Kenwood DP-1100 B Service Manual page 5

D P - 1 1 0 0 B II
1-3 S A M P L I N G T H E O R E M
S / H
A/D
T h e f r e q u e n c y of p i c k i n g u p an a n a l o g s i g n a l , for e x a m p l e ,
5 0 , 0 0 0 t i m e s per s e c o n d , is called " a s a m p l i n g f r e q u e n c y . It
is p r o v e n t h a t if s a m p l i n g is c o n d u c t e d at t h e rate larger t h a n a
c e r t a i n v a l u e , t h e original w a v e f o r m c a n be r e p r o d u c e d j u s t
the s a m e t o a n i n c h . T h i s is called " a s a m p l i n g t h e o r e m " .
8
II. FUNDAMENTALS
Signal Waveform ( a )
Measurings at a fixed time ( b)
;
interval (sampling)
Converts the measured
values to figures
(quantization)
f
Binary coded figures
(Offset Binary)
Recording
Reproduction
Demodulation
D/A
(PAM signal)
Fig. 1.5
Sampling T h e o r e m : If s a m p l i n g is c o n d u c t e d at the f r e ­
q u e n c y ( 4 4 . 1 kHz) w h i c h is over d o u ­
ble the m a x i m u m f r e q u e n c y ( 2 0 kHz)
in a s p e c t r u m of a s i g n a l , t h e original
w a v e f o r m c a n be c o m p l e t e l y r e p r o d u c ­
e d .