Kenwood DP-1100 B Service Manual page 20

2 - 6 C R O S S - I N T E R L E A V E
Fig. 2 . 2 s h o w s a principle of a cross-interleave.
original series of signals is d i v i d e d into a n u m b e r
w o r d s , a n d parity w o r d s are inserted.
P = W + W + W + W
1 1 2 3 4
P = W + W + W + W
5 5 6 7 8
P =
W + W + W + W
9
9 1 0 N 1 2
Four original series of signals ( W
W , W , W , . . . ) , ( W , W
6 1 0 u 3
W , W , . . . ) a m o n g m a n y original series of signals are
1 2 1 6
a r r a n g e d f o r f o u r lines N o . 1 via N o . 4 in Fig. 2 . 2 of
these w o r d s , the w o r d s passing t h r o u g h
Original series of signals
,W W W W
8 7 6 5
p = w + w + w + w
1 1 2 3 4
Q = Wj + W + W_ + W_„ + W .
t 2 5 1 5
P = W + W + W + W
S 5 6 7 8
Q = W + W + W.n + W_ + P_
5 5 2 4 n
(2) Fig. 2 . 3 indicates relations b e t w e e n t w o parity c o d e s .
T h e solid lines m e a n a P's series, a n d the d o t t e d lines
m e a n a Q's series. Each of t h e m has the capability of
single erasure c o r r e c t i o n , so t h a t an error of a single
w o r d c a n be easily c o r r e c t e d of c o u r s e .
T h e s y n d r o m e of e a c h o t h e r ' s series c a n be used as a
p o i n t e r f o r p o i n t i n g o u t a l o c a t i o n of error.
II. FUNDAMENTALS
A n
of
(5)
W , W , W . . . ) , ( W ,
1 ( 5 9 1 3 2
, W , W , . . . ) a n d ( W , W ,
7 u 1 5 4 8
N o . 1 are
1 Word
2 Words
3 Words
Adder
4 Words
Delay memories
Fig. 2 . 2 Principle of C r o s s - I n t e r l e a v e E n c o d e r
delivered directly, b u t w o r d s f e d into N o . 2 t o N o . 4 lines
are s u b j e c t t o delay w i t h delay m e m o r i e s by o n e t o three
w o r d s so t h a t the w o r d o r d e r is c h a n g e d (interleaved) at
their respective t e r m i n a l s .
T h e r e is an a d d e r f o l l o w i n g the delay m e m o r i e s , w h e r e
a n o t h e r parity w o r d Q is c r e a t e d .
Q = W + W . + W . + W -
1 1 2 5
Q = W + W + W . + W .
5 5 2 1
Q = W + W + W + W
9 9 6 3
In other w o r d s , t w o s y s t e m of c o d e s are used o n b o t h
sides of t h e delay m e m o r i e s .
Recorded series of signals
w Q P.
5 t 1 5
Disc recording sequence
Adder
Data Word
Fig. 2 . 3 C o d e S e r i e s of C r o s s Interleave
(Black circules indicate errors).
DP-1100B II
+ W .
8 1 5
+ P .
4 U
+ P.?
0
W_ W . W . W
8 5 2 t
Check Word
(6)