Softel MLE-02 User manual

MLE-02
Bidirectional Amplifier
User Manual

Notice
This user manual is only for professionals.
To avoid electric shock, non-professionals should not operate any maintenance
including installation and troubleshooting. All installation and maintenance should be
carried out after professionals read the user manual and in strict accordance with the
instructions.
If replacing the components or circuit without our permission, we will not take any
responsibility.
To keep the best specification of the amplifier, do fasten all the screws on the panel
when you remove and install it again.

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MENU
Notice...........................................................................................................................................1
1. Foreword.............................................................................................................................3
1.1 Introduction.................................................................................................................3
1.2 Feature.........................................................................................................................3
1.3 Technical Support.....................................................................错误！未定义书签。
2. Description..........................................................................................................................3
2.1 Power Supply.............................................................................................................. 3
2.2 Forward Path.............................................................................................................. 4
2.3 Reversed Path..............................................................................................................4
2.4 Control Forward Output Level................................................................................. 5
2.5 Accessories...................................................................................................................6
3. Installation.......................................................................................................................... 6
3.1 Preparation..................................................................................................................6
3.2 Installation...................................................................................................................7
3.3 Check Forward System.............................................................................................. 7
3.4 Check Reversed System............................................................................................. 8
3.5 Finish installation........................................................................................................8
Appendix A Specification.......................................................................................................... 9

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1. Foreword
1.1 Introduction
MLE-02 is kind of bidirectional amplifier with one input port and one output port, which
forward gain range from 28dB to 41dB and the max gain of reversed path can reach 23dB. It
can be used as a trunk amplifier in the traditional coaxial network, also it can be used as an line
extender amplifier in the HFC network. Its tank-type construction is convenient for
maintenance.
1.2 Feature
●5-1002MHz, bidirectional
●Output slope and reversed equalizer can be debugged by fixed attenuator, 1dB stepping
●Frequency of the diplexer can be specified
●GaAs module
●35V-90V power supply
●Max overcurrent capability 15A
●MTBF>50000hours
2. Description
MLE-02 adopts two-stage GaAs module in forward path, which gain ranges from 28dB to
38/41dB, so it can be applied widely. The working voltage ~60V is fed by cable, and the
working AC voltage is 35V~90V, so both of the input and output port can feed the next
amplifier. MLE-02 can be set as unidirectional mode, and upgrade to bidirectional mode in the
future.
MLE-02 contains RF amplifier hybrid and power supply. The water-proof aluminum casting
housing is suitable for outdoor operation. Various components and options can meet many
different requirements.
2.1 Power Supply
The power supply of MLE-02 is SMPS (Switching Mode Power Supply), which is fixed in the

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bottom half of the tank. The input voltage is ~35~90V, and the working bandwidth is 47~63MHz.
The output voltage is +24V. The DC output current can reach 1.5A.
2.2 Forward Path
MLE-02 can be divided into forward path and reversed path. The forward input contains cable
equalizer (simulator) and fixed attenuator. The EQ range of the cable equalizer (simulator) is
3~21dB/0~12dB, 1.5dB/step. Equalizer (simulator) is used to compensate the attenuation of
different frequency in transmission and correct the forward input level. Attenuator is used to adjust
the forward input level to suitable value.
Figure 1 Block Diagram
In forward path, it adopts two-stage amplify hybrid and provide 28~41Bm gain. The bandwidth is
54/87/105/258 ～1002MHz. It adopts low-noise push-pull or GaAs module in first stage to
pre-amplify the input signal and double-power GaAs module in latter stage to ensure the minimum
non-linear distortion when output high level. Between two-stage amplify modules, there are
attenuators, frequency correction circuit and equalizers. The installation of equalizers is same as
fixed attenuators, and it can be changed according to the requirement. The circuit between
two-stage modules is to adjust the forward output gain and RF output slope.
The forward equalizer contains build-in 6dB fixed equalizer circuit and changeable equalizer
circuit made up of fixed attenuator and peripheral circuit, ensuring the amplifier gaining certain
equalization output.
There are -20dB test port for both input and output port. It adopts directional coupling mode and
operate without external 75Ω load.
2.3 Reversed Path

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The reversed bandwidth of MBC-02 begins from 5MHz, and various ended frequency
(42/65/85/204MHz) are available for choice. The input attenuators, low-pass filters, reversed
amplifier module and equalizers are pluggable, which is convenient to change. There are fixed
attenuators at output port and reversed amplify gain is adjusted by output attenuator RATT (Gain).
If the reversed signal does not require amplify, user can choose pass-through mode.
Reversed equalizer circuit is made up of fixed attenuator and external circuit to realize 0-16dB
equalization. The reversed equalizer is used to compensate the cable loss among the reversed
output, reversed input of next amplifier and the duplexer. To meet the equalization requirement,
user can plug fixed attenuators in REQ position:
Note: Reversed equalizer circuit adopts pedestal design, classify the specification by reversed
end frequency. REQ pedestal with different frequency can be changed to change the splitting
frequency of the amplifier.
There is a -20dB test point at both of input and output port of the reversed path. The test point
works in directional coupler mode, without external 75Ω load.
2.4 Control Forward Output Level
In CATV cable network, the cable loss will change with the temperature, and some passive
components and amplifier module in the amplifier also will be affected by the temperature, so the
level will change accordingly. If the numbers of cascade increase, the fluctuation of the output
level will increase. To adjust the output level to meet the requirement, user can use the AGC
plug-in ADU-W and enable AGC to ensure the reliability of the forward output level.

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2.5 Accessories
If without any special requirement, we will attach the defaulted directional accessories, set the
fixed attenuation as 0dB and set the forward equalization between stages as 14dB.
To ensure the basic function, user must plug suitable fixed attenuators to adjust the signal
equalization and attenuation.
Table 1 Accessories
Model
Name
Description
Remarrk
GSJ-A-30-**
Fixed Attenuator
To adjust the RF level or signal slope, 1dB step
Options
DF(C)-**
Diplexer
To change the splitting frequency for the device
Parts
ADU-W
AGC Plug-in
To keep the forward level stable
Options
EQ(C)- 1G/**
Forward Equalizer
To Equalizing the forward RF level
Options
MB-RLP-**MHz
Reverse Filter
To filter out the reversed RF signal which is above
the end frequency
Options
BLE-REQPAD-
**MHz
Reverse Equalizer
To work with the fixed attenuator to equalizing
the reverse RF level
Options
3. Installation
This chapter describes how to install and debug the amplifier. It requires power, several TV signal,
TV carrier and test equipment for debugging. Below are the steps:
3.1 Preparation
Steps:
1. To ensure the circuit and personal safety, before installation do cut off the power or remove
the short circuit plug-in at Shunt (P1) or Shunt (P2) position to cut off external feedback from
relative port.
2. The amplifier connects with the cable by standard needle-type RF connector, which diameter
of the central conductor is 1.5mm. Connect the cable with the amplifier well.
3. To prevent water coming into the amplifier, do tighten the cable connector.
4. Use cross screwdriver to tighten the screw in the central conductor of the RF connector.
5. Power on and check whether the power LED indicator is on. After power properly, please
preheat the amplifier for a few minutes.
6. Check the AC voltage, which should be in proper working range.
7. Check the DC voltage, which should be in 23.5~24.5V range.

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Note: DO NOT remove the 20A plug-in at Fuse position in any case. It is used for
over-current protection.
3.2 Installation
The amplifier can be placed on horizontally or hanged. For horizontal installation, generally it can
be placed in the cabinet. For outdoor installation, it can be hanged on something like telephone
pole. It just requires one steel wire to pass through two claws of the amplifier. If both amplifier
and cable are hanged outdoor, they will be in the environment with same temperature. If the
amplifier is in outdoor, while the cable is buried underground, they will be in the environment
with different temperature. In these two cases, the output level will change with the temperature,
just the range different. Generally, the attenuator can be adjusted to change the level.
3.3 Check Forward System
The adjustment of the amplifier includes input level setting, output level setting and output slope
setting, and attenuator adjustment or equalizer replacement if necessary. All test ports are -20dB
without 75Ω load. The steps are as below:
1. Open the upper cover, check whether the AC and DC voltage are normal. Connect the input
test port with field-intensity meter, and measure the input level and flatness of the pre-stage
amplifier module. It should meet the specification requirement. If the level is too high or too
low, the attenuation of the attenuator should be adjusted. Meanwhile, measure whether the
difference between the high-end and low-end level is less than 1.5dB, otherwise the
attenuator at the cable equalizer position should be changed. (The input level should be
around 72dBuV, which is not too high or too low). For example, the high-end input level
which the system record is +17dBmV, while the actual level is +23dBmV. Then the
attenuator must be adjusted to decay 6dB.
2. To test output slope, measure the difference between high-end and low-end gain. Choose the
fixed attenuator accordingly and plug in EQ (P2) position. If the measured value is small than
the actual one, then user should replace the slope plug-in with bigger tilt. (e.g. the actual
value is 10dB, then 4dB fixed attenuator can be used to work with the built-in fixed
attenuator which the tilt is 6dB.)
3. Measure the level at the high-end, which should be meet the specification requirement. (The
difference between the recorded value and measured value should be less than 1dB).

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4. Adjust output level: the forward fixed attenuator ATT (P2) can be adjusted
5. Adjust AGC
5.1 Before setting AGC, user should change ATT (P2) attenuator to adjust the output level of P2
port in MGC mode. ATT (P2) must be more than 3dB sot that it can work properly in AGC
mode.
5.2 Set the AGC/MGC as AGC, and reduce 3dB for the forward attenuation ATT (P2)
5.3 After finishing step 5.1 and 5.2, adjust the fixed attenuator at ADJ (ADU) position to restore
the output level of P2 port in MGC mode.
3.4 Check Reversed System
The reversed output port equips fixed attenuator and reversed equalizer. Adjust the attenuator
RATT (Gain) after reversed amplifier module to adjust the reversed output level, so that it can
output the proper input level for the next amplifier.
In the reversed path, the cable equalizer REQ is used to compensate the attenuation of reversed
output cable at different frequency. Select the fixed attenuator according to the cable transmission
to correct the level of forward and reversed path.
3.5 Finish installation
Record all the information in a table. It will be useful for future maintenance. At last, cover the
amplifier and fasten all the bolts.

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Appendix A Specification
No
Item
Forward
Reversed
Remark
1
Frequency（MHz）
54/105/258~1002
5~42/87/204
According to the split frequency
2
Flatness（dB）
±0.6
±0.5
3
Return Loss
≥16(FH～750MHz)
≥14(751～1002MHz)
≥16
4
Nominal Gain
28～38/41
0/20
5
Min Full Gain
≥42
≥22
6
Equalization/Analog
3～21/0～12
0～16
Forward 1.5dB step, reversed
1dB step
7
Forward Slope
Output
14dB(54M-1002M)
null
8
Noise Figure（dB）
＜8
9
AGC Range
±3dB (Broadband mode, output level
change 0.3dB)
Forward
10
Forward Level
38dBmV～50dBmV
11
Test Port Level（dB）
-20±1
12
Test Port Frequency
Respond（dB）
±1
13
Working Voltage
（V/DC）
+24
14
HUM（dB）
≥66
15
AC Input（V/AC）
~35-90V
16
AC（A/AC）
15
Max continuous over current
17
Level Adjustment
（dB）
0～20
1dB step
18
Connector
5/8 inch 24-tooth Connector
19
Input/Output
Resistance（Ω）
75
20
C/CSO（dB）
63
-
110 NTSC channels + 22 10dB
low QAM signal, 48 dBmV
(750MHz), 14dB slope output,
10dB（54M～750M）
21
C/CTB（dB）
65
-
22
Working Temperature
（%）
-25℃～+55℃
23
Power Consumption
25W
24
Storage Temperature
-40℃～+70℃non-condensation
25
Dimension（mm）
320L×200W×100H
26
Weight（kg）
Max 2kg
27
Shell Waterproof
IP67

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