Digital Control And Autoranging Circuit - Philips PM2517E Service Manual

4 8
3.4.4.
Digital Control and Autoranging cilcuit OO 0059
3.4.4.1. General
w i t h t h e o o o o 5 9 a A D c w i t h d e l t a m o d u l a t i o n p r i n c i p l e c a n b e c o n t r o l l e d .
The OO 0059 consists of:
- UP/DOWN control to determine whether incoming data should be counted up or down
- POLAR ITY detection circuit
- T|\4 E R + 12288
-
R A N G I N G c o u n t e r f o r u p / d o w n r a n g i n g . F r o m t h e r a n g i n g c o u n t e r t h e d i g i t a l r a n g e i n f o r m a t i o n i s
availabls. Number of ranges: 6.
- UP/DOWN counter for counting the result
-
L A T C H E S a n d I M U L T I P L E X E R S f o r c o n t r o l l i n g a L E D o r L X d i s p l a y
-
LEVEL DETECTOR to determine whether should be ranged up or down in the auto range mode
- C O N T R O L L O G I C w h i c h g e n e r a t e s t h e s i g n a l s ; a u t o z e r o , p o l a r i t y , o v e r l o a d a n d t o w h i c h t h e i n f o r m a t i o n ;
a u t o r a n g i n g a n d d a t a h o l d c a n b e g i v e n .
r-.
r ,
r
r - -
t_
L ,
t ,
t_
t
5 ,
t
t_
t ,
t ;
t-
r
L
?
t
t
L
L
t
t_
L
L_
D S 1
0 5 2
L Ä E N
A U T O
R G X T
R N G C
R N G 8
R N G A
DOWN
.
T E S T
( 8 . 5 V )
Fig.33.
GNO !t
A O
ovR
D H
POL
OATA
C L O C K
0 a 0 0 5 9
2 3
2 2
2 1
1 9
1 8
1 7
16
1 5
l 3
v s s ( - 8 . 5 V )
G N o V
T E S T
: l o i
: l 0 i
i r 0 i
U P / D O W N C O N T R O L
P O L A R I T Y O E T E C T .
MU LTIPL EX E R
RAN G ING
C O U N T E R
Fis. 34.