Tektronix 7704A User Manual

Circ
u
it Description -7704A Service
W or d -
Α
word is ma de up of α
related group
of
c h
aracters .
In t h e 7704 Α
R
ead out
System,
α
wor
d
can consist of
up
to ten ch aracters .
F
rame-
Α
frame is α
display
of all
wor d s for α given
operating mo d e and p
lug-in combination . U p to eig h t
word s can b e d is played
in one frame . F igure 2-32 s h ows
t h e position of
each wor
d
in α com p lete frame .
Column-One of t he vertical lines in t h e C h aracter Selection
M atrix (see
F
ig . 2-33) . Columns
C-0 (column zero) to
C-10 (column 10) can
b e a dd ressed in t h e 7704 Α
system .
R ow-One of t h e h orizontal lines in t h e C h
aracter Selection
M atrix . R ows R -1 (row 1)
t
h roug h R
-10 (row 10) an d
R -14 (row 14) can be a dd resse d in
t
h e
7704
Α
system
.
Time-Slot-A location in α pulse train . In the 7704A
R
ea d out System, t h e p ulse train consists of 10 negative-
goi
n
g
p
ulses . E ac h time-slot pulse is assigne d α nu m b er
between one an d ten .
F
or example, t he first time-slot is
TS-1 .
Time-multi p lexing-Transmission of data from two or more
sources over α common p at h by u sing d ifferent time
intervals for d ifferent signals .
Dis p lay F ormat
U p to eig h t words of readout
information
can
be
d isplaye d on t h e C R T .
T
h e p osition of
each word is fixe d
and is d irectly related to t
h e p lug-in unit from w h ic h it
originate d . F igure 2-32 s
h ows t he area of t he graticule
w h ere t he rea d out from
each p lug-in unit is dis p layed .
N otice t h at C hannel
1 of each p lug-in unit is d is p laye d
with in t he to p d
ivision
of
t he CRT and C h annel 2 is
displaye dd irectly b elow
with in t h e bottom d ivision .
F
igure
2-34 s h ows α typ ical d isplay
w h ere only C hannel 1 of t he
R ig h t V ertical an d
Β H orizontal units is selecte d for
d isplay .
Eac h word in t h e rea d out d is p lay can contain up to 10
c h aracters, alt h oug h t h e typical d is p lay will contain
between two and seven ch aracters p er wor d . T he ch aracters
are selecte d from t h e C h aracter Selection M atrix sh own in
F
ig . 2-33 . Any one of t h e 50 se p arate ch aracters can be
a dd resse d an d d is p layed on t he CR
T .
In instruments ab ove
serial
num
b er
Β
050000, α d ecimal-point c
h
aracter can be
a dd resse d
an
d d isplaye d .
In ad
d ition, 12 operational
a dd resses are p rovi de d for special instructions to t h e
R ea d out System . T h e unuse d locations in t he M atrix
(s h a d ed area) are available for future expansion of t he
R
eadout System .
T
he met
h
od of a dd ressing t
h
e locations in
t
h
e C
h aracter Selection M atrix is descri
b
e d in t h e following
d iscussion .
2-40
F ig . 2-32 . L ocation of reado u t wor d s on t h e C R T i d e n tifyi n g t h e
origi n ating p lug-in a nd c h a nn el lo n e com p lete frame s h own,
sim u lated rea do u t) .
Develo p ing t he Dis p lay
T he following basic descri p tion
of
t
he R eadout
System
uses t he block d iagram s h own in
F
ig . 2-35 .
T h
is d escription
is inten ded to relate t
h e
b
asic function
of
each stage
to
t he
o p eration of t h e overall R ea d out System . Detaile d informa-
tion on circuit o peration is given later .
T he k ey b loc k
in
t
h e R
ea
d out System is t h e Timer stage .
T h
is stage
p
ro
d uces t he basic signals w h ic h establis h th e
timing se q uences with in t he R ea d out System . P erio d of t h e
timing signal is a b out 250 microsecon d s (drops to ab out
210 microsecon d s w hen Disp lay-S k i p is receive d ; see
d etaile d d escri ption of Timing stage
for furt h er informa-
tion) .
T
h is stage also p ro
duces control signals for ot h er
stages wit
h
in t
h
is
circuit
an
d interr up t signals to t h e
V ertical Interface,
H
orizontal
Interface, and CR T Circ u it,
w h ic h allow α readout d isplay to be
p resente
d .
T h e
Time-Slot Counter stage receives α tra p
ezoidal
voltage
signal
from t h e Timer stage and d
irects
it to
one
of
ten
out put
lines .
T
h ese output
lines are
la
b ele d TS-1
t
h roug h TS-10
(time-slots one t h roug h ten) and are connected to t h e
vertical and h orizontal p lug-i n com p artme n ts as well as to
various
stages
with in
t
h e R
ea
d out System . T h e out p ut lines
are
energized
se
q uentially,
so t
h ere is
α p
ulse
on only one of
t
he
10
lines during
any
250-microsecon d timing period .
After t
he Time-Slot Counter stage h
as
counte d time-slot 10,
it p
roduces
an
E
nd-of-
W or d p ulse w h ic h
a
d vances the
system to
t h e next ch annel .
Two output lines, rowand column, are connecte d from
each c h annel of t h e p lug-in unit bac k to t h e R eadout
System . Data is typically enco d ed on t h ese out p ut lines by
connecting resistors b etween t h em and t h e time-slot in
p
ut
lines . T h e resultant out put is α se
q uence
of
ten analog
current levels w
h ic h range from zero to one milliamp ere
(100 microam
peres/ste p )
on
t h e row a n d column output
ι
L eft V ertical
c
h annel 1
ι
R ig h t V ertical
Channel l
Ι - t
Α H orizontal
Ch annel 1
Ι t
Β H orizontal
C h annel 1
1
MENEEMENE
Ι ~~ Ι
ES
OMME
L eft V ertical
C h annel2
R ig h t V ertical
Ch annel2
Α H orizontal
C
h
annel2
Β H orizontal
C
h
annel2

Tektronix 7704A Specifications

General

Brand	Tektronix
Model	7704A
Category	Test Equipment
Language	English