The amplitude of the waveform can be increased or decreased by
using the Oscillograph’s GAIN control [M] and the Preamplifier’s
GAIN control (6).
If either of the GAIN controls are re-adjusted, it may be necessary to
adjust the Preamplifier’s DC LEVEL control (3) to bring the pen back to
the center of the chart.
Drift caused by the polarization of the electrodes can be overcome
by selecting AC on the Preamplifier’s AC/DC control (5).
Filtering can be introduced using the Preamplifier’s FREQ CUT
control (4).
If you are performing a 5-lead ECG you may select the various limb
configurations using switch (2).
Calibrate the waveform, using the Oscillograph’s the CAL 0.1 switch [Q].
This will cause the pen to move on the chart. The distance moved by
the pen when this switch is operated, is equivalent to 0.1 V (100 mV).
You can now calculate how many mV equals 1 mm of pen deflection.
Let this equal d.
Measure the height of the waveform in mm. Let this value equal h.
Let g equal the gain selected on control (6).
Therefore the waveform (mV) = d x h
g
11
Figure 6
PEN ZERO
8
GAIN
2
3
4
5
6
7
9
10
1
0
CAL. 0-1V.
DIRECT INPUT
D.C.
A.C.
EVENT
INTERFACE
OFF
CHART SPEED
2
3
4
5
6
7
9
10
1
0
POWER
HARVARD
[L]
[Q]
[N]
[M]
