CAUTIONS
1 . T h e signal voltage a p p l i e d t o I N P U T s h o u l d be l o w e r
t h a n 17 V r m s .
2 . T o a v o i d leakage o f signal a n d m i n i m i z e t h e e f f e c t o f
phase d e v i a t i o n , be sure t o use shielded cables o n t h e
i n p u t and o u t p u t o f t h e u n i t . These cables s h o u l d be as
s h o r t as possible. T h i s is p a r t i c u l a r l y i m p o r t a n t w h e n
pulse signals are used as a signal source.
3. When t h e u n i t is used w i t h t h e case g r o u n d f l o a t e d f r o m
the c i r c u i t g r o u n d , t h e p o t e n t i a l d i f f e r e n c e ( D C + A C
peak) b e t w e e n these t w o p o i n t s s h o u l d n o t e x c e e d
± 6 0 0 V .
4 .
Dial setting
Select a p p r o p r i a t e dials f o r t h e desired a t t e n u a t i o n at
a n y f r e q u e n c y . N o t e t h a t t h e m a r k i n g s o n each dial
indicate a p p r o x i m a t e settings o f a t t e n u a t i o n i n c l u d i n g
e r r o r . A t y p i c a l e x a m p l e o f a t t e n u a t i o n e r r o r a n d f r e -
q u e n c y c h a r a c t e r i s t i c e r r o r is s h o w n i n T a b l e 1 , w h e r e
1 0 0 k H z signal is a t t e n u a t e d t o 1 0 0 d B , e is t h e e r r o r
3
at 1 k H z o f each dial a n d £
f
is t h e e r r o r o f f r e q u e n c y
c h a r a c t e r i s t i c .
T h e overall e r r o r depends o n t h e n u m b e r o f dials t o be
used as e x p l a i n e d b e l o w .
I) W h e n t h e dials are set t o 3 0 d B x 2 = 6 0 d B , 10 d B x 3
= 3 0 d B , 1 d B x 9 = 9 d B a n d 0.1 d B x 10 = 1 d B ,
t h e n t h e o v e r a l l error
(e)
caused b y each dial and
f r e q u e n c y characteristic is o b t a i n e d f r o m t h e f o l l o w -
i n g e q u a t i o n :
£ =
±V
(0.15
2
+ 0 . 1
2
) + ( 0 . 1
2
+ 0 . 1
2
) + ( 0 . 1
2
+ 0 . 0 5
2
;
+ ( 0 . 0 1
2
+ 0 . 0 5
2
) = ± 0 . 2 8 d B
II) W h e n t h e dials are set t o 3 0 d B x 2 = 6 0 d B , 10 d B x
4 = 4 0 d B , t h e n :
£ = ± V ( 0 . 1 5
2
+ 0 . 1
2
) + ( 0 . 1
2
+ 0 . 1
2
) = 0 . 2 3 d B
A s w i l l be u n d e r s t o o d f r o m t h e above e q u a t i o n s , t h e
less t h e n u m b e r o f dials, t h e higher t h e a c c u r a c y .
T a b l e 1 . T y p i c a l E x a m p l e o f A t t e n u a t i o n E r r o r a n d
F r e q u e n c y C h a r a c t e r i s t i c E r r o r
E r r o r
3 0 d B step 10 d B step 1 d B step 0.1 d B step
± 0 . 1 5 d B
± 0 . 1 d B
± 0 . 1 d B
± 0 . 0 1 d B
£ f
± 0 . 1 d B
± 0 . 1 d B
± 0 . 0 5 d B
± 0 . 0 5 d B
7