IVIE IE-10A, Owner'S And Operator'S Manual

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U S I N G EXTERNAL ATTENUATORS
The can a n a l y z e s i g n a l s as l a r g e as
+
9 (2.2 Vrms) w i t h o u t
t h e use o f e x t e r n a l a t t e n u a t o r s . When an e x t e r n a l a t t e n u a t o r i s used,
however, t h e d i s p l a y e d s i g n a l on t h e r e q u i r e s compensation f o r
t h e e f f e c t o f t h e a t t e n u a t o r . shows a s i g n a l b e i n g fed
i n t o an t h r o u g h a 20 dB a t t e n u a t o r . The a n a l y z e r i s measuring
t h e i n p u t s i g n a l a f t e r
i t
has been a t t e n u a t e d by 20 dB, so we must add
t h e a t t e n u a t o r v a l u e t o the s i g n a l l e v e l d i s p l a y e d on t h e i n
o r d e r t o determine t h e t r u e s i g n a l l e v e l . I n t h e example of F i g . 32,
t h e a n a l y z e r i s d i s p l a y i n g a s i g n a l l e v e l o f a f t e r 20 dB of
a t t e n u a t i o n . The a c t u a l s i g n a l l e v e l i s +24
(+4 +20 dB), o r ,
u s i n g t h e v o l t a g e c o n v e r s i o n e i s equal t o 12.3 Vrms.
F i g u r e 32
One more example o f t h e use o f e x t e r n a l a t t e n u a t o r s s h o u l d p t o
c l a r i f y t h e procedure. A s i g n a l i s s e n t through a 40 dB a t t e n u a t o r and
t h e n i n t o an which d i s p l a y s a s i g n a l l e v e l of -16 How l a r g e
i s t h e r e a l s i g n a l ? We s i m p l y r e a d i n g o f t h e i n c l u d i n g
t h e c o r r e c t s i g n , t o t h e a t t e n a t o r value b e i n g used. I n t h i s example
t h e t r u e s i g n a l l e v e l i s 24 (-16
+
40 dB), o r 12.3
page 37