HP 5383A

M od el
5383 Α
T heory
of O pe r atio
n
4-15 . MUL TI PLE XE D DIS P LAY
FUN CTIO N
4-16 .

T h e sample and
d is p lay ti m ing circ u its p r ovi d e sig n als W XYZ, a
nd
50
t h ro ugh S9 . T h ese
sig n als se qu
entially t r a n sfe r co u nte r d ata, one ( B CD) ch a
r acte r at α ti m e to t he appropriate d is p lay
d igit .
F ig ure 4-1 s h ows α mec h anical
r
e pr
ese n tation of t he act u al elect r on ic m u ltiplexi n g
f un ction . T he wi p e r a r ms of t h e
m
u
lti p lexe r "switc h es" a r e lin ked so t h at w h enαB CD c h a
r
acte
r is
sam p le d , t h e co rr ect d isplay
d igit is activate d . F o r exam p le, dur i ng time S5, t h e most
significa n t
c h a r acte r ( M SC) is sam
p
le
d at t heco un te r latc h es as α r es u lt of an ΧΥΖ "101"
(
B CD "5")
sig n al . At
t he same time α low S5
sig n al activates t h e most significa n t co un ter d isplay
d igit (i .e ., t he left-most
d is p lay d igit) .
T h e r efo r e, dur i n g time S5, t he M SC is t r ansfe
rr
e
d to t he B CD-to-seve n li n e
deco de
r via
t he
d isplay bu s . The r es u lti n g d eco d e r ou t pu t dr ives
t h
e
activate d left-most d is p lay
d
igit . In α simila r man ne r , lowe r sig n ifica n t c h a
r
acte
r
s a
r e t r a n sfe rr ed a nd lowe r sig n ifica n t
d is p lay d igits a r e activate d du ri
n g
s u
bse qu en t sca n times . Table 4-1 s h ows co rr elatio
n between
sca n times, m u lti p lexi ng sig n als, t
h
ec
h aracte r s sample d , a nd t h ed is p lay d igits t h at a
r
e
activate d .
Also r efe r to t h e sca n sig
n
al
timi ng d iag r am ( F ig ur e 4-2) .
4-17
.
LE
ADI NG Z ER O B LA NK I NG
4-18 .

( R efe r to sc hematic .)
T h
e
Scan Timing ci r c u its also p r ovi d es t he logic fo
r
t
h
e
lea d i n gze r o
bla nk i n g f u nction . F
igu r e 4-4 (page 4-7) d esc r ibes t h is f u nctio
n i n d etail . Wh en t he GAT E 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 h a n ges t h e RB I gate
wid
t
h and co rr es p o nd i ng eve n ts to r es p ective 0 .4
milliseco nd o r 0 .6 milliseco nd ti m e dur atio
n
s .
4-19 . UN IQ UE I N T E GRAT
E D CI R C U ITS
4-20 .

F ig ure 4-5 (page
4-8) a nd 4-6 (page 4-8) co n tai n ci r c u it
d
esc
r i p tio n s of V a r ia b le Time B ase
Co un te
r
A
1
U 11
and H ex M ulti p lexe d Co un te r Α 1IJ18 . Th
ese d esc r i p tio n s pe r tain to t he d i
r
ect
applicatio
n of t h ese i n teg r ate d ci r cu its i n t he 5383 Α
Fr
e qu
e n cy Co un te r .
Table 4-1 . Sa m p le a nd Display
Timi n g
SCA
N
TIME
S5 S4 S3 S2 S1
SO S9 S8 S7 S6
Samp 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 r ol Sig n al Ζ
1 1 0 0 0
0
Co un te r / L atc h C
n t r . Α 1IJ18 A 1 U 18 Α 1IJ18 Α 1IJ18 A
1
U
18 A 1 U 18 A 1 U 15 A1 U
4
A
1U 15
A
1 U 1
Α 1IJ4
L atc h A l U 18 A
1
U
18 Α 1IJ18 Α 1IJ18 Α 1IJ18 Α 1IJ18 A
1
U 15
A 1 U 16 A 1 U 12
Display Activate d DS1
( M SD)
DS2 DS3 DS4 D55
D56 D57 DS8 DS9
(
L SD)
M
SD =
M ost sig n ificant d is p lay d igit .
L SD
= L east sig n ificant d is p lay d igit .