MAIN MENU provides useful information:
In this mode the actual status of the instrument can be seen.
The status includes the following parameters:
• Serial number
• Calibration date
• Hardware and software ID.
In case of "Master-Slave" measurements, the version number of the
master and the slave instruments must be the same.
In case of PC transfer option the version number of the instrument
and the PC program must be the same.
This screen shows the list of the activated software options.
If you order additional software options, please send the status data to
Elektronika.
12-2
ELQ 2+
13
13 Calibration
CALIBRATION
The accuracy given in Specifications is only valid for ELQ2+ if the
device has been properly calibrated!
ELQ2+ has two calibration systems:
• Self Calibration
• Yearly Calibration
If the device has been shipped with bridge option, then there is also a 3
calibration:
• Bridge Cal. of Test Leads
rd
In order to do a calibration
• Press the CAL (F6) key in the MAIN MENU.
• Now the CALIBRATION menu appears:
• Select the calibration you want to do with the vertical cursor keys and
press ENTER
• Follow the instructions appearing on the display regarding the wire
connections
• Start the calibration by pressing the START key
• If you discover that there was any mistake during the calibration process (e.g. wrong cabling/wiring), then you should repeat the calibration under proper conditions!
13-1
13 Calibration
ELQ 2+
The Self Calibrations do not have to be done before every measurement
in order to measure accurately. They have to be done only if the ambient
conditions have changed since last self calibration. The results of the last
self calibration are stored in the device’s memory also in switched off
state if the battery is not discharged. There are following self calibrations
in the device:
• xDSL SELF CALIBRATION is needed for all xDSL (and TDR)
measurements.
• BRIDGE SELF CALIBRATION (only with bridge option) is needed
for all bridge measurements. All test leads must be disconnected
during this calibration! This calibration must not be interrupted!
• DMM SELF CALIBRATION (only with DMM option) is needed for all
DMM measurements.
The Bridge Cal. of Test Leads is important for the following bridge measurements only:
• Resistance Difference!
• Loop Resistance
• Resistance 2Wire&Ground
• fault location with Murray, Kupfmuller-methods
If the serial resistance of the test leads have a considerable effect on the
result of the measurement, then it is recommended to do this calibration
before the measurement. If you use the test leads that ELQ 2+ had been
shipped with, then in most cases you need not do this calibration, but if
you measure short wires or small resistances or small difference of high
resistances, you also need to do this calibration even if you use the test
leads that ELQ 2+ had been shipped with.
Without this calibration the program assumes all test lead resistances to
be equal to 0 Ohm.
When doing this calibration you should connect to the device the three
test leads only! The free „far” ends of the three test leads are to be shorted.
If the sum of the three test lead resistances is greater than 4500 Ohm,
then the device will take the measurement for invalid and set the values of
all test lead resistances to 0 Ohm.
The result of this calibration will be valid only until you switch off the device. When you switch on the device all test lead resistance values will be
reset to 0 Ohm.
13-2
ELQ 2+
13 Calibration
Yearly calibration
According to the regulations of the user organizations calibration is obligatory in every year or every two years. The yearly calibration should be
done by authorized persons. There are two levels of yearly calibration:
• First level: the authorized inspector is allowed to check the accuracy of the selected parameters, but he has no possibility to do adjustments.
• Second level: the authorized inspector has the right to modify the
internal calibrating constants of ELQ 2+.
There are two code numbers belonging to the two levels.
• The first code number is: 123456
• The second one may be given to the authorized inspector of a service station, against an official statement undertaking the responsibility of adjustment.
To start the program, enter the YEARLY CALIBRATION option and type
in the first code number.
(Details in Service Manual (SM 379-000-000)
13-3
ELQ 2+
14
14.1
14 PC Programs
PC PROGRAMS
Software Upgrade.(EL2u.exe)
The software of ELQ 2+ can be upgraded without disassembling the instrument. The new software version can be downloaded from a PC using
the upgrade file made by the manufacturer. This file contains the description of the upgrade process.
14.2
Data Transfer program option (ELQ2c.exe)
The purpose of the program:
• Transfer of test results from ELQ 2+ to PC
• Transfer of test results from PC to ELQ 2+
• Creating test protocols in Excel-format.
• Creating printed test protocols in numeric and graphic form.
• Creating archives of test results saving them for the future.
14.3
Parameter Set Editor option (ELQ2e.exe)
Running this program user defined test parameter sets can be compiled
and down loaded to ELQ 2+.
14.4
Demo Program (ELQ 2d.exe)
Running the demo program the front panel of the instrument with display
and keyboard is shown. By clicking with the mouse on the keyboard, the
“virtual” ELQ 2+ will behave as the real instrument, helping the user to
carry out complete measuring procedures, but of course only virtually.
14.5
PC Control Mode
Select the PC CONTROL item of MAIN MENU and press ENTER.
Doing so ELQ 2+ is ready for PC control. To return to keyboard control,
press the ESC
key.
14-1
ELQ 2+
15
16 ORDERING INFORMATION
SPECIFICATIONS
15.1 General specifications
Power supply:
Internal rechargeable NIMH battery pack
Operation time ........................................................... approx. 8 hours
(Without backlight)
Charging (without taking the battery pack out)
From 230 V mains ............................................... with mains adapter
From 12 V car battery ................................................ with car adapter
Charging time .............................................................. less than 3 hours
(Fast charging mode)
Display ................................... 320 x 240 dot graphic LCD with backlight
Connectors
Serial interface ....................................................................... RS232C
Line connectors .............................................. 2 pcs of 3 pol CF sockets
Over voltage protection
For high impedance input .................................................... 250 V DC
For terminated input/output.................................................... 60 V DC
Ambient temperature ranges
Reference ............................................................................... 23±5°C
Rel. humidity 45% to 75%
Normal operation ............................................................... 0 to +40°C
3
Rel. humidity 30% to 75% *(<25g/m )
Limits of operation ............................................................ -5 to +45°C
3
Rel. humidity 5% to 95% *(<29g/m )
Storage and transport .................................................... –40 to +70°C
3
Rel. humidity 5% to 95% *(<29g/m )
Dimensions ...............................................................224 x 160 x 44 mm
Weight (Including battery pack) ....................................... approx. 1.5 kg
Memory Locations
38 locations for standard system templates
36 locations for user defined system templates
50 locations for single test results
28 locations for automatic test sequences
30 locations for TDR measurements
50 locations for Bridge or DMM option
100 locations for cable parameters
15-1
16 ORDERING INFORMATION
15.2
ELQ 2+
Single Manual Tests
Transmitter
Frequency range ........................................................ 200 Hz to 2.2MHz
Impedances:
10 kHz to 2.2 MHz ........................................ 100, 120, 135, 150 Ohm
200 Hz to 10 kHz .................................................................. 600 Ohm
Transmitting modes:
Generation of 1 single frequency
Generation of 10 frequencies at the same time
Single frequency mode
Frequency resolution:
200Hz to 4 kHz (with 10 HZ RESOLUTION option) ...................... 10 Hz
4 kHz to 10 kHz....................................................................... 100 Hz
10 kHz to 100 kHz.................................................................... 1 kHz
100 kHz to 2.2 MHz ................................................................. 10 kHz
Output level:
Level range .................................................................... 0 to −24 dBm
Resolution ................................................................................. 0.1 dB
Accuracy at 0dBm .................................................................. 0.3 dBm
10 frequency mode
Frequency raster ............................ 1, 5, 10, 20, 50, 100, 200 kHz steps
Frequency sets with 10 HZ RESOLUTION option
Frequency set 1 ................................. 300, 500, 1000, 1600, 2000 Hz
2200, 2500, 2800, 3000, 3400 Hz
Frequency set 2 ..................................... 300, 400, 500, 600, 1000 Hz
2000, 2500, 2800, 3000, 3600 Hz
Output level:
Z =100, 120, 135, 150 Ohm ................................. −6 dBm / frequency
Z = 600 Ohm ...................................................... −12 dBm / frequency
15-2
ELQ 2+
16 ORDERING INFORMATION
Receiver
Frequency range......................................................... 200 Hz to 2.2MHz
Input Impedances:
10 kHz to 2.2 MHz ....................................... 100, 120, 135, 150 Ohm
200 Hz to 10 kHz ................................................................. 600 Ohm
200 Hz to 2.2 MHz ............................................... >20 kOhm  50 pF
Input Level Range:
Z line=100, 120, 135, 150 Ohm ................................... −90 to +5 dBm
Z line=600 Ohm ........................................................... −90 to +0 dBm
Resolution ................................................................................. 0.1 dB
Accuracy at 0 dBm ..................................................................... ±0.2 dB
Receiving modes:
Receiving of 1 single frequency
Receiving of 10 frequencies at the same time
Single frequency mode
Frequency resolution:
200Hz to 4 kHz with 10 HZ RESOLUTION option..................... 10 Hz
4 kHz to 10 kHz ...................................................................... 100 Hz
10 kHz to 100 kHz ..................................................................... 1 kHz
100 kHz to 2.2 MHz ................................................................. 10 kHz
10 frequency mode
Frequency raster........................ 1, 5, 10, 20, 50, 100, 200 kHz steps
Frequency sets with 10 HZ RESOLUTION option
Frequency set 1 ................................. 300, 500, 1000, 1600, 2000 Hz
2200, 2500, 2800, 3000, 3400 Hz
Frequency set 2 ..................................... 300, 400, 500, 600, 1000 Hz
2000, 2500, 2800, 3000, 3600 Hz
LOSS, NEXT and FEXT Measurement
Frequency range........................................................ 200 Hz to 2.2 MHz
Line impedances:
10 kHz to 2.2 MHz ....................................... 100, 120, 135, 150 Ohm
200 Hz to 10 kHz ................................................................. 600 Ohm
Measuring range ..................................................................... 0 to 80 dB
Accuracy:
In frequency range 200 Hz to 1 MHz
LOSS, NEXT, FEXT <50 dB ................................................. ±0.5 dB
LOSS, NEXT, FEXT <70 dB .................................................... ±1 dB
LOSS, NEXT, FEXT >70 dB ................................................. ±1.5 dB
In frequency range 1 to 2.2 MHz ............................................. ±2 dB
15-3
16 ORDERING INFORMATION
ELQ 2+
LCL Balance Measurement
Frequency range ....................................................... 200 Hz to 2.2 MHz
Measuring range..................................................................... 0 to 40 dB
Line impedances:
10 kHz to 2.2 MHz ........................................100, 120, 135, 150 Ohm
200 Hz to 10 kHz ..................................................................600 Ohm
Accuracy:
10 kHz to 1 MHz ........................................................................ ±1 dB
200 kHz to 2.2 MHz ................................................................... ±2 dB
Return Loss Measurement
Frequency range ....................................................... 200 Hz to 2.2 MHz
Measuring range
Return loss measurement................................................. up to 40 dB
Impedance ............................................................................ Z/2 to 2Z
Line impedances:
10 kHz to 2.2 MHz ........................................100, 120, 135, 150 Ohm
200 Hz to 10 kHz ..................................................................600 Ohm
Accuracy at 20 dB:
10 kHz to 1 MHz ........................................................................ ±1 dB
200 Hz to 2.2 MHz .................................................................. ±2.5 dB
Impedance Measurement
Frequency range ....................................................... 200 Hz to 2.2 MHz
Measuring range:
200 Hz to 10 kHz .................................................... 300 to 1600 Ohm
10 kHz to 2.2 MHz ...................................................... up to 400 Ohm
Accuracy:
10 kHz to 1 MHz ........................................................... ±5% ± 5 Ohm
0.2 kHz to 2.2 MHz ...................................................... ±10% ±5 Ohm
15-4
ELQ 2+
16 ORDERING INFORMATION
Wide Band Noise Measurement
Input Impedances:
10 kHz to 2.2 MHz ....................................... 100, 120, 135, 150 Ohm
200 Hz to 10 kHz ................................................................. 600 Ohm
200 Hz to 2.2 MHz ............................................... >20 kOhm  50 pF
Noise Level Measurement
Weighting filters:
∗ P .................................................................................... For POTS
∗ 1010 Hz Notch (with 10 HZ RESOLUTION option) ...... For VOICE
∗ E Filter .................................................................... For ISDN BRA
∗ G2-E Filter ................................................... For ISDN PRA HDB3
∗ F-E Filter ................................................ For HDSL, 2 PAIR, 2B1Q
∗ F1-E Filter .............................................. For HDSL, 1 PAIR, 2B1Q
∗ G Filter .................................................................. For ADSL, DMT
∗ 3dB at fmin and fmax Filter .................................. For auto modes
Measuring Range:
With P and E filter .......................................................... 0 to −80 dBm
With F and G filters ........................................................ 0 to −70 dBm
Without filter................................................................... 0 to −65 dBm
Measurement times ......................................................1, 5, 10, 15, 30 s
1, 5, 10, 15, 30 min
Noise Spectrum Measurement
Frequency range
.................................................. 10 kHz to 2.2 MHz
Frequency step ............................................................................ 10 kHz
Band width
............................................................................. 15 kHz
Spectrum Analyzer
Frequency range: ....................................................... 200 Hz to 2.2MHz
Input Impedances:
10 kHz to 2.2 MHz ....................................... 100, 120, 135, 150 Ohm
200 Hz to 10 kHz ................................................................. 600 Ohm
200 Hz to 2.2 MHz ............................................... >20 kOhm  50 pF
Bandwidth: ............................................................Zoom ON / OFF
10 ÷ 2100 kHz.................................................................. 5 / 10 kHz
2.5 ÷ 500 kHz............................................................. 1.25 / 2.5 kHz
1 ÷ 200 kHz............................................................... 0.5 / 1 kHz
0.2 ÷ 20 kHz................................................................ 50 / 100 Hz
0.2 ÷ 4 kHz (with 10 HZ RESOLUTION option) ........ 10 / 20 Hz
Evaluation .......................................................... Normal, Peak, Average
15-5
16 ORDERING INFORMATION
ELQ 2+
Impulse Noise Measurement
Input Impedances:
10 kHz to 2.2 MHz ........................................100, 120, 135, 150 Ohm
200 Hz to 10 kHz ..................................................................600 Ohm
200 Hz to 2.2 MHz ................................................>20 kOhm  50 pF
Pulse width ................................................................................> 500 ns
Interval size ............................................................................... > 10 ms
Threshold range ................................................................ 0 to −60 dBm
Maximum count: ........................................................................... 65000
Measurement times: .................................................... 1, 5, 10, 15, 30 s;
1, 5, 10, 15, 30 min
15-6
ELQ 2+
15.3
16 ORDERING INFORMATION
Automatic Measurements
Preprogrammed Parameter Sets
ADSL2+ (ITU–T G.992.5 Annex A, B, I, J, M) (Option)
EC : 8 MBPS, 16 MBPS, 24 MBPS
FDD: 8 MBPS, 16 MBPS, 24 MBPS
ADSL2 (ITU–T G.992.3 Annex A, B, I, J, M)
EC : 4 MBPS, 6 MBPS, 8 MBPS
FDD: 4 MBPS, 6 MBPS, 8 MBPS
ADSL ( ITU–T G.992.1 Annex A, B)
EC : 2 MBPS, 4 MBPS, 6 MBPS
FDD: 2 MBPS, 4 MBPS, 6 MBPS
ADSL (ETSI TS 101 388 v 1.3.1)
EC : 2 MBPS, 4 MBPS, 6 MBPS
FDD: 2 MBPS, 4 MBPS, 6 MBPS
READSL2 (ITU–T G.992.3 Annex L)
EC : 768 KBPS, 1 MBPS, 1.5 MBPS
FDD: 768 KBPS, 1 MBPS, 1.5 MBPS
ADSL G.LITE (ITU–T G.992.4 Annex A)
EC : 768 KBPS, 1 MBPS, 1.5 MBPS
FDD: 768 KBPS, 1 MBPS, 1.5 MBPS
ADSL G.LITE2 (ITU–T G.992.4 Annex I)
EC : 768 KBPS, 1 MBPS, 1.5 MBPS
FDD: 768 KBPS, 1 MBPS, 1.5 MBPS
HDSL (ITU–T G.991.1)
1 PAIR 2B1Q/CAP, 2 PAIR 2B1Q/CAP
SHDSL (ITU–T G.991.2 Annex B)
1 PAIR 16 TC PAM 256, 512, 1024, 2048, 2304 KBPS
2 PAIR 16 TC PAM 512, 1024, 2048, 4096, 4608 KBPS
SHDSL (ETSI TS 101 524 v 1.3.1 Annex E)
1 PAIR 16 UC PAM 512, 1024, 2048, 3848 KBPS
2 PAIR 16 UC PAM 1024, 2048, 4096, 7696 KBPS
1 PAIR 32 UC PAM 768, 1536, 3840, 5696 KBPS
2 PAIR 32 UC PAM 1536, 3072, 7680, 11392 KBPS
ITU-T VOICE FREQUENCY MODEMS
2.4 KBPS (V26), 56 KBPS (V92), Fax14.4 KBPS(V17)
ISDN
ITU–T G.962 Basic Rate, ETSI ETR 080 Primary Rate
15-7
16 ORDERING INFORMATION
15.4
ELQ 2+
TDR measurements
Measuring Modes
Single pair
Short time............................................................................... L1 or L2
Long time ...................................................................... L1LT or L2LT
Pair comparison .......................................................................... L1 & L2
Comparison to memory .....................................................L1 & M, L1-M
XALK point location
Transmitting ............................................................................... on L1
Receiving ................................................................................... on L2
Measuring range .................................. up to 20 km (depends on cable)
Ranges............. 100m, 250m, 500m, 1km, 2.5km, 5km, 10km, 20km
Zoom .............................................................................................. 1 to 4
Gain range .............................................................................. 0 to 72 dB
Gain regulation .................................................................. in 6 dB steps
Measuring pulse
Width.............................................................................. 10 to 5000ns
automatically changed with range
Amplitude into 120 Ohm
For 25 to 5000 ns pulse ............................................................. ≈5 V
For 10 ns pulse .......................................................................... ≈4 V
Propagation velocity
V................................................................................... 90 to 299m/µs
V/2............................................................................... 45 to 150 m/µs
PVF .................................................................................. 0.3 to 0.999
Resolution ................................................................... ±0.1% of range
Accuracy ..................................................................... ±0.4% of range
15-8
ELQ 2+
15.5
16 ORDERING INFORMATION
Micro Interruption Measurement (SW option)
Test Signal
Frequency ...........................................................2kHz, 82 kHz ± 100 Hz
Input level range ................................................................ 0 to –30 dBm
Input Impedance
For 2 kHz test signal .............................................................. 600 Ohm
For 82 kHz test signal .............................................................. 100 Ohm
Selectable Threshold
Below the normal input level
For 2 kHz test signal ...................................................... 3, 6, 10, 20 dB
For 82 kHz test signal ............................................................ 3, 6, 10 dB
Accuracy of Threshold
For 3, 6, 10 dB .............................................................................. ± 1 dB
For 20 dB ...................................................................................... ± 2 dB
Measuring Time
Adjustable. .................................................................. 4 min to 72 hours
4, 8, 12, 24 min
1, 2, 4, 8, 12, 24, 48, 72 hour
Interruption Categories .............................................0.3 ms to 3 ms
3 ms to 30 ms
30 ms to 300 ms
300 ms to 1 min
>1 min
Evaluation ..................................................Relative duration, Errored s
Count & time distribution/category
15-9
16 ORDERING INFORMATION
15.6
ELQ 2+
Group delay distortion measurement (SW option)
Transmitter
Test Signal
37MTT signal ..................................................................200 to 3700 Hz
Output level ......................................................–30 dB/tone (-7dB peak)
Impedance
Z output .................................................................................... 600 Ohm
Receiver
Impedance
Z input ...................................................................................... 600 Ohm
Group delay measurement
Frequency range .............................................................200 to 3700 Hz
Resolution ....................................................................................100 Hz
Group delay distortion range .................................................. 0 to 10 ms
Resolution ........................................................................................ 1 µs
Input level range........................................................ -60 to –20 dB/tone
Accuracy .................................................. According to ITU.O.81 (4.1.1)
Loss measurement
Frequency range .............................................................200 to 3700 Hz
Resolution ....................................................................................100 Hz
Measuring range .................................................................. 10 to 40 dB
Resolution .................................................................................... 0.1 dB
Accuracy ....................................................................................... ±1 dB
15-10
ELQ 2+
16 ORDERING INFORMATION
15.7
AC/DC Bridge (Built in panel option)
Loop Resistance Measurement (RL)
Measuring range..............................................................up to 10 kOhm
Accuracy (RL>100 Ohm) ......................................... ±0.4% ±0.1 Ohm
Resistance difference (∆R)
Measuring range of RL: .............................................. 1 Ohm to 5 kOhm
Measuring range of ∆R: .....................................................up to 1 kOhm
Accuracy
1 Ohm to 10 Ohm ....................................................... ±1% ±0.1 Ohm
10 Ohm to 100 Ohm ...................................... ±1% to 0.2% ±0.1 Ohm
100 Ohm to 1000 Ohm ............................................ ±0.2% ±0.1 Ohm
Insulation Resistance Measurement
Measuring range:................................................. 10 kOhm to 10 GOhm
Accuracy
0.1 to 100 MOhm: ........................................................................ ±2%
100 MOhm to 1 GOhm: ............................................................. ±10%
Capacitance Measurement
Measuring range:............................................................... 1 nF to 10 µF
tan δ: ................................................................................... 0.0001 to 10
Accuracy (10nF to 10 µF): .................................................± 5% ± 1 digit
Measuring frequency: .................................................................... 11 Hz
Voltage Measurement
DC voltage: ........................................................................... up to 100 V
AC voltage: ..................................................................... up to 100 V RMS
Frequency range: ............................................................... 15 to 300 Hz
Accuracy: .................................................................................. ± 1%±1V
Leakage Location
Measuring methods .................................................. Murray, Küpfmüller
Loop resistance range (RL) ...................................... 1 Ohm to 10 kOhm
Leakage resistance range (F) .................................... 0,1 to 100 MOhm
Accuracy of Lx/L (RL=2 kOhm, Lx/L=0.1 to 1)
F<1 MOhm .................................................................... ±0.1% ±1 digit
F=1 to 5 MOhm .............................................................±0.2% ±1 digit
F=5 to 25 MOhm .............................................................. ±1% ±1 digit
F=25 to 100 MOhm ..........................................................±5% ±1 digit
Break Location
15-11
16 ORDERING INFORMATION
ELQ 2+
Measuring range ............................... up to 10 km (depending on cable)
Accuracy (C=20nF to 10 µF):............................... ±0.2% to ±1% ±1 digit
Measuring frequency: .................................................................... 11 Hz
15.8
Digital Multimeter (Built in panel option)
Loop resistance
Measuring range......................................................... 1 Ohm to 2 kOhm
Accuracy ..................................................................... ±0.5% ±1 Ohm
Test voltage .................................................................................... 6.3 V
Insulation resistance
Measuring range.................................................1 MOhm to 500 MOhm
Accuracy up to 100 MOhm .......................................................... ±5%
Test voltage .................................................................................... 6.3 V
DC voltage
Measuring range................................................................. up to ±200 V
Accuracy ............................................................................. ± 1% ±1 V
DC current
Measuring range.............................................................. up to ±150 mA
Accuracy ........................................................................... ±1% ±1 mA
Mutual capacitance
Measuring range................................................................. 10 to 500 nF
Accuracy
R loop <1200 Ohm .................................................................... ±3%
R loop =1200 to 2400 Ohm ....................................................... ±5%
15-12