070-3783-01
492/492P Service Vol. 1
9-2-B3 Rev
C a l i b r a t i o n - A d j u s t m e n t P r o c e d u r e
P a g e 3-58/ R E P L A C E the e n t i r e S t e p 8 w i t h t h e f o l l o w i n g :
8. B a s e l i n e L e v e l i n g ( V i d e o P r o c e s s o r )
Th is p r o c e d u r e a d j u s t s th e b a s e l i n e so B a n d 1 a n d 4 r e s p o n s e
p e r t u r b a t i o n s a r e o f f s e t to l e v e l the d i s p l a y .
a. T e s t e q u i p m e n t s e t u p is s h o w n in Fig. 3-35. T h e o u t p u t of
the sw e e p g e n e r a t o r is a p p l i e d t h r o u g h a 3 db a t t e n u a t o r a n d h i g h -
p e r f o r m a n c e c o a x i a l c a b l e to a p o w e r d i v i d e r . C o n n e c t one o u t p u t of
t h e p o w e r d i v i d e r d i r e c t l y to t h e R F I N P U T of t h e 4 9 2 / 4 9 2 P a n d th e
o t h e r to the s e n s o r f o r t h e p o w e r meter. S e t t h e R F p l u g - i n A L C s w i t c h
to the M T R p o s i t i o n , a n d c o n n e c t a c o a x i a l c a b l e b e t w e e n R e c o r d e r
O u t p u t of the p o w e r m e t e r a n d t h e E x t A L C I n p u t of t h e p l u g - i n u n i t
on the sw ee per . S e t t h e P o w e r L e v e l to a p p r o x i m a t e I y - 1 0 dBm, t h e n
a d j u s t t h e G a i n on th e u n i t f o r s t a b l e o p e r a t i o n ( o u t p u t s t o p s
o s c i l l a t i n g ) .
b
S e t the
FREQUENCY t o 1 0 0 MHz,
F R E Q S P A N / D I V to 5 MHz,
REF
L E V E L
to - 2 0
dBm,
T I M E / D I V to AUTO, a n d a c t i v a t e A U T O R E S O L N a n d 2 dB /DIV.
c. A p p l y the C A L O U T s i g n a l to the R F INPUT, a n d a d j u s t R E F L E V E L
for an ο π - s c r e e n d i s p l a y of a p p r o x i m a t e l y 6 d i v i s i o n s . N o t e t h e s i g n a l
am p 1 i tud e .
d. R e m o v e the C a l i b r a t o r s i g n a l a n d a p p l y t h e o u t p u t of t h e s w e e p
o s c i l l a t o r as s h o w n in Fig. 3-35. S e t t h e F R E Q U E N C Y to 1 . 8 G H z a n d
a p p l y a 1.8 GHz s i g n a l at - 2 0 dBm, f r o m t h e S w e e p O s c i l l a t o r to the
R F INPUT. N o t e t h e a m p l i t u d e of t h e 1 . 8 G H z s i g n a l . (It m a y be n e c e s s a r y
to s w i t c h to 10 d B / D I V m o d e to o b s e r v e t h e si gn a l .
e. A d j u s t B a n d 1 S l o p e R 1 0 1 2 so the s i g n a l a m p l i t u d e e q u a l s t h a t
of the 1 0 0 M H z r e f e r e n c e . R 1 0 1 2 is l o c a t e d on th e V i d e o P r o c e s s o r b o a r d
n e x t to hi g h l e v e l e r a d j u s t m e n t R1013.
f. On the V i d e o P r o c e s s o r b o a r d , p u l l th e L e v e l e r D i s a b l e plug,
P 3 0 3 5
' F i g .
3-36).
g.
S e t the F R E Q U E N C Y to 10 GHz, F R E Q U E N C Y R A N G E to 5 . 4 - 1 8 0 G H z
(Band 4). F R E Q S P A N / D I V to MAX, R E F L E V E L to - 1 0 dBm, a n d T I M E / D I V to
10 ms. A c t i v a t e 10 d B / D I V a n d A U T O R E S O L N .
h. G n the s w ee p o s c i l l a t o r , s e l e c t a 5. 5 G H z cw m a r k e r a n d a d j u s t
t h e o u t p u t for a - 1 0 d B m r e a d i n g on the p o w e r meter.
i. A c t i v a t e 2 dB /D IV, a n d a d j u s t the R E F L E V E L so t h e s i g n a l
a m p l i t u d e is h a l f sc reen. A d j u s t M A N U A L P E A K f o r m a x i m u m r e s p o n s e or
a c t i v a t e A U T O PEAK.
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