Alinco DR-610E, Service Manual

Page: 14 / 89

7 . P a c k e t C i r c u i t
1 2 0 0 b p s m o d e i s t h e n o r m a l p a c k e t e q u i p p e d w i t h t h e s q u e l c h c o n t r o l .
T h e m o d u l a t i o n s i g n a l I n p u t f r o m t h e f r o n t M I C c o n n e c t o r C N 5 0 4 i s a m p l i f i e d b y
m i c r o p h o n e a m p l i f i e r o f I C 5 0 4 , a n d l e d t o I D C c i r c u i t , t h e n V C O i s m o d u l a t e d .
A s f o r t h e r e c e i v i n g s i g n a l , s q u e l c h c o n t r o l l e d A F s i g n a l i s o u t p u t f r o m S P O U T .
9 6 0 0 b p s m o d e i s u s e d f o r 9 6 0 0 b p s G M S K / G 3 R U H P a c k e t c o m m u n i c a t i o n .
T h e m o d u l a t i o n s i g n a l i s i n p u t f r o m r e a r j a c k , a n d t h e s i g n a l i s l i m i t e d i n D 5 0 4 ,
Q 6 2 1 , t h e V C O i s m o d u l a t e d d i r e c t l y w i t h o u t p a s s i n g t h e I D C c i r c u i t .
A s f o r t h e r e c e i v i n g s i g n a l , F M d e m o d u l a t e d s i g n a l o u t p u t i s i n p u t t o t h e V / U
s e l e c t o r o f I C 1 1 p a s s i n g t h r o u g h t h e b u f f e r o f Q 1 2 a n d Q 3 3 4 .
T h e V / U s e l e c t o r i s c o n t r o l l e d b y t h e c o n t r o l s i g n a l o f C P U s o t h a t t h e d e t e c t i o n
,*N..+rN..+ :,•> 1 11/ -1
u u i p u i
io
i c u
iu
ur\ i .
1200
bps 9600bps
Input level 10
mVp-p
2
Vp-p
Deviation 3.5+/-0.5kHz 2+/-0.5kHz
Output level
0~5Vrms/8Q
Variable
300mvp-p/47k0
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