Tektronix 2213 - Page 62

DEL AY E
D-S
WEEP
M
AG
N I F ICATIO N
Th e delaye d -swee p featu r e of t he 2213 Α can be u sed to
provi de h ig he r a pp arent magnification t han is p rovide d by
t he

X10 M agnifier switc
h .
App a
r
e n t mag
n ificatio n occu r
s
as
α
r
esu lt of dis p laying α selected p ortio
n
of
t h e trace
(I N
T
EN S
H
O
R
IZO
N
TA
L M
OD
E)
at
α
faster
swee p s p eed
(DL Y'D H O R IZO
N
TA L M OD E) .
Wh en I
N
T EN S
H
O
R IZO N TA L M
OD
E
is
selecte d , t he i n-
tensified zone i n dicates bot
h t h e locatio na nd t he start of
t he sweep t
h
at
will
b e displayed
in D L Y'D H O R IZO N TA L
M
OD
E . P ositio n ing of t h e inte n sified zone (i .e ., setting t h e
amount of time betwee
n
start of t
h
e swee p
and start of t h e
i n tensified zone) is accom p lis h ed wit
h
t h
e MUL TI PL I ER
cont r ol and t
h
e
D E
LAY TIME
R ange Selecto r switc h . At
h ig h er swee p s p eeds t h
e
delay
time can be ad j usted to al-
low t
h
e starting
point
of
t h
e
i n
te
n sified zone to occur p ast
t h
e
e n
d of
t he d is p lay .
W it h eit h er I NT EN S or D L Y'D H O R IZO N TA L M OD E se-
lected, t he
D
EL AY TIME R a
n
ge Selector switc h and
t h
e
MUL TI PL I ER co n trol p r ovide continuo u sly variable p ositio
n -
i n g of t he start of t he d elaye d swee p . T h eD ELAYTIME
R
ange Selector switc h allows t
h
e
start
of
t h
e
intensified
zone
to b
e p
laced
near
t
h
e point of
i n
terest,
w h ile t h
e
MUL TI
PL I
ER control p rovides fine
a
dju stment
of
t he inten-
sifie d zo ne .
Wh en viewing
aperio
d ic signals
(suc
h
as
complex d igital
waveforms) wit h DL Y'D H
O
R
IZO
N TA L M
OD
E selected,
t
h e
sta
r t of t h
e swee p may
n ot
be
at t h
e same
poi n t
as
t h
e
start
of t he intensified zon e . It may be n ecessary to con n ect α
r efe r e nce signal from t he system under test to t he ΕΧΤ
I NPU T
con
n ecto r a nd to a dju st V A RHO L DO FF
co
n trol to
ensu r e cor r ect dis p lay of t he selected p ortio n of t h e
waveform .
U si ng delaye d -swee p magnification may prod u ce α dis-
play wit h some
slig
h t
h
orizontal movement (pulse j itter) .
P
ulse
j itter
includes not only t he
i nh erent
u
n certai n ty
of
trig-
geri
n g t h
e d elayed swee p at exactly
t h
e same t
r igger poi n t
eac
h time, bu t also j itter t h
at may b
e p
rese
n t i n t h
e
i n put
signal .
T he followi ng p r oced u re explains h ow to op erate t he de-
layed-sweep feature a nd to determi ne t he res u lting ap par-
ent magnificatio n factor .
1 . P reset instrument controls and o b tai n α b aseli ne
tr ace .
2 . Apply
t h
e
signal to eit h er vertical chann el in p ut co n -
n ector an d set t he VER TICA L M OD E switc h to dis p lay t he
ch annel
used
.
3 . Set t h e appro p riate VO LTS/DI V switc h to produ ce α
dis p lay of a pp roximately 5 divisions in am p litude and cen ter
t h e dis p lay .
4 . Set t he
S
E C/DI V switc h to α swee p
speed
w h ic h dis-
p lays at least one com p lete waveform cycle .
5 . Select I NT EN S H OR IZO N TA L M OD E and set t h e
D EL AY
TIME
R ange Selecto r switc h for t he app ro p r iate de-
layed time
.
Ad
ju st
t h e MUL TI PL I ER control to p ositio n t h e
start
of t h
e
intensified zone
to
t h e p ortion
of
t h
e
dis p
lay
to
be magnified .
NOTE
Si n ce t he Delay R an ges a r e ove r la pp ing a nd delay f it-
ter is p ro p ortio n al to maxim u m delay of t h e ra n ge,
always use t he smallest delay ra n ge w hen in t he over-
la pp i nga r eas .
E XA MPLE : if t he d elay required Is 0 .9 ms, use t he
20, u s r an ge (less t h an 100 ns j itte
r )
instead of
t h
e
0 .4 ms ra n ge (less t han 2, us fitter) .