Kenwood DP-1100 B Service Manual page 53

1 - 5 - 1 7 . E F M I S I G N A L C I R C U I T O P E R A T I O N
1 . O u t p u t s A , B, C a n d D f r o m the 4-division p h o t o d e t e c t o r
are sent t o pin 4 t o 7 of h e a d a m p IC ( Q 1 0 3 ) . (B + D) a n d
(A + C) are o u t p u t t o pin 12 a n d 13 respectively. T h e t w o
signals are a d d e d t o be ( A + B + C + D) t h r o u g h R 1 0 1 a n d
R 1 0 0 . T h e totally a d d e d signal (RF signal) p r o v i d e d by the
4-division p h o t o d e t e c t o r is s h a p e d into a proper w a v e f o r m ,
converted to a T T L level and fed to pin 17 (EFMI) of IC15 as
EFM signal.
2 . The EFM signal i n p u t t o pin 17 of IC15 g o e s t h r o u g h a
buffer a n d EFMO signal is o u t p u t to pin 4 1 . It is t h e n a p ­
plied t o pin 1 4 of IC9. Being l o c k e d by bit lock signal
(PLCK), D O U T signal w i t h its jitter c o m p o n e n t e l i m i n a t e d is
p r o d u c e d . (Refer t o section 1 - 5 - 1 8 . PLL CIRCUIT OPERA­
T I O N . )
T h e EFMI, PLCK a n d D O U T signals are fed to
( T C 9 1 7 8 F ) a n d p r o c e s s e d .
3. 1 4 - b i t 1 s y m b o l is c o n v e r t e d t o 8-bit 1 s y m b o l , using the
EFM signal f e d t o pin 5 3 of IC8. T h e 8-bit o u t p u t s are p r o ­
v i d e d at pin 5 7 t o 6 5 . T h e 8 - b i t data is o n c e m e m o r i z e d in
IC17 ( R A M ) . A f t e r being d e l a y e d by necessary n u m b e r
a n d jitter a b s o r b e d inside I C 1 7 , it is read o u t for IC6
( T C 9 1 7 9 F ) . Inside IC6, C1 error pattern is first p r o d u c e d
to c o r r e c t the error s y m b o l d a t a .
4 . N e x t , e a c h data of every s y m b o l is again read o u t by IC6 to
c o r r e c t the C2 error, after being properly delayed for the
p r o c e s s i n g de-interleave. T h e p r o c e s s e d data is finally sent
f r o m IC17 t o IC6, w h e r e the d a t a , w h i c h w a s impossible
to c o r r e c t , is average c o m p e n s a t e d . T h e o u t p u t
available at pin 4 7 as a serial 1 6 - b i t data alternately for the
Lch a n d R c h .
5. L a n d R alternating 1 6 - b i t serial data signal a n d c l o c k
(BCLK, LRCK, W C L K ) signal are originally sent f r o m IC6
(BCK, L/RG, W D C K respectively). BCLK is 1.411 M H z ,
LRCK is 4 4 . 1 kHz a n d W C L K is 2 x LRCK ( 8 8 . 2 k H z ) ,
logic signal respectively. T h e BCLK signal is applied to pin
9 of I C 2 1 . T h e W C L K , D I N , BCLK a n d LRCK signals are
applied t o pin 1 0 , 8 , 9 a n d 7 of IC21 respectively. The
data W C L K , DIN a n d LRCK is s y n c h r o n i z e d w i t h the rising
e d g e of t h e BCLK signal being applied t o pin 9 .
5 6
D P - 1 1 0 0 B II D H 1 0 0 B II
1. CIRCUIT DESCRIPTION
IC8
The integral c u r r e n t o u t p u t of IC21 appear at pin
(IOUTR) a n d pin 18 (IOUTL), a n d at the s a m e t i m e are
level-shifted by V R 2 a n d V R 3 c o n n e c t e d t o pin 1 of IC23
a n d pin 7 of IC22 respectively (DC offset a d j u s t m e n t ) .
In I C 2 4 a n d 2 5 , t h e L a n d R signals of the integrator o u t ­
puts are selected by a p p l y i n g an L/R s w i t c h i n g
(LRCK O U T 11 of I C 2 1 ) . T h e Lch a n d Rch o u t p u t signals
are o u t p u t t o pin 3 a n d 5 respectively. I C 2 2 , 2 3 are a s i m ­
ple l o w - p a s s filter t o shape the w a v e f o r m s , w h i c h are put
into LPF1 a n d LPF2 respectively.
is
Fig. 1 - 5 - 1 7
17 7. LPF1 a n d LPF2 e l i m i n a t e u n w a n t e d f r e q u e n c i e s b e y o n d
2 0 kHz outside the a u d i o f r e q u e n c y range a n d required
a u d i o signals are available at the Lch o u t p u t a n d the Rch
o u t p u t respectively. The signals are applied to pin 3 a n d 5
of buffer a m p IC27 (also w o r k s as an e m p h a s i s ON/OFF
pulse s w i t c h . Refer t o s e c t i o n 1 - 5 - 2 1 . ) t h r o u g h resistors a n d
their o u t p u t s are p r o v i d e d at pin 1 a n d 7. A part of the out­
puts is directly c o n n e c t e d t o FIXED O U T P U T a n d the other
is f e d t o buffer a m p IC19 t h r o u g h V R 1 (on the f r o n t panel)
a n d o u t p u t t o pin 1 a n d 7 for h e a d p h o n e s .