4
FRRA Series
Instruction Manual
Figure 1 shows the end-to-end RF gain of the Transmitter/Receiver combination. The main factor that determines the end-
to-end gain is the amount of light that reaches the receiver. A typical transmitter/receiver combination will have unity gain
(0 dB) at a received optical power of 0 dBm (1 milliwatt). The RF gain changes by 2 dB for every 1 dB change in received
optical power. This curve will shift up and down by 3 or 4 dB due to variations in the lasers and amplifiers, however the
slope will always be 2.
The receiver contains a tri-colored indicator LED that may be used to determine the optical signal strength reaching the
receiver. When the LED is green, the signal is at optimum input levels. When the LED is yellow, the optical signal has
dropped to insufficient levels (<-6 dBm), and when the LED is red, the signal is overloading the receiver (>+3 dBm). Because
the LED is always lit, it also serves as a positive indication that the unit is turned on.
The Fiber Optic Link is optimized for single-mode operation only. Use of multi-mode fiber is not recommended, even for
short distances, because of the large amount of modal noise that could result.
This product conforms to European Community Directive #89-336-EE-C for electromagnetic compatibility requirements.
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
2
4
6
8
10
Figure 1 - End-to-End Link
Operating Instructions
The optical emission from the units are laser-based and may
present eye hazards if improperly used. As always, be careful
when working with optical fibers. Fibers can cause painful
injury if they penetrate the skin.
NEVER USE ANY KIND OF OPTICAL INSTRUMENT
TO VIEW THE OPTICAL OUTPUT OF THE UNIT.
WARNING!
Figure 3 - Rack Mount Front Panel
Input Optical Power
The FRRA’s power monitor provides a proportional DC voltage output to optical milli-Watt input. The scale is 1 Volt DC
equals 1 mW or 0 dBm of optical input. A standard voltmeter can be used to accurately determine the optical input
level into the node. Prior to applying AC power, make sure the gain and slope controls are fully counter-clockwise.
Connect the optical input and apply AC power. Insert the voltmeter’s positive probe into the jack marked “optical
power 1V/mW”, and the negative probe into the “ground” jack (see Figure 3). Measure the DC voltage and refer to
the FRRA Configuration Table in Figure 4 for the corresponding optical input level conversion to mW and dBm.
POWER
OUTPUT TEST
SLOPE
FLAT
GAIN
MAX
-20dB
GROUND
OPTICAL POWER
1V/mW
INPUT
ALARM
FRRA SERIES
FIBER RECEIVER DISTRIBUTION AMP
Содержание FRRA-S4A-860-43P
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