3 AC ONLINE 2-2

1 . T h e S i gn a l t o N o i s e o f F m a t m o d u l a t i on i n d e x = 5 i s f a c t or of S /N of A M ( a) 7 5 ( b ) 5 7 ( c ) 8 1 ( d ) 7 0

2 . T h e S i gn a l t o N o i s e r a t i o of V S B - S C s ch e m e i s ( a) 2 ( b ) 1 ( c ) 3 ( d ) z e r o

3 . I n P M , t h e p owe r s p e c t r a l d e n s i ty o f t h e O/ P n o i s e , va r i e s w i th f r e q u e n c y a s ( a) c i r c l e ( b ) Pa ra b o l a ( c ) H y p e r b o l a ( d ) U n i f o r m

4 . T h e S N R of P M ove r A M i s o f B W o f Tr an s m i s s i on ( a) s q u a re ( b ) d o u b l e ( c ) q u ad r u p l e ( d ) S a m e

5 . B r o ad c as t tr a n s m i t te rs a re d e s i g n e d f or t r a n s m i t ti n g ( a) S p e e ch or mu s i c ( b ) C o d e d s i gn a l ( c ) C o nti nu o u s c a r r i e r ( d ) Te l e p h on e s i g n al

6 . M i c r owave t r an s m i t t e r s h ave t h e i r wo r ki n g f re qu e nc i e s a t a r e a b o u t ( a) 1 00 0M H z ( b ) 1 00 M H z ( c ) 1 0M H z ( d ) 8 0 M H z

7 . B o o s t i n g h i gh f r e q u e n c y c o m p o n e nts i n m o d u l a ti n g s i gn a l i s c a l l e d ( a) At te nu a t i n g ( b ) E ch o s u p p r e s s i n g ( c ) Ton e f o rr e c t i o n ( d ) p r e e m p h a s i s

8 . M o s t o f t h e p owe r i n A M s i gn a l l i e s i n i ts ( a) C a r ri e r ( b ) U S B ( c ) B o t h U S B a n d L S B ( d ) L S B

9 . A p u s h p u l l p owe r a m p l i fi e r t h a t i s u s e d f o r c a r ri e r s u p p r e s s i o n i s c a l l e d ( a) H o rm o n i c ge n e r a t or ( b ) B a l a n c e d m o d u l a to r ( c ) Fr e q u e n c y m i xe r ( d ) Fr e q u e n c y mu l t i p l i e r

1 0. T h e ab i l i ty o f a r e c e i ve r to r e s p on d to t h e we ake s t s i gn a l i s c a l l e d ( a) S i g n al h an d l i n g a b i l i ty ( b ) S e n s i t i v i ty ( c ) fi d e l i ty ( d ) s e l e c t i vi ty

1 1. A l l c om m e r c i a l r e c e i ve r s e m p l oy I F b e twe e n ( a) 2 00 t o 3 00 K H z ( b ) 1 2 to 1 3 K H ( c ) 4 55 t o 4 65 K H z ( d ) 7 40 t o 8 40 K H z

1 2. T h e nu mb e r of m i x e r s t a ge s o f a t r i p l e d e te c t i on r e c e i ve r ( a) 2 ( b ) 1 ( c ) 4 ( d ) 3

1 3. S e l e c ti v i ty of a r e c e i ve r i s d e p e n d e nt on ( a) m i x e r ( b ) m i x e r a n d I F ( c ) I F am p l i fi e r ( d ) R F & M i x e r

1 4. I n d i c a t e w h i ch on e o f t h e f ol l ow i n g b l o cks i s u s e d i n b ot h c om mu n i c a t i on re c e i ve r s a n d b r oa d c a s t r e c e i ve r s ( a) m i x e r ( b ) L i m i t e r ( c ) b e a t f r e q u e n c y os c i l l at o r ( d ) S q u e l ch

1 5. I n a s u p e r h e te ro d y n e r e c e i ve r ( a) L o c al Os c i l l at o r f r e q u e n c y i s d o ub l e I F ( b ) T h e ou t p u t c i r c u i t of m i xe r i s t u n e d t o s i gn a l f r e q u e n c y ( c ) L o c al os c i l l at o r f r e q u e n c y i s g re at e r t h a n i n c o m i n g s i gn a l f re qu e n c y ( d ) R F wo rk s at 45 5 K H z

1 6. T h e m i n i mu m ch an n e l b an d w i d t h r e q u i r e d f o r t r an s m i tt i n g 3 b a s e b a n d s i g n al s , e a ch i s b an d l i m i te d t o 3 K H z ( a) 3 K H z ( b ) 1 . 5 K H ( c ) 6 K H z ( d ) 9 K H z

1 7. I n d i c a t e t h e f al s e s ta t e m e nt : I f t h e I nt e r m e d i a t e f r e q u e n c y i s h i g h ( a) t h e l o c a l o s c i l l a t or n e e d n o t b e h i gh l y s ta b l e ( b ) i m a ge f r e q u e n c y r e j e c t i on i s ve r y go o d ( c ) t ack i n g w i l l b e i m p r ove d ( d ) t h e s e l e c t i v i ty w i l l b e p o or

1 8. W h i ch f u n c t i on a l b l o ck r e a d i ly i d e nti fi e s i t i s a n F M re c e i ve r ( a) I F am p ( b ) R F a m p ( c ) d e t e c t o r ( d ) m i x e r

1 9. AG C fi l te r u s e s n or m a l l y t h e val u e s o f R = 5 00 K a nd C e qu a l t o ( a) 1 µF ( b ) 2 0 µF ( c ) 2 µF ( d ) 1 0 µF

2 0. Q u ant i s i n g n oi s e i n a P C M s y s t e m c a n b e r e d u c e d by ( a) D e c r e a s i n g t h e nu mb e r o f s t an d a rd l e ve l s ( b ) I n c r e a s i n g t h e nu mb e r of s t an d a r d l e ve l s ( c ) U s i n g l ow n o i s e c i rc u i tr y i n P C M r e c e i ve r ( d ) H av i n g m o r e n o . of s a m p l e s p e r s e c on d

ABDAA ADABB CABCC DBCBB

2 AC ONLINE 2-2

1 . T h e S i gn a l t o N o i s e o f F m a t m o d u l a t i on i n d e x = 5 i s f a c t or of S /N of A M ( a) 7 0 ( b ) 8 1 ( c ) 7 5 ( d ) 5 7

2 . T h e S i gn a l t o N o i s e r a t i o of V S B - S C s ch e m e i s ( a) 3 ( b ) z e r o ( c ) 2 ( d) 1

3 . I n P M , t h e p owe r s p e c t r a l d e n s i ty o f t h e O/ P n o i s e , va r i e s w i th f r e q u e n c y a s ( a) H y p e r b o l a ( b ) Pa ra b o l a ( c ) U n i f o r m ( d ) c i r c l e

4 . I n F M , t h e p owe r s p e c t r al d e n s i ty o f t h e O / P n o i s e , va ri e s w i t h f re qu e n c y a s ( a) U n i f o r m ( b ) H y p e r b o l a ( c ) Pa ra b o l a ( d ) c i r c l e

5 . H a rm o n i c ge n e r a t or i s o p e r at e d as a a m p l i fi e r ( a) A B ( b ) B ( c ) C ( d ) A

6 . O n e o f t h e f ol l ow i n g i s u s e d i n ra d i o t e l e p h o n e t r an s m i tt e r s ( a) Va c u u m Tu b e ( b ) VODA S ( c ) Tra n s i s t o r ( d ) F E T

7 . A d e vi c e t h a t re d u c e s th e g ai n o f A . F . a m p l i fi e r w h e n t h e i n p u t e x c e e d s p re d e t e r m i n e d va l u e i s c a l l e d ( a) D i s c r i m i n a to r ( b ) Pe a k c l i p p e r ( c ) e ch o s u p p r e s s or ( d ) D e t e c t o r

8 . M o s t o f t h e p owe r i n A M s i gn a l l i e s i n i ts ( a) U S B ( b ) C a r ri e r ( c ) L S B ( d ) B o t h U S B a n d L S B

9 . T h e r an g e o f F . M . t r an s m i t t e r wo r ki n g i n t h e U H F ra n g e i s ( a) ve r y l ar g e ( b ) l a rg e ( c ) l i n e of s i g ht d i s ta n c e ( d ) S m a l l

1 0. T h e p r e d i s t o rt e r i n A r m s t r on g F . M ge n e ra t i on i s n o t h i n g b u t ( a) I nt e g ra t or ( b ) At te nu a t or ( c ) R e c t i fi e r ( d ) D i ff e r e nt i at o r

11. A l l c om m e r c i a l r e c e i ve r s e m p l oy I F b e twe e n ( a) 2 00 t o 3 00 K H z ( b ) 7 40 t o 8 40 K H z ( c ) 4 55 t o 4 65 K H z ( d ) 1 2 to 1 3 K H

1 2. T h e s e l e c ti v i ty of a T R F r e c e i ve r i s ( a) l ow ( b ) t o o h i gh t o r e d u c e fi d e l i ty ( c ) ve r yl ow ( d ) m e d i u m

1 3. T h e l o c al Os c i l l at o r of a s u p e rh e t e r o d y n e r e c e i ve r w i l l b e t u n e d t o a f r e q u e n c y ( a) l owe r t h an s i gn a l f r e q u e n c y ( b ) S i g n al f r e qu e n c y + I F ( c ) O f t h e s i gn a l ( d ) s i g n al f r e q u e n c y - I F

1 4. T h e f o l l ow i n g i s n ot o n e of th e c o m m on s t ag e f or A M & F M re c e i ve r s ( a) l i m i t e r ( b ) m i x e ( c ) r at i o d e t e c t o r ( d ) I F am p l i fi e r

1 5. T h e l o c al os c i l l at o r of a b r oa d c a s t r e c e i ve r i s t u n e d t o s f r e q u e n c y h i g h e r t h an t h e i n c o m i n g f r e q u e n c y ( a) t o al l ow a d e q u at e f r e q u e n c y c ove ra g e w i t h o u t s w i t ch i n g ( b ) t o p e r m i t e a s i e r t r a cki n g ( c ) o th e rw i s e i nt e r m e d i a te f r e q u e n c y c an n o t b e p ro d u c e d ( d ) t o al l ow t h e i m ag e f re qu e n c y r e j e c t i o n

1 6. A b as e b an d s i g n a l ba n d l i m i t e d t o 5 K H z i s t o b e re c on s tr u c t e d f r o m i ts s am p l e s . T h e m i n i mu m p a s s b a n d w i d t h o f t h e re c on s t r u c t i o n fi l t e r s h o u l d b e ( a) 1 0 K H z ( b ) 2 0 K H z ( c ) 2 . 5 K H z ( d ) 5 K H z

1 7. B a n d l i m i t e d s i gn a l i s ( a) B a n d p a s s s i g n al w i th i n fi n i t e B W ( b ) B a n d p a s s s i g n al w i th U p p e r f re qu e n c y l i m i t e q u a l t o z e r o ( c ) B a n d p a s s s i g n al b ot h w i th u p p e r a n d l owe r f r e q u e n c y l i m i t s ( d ) B a n d p a s s s i g n al w i th l owe r f r e q u e n c y l i m i t e q u a l t o z e r o

1 8. A ty p i c a l s q u e l ch c i rc u i t ( a) c u t s off t h e a u d i o am p l i fi e r w h e n t h e c ar r i e r i s b l o ck ( b ) e l i m i n a t e s t h e RF i nt e r f e re n c e w h e n t h e s i gn a l i s we ak ( c ) c u t s off t h e I F am p l i fi e r w h e n t h e AG C i s m i n i mu m ( d ) c u t s off t h e I F am p l i fi e r w h e n t h e AG C i s m a xi mu m

1 9. T h r e e p o i nt t r a cki n g i s a ch i e ve d w i t h ( a) d o u b l e s p ot t i n g ( b ) Pa d d e r C a p ac i t o r ( c ) b l o ck i n g ( d ) d o u b l e c o nve r s i o n

2 0. Q u ant i s i n g n oi s e o c c u r s i n ( a) T i m e - d i vi s i on mu l t i p l e x i n g ( b ) Fr e q u e n c y- d i vi s i on mu l t i p l e x i n g ( c ) P u l s e p o s i t i on m o d u l a t i on ( d ) P u l s e - c o d e m o d u l a t i on

CDCCC BBBCD CBBCB DDDBD

1 AC ONLINE 2-2

1 . T h e S i gn a l t o N o i s e o f F m a t m o d u l a t i on i n d e x = 5 i s f a c t or of S /N of A M ( a) 8 1 ( b ) 7 5 ( c ) 5 7 ( d ) 7 0

2 . N o i s e p e r f or m a n c e o f A M - D S B - S C s i gn a l i s s a m e a s t h a t of A M - S S B - S C s y s t e m d u e t o ( a) M o r e b a n d w i d t h ( b ) M o r e i / p s i g n al p owe r ( c ) L e s s i /p s i g n al p owe r ( d ) L e s s N oi s e p owe r

3 . Fo r a m o d u l at i o n i n d e x β > 0 . 5 th e n oi s e p e rf or m a n c e o f F M w h e n c o m p ar e d t o A M i s ( a) C a n ’ t b e c om p a r e d ( b ) S a m e ( c ) wo rs t ( d ) B e tt e r

4 . P r e - e m p h as i s i n F M i s u s e d a t ( a) B e f or e D e m o d u l a t i on ( b ) R e c e i v i n g e n d ( c ) Tra n s m i t t i n g e n d ( d ) I n th e C h a n n e l

5 . L on g wave s t r an s m i t t e r wo r k s i n th e f r e q u e n c y r a n ge ( a) 1 M H z ( b ) 2 0 M H Z ( c ) 6 0 M H z ( d ) 3 00 K H z

6 . M i c r owave t r an s m i t t e r s h ave t h e i r wo r ki n g f re qu e nc i e s a t a r e a b o u t ( a) 8 0 M H z ( b ) 1 00 0M H z ( c ) 1 00 M H z ( d ) 1 0M H z

7 . A d e vi c e t h a t re d u c e s th e g ai n of A . F . a m p l i fi e r w h e n t h e i n p u t e x c e e d s p re d e t e r m i n e d va l u e i s c a l l e d ( a) Pe a k c l i p p e r ( b ) e ch o s u p p r e s s or ( c ) D e t e c t o r ( d ) D i s c r i m i n a to r

8 . I n A M m o d u l a to r c i r c u i t s , th e c a r ri e r an d th e m o d u l at i n g s i g n al ar e ( a) S u b t r ac t e d ( b ) A d d e d ( c ) M u l t i p l i e d ( d ) M i x e d

9 . T h e r an g e o f F . M . t r an s m i t t e r wo r ki n g i n t h e U H F ra n g e i s ( a) l a rg e ( b ) ve r y l ar g e ( c ) S m a l l ( d ) l i n e of s i g ht d i s ta n c e

1 0. T h e m ax i mu m d e v i a t i on us e d i n p ol i c e F M r ad i o i s ( a) 2 0K H z ( b ) 1 5K H z ( c ) 3 K H z ( d ) 5 K H z

1 1. T h e ab i l i ty o f a r e c e i ve r to d i s t i n g u i s h t h e want e d a n d u nwa nt e d s i g n al s i s ( a) s e l e c t i vi ty ( b ) S e n s i t i v i ty ( c ) S / N r at i o ( d ) e ffi c i e n c y

1 2. T h e ou t p u t f r o m r a d i o re c e i ve r va r i e s a b r u p tl y m any t i m e s w i t h o u t n ot i c e . T h i s i s c a l l e d ( a) M o t or b oa t i ng ( b ) n o i s e ( c ) H u m ( d ) f a d i n g

1 3. I n a s u p e r h e t e r o d yn e r e c e i ve r f re q u e n c y c o nve r s i o n t ake s p l ac e a t ( a) d o e s n o t ( b ) 2 p l a c e s ( c ) 4 p l a c e s ( d ) 3 p l a c e s

1 4. T h e f o l l ow i n g i s n ot o n e of th e c o m m on s t ag e f or A M & F M re c e i ve r s ( a) m i x e ( b ) I F am p l i fi e r ( c ) r at i o d e t e c t o r ( d ) l i m i t e r

1 5. I n a s u p e r h e te ro d y n e r e c e i ve r ( a) L o c al os c i l l at o r f r e q u e n c y i s g re at e r t h a n i n c o m i n g s i gn a l f re qu e n c y ( b ) T h e ou t p u t c i r c u i t of m i xe r i s t u n e d t o s i gn a l f r e q u e n c y ( c ) R F wo rk s at 45 5 K H z ( d ) L o c al Os c i l l at o r f r e q u e n c y i s d o ub l e I F

1 6. W h i ch o f th e s t a te m e nt s ab ou t t h e am p l i t u d e l i m i te r i s u nt r u e ( a) T h e c i r c u i t i s al ways b i a s e d i n c l as s C , by v i rt u e of t h e l e a k ty p e b i a s ( b ) T h e ou t p u t mu s t b e t u n e d ( c ) L e a k ty p e b i as mu s t b e u s e d ( d ) W h e n i n p u t i n c r e as e s f as t th e t h r e s h o l d of l i m i t i n g, t h e g ai n d e c r e a s e s to ke e p th e o u tp u t c on s ta nt

1 7. Fr o m t h e p oi nt o f v i e w , t h e m a i n d i ff e re n c e b e twe e n t u b e a n d t r a n s i s t or re c e i ve rs i s th a t t h e l at t e r ( a) mu s t h ave I F s ta g e s e ve n m or e s t ab i l i z e d t h an th e y ar e n or m a l l y ( b ) r e q u i r e AG C p owe r r at h e r t h a n t h e vol t a ge ( c ) d o n o t r e al l y n e e d AG C b e c a u s e ove r l oa d i n g c a u s e s l i m i ti n g ( d ) h ave tr o u b l e s b e c a u s e AG C i s n ot ve r y e ff e c t i ve i n t h e m

1 8. A ty p i c a l s q u e l ch c i rc u i t ( a) c u t s off t h e I F am p l i fi e r w h e n t h e AG C i s m a xi mu m ( b ) c u t s off t h e a u d i o am p l i fi e r w h e n t h e c ar r i e r i s b l o ck ( c ) c u t s off t h e I F am p l i fi e r w h e n t h e AG C i s m i n i mu m ( d ) e l i m i n a t e s t h e RF i nt e r f e re n c e w h e n t h e s i gn a l i s we ak

1 9. AG C fi l te r u s e s n or m a l l y t h e val u e s o f R = 5 00 K a nd C e qu a l t o ( a) 2 µ F ( b ) 1 0 µ F ( c ) 1 µ F ( d ) 2 0 µ F

2 0. F M c ap t u r e e ff e c t i s d u e to t h e f ol l ow i n g c i r c u i t ( a) D e e m p h a s i s ( b ) AG C ( c ) L i m i t e r ( d ) D i s c r i m i n a to r

BADCD BABDD ADBCA ABADC

introduction

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