Kenwood DP-1100 B Service Manual page 22

3 - 3 - 3 C L V S e r v o Circuit
C o n s t a n t linear v e l o c i t y (CLV) m e a n s t o keep a line s p e e d at a
c o n s t a n t speed of a p p r o x . 1.2 m / s e c .
For this p u r p o s e disc is r o t a t e d : a p p r o x . 5 0 0 r . p . m . at inside
EFM
Signal
3 - 4 E Y E P A T T E R N
T h e RF signal is being delivered f r o m the signal processing
c i r c u i t as d e s c r i b e d u n d e r 3 - 2 . T h e RF signal is vaired acor-
d i n g t o a p p e a r a n c e or d i s a p p e a r a n c e of a pit o n a disc. This
signal c a n be displayed o n an o s c i l l o s c o p e as illustrated in the
Fig. 3 - 5 .
II. FUNDAMENTALS
radios
a p p r o x . 2 0 0 r . p . m . at o u t ­
side radios
Bit Sync
Signal Generation
Fig. 3 . 3
Fig. 3 . 5
The CLV servo c i r c u i t is t h e c i r c u i t t o s e r v o - c o n t r o l r e v o l u t i o n s
of the disc m o t o r t o keep c i r c u m f e r e n t i a l s p e e d of t h e disc
c o n s t a n t .
C L V
Servo Amp. Disc
Motor
The w a v e f o r m is generally called " E y e P a t t e r n " .
Fig. 3 - 5 is s k e t c h e s e x p l a i n i n g c o n c e p t of t h e eye p a t t e r n .
The RF signal is c o n v e r t e d t o a digital signal c o m p o s e d of 1s
a n d Os w i t h the aid of a c o m p a r a t o r t o g e n e r a t e an EFM
signal.
1 V/div
0.5 /ts/div
D P - 1 1 0 0 B II
2 5