7
FIBT/MIBT Series
Instruction Manual
RF LEVEL
FIBT-S3A SERIES
FIBER BROADBAND TRANSMITTER
LASER
POWER
0.1V/mW
LASER
CURRENT
1V/50mA
ADJUST
STATUS
GRD PWR COOLER RF LASER
A B C
D E FHG
A. RF Level Adjust - Provides 4 dB of variable attenuation of the RF
input level. Allows precise input level adjustment to the nominal
level requirements noted in Fig. 3.1 to provide a green indication
on the tri-color RF LED.
B. Laser Power Monitor - This jack allows accurate measurements of
the optical output power with a standard voltmeter. The voltage
is scaled at 0.1VDC per mW of optical output.
Therefore, mW = VDC x 10.
Output level in dBm = 10 x LOG(mW).
Example: A 1.0 VDC reading is therefore a 10 mW or
10 dBm of optical output power. Refer to the table below.
E. Power Indicator LED (Green LED) - The LED is on when the
unit is receiving AC power and off when there is no power to
the unit.
F. Cooler Status LED (Bi-colored Green/Red LED) - When
green, this LED indicates that the laser cooler (TEC) is functioning nor-
mally, and the laser temperature is stable.
Figure 2.1 MIBT Front
2.4 Front Panel Unit Drawings and Diagram Notes
2.4.1 Front Panel Diagram Notes
Laser Power
0.1 V/mW Monitor
VDC dBm mW
0.25 4 2.51
0.32 5 3.16
0.40 6 3.98
0.50 7 5.01
0.63 8 6.31
0.79 9 7.94
1.00 10 10.00
1.26 11 12.59
1.59 12 15.85
2.00 13 19.95
2.51 14 25.12
3.16 15 31.62
3.98 16 39.81
It is normal for this LED to be red or change from
red to green in the first ten seconds after power
has been applied to the transmitter. If the LED
turns red at any time other than in the first ten
seconds of operation, the unit should be turned off IMMEDIATELY to avoid laser
damage.
C. Laser Current Monitor - Provides a scaled DC output of 1V per 50
mA of laser current. Nominal current draw varies between lasers.
Refer to the transmitter’s birth certificate or record the voltage
reading upon the initial installation. Lasers draw more current as
they age. A sudden change in current or a 20% increase from the
initial recorded level indicates a laser problem. If this happens, the
transmitter should be returned to Blonder Tongue for servicing.
D. Ground Connection - For laser power and laser current monitors.
G. RF Input Level LED (Tri-colored Green/Yellow/Red) - This LED
indicates the RF signal input level into the transmitter. The RF
input indicator is green when the RF signal input is within ±1 dB
of the optimum input level. When the signal input falls below the
optimum ±1 dB range, the LED becomes yellow. When the signal
input rises above the optimum range, the LED turns red.
H. Laser Status LED (Bi-colored Green/Red LED) - When green, this
LED indicates that the laser is initialized and operating normally.
It is normal for this LED to be red or
change from red to green in the first
ten seconds after power has been
applied to the transmitter. During
this ten second initialization period, the laser is held in shut-
down mode while the rest of the circuitry initializes. It is then
switched to normal operation, and the LED turns green. If
the LED turns red at any other time, this may indicate a laser
failure.
MIBT-S3A
SERIES
LASER
POWER
0.1V/mW
RF LEVEL
ADJUST
dBm
LASER
CURRENT
1V/50mA
GRD
PWR
COOLER
S
T
A
T
U
S
RF
LASER
A
D
E
FB
C
G
H
Figure 2.1 FIBT Front
