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M
o del 5383Α
T
heory of O p e ratio n
4-15 .
MULTI PLEXED DISP LAY FUN CTION
4-16 . T h e sample and disp lay ti m ing circu its p rovid e sig n als
W
XYZ, a nd 50 t h ro u gh S9 . Th ese
sig n als sequ entially t r an sfe r cou nte r d ata, one ( BCD) ch a r acte r at α ti m e to t h e appropriate
d
is p lay
d
igit.
F
ig ure 4-1 sh ows α mec h anical
r
e pr ese n tation of t h e act u al electro n ic mu ltiplexi n g
fun ction . Th e wi
p
er a rms of th e m u lti p lexer "switc h es" a re lin k ed so t h at w h e n α B CD c h a r acte r is
sam p led , t h e co rr ect
d
isplay
d
igit is activated.
F
or exam ple, dur i n g time S5, th e most significa n t
c h a racte r ( MSC) is sam p le d at t he counte r latch es as α
r
esu lt of an ΧΥΖ "101" ( BCD "5") sig n al . At
t h e same time α low S5 sig n al activates t he most significa nt co un ter
d
isplay
d
igit (i .e ., the left-most
d
isp lay
d
igit). T h e r efo r e, durin g time S5, th e
M
SC is t r ansfe rr e d to t h e BCD-to-seve n li n e
deco d e r via th e
d
isplay bu s . The
r
es u lti n g
d
ecode r
o
u tput dr ives t h e activate d left-most
d
isp lay
d
igit. In α simila r man ne r , lower sig n ificant c ha r acte r s a re t ra n sfe rred and lowe r sig n ifican t
d
isp lay
d
igits a re activated du ri ng su bseque nt sca n times . Table 4-1 s h ows corr elatio n between
sca n times, m u lti p lexi ng sig nals, t h e c haracte rs sample d , and
t
h e
d
isp lay
d
igits t h at a r e activate d .
Also
r
efe r to th e sca n sig n al timi ng
d
iag ram ( F ig ur e 4-2) .
4-17 . LE ADI N G ZERO
B
LA NK ING
4-18 .
(R efe r to sch ematic .) Th e Scan Timing ci rc u its also p rovi des th e logic fo r
t
h e lea d i n g ze r o
bla nk i n g f u nction .
F
igu re 4-4 (page 4-7)
d
esc r ibes th is f unctio n
i
n d etail . Whe n
t
h e GATE TIME
switc h is i n
t
h e 10 S/ ΜΗτ positio n
t
h e ci r cu it ope r ates as s h ow n . Α 1 5/MHz or 10 5/MH z GAT E
TIME selectio n
c
ha nges t he
RB
I gate wi d t h an d co rr es
p
o nd i n g eve n ts to
r
esp ective 0 .4
milliseco n d o r 0 .6 milliseco nd ti me duratio n s .
4-19. UN IQUE
I
NTEGRAT ED CI RCU ITS
4-20 .
F
igure 4-5 (page 4-8) a nd 4-6 (page 4-8) con tai n cir c u it
d
esc r i p tio ns of V a r ia ble Time B ase
Coun te r A 1 U 11 and Hex
M
ulti plexe d Co unter Α1IJ18 . Th ese
d
escri p tio n s per tain to t he
d
i r ect
applicatio n of th ese i nteg rate d ci rcu its i n
t
h e 5383 Α Fr equ e n cy Co unte r .
Table 4-1.
Sa
m
ple
a
nd Display Timi ng
SCA N TIME
S5
S4
S3
S2
S1
SO
S9
S8
S7
S6
Sam p le
W
0
0
0
0
0
0
1
0
0
Χ
1
0
1
0
1
0
Mu ltiplexi n g
Υ
0
0
1
1
0
0
S9
S7
S6
Cont rol Sig n al
Ζ
1
1
0
0
0
0
Co un te r/ L atch
C
n t r. Α 1IJ18 A1 U18 Α1IJ18 Α1IJ18 A 1 U 18 A 1 U 18 A 1 U 15
A1 U 4
A
1
U
15
A 1 U 1
Α 1IJ4
L
atc h
A
l U18
A
1 U 18 Α1IJ18 Α1IJ18 Α1IJ18 Α 1IJ18
A
1 U 15
A
1U 16
A
1 U 12
Display Activated
DS1
(M SD)
DS2
DS3
DS4
D55
D56
D57
DS8
DS9
( LSD)
M
SD =
M
ost sig nificant
d
isp lay
d
igit .
L
SD = Least sig n ificant
d
is play
d
igit .
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