Tektronix 454A - Page 125

e . C HE C K - C
R T d i s p l ay f i ve d i vi si ons or
gr eat er i n

d . C HE C K -
L
engt
h of eac h segment i s bet ween 2
. 0
and
am p
l i t u d e ( 400zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA ¼ V / d i vi si on, or l ess, mi ni m
u m def l ect i on

3 . 25 di vi si ons ( 400 t o 650 nanosecon d s ; see F i g . 5- 1) .
f act or ) .
e . C HE C K - C R T d i s p l ay f or com p l et e bl an k i ng of
f . Di sconnect al l t est
e q ui p ment .

swi t c h i ng t r ansi ent s bet ween c h o p p e d segment s ( see
F i g .
5- 1) .
11 . C h ec k Al t er nat e O p er at i on
± .
Set t h
e
M OD E swi t c h t o A L T
.
b . P osi t i on t h e t r aces about t wo d i vi si on a p ar t .
c . T u r n t h e ‘ ¤™œ• / DI V swi t c h t h r oug h out i t s r ange .
d . C HE C
K - Tr ace al t er nat i on
b
et ween C h annel 1 an
d
2
at al l
swee p r at es .
At
f ast er sweep r at es, al t er nat i on wi l l not
be ap p ar e n t ; d i s p l ay wi l l a p pear as t wo t r aces on t h e scr een .
12 . C h ec k C h o pp e d O p er at i on
± . Set t h e V er t i cal M OD E swi t c h t o C H O P , t h e ™• ¤
T R I G swi t c h t o N O RM, t h e H O R I Z DI S PL AY swi t c h t o ‘ ,
t h e ‘ T R I GG ER I N G
LEVEL cont r ol t o 0, an d t h e ‘
¤™œ• / DI V swi t c h t o . 2 ¼ s .
b . P osi t i on t h e t wo t r aces about
4 d
i vi si o
n s apar t .
c . C HE C K - D u r at i on of eac
h cycl e of t h e c h o p p ed wave-
f or m
i s
abo
u t f i ve
d
i vi si ons ( see
F i g . 5- 1) .
- - Ë

Ch o pp e d r e p et i t i o n

FF
¹

r at e
co
r
r ect wi t h i n

1
¤

t h ese l i
m
i t s
¹

¹
i

j

Swi t c h i ng t r ansi e n t
b l a nk e d o u t
¹
¹
¹

¹
¹
¹

¹
¹
¹

¹
¹

¹

¹
¹

i

¯
¹

¹

¹
E ac h segment 2 . 0 t o 3 . 25
d i vi si o n s i n l e n gt h
P er f or mance C h ec k - 454 ‘ / R 454A
13 . C h ec k U pp er V er t i cal Ban dwi d t h L i mi t of
C h annel s 1 and 2
± . Set t h e V er t i cal M
OD
E swi t c h t o C H 1, t h e i n p ut
co u p l i ng swi t c h es t o DC, t h e V
O
L TS/ DI V swi t c h es t o 10
m V , t h e H O R I Z DI S PL AY swi t c h t o ‘ , t h e ‘ ¤™œ• / DI V
swi t c h t o . 5 ms, an d t h e ‘ T R I GG ER I N G LEVEL cont r ol
f ul l y cl oc k wi se .
b . Connect t h e o u t pu t of t h e h i g h - f r e q uency co n st ant -
am p l i t u d e si gnal ge n er at or ( 067- 0532- 01) t o t h e C H 1 i n p ut
connect or t h r oug h ± G R 10 § at t en u at or and ± G R 50
©
i n- l i ne t er mi nat i on .
c . A dj u st t h e h i g h - f r e qu ency si gnal gene rat or f or 4 d i vi -
si ons of d ef l ect i on at 3 . 0 mega h er t z r ef er ence .
d . W i t h o u t c ha n gi ng t h e si gnal gener at or o u t pu t am p l i -
t u d e, c h ange t h e out p ut f r e q uency unt i l t h e ver t i cal d ef l ec-
t i on i s r e
d
uce
d
t o
2 . 8
d i vi si ons .
e . C HE C K - O u t pu t f r e q u ency of gener at or m u st b e 150
mega h er t z or
h
i g h er .
f . Set t h e C H 1 VO L TS/ DI V swi t c h t o 5 m V an d a dd
anot h er G R 10 § at t e nu at or t o t h e one al r eady i n,
g . Ad j ust t h e h i g h - f r e qu ency gener at or f or 4 d i vi si ons of
d ef l ect i on
at 3 . 0 mega
h
er t z r ef er e n ce .
h . W i t h o u t c h angi ng t h
e si gnal gener at or o u t p u t ampl i -
t ude, c h ange t h e out p u
t
f r e q uency
u nt i l t h e ver t i cal d ef l ec-
t i on i s r e d u ce d t o 2 . 8 d i vi si o n s .
i . C HE C K
- O
u t p u t f r e
qu ency
of
gener at or m u st b e 100
mega h er t z or h i g h er .
j . C h ange t h e ver t i cal M OD E swi t c h t o C H 2 .
k . R emove one G R 10 § at t en u at or an d a d j ust t h e h i g h -
F i g . 5- 1 . Ty p i cal
C
R T d i s p l ay w h
en
c h
ec k
i ng
c h o pped r e p et i t i o n
 f r e qu ency
gene r at or f or
4
d i vi si ons of def l ect i on at 3 . 0
r at e a nd bl anki ng .

mega h er t z r ef er ence .
5- 1 1