A dual trace oscilloscope is set to operate in the Alternate mode. The control input of the multiplexer used in the y-circuit is fed with a signal having a frequency equal to
**A. ** the highest frequency that the multiplexer can operate properly

**B. ** twice the frequency of the time base (sweep) oscillator

**C. ** the frequency of the time base (sweep) oscillator

**D. ** haif the frequency of the time base (sweep) oscillator

**Answer : ****Option C**

**Explaination / Solution: **

No Explaination.

No Explaination.

Workspace

Report

A Hilbert transformer is a

**A. ** non-linear system

**B. ** non-causal system

**C. ** time-varying system

**D. ** low-pass system

**Answer : ****Option A**

**Explaination / Solution: **

No Explaination.

No Explaination.

Workspace

Report

Given two continuous time signals which exist for t > 0,
the convolution z(t) = x(t)* y(t) is

**A. **

**B. **

**C. **

**D. **

**Answer : ****Option A**

**Explaination / Solution: **

Workspace

Report

A zero mean random signal is uniformly distributed between limits –a and +a and its mean square value is equal to its variance. Then the r.m.s value of the signal is

**A. **

**B. **

**C. **

**D. **

**Answer : ****Option A**

**Explaination / Solution: **

Workspace

Report

Consider a linear system whose state space representation is x(t) = Ax(t). If the initial state vector of the system is then the system response is If the itial state vector of the system changes to the system response becomes

The system matrix A is

No Explaination.

Workspace

Report

Consider the function ݂f(z) = z + z^{*} where z is a complex variable and z^{*} denotes its complex
conjugate. Which one of the following is TRUE?

**A. ** f(z) is both continuous and analytic

**B. ** f(z) is continuous but not analytic

**C. ** f(z) is not continuous but is analytic

**D. ** f(z) is neither continuous nor analytic

**Answer : ****Option B**

**Explaination / Solution: **

Workspace

Report

A linear, time - invariant, causal continuous time system has a rational transfer function with simple poles at s =- 2 and s =- 4 and one simple zero at s =- 1 . A unit step u(t) is applied at the input of the system. At steady state, the output has constant value of 1. The impulse response of this system is

**A. ** [exp(- 2t) + exp(- 4t)]u(t)

**B. ** [- 4 exp(- 2t) - 12 exp(- 4t) - exp(- t)]u(t)

**C. ** [- 4 exp(- 2t) + 12 exp(- 4t)]u(t)

**D. ** [- 0.5 exp(- 2t) + 1.5 exp(- 4t)]u(t)

**Answer : ****Option C**

**Explaination / Solution: **

Workspace

Report

{ x(n)} is a real - valued periodic sequence with a period N . x(n) and X(k) form N-point Discrete Fourier Transform (DFT) pairs. The DFT Y(k) of the sequence is

**A. **

**B. **

**C. **

**D. ** 0

**Answer : ****Option A**

**Explaination / Solution: **

Workspace

Report

Let a causal LTI system be characterized by the following differential equation, with initial rest condition

Where x(t) and y(t) are the input and output respectively. The impulse response of the system is (u(t) is the unit step function)

Workspace

Report

The ROC of z -transform of the discrete time sequence

**A. ** 1/3< |Z| < 1/2

**B. ** |Z| > 1/2
**C. ** |Z| < 1/2
**D. ** 2<|Z| < 3

**Answer : ****Option A**

**Explaination / Solution: **

Taking z transform we have

Taking z transform we have

Workspace

Report

**Preparation Study Material**- Circuit Theory (Study/Preparation)
- Electromagnetic Theory (Study/Preparation)
- Digital Logic Circuits (Study/Preparation)
- Signals and Systems (Study/Preparation)
- Electrical Machines I (Study/Preparation)
- Electrical Machines II (Study/Preparation)
- Transmission and Distribution (Study/Preparation)
- Power System (Study/Preparation)
- Control Systems (Study/Preparation)
- Digital Logic Circuits (Study/Preparation)
- Electronic Devices and Circuits (Study/Preparation)
- Microprocessors and Microcontrollers (Study/Preparation)
- Power Electronics (Study/Preparation)

- Engineering Mathematics (Practise Test)
- Electric Circuits (Practise Test)
- Electromagnetic Fields (Practise Test)
- Signals and Systems (Practise Test)
- Electrical Machines (Practise Test)
- Power Systems (Practise Test)
- Control Systems (Practise Test)
- Electrical and Electronic Measurements (Practise Test)
- Analog and Digital Electronics (Practise Test)
- Power Electronics (Practise Test)