Download 910 User Manual - Electro Tech Systems

7934 storage oscilloscopes. Digital Storage Oscilloscopes (DSO)
should also have a minimum frequency response of 350 MHz or better
and a sampling rate 1 Gs/sec or better. Tektronix TDS 300 and 3000
series, Agilent Technologies Model DSO6102A or any other
oscilloscope that meet this criteria are satisfactory. If CDM testing is
also to be performed then a 1GHz scope should be obtained to
perform all three tests. Tektronix Models CT-1 or CT-2 current
transducers are satisfactory for detecting the current pulse.
The 50 Ohm impedance of the current probe must be matched to the
input impedance of the oscilloscope. For oscilloscopes with only a 1
MegOhm input impedance, a terminator is available to match the 50
Ohm impedance of the probe to the 1 MegOhm impedance of the
scope. Because of the very high frequencies being measured it may be
necessary to double shield the current probe.
Figure 4.0-1 is the waveform requirement.
The current pulse shall have the following characteristics:
Tr
Td
Ip
Ir
(rise time)
(decay time
(peak current)
(ringing)
2-10 nanoseconds
150 +20 nanoseconds
within +10%
The decay shall be smooth, with
ringing, break points, double time
constants or discontinuities less
than 15% Ip maximum, but not
observable 100 nanoseconds after
start of the pulse.
Figure 4.0-1: Current Waveform per Method 3015.7
To obtain this waveform place a 1.25” (31mm), 18 gauge wire through the
CT-1 sensor then connect the minigrabber leads to the wire. The current
probe (Tektronix CT-1) is polarized and is marked with a + on one side. When
20