21. Ring modulator is used to produce—
    

1. 1. DSB-SC
      

   
   
   

   2. SSB
      

   
   
   

   3. USB
      

   
   
   

   4. VSB

   
   
   

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1. View Hint View Answer Discuss in Forum

   Ring modulator is used to produce DSB-SC wave.

   Correct Option: A

   Ring modulator is used to produce DSB-SC wave.

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22. The type of modulator amplifier used in AM transmitter is—
    

1. 1. Class–A
      

   
   
   

   2. Class–B
      

   
   
   

   3. Class–C with negative feedback
      

   
   
   

   4. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   The type of modulator amplifier used in AM transmitter is class–C with negative feedback.
   

   Correct Option: C

   The type of modulator amplifier used in AM transmitter is class–C with negative feedback.
   

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23. If modulation index in an AM system is low, it means the system is—
    

1. 1. Less efficient
      

   
   
   

   2. More efficient
      

   
   
   

   3. More reliable
      

   
   
   

   4. Both and

   
   
   

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1. View Hint View Answer Discuss in Forum

   If modulation index in an AM modulation system is low, it means the system is less efficient.

   Correct Option: A

   If modulation index in an AM modulation system is low, it means the system is less efficient.

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24. Completely suppressed carrier transmission is—
    

1. 1. Cheaper in cost
      

   
   
   

   2. Simpler in design
      

   
   
   

   3. Never produced commercially
      

   
   
   

   4. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   Completely suppressed carrier transmission is never produced commercially.

   Correct Option: C

   Completely suppressed carrier transmission is never produced commercially.

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25. The output of an SSB modulator using a balanced modulator has frequencies—
    

1. 1. (ω_c + ω_m), (ω_c – ω_m)
      

   
   
   

   2. ω_c, (ω_c – ω_m)
      

   
   
   

   3. (ω_c – ω_m)
      

   
   
   

   4. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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