Tektronix 2235 - Alternate Display Switching Logic; HORIZONTAL

7 . Ad j ust
t h e Α TR IGG ER LEVEL co n tr ol fo r α stable
dis p lay .
8 . Set t h eΑ S E C/DI V switc h to α swee p s p eed
w h
ic
h
displays ab out one f u ll cycle of t h e reference wavefo r m .
9 .
P osition t he d isplays and a dju st t he SE C/DI V V aria b le
co n trol so t h at one reference-signal cycle occ u pies exactly 8
h orizo n tal g r aticule d ivisio ns at t h e 50% rise-time
points
(see F ig u re 4-9) . Each d ivisio n of t h e g r aticule now r ep re-
sents
45° of t he cycle (360°
-
8 d ivisio n s), an d t he h orizo n -
tal g r aticule calibration can be state d as 45° per d ivision .
Ph ase
ho r izo n tal h orizontal
Difference
=
differe nce χ calib r atio n
( d ivisions) ( d eg/ d iv)
E xample : T h e h orizontal difference is 0 .6 divisio n wit h α
g r aticule calibration of 45° per d ivision as s h ow n i n F ig-
u r e 4-9 .
Substituting t he given val ues into t h e ph ase differe
n ce
formula :
Ph ase d ifference = 0 .6 d iv χ 45°/div = 27°
M ore accu rate ph ase measu r eme n ts can be made by us-
ing t he X10 M agnifier f un ctio n to
inc r
ease
t h
e
swee p
s p
eed
wit hout ch anging t h e S E C/DI V V aria b le control setti ng .
Su b stituting t h e give n values in t
h
e p
h
ase d
ifference
formu la :
Ph ase difference = 6
div χ 4 .5°/ d iv = 27°
T V L ine Sig n al
Ope r ati n g Pr oced ur es-2235
ΑΝ / U S M -488 O pe r ato r s
CHANNEL 1

CHANNEL 2
(REFEREN C E)

l ( L AGGI N G)
_
14
Β
ME AS URE
++* +

TIME
FR
O
M
Α

ι

®
TO
- ι
ι
ιι
ι ι

HO
RIZO N TA L
8
DI V ISIO NS
~
ι
Ι
ι

(360°)

ι
10 . M easure t he h orizontal d ifference b etwee
n
co
r -
res p o n di ng p oi n ts on t he waveforms at α common h orizo n -
tal gratic u le line a nd calculate t h e ph ase difference u
sing
t
h
e
following formu la :

F ig ur e 4-9 . Ph ase diffe
r
e
n
ce .
C H A
NNEL 1
(REFEREN C
E)
T
ELEV ISIO N DIS PL AYS

4 . Set the
Α
S
E C/D ιν switc h to 10As .
CHANNEL 2
C4207 -19
C4207 -20
E XA MPLE : If t h e swee p s p eed we r e i nc r eased 10 times

F
ig ur e
4-10
.
H
ig
h
- r esol u tio n ph ase
d iffe
r en ce .
wit h t he magnifier ( Χ 10 M agn ifier kn ob out), t he mag n i-
fie d h orizontal gratic u le cali b ration would b e 45°/ d ivisio n
1 . P reset instrume
n
t co
n trols an d select Ρ - Ρ A U TO/T
V
divided by 10 or 4 .5°/ d ivision . F ig u re 4-10 sh ows t h e

L I NE ΑTR IGG ER
M
o
de .
same sig n als illust r ated in F igure 4-9, but mag n ifyi ng t h e
d isplays res u lts in α h orizo n tal diffe r ence of 6 d ivisions
between t h e two signals .

2 . A p ply t h e T V sig
n
al to
eit h er vertical-c h ann el i np ut
conn ector and set t
h
e
VER TICA L M OD E switc h to d isplay
t he chan nel used .
3 . Set t h eapp ro p
riate VO LTS/DI V switc h to display 1
division or more of
composite vi d eo sig n al .
T he followi
n g p
roced
u re is use d to d isplay α T V L ine

5 . F or
positive-goi ng TV signal sync pu lses, set
t h e
sig
n
al
.

Α TR IGG
ER
S
L O PE switc h to O U T an d ad j ust
t h e
4-13