Tektronix 7704A User Manual

Th e Decimal P oint L ogic p ortion of t h is stage allows
decimal p oints to b e add e d to t h e C
R T
display . W it h t
h
e
Standard R eadout Format, row 7, enco d ed coinci d
ent with
columns 3 t h roug h 7, a dd resses α d
ecimal
at
one
of t
h e five
locations i d entified in row 7 of t h
e
Ch aracter Selection
Matrix ( F ig . 2-33) . T h is instruction refers to t
h
e d ecimal
p oi n t location in relation to t he total num b er of c
h
aracters
possible i n one word (see Fig .
2-44) .
For
example, column
3 encod e d wit
h row 7 duri ng time-slot 1 p laces α decimal
point in location No . 3 . As s h own in Fig . 2-44, t h is displays
α decimal point after t he t h ir d c
h
aracter t
h at can be d is-
p laye d on t he C R T . (T h
e
first t
h
ree time-slots p
r
od
u
ce α
space w h et h er data is encoded or not ; see
previous
para-
gra ph .) T h e simultaneous app
lication of
row-7
data to t h e
Υ -input of t h e Format
Generator t h roug h R 3477 raises t h e
d ecimal
point
so
it appears b etween t h e d isplaye d c h aracters .
Wh en d ecimal-point d ata is encoded , the CR T is υη -
b lan k ed so α rea d out display is presente d . H owever, since
row 7 or row 8 d oes not activate any of the five C h aracter
Generators, t he CR T beam is deflected vertically α fixed
amount to display t h e d ecimal p oint between t h e ch aracters
along t h e bottom line of t he rea dout wor d . After t h e
O L
Deci m al- p oi
n t locatio n e n-
co d ed
du ring t h is ti m e-slot
--
no
display
Decimal poi n t
location No . 3
(col u m n
3)
F irst possible c h aracter dis-
p layed on C R T at t h is loca-
tion
Decimal-
P oi n t C h aracter
Deci m al poi n t
locatio n No . 4
(col u m n 4)
F irst nu m b e
r of meas u re-
ment no r
mally dis p laye d at
t h is location
Deci m al poi n t
location No . 5
(column 5)
Decimal poi n t
location
No .
6
(col u m n
6)
Decimal point
locatio n No . 7
(column 7)
F ig . 2-44 . R ea d o u t wo rd
r elati ng 10 possible ch aracte r locatio n s
to t he decimal
point i n str u ctions t h at can be e n co ded , and t h e
res u lta n t CR T dis p lay .
d
ecimal point is p ro d uced in t he a dd resse d location, t h e
C
RT
beam
returns to t h e location in d icate d by t h e
C
h
aracter
P osition Counter to produce t he remain d er of t h e
d is p lay .
In instr
u ments serial number
Β 050000 an d h ig h er, t
h
e
addition of R 3474- R 3478- R
3479 allows α decimal point to
be encoded fo r special formats . T
h
is d
ecimal point can b e
place d in any c h aracter positio
n by enco d ing column 9 with
row B during t h
e
correspon d
ing time slot . T h e application of
row 8 data to t
h e
Χ
an d Υ input of t h e Fo r mat Gene r ator
t
hrough R 3478 an dR 3479 res p
ectively, p rovides h orizontal
and
vertical p ositioning current for t he d ecimal
points .
Format Generator
T h e Χ - and
Υ -
d
eflection signals produced by t h e
Ch aracter Ge n erator stage
are connecte d to p ins 2 and 7,
respectively, of Format
Generator U 3480 . T he C han nel
Ad d ress Code from t
h e C h annel Cou n ter is also con necte d
to pins 1, 8, an d 15 of t
h
is
stage . T h e Ch annel A dd ress
Co d e d irects t he Format
Generator
to a
dd cu rre nt to t he Χ
and Υ signals to d eflect t h
e
C
RT
b eam to t
h
e area of
t h e
CR T associate d wit h t he plug-in ch annel t
h
at
originate d t he
information (see Fig .
2-32) . T he C h annel Ad d ress Co d e and
t he resultant
wor d p ositions are s h own in Tab le 2-3 . In
a
dd ition, t h e c h aracter position current from t he Decimal
P oi n t L ogic an d C h aracter P ositio n stage is ad de d to t
he Χ
(
h orizontal) input signal to space t h e c
h
aracters
h
ori-
zontally on t he CR
T
(see p revious d iscussion) .
T he R eady
signal at p in 13
(coinci d ent with t he V- Η In h i b it out p ut)
activates
t
h is stage w h e n α ch aracter is to be d isplayed on
t h e CR T .
Υ -Outp ut Am p lifier
T he Υ -out pu t signal at pin 6 of Format
Gene r ato r
U 3480 is connecte d to t
h
e
Υ -Output Am p lifier
Q3486-Q3493 . T h is stage provides α low
impedance loa d
for t he Format Generator w
h
ile
providing isolatio n b etween
t h e R ea d out System and t h e driven circuit(s) .
Vertical
Sep aration ad j ustment R 3490 ch anges t h e gain of t
h
is
stage
to control t h e vertical separation b etween t
h e r
ea
dout
wor d s d is p laye d at t h e to p a
n
d bottom
of t h e graticule
area .
Χ -Outp ut Am p lifier
T he Χ -Output Amplifier Q3489-Q3499 op erates
li ke t h e
Υ -Output Am p lifier, to provi d e t
h e h
orizo
n tal d eflectio n
from t h e rea dou t signal available at
p in 4 of U 3480 . T he
gain of t h is stage is
fixe d b y t h e values of t h e resistors in
the circuit .
Dis p lay Se
q uence
Ci
r
cuit
Descriptio n - 7704A Service
Figure 2-45 s h ows α flow c h art for t h e
R
ea dout System
.
T h is ch art illustrates t h e se q uence of events t h at occurs in
t h e R ea d out System each time α c
h
aracter is
generate d
an
d
d isplayed on t
h
e
C RT .
MAIN
I N T ER CO NNE CT
Th
e
M ain
Interconnect d iagram s h ows t h e signal an d
power interconnections
b etween t h e Ac q uisition an d Dis-
play
U nits .
2-
5 5

Tektronix 7704A Specifications

General

Brand	Tektronix
Model	7704A
Category	Test Equipment
Language	English