Tektronix Telescope 1502C Uživatelský manuál Strana 59

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Operator Tutorial
1502C MTDR User Manual
29
50 W impedance plus 9.5 W series resistance. You can check this by putting a
known reference on the end of the cable and measuring its impedance with
ohms-at-cursor. The difference between the actual reading and the expected
reference reading is the series resistance.
O
F
F
O
F
F
O
F
F
O
N
ac
59.5 W
408.000 ft
Ohms-at-Cursor
Readout
Figure 210: Ohms-at-Cursor
7. Turn the
n
o
POSITION control to set the cursor near the beginning of the
cable. In this example, the ohms-at-cursor reading is 50.9 W at 17.880 feet.
There is less loss at the beginning of the cable because there is less series
resistance.
O
F
F
O
F
F
O
F
F
O
N
ac
50.9 W
17.880 ft
Figure 211: Ohms-at-Cursor Near Beginning of Cable
8. Turn the
n
o
POSITION control clockwise to set the cursor past the reflected
pulse. Note that the ohms-at-cursor reading is 1 kW.
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