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In as Amplitude Modulated wave ,The ratio between the bandwidth of the modulated wave and the frequency of message signal is 

Option: 1

2


Option: 2

1


Option: 3

3


Option: 4

4


Answers (1)

best_answer

As we have learned

Voltage equation for AM wave -

e_{c}= E_{c}\cos \omega _{c}t

e_{m}= E_{m}\sin \omega _{m}t

- wherein

Resultant Modulated wave

e= \left ( E_{c} +e_{m}\sin \omega _{m}t\right )\cdot \sin \omega _{e}t

 

 If message signal is e_m = E_m \sin w_m t  and carrier waves e_c = E_c \sin w_c t

Amplitude modulatedwave e = (E_c + E_m \sin w_c t ) \sin w_ct

e = E_c \sin w_c t + E_m \sin w_m t \cdot \sin w_ct

= E_c \sin w_c t + \frac{V_m}{2}[ \cos (w_c - w_m)t - \cos (w_c+w_m)t]

Here we find three frequency w_c , w_c -w_m , w_c +w_m

w_c =  angular frequency of carrier 

w_c -w_m = angular frequency of lower side band 

w_c +w_m = angular frequency of upper side band 

NOw , \frac{Bandwidth }{ferquency\: \: of \: \: message \: \: signal}= \frac{(w_c-w_m)-(w_c-w_m)}{w_m}

\frac{2 w_m }{w_m}  = 2 

 

 

Posted by

Suraj Bhandari

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