Quiz Electronics Engineering 9 July 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 09/07/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. The number of memory cycles required to execute the following 8085 instructions
(i) LDA 3000H
(ii) LXI D, FOF1H would be
(a) 2 for (i) and 2 for (ii)
(b) 4 for (i) and 3 for (ii)
(c) 3 for (i) and 3 for (ii)
(d) 3 for (i) and 4 for (ii)

Q2. In a delta modulation system, granular noise occurs when
(a) Modulating signal increases rapidly
(b) Pulse rate decreases
(c) Pulse amplitude decreases
(d) Modulating signal remains constant

Q3. The fourier transform of a conjugate symmetric function is:
(a) imaginary
(b) conjugate anti-symmetry
(c) real
(d) conjugate symmetric

Q4. A Master-slave flip-flop has the characteristics that :
(a) change in the output immediately reflected in the output
(b) change in the output occurs when the state of the master is affected.
(c) change in the output occurs when the state of the slave is affected.
(d) both the master and the slave states are affected at the same time.

Q5. Light is confined within the core of a simple optical fiber by:
(a) Refraction.
(b) Total internal reflection at the outer edge of the cladding.
(c) Total internal reflection at the core cladding boundary.
(d) Reflection from the fiber’s plastic coating.

Q6. Four capacitors are connected as shown in figure. What is the total capacitance?

(a) 9 μF
(b) 20 μF
(c) 10 μF
(d) 36 μF

Q7. An antenna is cut for a resonant frequency of 10 MHz then the antenna can handle a BW of 2 MHz, quality factor is
(a) 5
(b) 20
(c) 8
(d) 25

Q8. Four voice signals each limited to 4 kHz and sampled at Nyquist rate, are
converted into binary PCM signal using 256 quantization levels. The bit transmission rate for the time division multiplexing signal will be
(a) 8 kbps
(b) 64 kbps
(c) 256 kbps
(d) 5126 kbps

Q9. The maximum number of nodes in a binary tree of level k, k ≥ 1 is :
(a) 2^k + 1
(b) 2^(k-1)
(c) 2^k – 1
(d) 2^(k+1) – 1

Q10. Regarding PPM which of the following statements is correct?
(a) It is a digital modulation technique
(b) It is a linear modulation technique
(c) It is an analog modulation technique
(d) None of the above

SOLUTIONS

S1. Ans.(b)
Sol. 4 memory cycles for Instruction (i) and 3 Memory Cycles for Instruction (ii). Instruction (i) follows Fetch, Read, Read and Write Cycle.
Instruction (ii) follows Fetch, Read and Read Cycle.

S2. Ans.(d)
Sol. In a delta modulation system, granular noise occurs when the modulating signal remains constant.
For GE to occur condition is,
⇒ Δ/T_s > |(dm(t))/dt|_max
⇒ Δ/T_s > 2πfmAm

S3. Ans.(c)

S4. Ans.(c)
Sol. When input of Master changes then there is change in the output of Master only. When there is shift in the pulse of the clock then input of slave changes hence final output also changes.

S5. Ans.(b)
Sol. The working principle of Simple optical fibre is Total Internal Reflection at the core cladding boundary. The incident ray on the boundary must be greater than the critical angle so that light can travel through the fibre.

S6. Ans.(a)
Sol. All the three 6 μF capacitors are connected in parallel.
Net capacitance is
⇒ 6 + 6 + 6 = 18 μF
Now, Net capacitance 18 μF is in series with 18 μF.
The equivalent capacitance is
C_eq=(18 × 18 )/(18 +18 )=(18 × 18)/36=9μF

S7. Ans.(a)
Sol. Given:
resonant frequency(f_r) = 10 MHz
BW = 2 MHz
Now,
Q = f_r/BW
⇒ Q = 10/2
So, Q = 5
Hence, quality factor is 5.

S8. Ans.(c);
Sol. Given:
No. of voice signals(N) = 4
fm = 4 kHz
No. of quantisation level = 256
We know that,
Bit Rate (Rb) = Nnfs
Quantisation level (L) = 2n
Now, 2n = 256
∴ n = 8 bits
and, fs = 2fm = 2x4kHz = 8 kHz
⇒ Rb = Nnfs = 4 x 8 x 8 kHz
= 256 kbps
Therefore, The bit transmission rate for the TDM signal will be 256 kbps.

S9. Ans.(d)

S10. Ans.(a)
Sol. PPM(Pulse Position Modulation), PWM(Pulse Width Modulation) and PAM(Pulse Amplitude Modulation) are the examples of digital modulation techniques.

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