### DRDO Placement Paper Model For ECE ( Technical)

Paper: DRDO Placement Paper Model For ECE ( Technical)

Direct Theory question:

1. A triangular-square wave generator uses

* A sine wave oscillator and a comparator

* An integrator and a comparator

* A differentiator and comparator

* A sine wave oscillator and a clipper

2. An amplifier has two identical cascaded stages. Each stage has a BW of 20KHz. The overall BW shall be

* 10KHz

* 12.9KHz

* 20KHz

* 28.3HHz

Direct numerical problem:

1. A parabolic dish antenna has a diameter of 1m. the maximum possible ideal gain of the antenna at a wavelength 3.14cm is

* 20 dB

* 30 dB

* 40 dB

* 50 dB

2. The frequency deviation produced in a VHF carrier by a signal of 100Hz is 50KHz. The frequency modulation is

*100 radians

*250 radians

*500 radians

*750 radians

Application based theoretical or numerical problem:

1. Which one of the pulses has the same form in time domain as well as in frequency domain

*Rectangular

*Exponential

*Triangular

*Gaussian

2. Good voice reproduction via PCM requires 128 quantization levels. If the BW of voice channel is 4KHz then data rate is

*256 Kbps

*128 Kbps

*56 Kbps

*28 Kbps

3. Match the following:

1. List 1 List2

A. Thyristor 1. Second break down

B. MOSFET 2. Large on-state drop

C. IGBT 3. Small on state drop

D. BJT 4. Slow device

Codes:

(a) A-4, B-3, C-2, D-1 (b) A-1, B-2, C-3, D-4

(c) A-4, B-2, C-3, D-1 (d) A-1, B-3, C-2, D-4

4. List 1 List2

A. Free and forced response 1. Discrete time systems

B. Z transform 2. Dirichlet conditions

C. Probability theory 3. Non-homogenous differential equation

d. Fourier series 4. Random process

Codes:

(a) A-1, B-3, C-2, D-4 (b) A-3, B-1, C-2, D-4

(c) A-1, B-3, C-4, D-2 (d) A-3, B-1, C-4, D-2

Assertion and reasoning type:

The following item consists of two statements labeled as Assertion A and the other as Reason R. Use the following codes:

(a) Both A&R are individually true and R is the correct explanation of A

(b) Both A & R are individually true and R is not the correct explanation of A

(c) A is true and R is false

(d) A is false and R is true

5. Every materials has a different value of energy band gap except metals which have no band gap

R The energy band gap is decided by the equilibrium lattice constant, which is different in different materials.

6. AOp-amp are commonly used in instrumentation Op-amps do not load the circuit due to their very high input impedance