8 - 2 E i i m i n a t i o n o f u n d e s i r e d
s i g n a l
c o m p o n e n t s
By u s i n g the V. MODE c o n t r o l
1
s ADD s e t t i n g , u n d e s i r e d s i g n a l components can be e l i m i n a t e d ,
a l l o w i n g only d e s i r e d s i g n a l components to be d i s p l a y e d .
1) Apply s i g n a l s i n c l u d i n g u n d e s i r e d components to t h e CHI INPUT t e r m i n a l .
Now apply t h e components you want to e l i m i n a t e t o t h e CH2 INPUT t e r m i n a l .
2 ) S e t t h e V. MODE s w i t c h t o A L T o r CHOP. S e t t h e SOURCE c o n t r o l t o CH2. S e t t h e
t r i g g e r p o i n t t o t h e CH2 s i g n a l , and make s u r e t h a t CH2 c o n t a i n s t h e u n d e s i r e d
components o f C H I .
3 ) P r e s s t h e INV s w i t c h , and make s u r e t h a t t h e CH2 s i g n a l r e p r e s e n t s t h e u n d e s i r e d
components i n the r e v e r s e p o l a r i t y .
When t h e V. MODE s w i t c h i s s e t t o ADD i n t h e s e c o n d i t i o n s , o n l y t h e d e s i r e d s i g n a l
components a r e d i s p l a y e d on the CRT.
CH : S i g n a l w i t h u n d e s i r e d components
ADD : S i g n a l w i t h o u t u n d e s i r e d component
-CH2 : Undesired component
4 ) E l i m i n a t i o n c a p a b i l i t i e s v a r y w i t h t h e s i z e o f t h e u n d e s i r e d component. I n o r d e r t o
a t t a i n the b e s t r e s u l t s , d i s p l a y the CH2 s i g n a l w i t h s l i g h t l y h i g h e r VOLTS/DIV s e t t i n g .
A f t e r p r e s s i n g the INV s w i t c h and a c t i v a t i n g the ADD f u n c t i o n , a d j u s t the CH2 V. VARI
c o n t r o l to g e t a good waveform.
36
Figure 11
Common
Mode R e j e c t i o n
