Table of Contents
Advertisement
Basic Applications— 2221 Operators
ting , since large voltages may distort the display .
For example , with a VOLTS /DIV switch setting
of 0.5 V , the voltage applied to that channel
input should not exceed about 4 volts .
rejection .
The precautions
given under the preceding
' Algebraic Addition " procedure should be observed .
EXAMPLE: The signal applied to the Channel 1 input
connector contains unwanted frequency components
(see Figure 6-4A ) . To remove the undesired
com
ponents , use the following procedure:
EXAMPLE : Using the graticule center line as
V , the
Channel 1 signal is at a 3 - division , positive dc level (see
Figure 6-3A ) .
1. Preset instrument controls and obtain a baseline
trace .
1. Multiply 3 divisions by the VOLTS / DIV switch setting
to determine the dc-level value .
2. Apply
the
signal containing the unwanted
com
ponents to the Channel 1 input .
2. To the Channel 2 input connector, apply a negative
dc level (or positive level , using the Channel 2 INVERT
switch ) whose value was determined in step 1 ( see Figure
6-3B ).
3. Apply the unwanted signal to the Channel 2 input .
4. Select BOTH and ALT VERTICAL MODE and press
in the Channel 2 INVERT button .
3. Select ADD and BOTH VERTICAL MODE to place
the resultant display within the operating range of the
Vertical POSITION controls ( see Figure 6-3C ).
5. Adjust the Channel 2 VOLTS/ DIV switch and Vari
able control so the Channel 2 display is approximately the
same amplitude as the undesired portion of the Channel 1
display (see Figure 6-4A ).
L
COMMON- MODE REJECTION
The ADD mode can also be used to display signals that
contain undesirable frequency components . The undesir
able components can be eliminated through common -mode
6. Select ADD VERTICAL MODE and slightly readjust
the Channel 2 VOLTS /DIV Variable control for maximum
cancellation of the undesired signal component (see Figure
6-4B ).
}
ZZO 72
: 0 0
100
100
90
90
POSITIVE LEVEL
M
OV
OV
NEGATIVE OFFSET
I D
.
| 01
12
50mV
50us
50mV
50us
50mV + SØmV
Sous
( C) RESULTANT DISPLAY .
( A ) CHANNEL 1 SIGNAL
WITH 3 DIVISIONS OF
POSITIVE DC LEVEL .
( B ) CHANNEL 2 DISPLAY
WITH 3 DIVISIONS OF
NEGATIVE OFFSET.
4998-32
Figure 6-3. Algebraic addition,
u
6-6
u
Advertisement
Table of Contents
