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Amplifier
A G - 2 0 3
under
test
F i g . 5
M e a s u r e m e n t
o f
P h a s e
C h a r a c t e r i s t i c
F i g .
C h e c k
Oscilloscope
No
amplitude
distortion
Amplitude distortion
on both sides
6
o f
P h a s e
S h i f t
A n g l e
straight' line o n the oscilloscope is curved a t its top
b o t t o m s e c t i o n s as s h o w n in F i g . 5 B , it i n d i c a t e s t h a t t h e
o u t p u t signal o f a m p l i f i e r is s u f f e r i n g f r o m a n a m p l i t u d e
d i s t o r t i o n .
I n t h i s c a s e , r e d u c e t h e o u t p u t level o f A G
- 2 0 3 a l i t t l e t o
v a r y t h e
straight line o n t h e o s c i l l o s c o p e t o e x p a n d g r a d u a l l y
t u r n i n t o a n e l l i p s e . B y u t i l i z i n g t h e c o n f i g u r a t i o n o f t h i s
e l l i p s e , t h e p h a s e s h i f t c a n be c a l c u l a t e d as f o l l o w s :
F i r s t ,
m e a s u r e t h e m a x i m u m
a n d s u p p o s e t h a t t h i s d e f l e c t i o n
s e c t i o n a t w h i c h t h e ellipse c r o s s e s t h e h o r i z o n t a l a x i s is
" x " , as s h o w n in F i g . 6 . A n d , t h e p h a s e s h i f t angle e is
given b y t h e f o l l o w i n g .
F i n d e f r o m t h e t a b l e of t r i g o n o m e t r i c f u n c t i o n s
t h e v a l u e o b t a i n e d gives t h e angle o f p h a s e s h i f t .
4 . Using as S q u a r e Wave Oscillator
A G - 2 0 3 f e a t u r e s e x c e l l e n t r i s i n g a n d f a l l i n g c h a r a c t e r -
istics
( 1 2 0
ns
as s t a n d a r d
c o u p l i n g c a p a c i t o r s in t h e o u t p u t stage, so t h e sag (de-
f l e c t i o n
o f t o p
s e c t i o n ) is as l o w as 5 % a t 5 0 H z . B y
a p p l y i n g s u c h a g o o d s q u a r e w a v e t o a n a m p l i f i e r i n p u t ,
v a r i o u s c h a r a c t e r i s t i c s of a m p l i f i e r c a n be o b s e r v e d o n a n
o s c i l l o s c o p e . T o t e s t a n a m p l i f i e r , p r o c e e d as f o l l o w s :
and
f r e q u e n c y .
T h i s c a u s e s t h e
t o
h o r i z o n t a l
d e f l e c t i o n
is " X " a n d t h a t t h e
a n d
c h a r a c t e r i s t i c ) . It
has no
1 3
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