Fluke CombiScope PM3370B User Manual page 66

HOW TO USE THE INSTRUMENT
VERTICAL MENU
The 200 MHz models offer the selection of an input impedance of 50 on all input
channels. The EXTTRIG input has no 50
is a subfunction in VERT MENU.
The 50 input impedance is used to obtain a correct impedance to match signal
sources of the same impedance. For interconnection, a coaxial 50
be used. The 50
Low Impedance).
- Disconnect all signals from the inputs.
- Using a 50 coaxial cable, connect a 4 Vpp, 2 kHz signal from a
generator with 50
- Press the AUTOSET key.
- Press VERT MENU.
- Press the 50 CH1 softkey.
CH1 1V
Observe that the displayed signal amplitude changes to half of the original
amplitude. This is caused by the change of the input impedance to 50 , which
results in a voltage division between the 50 output of the generator and the 50
input of the oscilloscope.
- Remove the input signal from CH1.
VERTICAL
- Connect the probe again.
Since the 10:1 probe delivered with the instrument is a high
CHx
impedance probe, the 50
At the same time, the sensitivity readout is adjusted automatically
detector
when a 10:1 or 100:1 probe is used. This way you don't have to
ST6021
multiply the displayed amplitude by 10 or 100 when you use a Fluke probe with
range indication.
position is indicated on the display with the Lz sign (Low Z =
output impedance to channel 1.
VERT MENU
possibility. The impedance selection
50 CH.
ON
OFF
CH1
PROBE RANGE INDICATOR
termination is automatically turned off.
cable must
L Z
1V
ST5968
9312
4 - 21
50