1

GATE ECE 2017 Set 2

Numerical

+2

-0

The un-modulated carrier power in an AM transmitter is 5kW. This carrier is modulated by a
sinusoidal modulating signal. The maximum percentage of modulation is 50%. If it is reduced
to 40%, then the maximum un-modulated carrier power (in kW) that can be used without
overloading the transmitter is ___________

Your input ____

2

GATE ECE 2017 Set 2

Numerical

+2

-0

A modulating signal given By $$x\left(t\right)=5\sin\left(4\mathrm\pi10^3\mathrm t\;-\;10\mathrm{πcos}2\mathrm\pi10^3\mathrm t\right)$$ V
is fed to a phase modulator
with phase deviation constant k

_{p}=0.5rad/V. If the carrier frequency is 20 kHz, the instantaneous frequency (in kHz) at t = 0.5 ms is __________Your input ____

3

GATE ECE 2015 Set 1

Numerical

+2

-0

In the system shown in figure (a), m(t) is a low-pass signal with bandwidth W Hz. The
frequency response of the band-pass filter H(f) is shown in figure (b). If it is desired that the
output signal z(t) = 10x(t), the maximum value of W (in Hz) should be strictly less than
____________________.

Your input ____

4

GATE ECE 2012

MCQ (Single Correct Answer)

+2

-0.6

The signal m(t) as shown is applied both to a phase modulator (with
k

_{p}as the phase constant) and a frequency modulator (with k_{f}as the frequency constant) having the same carrier frequency.The ratio k_{p}/k_{f}
(in rad/Hz) for the same maximum phase deviation is

Questions Asked from Analog Communication Systems (Marks 2)

Number in Brackets after Paper Indicates No. of Questions

GATE ECE Subjects

Network Theory

Control Systems

Electronic Devices and VLSI

Analog Circuits

Digital Circuits

Microprocessors

Signals and Systems

Representation of Continuous Time Signal Fourier Series
Fourier Transform
Continuous Time Signal Laplace Transform
Discrete Time Signal Fourier Series Fourier Transform
Discrete Fourier Transform and Fast Fourier Transform
Discrete Time Signal Z Transform
Continuous Time Linear Invariant System
Discrete Time Linear Time Invariant Systems
Transmission of Signal Through Continuous Time LTI Systems
Sampling
Transmission of Signal Through Discrete Time Lti Systems
Miscellaneous

Communications

Electromagnetics

General Aptitude