Twin TV channel amplifier at422
Product description
The at422 twin TV channel amplifier is intended to filter and equalize TV signals of VHFIII channels before distributing
in the network.
There are incorporated two fully independent TV amplifiers in one unit and consist of: AGC (Automatic Gain Control) circuit,
SAW (Surface Acoustic Wave) based ultra high selective filter, IF (Intermediate Frequency) offset control circuit, adjustable
output attenuator and contro12 V DC feeding circuit for preamplifier (Figure 1).
The amplifier can be used as stand-alone unit as well as modular system powered from single power supply (Figure 3).
The amplifier has been designed in accordance with standard EN 50083-5 class 2.
The amplifier is intended for indoor use only.
RoHS compliant.
Safety instructions
Installation of the amplifier must be done according EN 60728-11 and local safety standards.
The amplifier is powered from power supply unit (PSU) +12 V. This voltage is not dangerous to life.
PSU +12 V must have a short circuit protection.
Any repairs must be done by qualified personnel.
Do not plug the PSU +12 V into the mains socket until all amplifier's cables have been connected correctly. The mains
socket of PSU +12 V must be easily accessible.
To disconnect the amplifier, disconnect the PSU +12 V from mains.
When amplifier is disconnected, LED display does not glow.
Amplifier shall not be exposed to dripping or splashing water and no objects filled with liquids, such as vases, shall be
placed on it.
Avoid placing amplifier next to central heating components and in areas of high humidity.
No naked flame sources, such as lighted candles, should be placed on amplifier.
If the amplifier has been kept in cold conditions for a long time, keep it in a warm room no less than 2 hours before
plugging into the mains.
The ventilation should not be impeded by covering the ventilation openings with items, such as newspapers, table-cloths,
curtains.
Mount the amplifier in vertical position.
From top, front and bottom of installed amplifier must be as least 10 cm free space.
This product complies with the relevant clauses of the European Directive 2002/96/EC. The unit must be recycled or
discarded according to applicable local and national regulations.
External view
1
- ◄ - RF input, DC 12 V switchable (F socket)
2
- ►- RF output (input signal loop-through) (F socket)
3
- two digit LED display
4
- +12 V powering input (screw terminal)
5
- ◄ - RF input (output signal loop-through) (F socket)
6
- ► - RF output (F socket)
7
- power distribution bus connector (under the cover)
Figure 1. External view and structure diagram
Draugystes str. 22, LT-51256 Kaunas, Lithuania, tel.: +370 37
-
31 34 44, fax: +370 37
-
31 35 55
E-mail: [email protected], http://www.terraelectronics.com
OPERATING
Settings menu
The amplifier has two modes of operating:
1. Normal mode: sets after switch on;
RF channel can be set in normal mode by pressing buttons ▼ or ▲.
2. Setting mode: to enter the setting mode press and hold ▼ and ▲ buttons simultaneously for 1 second, to exit mode
press and hold ▼ and ▲ buttons simultaneously for 1 second again.
Menu settings of each section should be set individually. Section 1 or 2 can be selected by pressing button “Enter” (for
example:
0
.
6
- 1 section, output channel 06;
08
.
- 2 section, output channel 08), see Figure 7:
Figure 7.
Position of glowing dot means which section is activated.
Select necessary to change parameter by pressing button ▼.
Enter necessary parameter values by pressing ▲ button:
1.
00 10
- Output attenuator 0 dB to -10 dB by 1 dB step
2.
ON
/
OF
- RF output on/off
3.
O
N
/O
F
- Analog/ Digital (
O
N
for analog channel)
4.
-8 8
- Offset of a central frequency in respect to filter (see table 1)
5.
0
/
12
- DC on RF input
6.
AU
/
B
- TV standard
If TV standard is changed, default settings are set automatically for selected standard.
NOTE
! DC on RF input (
0 /
12
) can be dangerous for some devices.
If no action is taken for 1 minute, sleep mode (
- -
) is activated. To leave sleep mode press any button.
The last selected parameters will remain in memory if the power is interrupted.
Technical specifications
Table 3.
pr.
pr.
pr.
pr.
Sections
2
Tuning range of channels
174-230 MHz (see table 1)
RF input
TV standard
analog (Au, B)
digital (DVB-T*)
channel bandwidth
7 MHz
level/impedance
60-85 dBµV/75
Ω
50-80 dBµV/75
Ω
frequency range of RF distribution
47-862 MHz
loop through gain
0 ± 1.5 dB
return loss
>10 dB
RF output
level/impedance, typical
90 dBµV/75
Ω
85 dBµV/75
Ω
MER of DVB-T signal
-
≥
36 dB (input signal MER 38 dB)
frequency range of RF combining
47-2150 MHz
DC pass through, max.
0.3 A 24 V
combining through loss Terr/SAT
1.5/2.5 dB
level adjustment range
0
÷ -
10 dB by 1 dB step
return loss
≥
10 dB
Noise figure
8 dB
Selectivity, typical
40 dB, ±1.25 MHz from 7 MHz bandwidth border 40 dB, ± 2 MHz from 7 MHz bandwidth border
Offset**
± 1 MHz by 0.125 MHz step
Spurious signals level
≤
-60 dBc
Mirror channel selectivity
≥
60 dB
Flatness of channel bandwidth, typical
± 1.5 dB
DC feeding for external
12 V
0.1 A max.
Supply voltage
12 ± 1 V
Current consumption***
0.45 A
Operating temperature range
0
o
÷
+50
o
C
Dimensions/Weight (packed)
198x107.5x36 mm/0.9 kg
* 6-12 channels by Au standard, 5-12 channels by B standard (see table 1)
** the offset is used for fine tuning of the channel frequency response
*** without external DC loading
pr. software control
Table 2.
Displayed Shift,
MHz
0
0
1
+0.125
2
+0.25
3
+0.375
4
+0.5
5
+0.625
6
+0.75
7
+0.875
8
+1.0
-8
-1.0
-7
-0.875
-6
-0.75
-5
-0.625
-4
-0.5
-3
-0.375
-2
-0.25
-1
-0.125
O
ffset tunning
Multichannel headend
