231. In 50% modulated signal, the carrier is suppressed for transmission. The saving in transmitted power would be—
     

1. 1. 88.9%
      

   
   
   

   2. 11.1%
      

   
   
   

   3. 72%
      

   
   
   

   4. 18%

   
   
   

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1. View Hint View Answer Discuss in Forum

   % Power saving =	Power saved	×100
   	Total Power

   
   

   =	Pc	×100
   	(1 + μ2/2)

   
   

   =	2	×100
   	2 + μ2

   
   

   =	2	×100
   	2 + (0.5)2

   
   (∴ μ = 50 % = 0.5)
   

   =	2	×100 = 88.88 %
   	2 + .25

   
   Hence alternative (A) is the correct choice.
   

   Correct Option: A

   % Power saving =	Power saved	×100
   	Total Power

   
   

   =	Pc	×100
   	(1 + μ2/2)

   
   

   =	2	×100
   	2 + μ2

   
   

   =	2	×100
   	2 + (0.5)2

   
   (∴ μ = 50 % = 0.5)
   

   =	2	×100 = 88.88 %
   	2 + .25

   
   Hence alternative (A) is the correct choice.
   

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232. Some properties are given below:
     (i) A signal f (t) and its Hilbert f_h(t) have the same energy density spectrum.
     (ii) A signal f (t) and its Hilbert transform f_h(t) have the same auto correlation function.
     (iii) A signal f (t) and its Hilbert transform f_h(t) are mutually orthogonal i.e ∫^infin; _–∞ f(t) f_h(t) dt = 0
     (iv) If f_h(t) is a Hilbert transform of f (t), then the Hilbert transform of f_h(t) is – f (t)
     i.e. If H [f(t)] = f_h(t)
     then H [f_h(t)] = – f (t)
     The correct statements are—

1. 1. (i) and (iv) only.
      

   
   
   

   2. (i) and (iii) only.
      

   
   
   

   3. (i), (ii) and (iii) only.
      

   
   
   

   4. All of these
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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233. Application of Hilbert transform are:
     (i) generation of SSB signals.
     (ii) design of minimum phase type filters.
     (iii) representation of bandpass signals.
     The correct statements are—
     

1. 1. (i) and (ii)
      

   
   
   

   2. (i) and (iii)
      

   
   
   

   3. (ii) and (iii)
      

   
   
   

   4. (i), (ii) and (iii)

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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234. One of the following cannot be used to remove the unwanted sideband in SSB. This is the—
     

1. 1. filter system
      

   
   
   

   2. phase-shift method
      

   
   
   

   3. balanced modulator
      

   
   
   

   4. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   Since balanced modulator basically used for generating the DSB-SC signal.
   

   Correct Option: C

   Since balanced modulator basically used for generating the DSB-SC signal.
   

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235. In an SSB transmitter, one is most likely to find a—
     

1. 1. class C audio amplifier
      

   
   
   

   2. tuned modulator
      

   
   
   

   3. class B RF amplifier
      

   
   
   

   4. class A RF amplifier
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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