Olson Technology OTPN-3850-SA User manual

Table of Contents
025-000641 REV X5 06 Sep 2012 Page 1
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Instruction Manual
Model OTPN-3850-SA
3.85GHz Wideband FTTH PON Receiver

8
ACCESSORIES AND SYSTEM APPLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7
SETUPAND OPERATION ....................................................
6
EXTERNAL INDICATORS AND CONNECTORS ................................
6
INTERNAL CONTROLS ....................................................
6
OPTICAL CONNECTORS AND CLEANING ...................................
3
THEORY OF OPERATION ..................................................
3
INTRODUCTION ..........................................................
Table of Contents
025-000641 REV X5 Olson Technology, Inc. Page 2
4
BLOCK DIAGRAM ........................................................
5
INSTALLATION / ENVIRONMENTALCONSIDERATIONS ......................

025-000641 REV X5 Page 3Olson Technology, Inc.
INTRODUCTION
The Olson Technology, Inc. Model OTPN-3850-SA provides 50-3,850MHz bandwidth,
allowing it to carry CATV signals from 50-870MHz along with two stacked 950-2,150MHz
groups of L-Band signals. The L-Band signals are at a level at least 10dB below the CATV
signals.
The optical input contains downstream forward path CATV and L-Band signals at 1550nm,
downstream Ethernet data at 1490nm and upstream Ethernet data at 1310nm. The optical
output passes the 1310nm and 1490 signals. The 1550nm wavelength goes to a photodiode
and is amplified. The optical input level is sensed to trigger an optical alarm when the input
light level is less than -10dBm. The input optical level is also used to control a PIN diode
attenuator to maintain constant RF level as the optical input level varies from 0dBm to -6dBm.
Thesignal is thenamplified and outputto a single“F”connectoroutput.
The OTPN-3850-SA Integrated PON Receiver dimensions are 1.05" H x 3.15" W x 4.75" L.
Optical connections are via two SC/APC connectors, one for the optical input carrying
1310nm, 1490nm & 1550nm, the second for the optical output carrying the 1310nm and
1490nm optical signals. The unit is powered from +12 to +16 Volts DC at 0.2A maximum. A
Green Power LED is lit whenever valid supply voltage is applied. A Red LED is lit only when the
1550nm optical power drops below -10dBm, the minimum usable optical input level. The right
sideof the unithas a single“F” connector providinga50-3,850MHz signal.
The OTPN-3850 is designed to give optimum performance at a received CATV optical power
(1550nm) of -4dBm although it will give good performance over the full rated optical input
rangeof0dBm to -6dBm.
THEORY OF OPERATION
Refer to the Block Diagram for the following discussion. The Optical In to the receiver, actually
carries three wavelengths. The 1550nm ±10nm wavelength carries the downstream CATV
and L-Band signals. This wavelength passes through the FWDM (Filter Wavelength Division
Multiplexer) to the optical detector. The 1310nm and 1490nm wavelengths usually carry the
Ethernet signals in a Fiber-to-the-Home (FTTH) PON application. They pass through the
FWDM to the Optical Out port. The 1490nm wavelength usually carries the downstream
Ethernetsignals and the1310nm wavelengthcarries the upstreamEthernetsignals.
The 1550nm light that reaches the photodiode (PD) is processed by two different circuits. The
first circuit measures the DC average current to determine what optical light level is hitting the
photodiode. This is converted to a logarithmic value with a scale factor of 1 Volt per decade. An
input level of -10dBm yields -1.0 Volts, 20dBm yields -2.0 Volts, etc. See Figure 3 for details of
this output. The photodiode RF output also goes to a low-noise, wide-bandwidth RF amplifier.
The output of the first amplifier goes to a wide bandwidth PIN diode attenuator which is con-
trolled by the Optical Level signal to keep the RF output constant. For each 1dB drop in the
input optical level, the RF attenuation of the PIN diode attenuator is decreased by 2dB, match-
ing the optical-to-RF conversion characteristics of the optical detector. This circuit is optimized
to operate over the optical input range from -6dBm to 0dBm. Note that these power levels
ONLY refer to the 1550nm energy in the fiber. Since there are multiple wavelengths
on the fiber, a simple optical power meter may be fooled by the 1310nm or 1490nm
power that may also be contained in the fiber. The easiest way to measure only the
1550nm power is to use the optical level function that is built into the OTPN-3850. See Figure
3 for the exact transfer function. The optical level function is calibrated at the factory and
rivalstheaccuracyofmost field opticalpower meters.

025-000641 REV X5 Page 4Olson Technology, Inc.
BLOCK DIAGRAM
Olson Technology OTPN-3850-SA
3.85GHz Wideband FTTH PON Receiver
Notes:
1) Bandwidth = 50MHz to 3,850MHz
2) Flatness 50-870MHz = ±1.5dB
950-3,850MHz = ±2.5dB
Any 20MHz = ±0.5dB
3) CATV Output Level is +23dBmV/Ch Typical at 3% OMI/Ch
4) L-Band Output Level is +13dBmV/Ch or Less (L-Band signals
require much lower CNR than CATV signals, thus can operate
at lower RF levels.)
5) AGC Range ±2dB for Opt. In from 0 dBm to -6dBm
6) At -4dBm Optical Input, Min. CATV performance is;
CNR = 47dB CSO = -55dBc CTB = -55dBc
7) Loss of Light Threshold = -10dBm ±1dB (1550nm power only)
Power
Filtering
+12 to +16
Volts DC
DC-DC
Converter
+5V Output
+12 to +16V
+5V
-5V
FWDM
1310, 1490, 1550nm
1310 & 1490nm
1550nm
Optical In
Optical Out
Optical
Level
Detect
PIN Diode
Attenuator
50-3,850MHZ
RF Output
50-3,850MHz
“F”Connector
Attenuator Control Voltage
Light Level
Optical Level
Control
Circuitry
Alarm
Out
C
E
Optical
Alarm
(-10dBm)
Photodiode
Amplifier
Amplifier

025-000641 REV X5 Page 5Olson Technology, Inc.
INSTALLATION / ENVIRONMENTAL CONSIDERATIONS
The OTPN-3850 receiver is specified to operate from -40°C to +65°C. It usually does not
require an air-conditioned environment. It should be mounted in an adequately-ventilated
area. Like all electronic equipment, it will generally have a longer life span if it is not operated
at the extremes of the temperature range. Installation in wet areas or areas of extremely high
humidityshould be avoided.Extremely dirty ordustyareas should alsobe avoided if possible.
The OTPN-3850 may be installed and operated in any position on a flat surface. The unit has
four slots in the bottom plate to accommodate mounting hardware. If mounting requires a
wood screw, use #4 pan-head sheet metal screws. These are commonly available at hardware
stores. If mounting with a machine screw (to tapped holes), use 4-40 pan-head screws.
Figure1 shows thedimensions of thebottom plate ofthe OTPN-3850.
FIGURE 1 - OTPN-3850 MOUNTING PLATE

025-000641 REV X5 Page 6Olson Technology, Inc.
OPTICAL CONNECTORS AND CLEANING
The standard optical connectors on the OTPN-3850 are SC/APC angle-
polished connectors. The internal fiber ends can be damaged by the insertion of con-
taminated connectors. Some types of customer damage to the connectors are not
covered under the warranty. Fiber connectors should never be left uncovered.
Prepackaged alcohol wipes are the most convenient means of cleaning optical connec-
tors.Cleanalcoholand lint free wipes or swabsmayalso be used.
INTERNAL CONTROLS
There are no internal user adjustments. There is no reason to open the unit. Any
attempt to do so will void the manufacturer’s warranty.
EXTERNAL INDICATORS AND CONNECTORS
There are two external indicator lights and a 10-pin electrical connector. One of the indicators
lights green to indicate that power has been applied to the unit. The second red indicator only
lightsred when the1550nm optical inputpower drops below-10dBm.
The10-pin connector matesto the followingconnector;
OTPN-3850Connector: Molex PartNumber: 87833-1020
MatingConnector: Molex PartNumber: 51110-1051
Terminals: MolexPartNumber:50394-8100
Thefunction of theten (10) pinsis shown below;
Pin1 AlarmCollector (Optically isolatedNPN transistor) (Yellow on OTPS-12A-10M)
Pin2 AlarmEmitter (Optically isolatedNPN transistor) (Blue on OTPS-12A-10M)
Pin3 InputPower, +12 to+16 Volts DC (Redon OTPS-12A-10M)
Pin4 Ground (Black onOTPS-12A-10M)
Pin5 Optical Monitor(Through1K resistor. See Figure3.) (White onOTPS-12A-10M)
Pin6 +5Volts (Through200Ohm resistor) (Orange onOTPS-12A-10M)
Pin7 (No wireonOTPS-12A-10M)
Pin8 Ground (Black on OTPS-12A-10M)
Pin9 (No wireonOTPS-12A-10M)
Pin10 (No wireonOTPS-12A-10M)
OlsonOTPS-12A-10M(Soldseparately) is recommended for use with theOTPN-3850.
GREEN
FIGURE 2 - Electrical Connector Pin Configuration

025-000641 REV X5 Page 7Olson Technology, Inc.
SETUP and OPERATION
Setting up the two transmitters shown in Figure 4 is key to successful operation. We recom-
mend the following steps. 1) Adjust the RF drive level into the CATV transmitter to yield 3%
OMI per channel. Measure it’s optical output power. 2) The optical output of the L-Band trans-
mitter should be set about 5dB below the optical output power of the CATV transmitter. This
mayrequire an opticalattenuator.
Mount the OTPN-3850 and apply power. Connect the incoming fiber (
1550nm CATV signal from the headend to the residence) to the port. Connect the
upstream fiber (the fiber that carries the 1310nm & 1490nm Ethernet signals from the resi-
dence to the headend) to the Optical Out port. Connect the Wideband Output “F” connector to
the equipment that processes the CATV and L-Band signals. Often this may be an L-Band
DeStacker. The OTPN-3850 is designed for optimum performance at an optical input of -4dBm
(1550nm power only). The easiest way to verify the 1550nm input power is to measure the
voltage on pin 5 of the electrical connector (See Figure 2 to locate pin 5). The voltage that is
measured on pin 5 can be interpreted in Figure 3. An optical input of -4dBm will yield a voltage
of about -0.365 Volts on pin 5. The OTPN-3850 will give acceptable CATV performance for a
1550nm optical input ranging from 0dBm to -6dBm. This corresponds to voltages on pin 5
from +0.115 Volts (0dBm) to -0.585 Volts (-6dBm). This is the preferred method to verify the
1550nm power. An optical power meter can be fooled if there is 1490nm or 1310nm energy on
the fiber as well. The Optical Alarm LED should be dark and the Power LED should be lit green.
Thesystem should nowbe functional.
Now verify the CATV RF Levels. They should be about +23dBmV per analog CATV channel.
Now return to the L-Band transmitter and adjust the RF drive level so that the L-Band channels
areabout +13dBmV orless.
the fiber that carries the
Optical In
FIGURE 3 - Optical Monitor Output Voltage vs. Input Light Level

025-000641 REV X5 Page 8Olson Technology, Inc.
ACCESSORIES AND SYSTEM APPLICATIONS
The OTPN-3850 makes up half of a typical FTTH PON system. The other half is the transmit
hardware. Figure 4 shows a typical configuration of a complete FTTH PON system. The two L-
Band signals are first stacked and then converted to light separately from the CATV signals.
The optical outputs of the CATV and L-Band transmitters are combined by a DWDM Mux and
then amplified by an EDFA. The EDFA output is then split a large number of times and a portion
of that signal input to numerous OTPN-3850’s. The two optical signals from the two
transmitters are added together at the photodiode and decoded as a single 50-3,850MHz RF
signal. The L-Band DeStacker then separates the two original 950-2,150MHz L-Band signals.
Typicallythe CATV signal ison the sameDeStackeroutput as theL-Band1 signal.
CATV Tx
e.g. OTOT-1000-FF
or
OTOT-1000-HH
(DWDM Ch 34)
L-Band Tx
e.g. OLAT-X4038
(DWDM Ch 38)
L-Band Stacker
e.g. Global
CATV Signals
50-870MHz
L-Band 1
950-2,150MHz
L-Band 2
950-2,150MHz
2-Channel
DWDM Mux
e.g. OT-DWDM-2
EDFA
e.g. OTEB-CO
or
OTEA-CM
Optical Splitter
e.g. OTCP-1x16
Optical Splitter
e.g. OTCP-1x16
OTPN-3850
Receiver
L-Band DeStacker
e.g. Global
CATV+L-Band 1
50-2,150MHz
L-Band 2
950-2,150MHz
Note: For simplicity, the hardware associated with the Ethernet Signals
usually associated with this type of system are not fully shown.
RF
Optical
Ethernet Equipment
RF
RF
Optical
Optical
Optical
Optical
Optical
FIGURE 4 - Typical SystemApplication Using the OTPN-3850
Diplex
Filter CATV
L-Band 1
950-2,150MHz
Optical output power is
typically at least 5dB below
the CATV transmitter optical
output power. This may
require an attenuator