Applications - Kenwood RA-920 Instruction Manual

APPLICATIONS

1 . M e a s u r e m e n t o f a m p l i f i e r gain
E x a m p l e : A u d i o f r e q u e n c i e s , 4 5 5 k H z I F f r e q u e n c y ,
pulse a m p l i f i e r , etc.
C o n n e c t an o s c i l l a t o r , R A - 9 2 0 , a m p l i f i e r t o be t e s t e d
a n d A C v o l t m e t e r ( D C v o l t m e t e r f o r D C a m p l i f i e r ) using
s w i t c h e s s u f f i c i e n t l y d u r a b l e
c u r r e n t s , as s h o w n i n F i g . 3 . Set t h e load i m p e d a n c e o f
R A - 9 2 0 t o 6 0 0 o h m .
Oscillator
RA-920
8
against f r e q u e n c i e s a n d
Amplifier
under test
voltmeter
F i g . 3
1) Set R A - 9 2 0 t o 0 d B ( m a y be a t t e n u a t e d t o a c e r t a i n
level d e p e n d i n g o n t h e c o n d i t i o n o f o s c i l l a t o r ) .
2) Set t h e s w i t c h e s t o
i n d i c a t i o n o f t h e v o l t m e t e r .
3) N e x t , set t h e s w i t c h e s t o t h e A p o s i t i o n . A d j u s t R A -
9 2 0 so t h a t t h e r e a d i n g o n t h e v o l t m e t e r is t h e same
as a t t h e B p o s i t i o n . T h e r e a d i n g o b t a i n e d is t h e gain
o f t h e a m p l i f i e r .
W h e n a DC a m p l i f i e r is t o be t e s t e d , be sure t h a t t h e
i n p u t level does n o t e x c e e d t h e m a x i m u m i n p u t voltage
o f t h e a m p l i f i e r . N o t e t h a t if t h e i n p u t i m p e d a n c e o f D C
a m p l i f i e r , e t c . is l o w e r t h a n 6 0 0 o h m , t h e e r r o r b e c o m e s
larger.
AC
t h e B p o s i t i o n a n d read t h e