The transconductance gm of an FET in the saturation region equals

1.  (-2IDSS/Vp)[1-VGS/VP]

2.  (-2IDSS/Vp)[1-VGS/VP]2

3.  (-2IDSS/Vp)[1-VGS/VP]1/2

4.  I/VP(IDSS.IDS)1/2

View Answer  
4
Correct Answer :

(-2IDSS/Vp)[1-VGS/VP]


Explanation :
No Explanation available for this question

The ratio (S/N)WBFM/(S/N)AM for 100% amplitude modulation with identical total transmitted power (mf is modulated index of F'M) is

1.  9/2 m2f

2.  3/2 m2f

3.  3/2m3f

4.  (9/2m8f

View Answer  
4
Correct Answer :

3/2 m2f


Explanation :
No Explanation available for this question

If radiated power of AM transmitter is 10 kW, then power in the carrier for modulation index of 0.6 is nearly

1.  8.24 kW

2.   8.47 kW

3.  9.26 kW

4.  9.6 kW

View Answer  
4
Correct Answer :

8.47 kW


Explanation :
No Explanation available for this question

A signal m(t) =5 cos 2πt 100t frequency modulates a carrier. The resulting FM signal is 10 cos (2π 105t)+ 15 sin (2π 100t). The approximate bandwidth of the FM would be

1.  0.1 kHz

2.  1kHz

3.  3.2kHz

4.  100 kHz

View Answer  
4
Correct Answer :

3.2kHz


Explanation :
No Explanation available for this question

In a superheterodyne receiver, IF is 455 kHz. If it is tuned to 1200 kHz, then image frequency will be

1.  1655kHz

2.  2110 kHz

3.   745 kHz

4.   910 kHz

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4
Correct Answer :

2110 kHz


Explanation :
No Explanation available for this question

If modulation index of an AM wave is changed from 0 to 1, the transmitted power

1.  increases by 50%

2.  increases by 75%

3.   increases by 100%

4.   remains unaffected

View Answer  
4
Correct Answer :

increases by 50\%


Explanation :
No Explanation available for this question

Which one of the following statements regarding the signal x(t) = 5 sin (2πx103 t) sin (2πx 106) is correct

1.  Upper side band frequency is 1001000

2.  Lower side band frequency is 999000

3.   x(t) is a DSB-SC signal

4.  All of these

View Answer  
4
Correct Answer :

All of these


Explanation :
No Explanation available for this question

For signal amplitude modulated to a depth of 100% by a sinusoidal signal, power is

1.  same as the power of un-modulated  carrier

2.  twice as the power of un-modulated carrier

3.  3/2 times the power of un-modulated carrier

4.  times the power of un-modulated carrier

View Answer  
4
Correct Answer :

3/2 times the power of un-modulated carrier


Explanation :
No Explanation available for this question

A 60Hz carrier is amplitude modulated by speech band of 300 to 3000Hz. The range of upper side bands will be

1.  60.8 to 63 kHz

2.   60 to 59.7 kHz

3.   57 to 59.7 kHz

4.  56.7 to 56.3 kHz

View Answer  
4
Correct Answer :

60.8 to 63 kHz


Explanation :
No Explanation available for this question

An arbitrary signal m(t) has zero average value and it is band-limited to 3.2kHz. It is sampled at the rate of 8k, samples/s. The samples are passed through an ideal band-pass filter with centre frequency of 3.2 kHz and band.dth of 6.4 kHz. The output of the band-pass filter is

1.  AM-DSB signal With suppressed carrier

2.  AM-DSB signal with carrier.

3.  AN-SSB signal with carrier

4.  a sequence of exponentially decaying sine waves

View Answer  
4
Correct Answer :

AM-DSB signal with carrier.


Explanation :
No Explanation available for this question
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