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Operating
Procedures-
2215A Operators
CH1
SIGNAL
-
WITH
UNWANTED
CH2 SIGNAL
FROM
LINE
FREQUENCY
SOURCE
(A)
CH1 AND
C H2
SIGNALS.
I
...
I
---------
SIGNAL
WITH
LINE
FREQUENCY
COMPON ENT
CANCELED
OUT
I
...
....
..
. ",.
(Bl
RESULTANT
SIGNAL.
4732-09
Figure 4-3. Common-mode rejection.
7. Select ADD VERTICAL
MODE
and press in the
INVERT
button,
and slightly readjust the CH 2 VOLTS/DIV
Variable
control
for maximum cancellation of the undesired
signal component (see Figure 4-38).
Amplitude
Comparison (Ratio)
In some applications it
may
be necessary to establish a
set of deflection factors other than those indicated by the
VOLTS/DIV switch settings. This is useful for comparing
unknown
signals to a reference signal of known amplitude.
To
accomplish
this,
a reference
signal
of known amplitude is
first set to an exact number of vertical divisions
by
adjusting
the VOLTS/DIV switch and
Variable
control. Unknown
sig-
nals can then be quickly and accurately compared
with
the
reference signal
without
disturbing
the
setting of the
VOLTS/DIV
Variable
control. This procedure is as follows:
1
.
Preset instrument controls
and
obtain a baseline
trace.
2. Apply the reference signal to either
vertical
channel
input and set the
VERTICAL MODE
switch
to
display
the
channel used.
3. Set the amplitude of the reference signal to five
verti-
cal divisions by adjusting the
VOLTS/DIV
switch and
VOLTS/DIV
Variable control.
4-4
-
READ
PRECENT
RATIO
Figure
4-4. Voltage ratios.
REFEREN CE
SIGNAL
UNKNOWN
SIGNAL
4732-10
4.
Disconnect
the
reference
signal
and apply the
un-
known signal to be measured to the same channel input.
Adjust the
vertical
position of the waveform so that its bot-
tom edge just touches the
0%
line on the crt.
5.
Horizontally position the waveform so that its top
most features cross the center vertical graticule line (see
Figure
4-4).
6. Read the percent
ratio
directly
from
the graduations
of the center
line,
referring to the
0%
and
100%
percentage
marks on the left edge of the
graticule
(1 minor division
equals
4%
for a 5-division
display).
NONDELAYED
TIME MEASUREMENTS
Time Duration
To
measure
time between two points on a
waveform,
use the following
procedure:
1
.
Preset instrument
controls and obtain a baseline
trace.
2.
Apply
the
signal
to either
vertical-channel input
con-
nector
and
set the
VERTICAL MODE
switch to
display
the
channel used.
3. Adjust
the
A
TRIGGER
LEVEL
control
to
obtain a sta-
ble
display.
4. Set the A SEC/DIV switch to
display
one
complete
period
of the waveform. Ensure that
the SEC/DIV Variable
control
is
in the
CAL detent.
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