Reference
80E00 Electrical Sampling Modules User Manual
19
propagation time from the acquisition point to the short in the device under test
and back. See Figure 8.
250 mV
0 V
E
i
E
r
Figure 8: Step generator with a shorted output
Operation Into a 50
Ω
Load.
Initially, the diode switch is conducting --10 mA.
Since the step-generator output is connected to a 50
Ω
load, the resistance to
ground at the acquisition point is 25
Ω
(because of the internal 50
Ω
impedance).
+250 mV
0 V
E
i
E
r
Figure 9: Step generation with a 50
Ω
load
When the diode switch opens (reverse-biased), apparent resistance to ground at
the acquisition point (and at the channel connector) is 25
Ω
because the internal
termination resistance is 50
Ω
in parallel with the connector impedance of 50
Ω.
The voltage at the acquisition point rises to +250 mV.
The transition propagates to the 50
Ω
load and no reflection occurs.
Operation Into an Open.
Initially, the diode switch is conducting --10 mA. Since
the step-generator output is open, the resistance to ground at the acquisition point
is 50
Ω
(because of the internal 50
Ω
impedance).
+250 mV
0 V
+500 mV
E
i
E
r
Figure 10: Step generation with an open circuit
Содержание 80E01
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Страница 10: ...Environmental Considerations vi 80E00 Electrical Sampling Modules User Manual...
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Страница 22: ...Getting Started 10 80E00 Electrical Sampling Modules User Manual...
Страница 28: ...Operating Basics 16 80E00 Electrical Sampling Modules User Manual...