Tektronix 7704A User Manual

Fig. 2-39 . Ti
me r elatio n s h ip of t h e time-slot(TS) p u lses p ro du ce d
b y U 3445 .
Circuit Description -7704A
Service
going
E
nd -of-
W
ord
pulse is pro d u ced at p in 2 .
T
he
En
d -of-
W
or
d pu lse provi d es α drive pu lse for t h
e
W ord
Trigger stage
an
d also provides an enabling level to t
he
Dis
p lay-S
k i p Ge n erator during time-slot 1 only .
P in 16 is αreset input for t h e
Time-Slot Co u nter . Wh en
t h is p in is h eld L O, t h e Time-Slot
Counter r esets to
time-slot 1 . T he Time-Slot Co u nte r can be
reset in t h is
manner only w h en α J um p Comma nd is
received by
U 3447A and Β (see following d
iscussion)
.
W
or
d
T r igge r
T he W ord
Trigger stage is ma de up of U
3447 . Q u ί es-
cently, pin 8 of
U 3447C is L O as establis
h e d b y t he
operating con
d itions of U 3447A-U
3447B . T h erefore, t he
L O
E n
d -of-
W ord pu lse pro d uce d b y t
he Time-Slot Counter
results
in
α
HI level at p in 10 of
U 3447C . T h is level is
inverted by
U 3447D to p rovi de α negative-going
W ord
Trigger
pulse
to
t h e C h annel Counter .
Α W ord Trigger pu
lse is also prod uce dby U 3447D w h en
α Ju m p Co
m man d is receive d at p in 5 of U 3447
B . T h is
con d ition
can occur d uring any time-slot (see
R
ow
Decoder
for f u rt h er information on origin of t
h e J umpComman d ) .
U3447B an d U 3447A are
connected
as α
bista b le flip-flo p .
T he positive-going Ju
m
p Command at
pin 5 of U 3447B
pro du ces α L O at p
i n 4 . T h is L O is inverted by U 3447A to
p roduce α HI at
pin 1, w h ic h allows p in 6 to be p ulle d Hl
t hrough C R 3447 . T h e flip-flo p h as now
been set an d
remai n s in t h is co n d ition
un til reset, even t h oug h t he J um p
Comman d at p in 5
returns
to
its L O level . T h e ΗΙ output
level at pin 1 turns on
Q3445 to pull pin 16 of t he
Time-Slot Counter
L O . T h is resets t h e Time-Slot Cou n ter
to time-slot 1 and
h
ol
d s it t h ere until t h e W ord Trigger is
reset . At t
h e
same
time, α ΗΙ level is ap p lied to pi n 4 of t he
Timer
t
h roug h C R3445 and CR3432 . T h is HI level ca
u
ses
t
h eTimer
to
o p erate in t h e Dis p lay-S k ip mo d e, so α
ch aracter is not generate d .
T h e next Trigger pu lse is not recognized b y t
h e
Time-Slot Counter, since U 3445 is loc k ed in time-slot 1 by
U 3447 .
H owever, this Trigger pulse resets t
h
e
W
or
d Trigger
stage t
h roug h C3445 . P i n 1 of U 3447A goes L
O
to
ena b le
t
he Time-Slot Co unter and Timer stages for t
h e next
time-slot pu lse . Sim ultaneou sly, w
h
en U
3447A switc h es
outp u t states, t h e res u lti n g negative-goi
ng e d ge is connecte d
to p
i n 8 of U 3447C . T h is results in α
negative-going W ord
Trigger output at p i n 13 to advance t
he C h annel Counter to
t
h e next wor d . Wh en t h e next
Trigger pulse is received at
p in 15, t h e Time-Slot
Counter returns to t h e normal
sequence of o p eratio n an d pro d
uces
an
output on th e
time-slot 1 line .
2- 47
1
Ι
'7 1
Ι
I'll
Ι
'?I "1
Ι Ι
Ι 1
0 1 "9 1
""
Ι
Ι Ι
-'
°
l
Ι
Time-slot
MEN
pulse 1
ι
ι - ι 7 - 77- τ 77 - 77 - 77 Γ ι
Ον
Time-slot
pulse 2
P i n 13 ~~
Ι E Ι ~ Λ ΙΙ
1
1 1 t Ι Ι _ _
0
ν
Time-slot
pulse
3 ..
-
P i n 12
MENEMEMEME
. . . . Ι . . . . Ι
.
. . Ι
. : . . . ι τ . __ ι ___ . l . . .
T
. . . . i
. .
. . l
Ι
Ι Ι Ι I
Ι Ι Ι Ι
Ι
Ο ν
Time-slot
pulse
"" ί 1
ιιι ~ ιυι ~ ιιιιι
γ _ γ ._
Ο ν T i m e-slot
pu lse 5
"
P i n 10 ~ Ι
Time-slot :~ : :~
M
: :" :~
Ο
ν
pulse
s
Pin 9
M
Ι
Ο ν Time-slot
pu lse 7
"" "
P i n 7
~_ . . . ι . . . . Ι . . . .
I
. . f_,_
7
__ Ι,__ r ~_
_
pulse8
t
ONMEEMENIME
1
Ον
~
Ι _ _ Ι Ι # Ι
Ι Ι
Ο
ν
Time-slot
p P i n 5 ""
MEMEMEMEN
VIMM
ι . ι - r ,- -τ τ
- τ -- r - γ --
7 ---
Ι _ Ι Ι
~ Ο ν
Time-slot
p pulse
1 Ο
WOMEN
4
MEN
NMI
No
SWIM
m i
Ι
. . . .
ι . .,] ___
T-
_γ __ γ __
-r
--- γ --- - Ι
ΝΟΤΕ : Test oscillosco p e exte rn ally
triggere d f r o m
ΤΡ 3450 . Swee p r ate un cali br ate d .

Tektronix 7704A Specifications

General

Brand	Tektronix
Model	7704A
Category	Test Equipment
Language	English