156. Short term fading in microwave communication links can be overcome by:
     

1. 1. Increasing the transmitted power
      

   
   
   

   2. Changing the antenna
      

   
   
   

   3. Changing the modulation scheme
      

   
   
   

   4. Diversity reception and transmission

   
   
   

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   NA

   Correct Option: D

   NA

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157. The front end of an amplifier chain in manufacture of communication system is kept immersed in liquid nitrogen, to:
     

1. 1. Dissipate heat generated by amplifier
      

   
   
   

   2. Expand its frequency response
      

   
   
   

   3. Improve its noise figure
      

   
   
   

   4. Reduce the distortion by the amplifier

   
   
   

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   NA

   Correct Option: B

   NA

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158. In microwave we take the elements as:
     

1. 1. Lumped circuit element
      

   
   
   

   2. Distributed circuit element
      

   
   
   

   3. Both (a) and (b) above
      

   
   
   

   4. None of the above

   
   
   

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   NA

   Correct Option: B

   NA

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159. The advantage of microwave lower frequency signals are:
     

1. 1. Increased bandwidth
      

   
   
   

   2. Ability to use high gain, directivity antenna
      

   
   
   

   3. Greater secrecy
      

   
   
   

   4. All of the above

   
   
   

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   NA

   Correct Option: D

   NA

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160. The noise produced in a microwave tube due to random nature of emission and electron flow is called:
     

1. 1. Partition noise
      

   
   
   

   2. Shot noise
      

   
   
   

   3. Johnson noise
      

   
   
   

   4. Shannon noise
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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