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Electronics and Communication Engineering - Communication Systems

Exercise : Communication Systems - Section 8
46.
Microwave link repeaters are typically 50 km apart in TV transmission due to
atmosphere attenuation
output power tube limitations
attenuation of surface wave
earth's curvature
Answer: Option
Explanation:

Earth's curvature limits line of sight distance. Therefore, repeaters are needed.

47.

Assertion (A): The colour signal consists of only luminance signal

Reason (R): In India PAL colour signal system is used.

Both A and R are correct and R is correct explanation of A
Both A and R are correct but R is not correct explanation of A
A is correct but R is wrong
A is wrong but R is correct
Answer: Option
Explanation:

Colour signal consists of luminance and chrominance.

48.
To separate channels in FDM receiver we have to use
integration
AND gate
band pass filter
differentiation
Answer: Option
Explanation:

Band pass filter allows a band of frequencies to pass through and attenuates other frequencies.

49.
A device with input x(t) and y(t) is characterized by y(t) = x2(t). An FM signal with frequency deviation of 90 kHz and modulating signal bandwidth of 5 kHz is applied to this device. The bandwidth of the output signal is
370 kHz
190 kHz
380 kHz
95 kHz
Answer: Option
Explanation:

If we square the signal, bandwidth will becomes double.

B.W. for x(t) = 2(90 + 5) = 190 kHz

for x2(t) = 2 x 190 380 kHz.

50.

Assertion (A): Bandwidth of a TV signal is 5 MHz.

Reason (R): TV systems use vestigial side band transmission.

Both A and R are correct and R is correct explanation of A
Both A and R are correct but R is not correct explanation of A
A is correct but R is wrong
A is wrong but R is correct
Answer: Option
Explanation:
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