Electronics & Communication Gate Yearwise
Electronics and Communication GATE 2019 Questions with Answer
Ques 1 Analog Communication
The baseband signal m(t) shown in the figure is phase-modulated to generate the PM signal φ(t)=cos(2πfct+k m(t)). The time t on the x-axis in the figure is in milliseconds. If the carrier frequency is fc=50 kHz and k=10π, then the ratio of the minimum instantaneous frequency (in kHz) to the maximum instantaneous frequency (in kHz) is... (rounded off to 2 decimal places).
0.75 is the correct answer.
Ques 2 Control Systems
For an LTI system, the Bode plot for its gain is as illustrated in the figure shown. The number of system poles Np and the number of system zeros Nz in the frequency range 1 Hz ≤ f ≤ 107 Hz is
Ques 3 Control Systems
Consider a causal second-order system with the transfer function G(s)=1/(1+2s+s2) with a unit-step R(s)=1/s as an input. Let C(s) be the corresponding output. The time taken by the system output c(t) to reach 94% of its steady-state value limt→∞c(t), rounded off to two decimal places, is
Ques 4 Control Systems
The block diagram of a system is illustrated in the figure shown, where X(s) is the input and Y(s) is the output. The transfer function H(s)=Y(s)/X(s) is
Ques 5 Control Systems
Let the state-space representation of an LTI system be ̇x(t)=A x(t)+B u(t), y(t)=C x(t)+d u(t) where A, B, C are matrices, d is a scalar, u(t) is the input to the system, and y(t) is its output. Let B=[0 0 1]T and d=0. Which one of the following options for A and C will ensure that the transfer function of this LTI system is H(s)=1/(s3+3s2+2s+1)?
Ques 6 Control Systems
Consider a unity feedback system, as in the figure shown, with an integral compensator and open-loop transfer function G(s)=1/(s2+3s+2) where K>0. The positive value of K for which there are exactly two poles of the unity feedback system on the jω axis is equal to... (rounded off to two decimal places).
6 is the correct answer.
Ques 7 Digital Circuits
In the circuit shown, what are the values of F for EN=0 and EN=1, respectively?
Ques 8 Digital Circuits
In the circuit shown, A and B are the inputs and F is the output. What is the functionality of the circuit?
Ques 9 Digital Circuits
In the circuit shown, the clock frequency, i.e., the frequency of the Clk signal, is 12 kHz. The frequency of the signal at Q2 is... kHz.
4 is the correct answer.
Ques 10 Digital Circuits
The state transition diagram for the circuit shown is
Ques 11 Digital Communication
A linear Hamming code is used to map 4-bit messages to 7-bit codewords. The encoder mapping is linear. If the message 0001 is mapped to the codeword 0000111, and the message 0011 is mapped to the codeword 1100110, then the message 0010 is mapped to
Ques 12 Digital Communication
A single bit, equally likely to be 0 and 1, is to be sent across an additive white Gaussian noise (AWGN) channel with power spectral density N0/2. Binary signaling, with 0↦p(t) and 1↦q(t), is used for the transmission, along with an optimal receiver that minimizes the bit-error probability. Let φ1(t) and φ2(t) form an orthonormal signal set. If we choose p(t)=φ1(t) and q(t)=-φ1(t) we would obtain a certain bit-error probability Pb. If we keep p(t)=φ1(t), but take q(t)=√Eφ2(t) for what value of E would we obtain the same bit-error probability Pb?
Ques 13 Digital Communication
A voice signal m(t) is in the frequency range 5 kHz to 15 kHz. The signal is amplitude-modulated to generate an AM signal f(t)=A(1+m(t))cos(2πfct), where fc=600 kHz. The AM signal f(t) is to be digitized and archived. This is done by first sampling f(t) at 1.2 times the Nyquist frequency, and then quantizing each sample using a 256-level quantizer. Finally, each quantized sample is binary coded using K bits, where K is the minimum number of bits required for the encoding. The rate, in Megabits per second (rounded off to 2 decimal places), of the resulting stream of coded bits is... Mbps.
11.81 is the correct answer.
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