Digital Signal Processing

Discrete Time Systems

Question 1
Marks : +2 | -2
Pass Ratio : 17%
What is the output y(n) when a signal x(n)=n*u(n)is passed through a accumulator system under the conditions that it is initially relaxed?
\\(\\frac{n^2+n+1}{2}\\)
\\(\\frac{n(n+1)}{2}\\)
\\(\\frac{n^2+n+2}{2}\\)
None of the mentioned
Explanation:
Given that the system is initially relaxed, that is y(-1)=0
Question 2
Marks : +2 | -2
Pass Ratio : 17%
The output signal when a signal x(n)=(0,1,2,3) is processed through an ‘Identical’ system is?
(3,2,1,0)
(1,2,3,0)
(0,1,2,3)
None of the mentioned
Explanation:
An identical system is a system whose output is same as the input, that is it does not perform any operation on the input and transmits it.
Question 3
Marks : +2 | -2
Pass Ratio : 17%
The system described by the input-output equations y(n)=x2(n) is a Non-linear system.
True
False
Explanation:
Given equation is y(n)=x2(n)
Question 4
Marks : +2 | -2
Pass Ratio : 33%
The system described by the input-output equation y(n)=nx(n)+bx3(n) is a __________
Static system
Dynamic system
Identical system
None of the mentioned
Explanation:
Since the output of the system y(n) depends only on the present value of the input x(n) but not on the past or the future values of the input, the system is called as static or memory-less system.
Question 5
Marks : +2 | -2
Pass Ratio : 17%
If a signal x(n) is passed through a system to get an output signal of y(n)=x(n+1), then the signal is said to be ____________
Delayed
Advanced
No operation
None of the mentioned
Explanation:
For example, the value of the output at the time n=0 is y(0)=x(1), that is the system is advanced by one unit.
Question 6
Marks : +2 | -2
Pass Ratio : 17%
The block denoted as follows is known as __________
Delay block
Advance block
Multiplier block
Adder block
Explanation:
If the function to this block is x(n) then the output from the block will be x(n-1). So, the block is called as delay block or delay element.
Question 7
Marks : +2 | -2
Pass Ratio : 17%
If the output of the system of the system at any ‘n’ depends only the present or the past values of the inputs then the system is said to be __________
Linear
Non-Linear
Causal
Non-causal
Explanation:
A system is said to be causal if the output of the system is defined as the function shown below
Question 8
Marks : +2 | -2
Pass Ratio : 17%
Whether the system described by the input-output equations y(n)=x(n)-x(n-1) a Time-variant system.
True
False
Explanation:
If the input is delayed by k units then the output will be y(n,k)=x(n-k)-x(n-k-1)
Question 9
Marks : +2 | -2
Pass Ratio : 17%
The output signal when a signal x(n)=(0,1,2,3) is processed through an ‘Delay’ system is?
(3,2,1,0)
(1,2,3,0)
(0,1,2,3)
None of the mentioned
Explanation:
An delay system is a system whose output is same as the input, but after a delay.
Question 10
Marks : +2 | -2
Pass Ratio : 17%
If the output of the system is \\(y(n)=\\sum_{k=-\\infty}^nx(y)\\) with an input of x(n) then the system will work as ___________
Accumulator
Adder
Subtractor
Multiplier
Explanation:
From the equation given, y(n)=x(n)+x(n-1)+x(n-2)+…. .This system calculates the running sum of all the past input values till the present time. So, it acts as an accumulator.