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M
od el 5383Α
T
h eory of O p e r atio n
ΜG
(Al U23-12)
R
ST
B
( Α 1
U
23-8)
TR
(Al
U
22-10)
T
R
(Al
U
19-10)
R
SC
(AlU20-3)
R
SC
(AI
U
19-2)
DISPLAY SCA
N
TIME
(S EE ΝΟΤΕ 1)
N
OT
E
S
1 .
M
GE is an EEC L ve rsion of the TT L MG sig n al .
2.
Dis p lay sca n timi n g an d
t
h e timi n g of t h e
M
G (o r MGE)
sig n al a re asy n c hr o n o u s .
T h e refo re, t h e
p
ositive t ra n si-
tion of t h e
M
G (o r M G E) signal (i .e ., t raili ng ed ge)
occurs dur i ng any
r
a ndom time .
3 . MG (o r M G E) wid t h ("t") depend s on t h e setti ng of t he
GAT E TIME switc h .
M
G E is low duri ng time "t", allowing t he frequ e ncy co unte rs to co unt t h e i npu t signal
fr equ e n cy . T h e stor age latches are isolated
f
rom t h e co un ters at t h is time.
Ο 2 Afte r
t
h e MG signal termin ates, t he
R
STB latc h is set at th e b egi nn ing of sca n time S9.
Th is i n itiates t he upd ate sequ e nce.
Α R ST B sig n al
h
old s
M
G E off (i .e., h ig h) un til t h e
com p letio n of t he
u
p d ate sequ e n ce (ap proximately 0 .5 mi Γlisecon ds late r) .
D ur ing sca n time 99,
T
R and
T
R
p
u lses are ge n erate d . T h ese sig nals co nnect th e co un te r
o
u tp uts to t h e sto rarge latc hes ; resu lti ng i n
t
h e t ra nsfe r of
n
i n e
B
CD c h a r acte r s to t h e
latch es . Wh en th e TR an d TR
p
u lses e n d, t h e latc h es a re again isolate d
f
rom t h e fre-
quency co un te rs .
Du ring scan time S8
R
SC an d R S C pu lses reset the f requ e n cy co unters to ze r o .
Dur ing scan time S7, t h e
R
STB latch is clea red , e nd in g t h e update seque n ce, a nd releas-
i n g
M
G E (i .e ., allo
w
i n g it to go low) to allow a n ot h e r frequency co un t .
F
ig
ur
e 4-3 . Up
d
ate
Fun
ctio
n
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