TB 9-6625-2309-35
NOTE
At Index = 1.4990, 10 sec A = T+ delay corresponds to
approximately 1.0 km location where leading edge of FOCUS
generated pulse will occur on TI display; 20 sec to 2.0 km, etc.
NOTE
For optical module TD-285C, set digital delay/pulse generator
for A=T+0.000020000000 (20 sec).
(4) Perform steps (a) and (b) below:
(a) Press REAL TIME pushbutton and adjust FOCUS VAR ATTN 1 control
for minimum noise on trace prior to FOCUS generated pulse (fig. 4).
0 km
4 km
8 km
A
V- OFFSET:
0.00 dB
FOCUS
GENERATED
PULSE
ADJUST FOR
MINIMUM NOISE
0. 0
2, 048. 0
4,095. 9
↑ 8.0 dB / div
512.0 m / div →
A = 1, 024. 0 m
INDEX: 1. 4990
B = 4, 927. 9 m
λ: 850 MM
PW: 5 ns
A→B = 3, 903.9 m
# AVG = 4, 096. 0
2-POINT LOSS: 19.76 dB
(b) Press FAST SCAN pushbutton and wait for LASER ON/AVG indication on TI
display to go off.
NOTE
Digital delay/pulse generator TRIG and BUSY lights will be
illuminated during TI acquisition cycle indicating a good
external trigger and equipment working correctly.
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