Time Duration; Time D U Ra Tio N; Amplitude Comparison - Tektronix 2213A Instruction Manual

Operating Procedures— 2213A Operators
V
C H I SIGNAL
N
m
\
WITH UNWANTED
LINE FREQUENCY
-s
COMPONENT
%
-
CH2 SIGNAL
\
FROM LINE
FREQUENCY
SOURCE
(A) C H I A N D C H 2 SIGNALS.
SIGNAL WITH
LINE FREQUENCY
COMPONENT
CANCELED
OUT
'
(B) RESULTANT SIGNAL.
Figure 4-3. Common-mode rejection.
6. 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 4-3B).
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.
4-4
• ^
>
y \
—
* ^
*
:
*
~
•x
X
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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. 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).
....
1 — ;
-
fl
4
1
_ L _ L
X
:
READ
PRECENT
RATIO
Figure 4-4. Voltage ratios.
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.
REFERENCE
SIGNAL
....
—
UNKNO W N
SIGNAL
1
X
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