Fluke Biomedical QED 6 - Manual (Page 41)

Operation
Viewing Oscilloscope Output
2
2-15
2. Make the following settings:
a. Set the oscilloscope trigger on external and connect a lead between
the input of the oscilloscope and the external trigger input.
b. Set the time scale on the oscilloscope to 1 ms / division and adjust to
the desired expansion after observing the waveform output.
c. Set the gain on the oscilloscope to 0.2 v / division and adjust to the
desired level after observing the waveform.
3. Activate the storage control on the oscilloscope.
4. For most applications, set the oscilloscope input coupling control to ac
mode.
Note
If the defibrillator under test uses a discharge waveform with sizable
dc components (trapezoidal or pulsatile discharge), improved output
waveform fidelity can be obtained by placing the oscilloscope in the
dc-coupling mode.
Viewing a Test
1. Initiate a test by following the steps described under Measuring
Defibrillator Energy, above.
The waveform is 1/1450 when in the 1000 joule range and 1/440 in the
100 joule range of the input voltage through 50
Ω . The actual magnitude
of the discharge voltage can be obtained by using the following equation:
V
discharge
= V
scope
(1450) High range
V
discharge
= V
scope
(440) Low range
2. Observe the waveform as it appears on the oscilloscope. Repeatedly
discharge the defibrillator while adjusting the time and the gain to the
optimal scale for observing the waveform.
Note
If the waveform does not appear on the oscilloscope, readjust the
trigger levels on the oscilloscope and repeat the appropriate steps in
the procedure.