Tektronix 1502C 用户手册
Operator Tutorial
1502C MTDR User Manual
2–11
Noise
On a longer cable, “grass” might appear on the displayed waveform. This is
primarily caused by the cable acting as an antenna, picking up nearby electrical
noise.
primarily caused by the cable acting as an antenna, picking up nearby electrical
noise.
1. Set the 1502C front-panel controls:
CABLE
3-ft cable
NOISE FILTER
1 avg
VERT SCALE
500 m
r
DIST/DIV
1 ft (0.25 m)
Vp
.66
n
o
POSITION
40.000 ft
2. Attach the 50
W terminator to the end of the test cable using the female-to-
female BNC adaptor (both of these items are supplied with the instrument).
3. Increase VERT SCALE to 1.00 m
r. Use the
n
o
POSITION control to keep
the waveform on the display. As the VERT SCALE setting increases, there
will be noise in the form of a moving, fuzz-like waveform with a few
random spikes.
will be noise in the form of a moving, fuzz-like waveform with a few
random spikes.
O
N
ac
40.000 ft
O
F
F
O
F
F
O
F
F
Figure 2–14: Noise on the Waveform
4. Turn the NOISE FILTER control clockwise to 8. This will average out much
of the noise.