Tektronix 454A - Page 44

O p er at i n g I n st r u
ct i ons- 454zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA ‘
/
R 454A
d et er mi n e d by t h e set t i ng of t he ‘ TI ME/ DI V swi t c
h
and
t h e DELAY- TI ME
M UL TI P L I E R d i al . F o r exa mp l e, t h e
del ay t i me
i ndi cat es
b y t h e DELAY- TI ME M U L TI P LI ER
d i al
set t i ng
s
hown i n F i g . 2- 16 i s
3
. 55 ;
t hi s
cor r espon d s t o
3 . 55 CRT d i vi si ons
of
‘ sw
eep,
T
h i s r eadi ng m u l t i pl i e d b y
t h
e
set t i n g
of
t h e ‘
TI ME/ DI V
swi t c h gi ves t h e cal i b r at e d
del ay t i me bef or e t h e st ar t of t h e ’ swee p ( Not e : Du e t o
syst em t i m e d el ays, t h e d el ay st a r t d et e r m i ne d by t
h e
‘
sweep i s acc u r at e onl y b et wee n 50 seco n d s a n d one
m i cr osecond) . The i nt ensi f i e d por t i o n of t he d i s p l ay i s
p r oduced b y t h e ’ sweep . T h e l engt h of t h i s por t i on i s
about 10 t i mes t h e set t i n g of t h e ’ TI ME/ DI V swi t ch
.
Wh en t h e —Ÿ R ™– D I S P LAY swi t ch i s
set
t o ’
( D EL AY E D S WEEP) , onl y
t h e i nt ensi f i e d p or t i o n ( as
vi ewe d i n t he ‘ ™• ¤• • DU R I NG ’
posi t i on) i s di s p l aye d
on t h e scr een at t h e
swee p r at e i n di cat ed b y t h e 13
TI ME/ DI V
swi t c h ( see F i g . 2- 15 ’ ) .
T h e M I X E D posi t i on of t he —Ÿ R ™– DI S P L AY swi t ch
p r ovi d es ± CR T d i s p l ay cont ai ni ng mor e
t ha n o n e t i me
f act or on t h e h o r i zont al axi s . T
h e f i r st par t of t h e d i s p l ay
wi l l b e at ± sweep r at e set by t h e ‘ TI ME/ DI V
swi t c h and
f o r ± t i me dur at i on d et er mi ne d by t h e set t i ng of
t h e
DELAY- TI ME MUL TI PL I E R cont r ol
.
T h e
l at t er pa r t of t h e
d i spl ay wi l l be at ± sweep
r at e set b y t h e ’ TI ME/ DI V
s w i t c h . F i g . 2- 17 i l l ust r at es ± t y p
i cal mi xe d sweep d i s p l ay .
’ Swee p M ode .
T h e ’ SW E E P M OD E swi t ch pr ovi d es
t wo m o d es of
del aye d sweep . Fi g . 2- 1$ i l l u st r at es
t h e
d
i f f e r ence bet ween t h ese t wo mo d es . I n t h e ’ STA R TS
AFT ER D EL AY TI ME p osi t i on, t h e ² sweep i s pr
ese n t e d
i m
medi at el y af t er t h e d el ay t i me ( see F i g . 2- 18A) , The B
swee p i s t r i gger e d at ± sel ect e d l evel on ‘ sweep
t o pr ovi d e
±
del ay f or
’
sw ee p . Si nce t hi s d el ay t i me i s t h e same
f or
eac
h sweep, t h e d i s p l ay a pp ear s st a b l e . I n t h e T R I GG
ER -
A BLE AF TE
R DE L AY TI ME p osi t i on,
t h e ’ swee p
2- 2
6
DELAY- TI ME M ULTI PLI ER
l
1- ¹ ©
Maj or di a
U »- C‘ L
¹
A AND
8
Mi n or d
i al
di vi s ¯ ¿ ns 15, 5
¹ _, r
! : , ~-
±
F i g . 2- 17 . ‘ t y p i cal
mi xed s w eep d i s p l ay ¶‘ TI ME/ DI V set t o 1 m s,
’ TI ME/ DI V set t o . 1 ms, and
t h e DELAY- TI ME MULTI PLI ER d i al
set t o 3 . 551
.
o p er at es onl y whe n i t i s t r i gge re d af t e r t h e sel ect e d d el ay
t i me ( see F i g . 2- 1$
² ) .
T h e ’ Tr i gger i n g co n t r ol s o p er at e as
desc r i bed i n t h i s sect i on .
Del aye d / M i xed S w ee p O p er at i on . To obt ai n ±
del ayed
swee p di spl ay, use t h e f ol l o w i n g pr oce d ur e :
1 . Set t h e H O R I Z DI S P LAY swi t c h t o ‘ ™• ¤• •
D U RI N G ’ .
2 . Set t h e ’ S WEE P MODE swi t c
h
t o t he d esi r e d
set t i ng . I f T R I GGE R ABL
•
A
F
T
E R
DELAY
TI ME i s u se d ,
cor r ect ’ Tr i gger i ng i s al so necessar y .
3 . Set t h e d el ay t i m e w i t
h t he
‘ TI ME/ DI V
swi t c h a nd
t h e DELAY- TI ME MUL TI PL I ER d i al
.
4 . Pul l
t h e D EL AYED S WEE P ( ’ ¤™œ• / DI V ) k nob out
an d set t o t h e d esi r ed s w eep r at e .
5 . I f t h
e TRI GG ER AB LE A F TE R D EL AY TI ME
p osi t i o n i s use d , c h ec k t he d i spl ay f or an i nt e n si f i e d
por t i o n . A b sence of t h e i n t ensi f i ed zone i n d i cat es t h at ’
sweep i s not cor r ect l y t r i gger e d .
TI ME/ DI V

6 . Set t h e —Ÿ R ™– DI SP L AY swi t ch
t o
’
( DELAYED
- - -

S WEEP) . T
h
e i nt e
n si f i ed z one s h o w n i n t h e ‘ ™• ¤• •
DU R I NG ’ p osi t i on i s now
di spl aye d at t h e swee p r at e
F i g . 2- 16 . DELAY- TI ME MUL TI P L I E R di al . R ea d i ng s h own : 3 . 55 .

sel ect e d b y t h e ’ TI ME/ DI V swi t c
h .