What is a collection of random variables indexed by time called?

Random process (or stochastic process)

Riddle: I am a signal type with a continuous time variable, but my amplitude is discrete. What am I?

Continuous-time and discrete amplitude signals

True or False: A random process is a collection of random variables dependent on time.

True

The mean function of a random process is the ______ of the process.

Expected value

Which of the following represents the auto-correlation function of a random process X(t)? A) Rxy(t1, t2) B) Rxx(t1, t2) C) mx(t) D) Sxx(f)

B) Rxx(t1, t2)

What type of stationary process has statistical properties independent of time origin?

Stationary process

True or False: All strict sense stationary random processes are also wide-sense stationary.

True

The power spectral density is only defined for ______ random processes.

Stationary

What is the expected value of the product of two random processes X(t1) and Y(t2) called?

Cross-correlation function

Fill in the blank: The ______ is used to analyze the relationship between a random process and its shifted version.

Auto-correlation function

Which of the following is characterized by zero mean and a delta function for its autocorrelation? A) Gaussian noise B) White noise C) Pink noise D) Brownian noise

B) White noise

Riddle: I have a flat power spectral density and am used to mask noise, yet I am not a color. What am I?

White noise

True or False: White noise is always Gaussian in nature.

False. White noise can also be non-Gaussian.

The power content of a random signal X is given by ______.

The limit of the time average of the square of the signal

What type of filter is used to simulate any arbitrary random process from white noise?

Linear, time-invariant filter

Fill in the blank: A random process is called ______ if its joint probability density function is independent of time.

Stationary

Which of the following properties is true for the auto-correlation function R(Z)? A) R(Z) is odd B) R(Z) is maximum at Z = 0 C) R(Z) is constant D) R(Z) has no maximum

B) R(Z) is maximum at Z = 0

What is the characteristic of a cyclostationary process?

The mean and autocorrelation functions are periodic.

Riddle: I’m a signal that can be a source of randomness, often used in electronic music, and I’m named after a color. What am I?

White noise

What is the relationship between the autocorrelation function Rxx(t1, t2) and the expected value of the product of X(t1) and X(t2)?

Rxx(t1, t2) = E[X(t1) X(t2)]