Group B

Which statement best describes a continuous-time signal?

• It is defined at every instant of time over a continuous input.

• It is defined only at separate points like every minute or hour.

• It can take only discrete values like 0 or 1.

• It only represents images in space.

Which description best matches a delayed unit sample sequence with a delay of 15 samples?

• The spike occurs at n = 0

• The spike occurs at n = 15

• The values increase linearly with n

• The values oscillate smoothly

In the example, x1(n)=2x(n−5)−3x(n+4). Which operations are used to build x1(n) from x(n)?

• Only folding

• Only addition

• Shifting and scaling, then addition

• Multiplication by itself

For the task x(n)=n[u(n)−u(n−10)]+10e−0.3(n−10)[u(n−10)−u(n−20)], which function turns the first part on from n=0 to 9?

• δ(n)

• u(n)−u(n−10)

• u(n−10)−u(n−20)

• cos(0.04πn)

In x(n)=cos(0.04πn)+0.2w(n), what is w(n) described as?

• A unit step

• A Gaussian random sequence with zero mean and unit variance

• A decaying exponential

• A unit impulse

In the plot labeled Sequence in Example a, the values move from negative to positive as n increases. Which operation could create such behavior?

• A constant zero signal

• A sequence that steps up over time

• A random signal with no mean

• A single impulse only

Which formula correctly decomposes any real sequence x(n)?

• x(n) = xe(n) − xo(n)

• x(n) = xe(n) + xo(n)

• x(n) = 2·xe(n)

• x(n) = 2·xo(n)

How do you compute the odd part xo(n) from x(n)?

• xo(n) = 0.5·[x(n) − x(−n)]

• xo(n) = x(n) + x(−n)

• xo(n) = 2·x(−n)

• xo(n) = 0

If a signal is odd, what is true about its value at n = 0?

• It must be 1

• It must be −1

• It must be 0

• It can be any value

Why do we use fliplr(x) in the MATLAB code for even and odd parts?

• To reverse the order to get x(−n)

• To make the signal louder

• To color the plot

• To remove zeros from the signal