TB 9-6625-2309-35
l. To find lowest A = T+ value for FOCUS generated pulse at cursor A, perform steps
(1) through (6) below:
(1) Press FAST SCAN pushbutton, wait for LASER ON/AVG to go off display.
(2) Press digital delay generator MENU DELAY pushbutton to decrease A = T+ in
3 nanosecond increments.
(3) Repeat technique of (1) and (2) above until beginning of FOCUS generated pulse
shifts to left just in front of cursor A (fig. 24).
(4) Press digital delay generator MENU DELAY pushbutton to increase A = T+ by
1 nanosecond.
(5) Press FAST SCAN pushbutton and wait for LASER ON/AVG to go off display.
(6) Repeat technique of (4) and (5) above until very beginning of FOCUS generated
pulse is on cursor A, figure 25. (Digital delay generator A = T+ value will be lowest value to
obtain this condition).
0 km
4 km
8 km
A
974. 0
982. 0
990. 0
↑ 8. 0 dB / div
2. 0 m / div →
A = 982. 0 m
INDEX: 1. 4990
B = 4, 927. 9 m
λ: 850 MM
PW:
40 ns
A→B = 3, 945. 9 m
# AVG = 4, 096. 0
2-POINT LOSS: 14. 50 dB
Figure 25. Example of
FOCUS generated pulse placed in
best possible position
with respect to cursor A (TD-260C).
m. Record this: A = T+ value in nanoseconds (ns) and use this A = T+ value as
"Equivalent Delay" in calculations below.
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