Probability, Random Variables, and Random Processes: Theory and Signal Processing Applications
by John J. Shynk
6.12 RANDOM PROCESSES
Next, we consider some random processes that evolve continuously over time. As was the case with random sequences, the time-indexed random variables can have discrete or continuous outcomes. We begin with a sequence of independent random variables having a Poisson distribution, and then allow the intervals between time instants to approach zero in order to generate a continuous-time random process that can have a discrete change in amplitude at any time instant. (Note that example plots of the various random processes are actually discrete-time realizations because, obviously, MATLAB can only plot a finite number of outcomes for a process.)
6.12.1 Poisson Counting Process
The outcomes of the Poisson random variable are discrete (countably infinite), given by all nonnegative integers
. Define the time interval
where
is continuous time and
. Consider the random process defined as follows:
(6.172)
where X[k] (with ) is the binomial counting sequence in (6.160). The ...
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