A RF signal is amplitude modulated to a depth of 100% by a sinusoidal signal. The ratio of modulated signal power to un-modulated carrier power is

1.  1

2.  2

3.  2/3

4.  3/2

View Answer  
4
Correct Answer :

3/2


Explanation :
No Explanation available for this question

When the gate to source voltage VGS of a p channel JFET is made more positive, the drain current

1.  increases

2.  decreases

3.  remains constant

4.  may increase or decrease

View Answer  
4
Correct Answer :

may increase or decrease


Explanation :
No Explanation available for this question

The antenna of an AM broadcast transmitter modulated to a depth of 100 by an audio sine wave is √3/2A, which increase to √2 due to simultaneous modulation by another audio sine wave. The modulation index due to

1.  0.5

2.  0.707

3.  1.0

4.   0.866

View Answer  
4
Correct Answer :

1.0


Explanation :
No Explanation available for this question

The main drawback of a JFET is its

1.  high input impedance

2.  low input impedance

3.  higher noise

4.  lower gain

View Answer  
4
Correct Answer :

higher noise


Explanation :
No Explanation available for this question

The frequency deviation produced in a VHF carrier by a signal of 100Hz is 50kHZ. The frequency modulation index is

1.  100 radians

2.  250 radians

3.  500 radians

4.  750 radians

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4
Correct Answer :

500 radians


Explanation :
No Explanation available for this question

In a JFET the amplification factor μ, trans conductance gm, and the dynamic drain resistance rd are related is

1.  μ=gm/rd

2.  μ=rm/gm

3.  μ=gm.rd

4.  m= gm. rd2

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4
Correct Answer :

μ=gm/rd


Explanation :
No Explanation available for this question

Out of the devices mentioned below, the fastest switching device is

1.  JFET

2.  BJT

3.  MOSFET

4.  Triode

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4
Correct Answer :

JFET


Explanation :
No Explanation available for this question

A20 kW carrier is sinusoidally modulated by two, carriers corresponding to a modulation index of 30% and 40. respectively. The total radiated power is

1.  25 kW

2.  22.5 kW

3.  30kW

4.  35kW

View Answer  
4
Correct Answer :

22.5 kW


Explanation :
No Explanation available for this question

The JFET can operate in

1.  depletion mode only

2.  enhancement mode only

3.  either depletion or enhancement mode at a time

4.  both depletion and enhancement modes simultaneously

View Answer  
4
Correct Answer :

both depletion and enhancement modes simultaneously


Explanation :
No Explanation available for this question

In a broadcast transmitter, the RF output is represented as xc(t)=100[1+0.9cos5000t+0.3si9000t] `cos(6x106 t) The sidebands frequencies are

1.  5.991, 5.995, 6.005, 6.009 MHz

2.   953.5, 954.1, 955.7, 956.4 kHz

3.  5, 9 kHz

4.   795.8, 432.4 Hz

View Answer  
4
Correct Answer :

953.5, 954.1, 955.7, 956.4 kHz


Explanation :
No Explanation available for this question
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