Tektronix 2235 Operator's Manual

10 . Calculate t
h
e
instantaneo us voltage, using t he fol-

met hod s coul d b e used eit he r to elimi n ate ot he r u n wa n ted
lowi ng fo r mula :

frequency components or to p rovi de α d o offset .
V
O
L TS/DI V
I n sta n ta-

vertical

switc h setting

1 .
Preset instrume n t co n trols an d obtai n α baseli ne
neo us

= d eflection
χ

p
ola
r
ity

χ

i n
dicate
d by 1 Χ
trace .
( d
ivisions)

(+
Or -)

(or 10 Χ PR O BE

.
w h en 10 Χ pro b e
is used)

2 .
Apply
t he signal containing t he un wante d li n e-
E XA MPLE : T he measured vertical d eflection
from t h
e

f r
e q
uency com ponents to t he CH 1 inp u t connector .
r efe r e nce li ne is
4
.6 d
ivisions
(see
Figure
4-3),
t h
e wave-
form p oi n t is above t he refe
r
e
n
ce
li n
e, α 10
Χ
atte
n
uato
r
probe is b
eing
u se d , an d
t h
e
V
O
L TS/DI V switc h is set to

3 . Apply α line-freq uency signal to t he C H 2 input con-
2 V (at 10
Χ PR
O
BE setting) .

n ecto r . To maximize can cellatio n , t he sig n al a pp lied to
C hann el 2 must be in p hase wit h t he unwanted line-
fre quency compo n ent on t h e C han nel 1 signal .
Substit u
ting
t
h
e
given
values :
Insta n ta n eous V oltage =
4
.6
div χ
(+1)
χ 2 V /div = 9 .2 V .
Algeb r aic
A
d dition
W it h t he VER TICA L M OD E switc hes set to BOTH and
ADD, t he waveform d isplayed is t h e alge b raic su m of t h e
signals a pp lied to t he C
h annel 1
an d C
h annel 2 inp
u
ts (C H 1
+
C H 2) . If t he C h a nn el 2
I NVER T
mode is selected (C
h an-
nel 2 POSITIO N co n trol kn ob p ulled out), t
h
e wavefo
r m
dis-
playe d is t
h
e d
ifference b etween t he sig n als a pp lied to t h e
C h annel 1 and C h annel 2
inp
u ts (C
H 1 -
C
H 2) . Wh
en b ot
h
ve r tical ch a nn els are set to t h e same voltage settings,
t h
e
d eflectio n facto
r
is eq ual to t
h
at
i n
d icate d by
eit he r
V O L
TS/DI V switc h .
The following general precautions should b e observed
when using the ADD mode .
α . Do not exceed t he input voltage
r ating
of the
oscilloscope .
b . Do not apply signals that exceed the equivalent of
a b out
eig h t times t he V O L TS/DI V switc h setti n gs,
since large voltages may d istort t
h
e d isplay .
For ex-
am p le, wit h α V O L TS/DI
V
switc
h
setti
ng
of 0 .5
V, t h
e
voltage a pp lied to t
h
at c
h
an
n
el s
h
ould
n
ot
exceed
ap-
proximately
4 volts
.
c . Use C hann el 1 a
n
d C
h annel 2 POSITIO N
co
n trol
settings
w h
ic
h most nearly p ositio n t he sig n al on eac h
chann el to midscreen, w hen viewe d
in
eit
h
er C
H 1
or
CH2 VER TICA L M OD E . T h is ensures t h e g
r
eatest
dynamic ra nge for ADD mode op e
r
atio
n .
d . To attai n similar
r
esp onse
f r
om eac
h
c
h annel, set
b ot h t he C h a nn el 1 a
n
d C
h
a
n nel 2 I np
ut Cou p
li ng
switc h
es to
t he same p ositio n .
Commo n - M ode R e j ectio
n
O p erating Pr oce dur es-2235 ΑΝ / US M -488 O pe r ato r s
4 . Select
BOTH
and AL T VER TICA L M OD E a nd set
bot
h VO L TS/DI V switc h es to prod u ce d isplays of a pp roxi-
mately
4
o
r
5
divisio n
s in am
p litude .
5 . Ad j ust t h e CH 2 VO L TS/DI V switc h and C H 2
V O L TS/DI V V a r iable con trol so t h at t he C h annel 2 display is
app roximately t he same amplit ude as t he undesired p ortion
of t h e C h annel 1 d isplay (see F ig u re 4-4 Α ) .
CH 1 SIG N A L

_
WITH UNWANTED
φ L I NE FRE Q
UEN CY

_
COMPONENT
CH2 SIGNAL
FROM LINE
FREQUENCY η
SOUR CE

σι . . .
. .
( Α ) CH 1 A N D C H2 SIG N A LS .
φ
SIG NA L W IT H -

-
L I NE FRE Q UEN CY
CO MP O NEN T
CA N C ELE D
ρ
οχ
. .
OUT
( Β ) RE S ULTA N T SIG N A L .
The followi ng pr ocedu
r
e s
h
ows
h
ow to
elimi n ate
un-
wanted ac
input-power fre quency com p one n ts . Similar

Fig ur
e
4- α . Commo n -mo d
e
re j ectio n .
4732-09

Tektronix 2235 Specifications

General

Brand	Tektronix
Model	2235
Category	Test Equipment
Language	English