46. In a broadcast superheterodyne receiver, the—
    

1. 1. Local oscillator operates below the signal frequency
      

   
   
   

   2. Mixer input must be tuned to the signal frequency
      

   
   
   

   3. Local oscillator frequency is normally double the IF
      

   
   
   

   4. RF amplifier normally works at 455 kHz above the carrier frequency

   
   
   

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1. View Hint View Answer Discuss in Forum

   In a broadcast superhetrodyne receiver, the mixer input must be tuned to the signal frequency.

   Correct Option: B

   In a broadcast superhetrodyne receiver, the mixer input must be tuned to the signal frequency.

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47. In a radio receiver with simple AGC—
    

1. 1. An increase in signal strength produces more AGC
      

   
   
   

   2. The audio stage gain is normally controlled by the AGC
      

   
   
   

   3. The faster the AGC time constant, the more accurate the output
      

   
   
   

   4. The highest AGC voltage is produced between stations

   
   
   

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1. View Hint View Answer Discuss in Forum

   In radio receiver with simple AGC an increase in signal strength produces more AGC.

   Correct Option: A

   In radio receiver with simple AGC an increase in signal strength produces more AGC.

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48. Show which of the following statements about the amplitude limiter is untrue?
    

1. 1. The circuit is always biased in class C, by virtue of the leak-type bias
      

   
   
   

   2. When the input increases past the threshold of limiting, the gain decreases to keep the output constant
      

   
   
   

   3. The output must be tuned
      

   
   
   

   4. Leak-type bias must be used

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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49. Indicate which of the following statements about the advantages of the phase discriminator over the slope detector is false?
    

1. 1. Much easier alignment
      

   
   
   

   2. Better linearity
      

   
   
   

   3. Greater limiting
      

   
   
   

   4. Fewer tuned circuits

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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50. In an FM stereo multiplex transmission, the—
    

1. 1. Sum signal modulates the 19 kHz subcarrier
      

   
   
   

   2. Difference signal modulates the 19 kHz subcarrier
      

   
   
   

   3. Difference signal modulates the 38 kHz subcarrier
      

   
   
   

   4. Difference signal modulates the 67 kHz subcarrier

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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