Worksheetsquiz Gruop A
Total questions: 10
Worksheet time: 8mins
Which statement best describes a discrete-time signal?
It is defined at every instant of time without gaps.
It is defined only at separate points in time, like every minute or hour.
It is a picture taken by a camera.
It is a sound that never changes.
In MATLAB, which function is used in the code to draw discrete-time sequences like unit impulse and unit step?
plot
line
stem
bar
Look at the idea of a unit step sequence u(n). It equals 1 when n is 0 or bigger, and 0 when n is less than 0. If n = −3, what is u(n)?
1
0
−1
It cannot be found.
Which statement best describes a continuous-time signal?
A signal that changes only at set steps
A signal defined for every moment in time
A picture made of dots
A number that never changes
In MATLAB, which command is used to draw the sine wave after computing y = sin(2*pi*t)?
title('Sine wave')
xlabel('Time')
plot(t,y,'k')
cos(2*pi*t)
You want to see a triangular waveform. Based on the instructions, which function and setting should you use?
sawtooth(t,0.5) to make a 50% duty cycle (triangular)
square(t) with a 10% duty cycle
sin(t) with amplitude 2
cos(2*pi*t) with phase shift
Which operation adds two discrete-time signals sample by sample?
Signal addition
Signal multiplication
Shifting
Folding
In shifting, each sample of x(n) is moved by k to make y(n). Which expression shows a right shift by k?
y(n) = x(n + k)
y(n) = x(n − k)
y(n) = −x(n)
y(n) = x(−n)
Which statement best describes an even signal xe(n)?
xe(−n) = −xe(n)
xe(−n) = xe(n)
xe(n) = 0 for all n
xe(n) = xe(n+1)
A real-valued sequence x(n) can be split into even and odd parts. Which formula correctly gives the even part xe(n)?
xe(n) = 1/2 [x(n) + x(−n)]
xe(n) = 1/2 [x(n) − x(−n)]
xe(n) = x(n) − xo(n)
xe(n) = x(−n)
